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Analytical techniques for boron quantification supporting desalination processes:A review

Ali Farhat, Farrukh Ahmad, Hassan Arafat

Water and Environmental Engineering Program, Masdar Institute of Science and Technology, PO Box 54224, Abu Dhabi, United Arab Emirates

a b s t r a c ta r t i c l e i n f o

Article history:

Received 27 October 2011

Accepted 24 December 2011Available online xxxx

Keywords:

Boron

Analytical techniques

Desalination

ICP-MS

Isotopic analysis

Severalstudies have been reported overthe last twodecades to improve theanalysisof boron andto determineits

isotopic composition. The isotopic composition of boron is of significance to SWRObecause second pass processes

resultin a boron isotopic shift in thepermeate, thereby creating a unique process signature. This paper reviews the

different boron detection and quantification techniques ranging fromplasma-based techniques,to thermal ioniza-

tion mass spectrometry (TIMS), andotherMS-basedand non-MSbasedtechniques. Themost recent precisionand

detection levels are reported, and the complexity of analysis and sample preparation, as well as the major disad-

vantages and limitations associated with the measurements of boron and its isotopic composition (e.g., spectral

and isobaric interferences, mass fractionation, and memory effect) are compared among analysis techniques.

While positive-TIMS (PTIMS) has been reported as the most precise, and the negative-TIMS (NTIMS) as the

most sensitive, plasma-based techniques such as multi-collector inductively coupled plasma-mass spectrometry

(MC-ICP-MS) are characterized by their fast speed of analysis and high sample throughput. Several recent

improvements have increased precision and lowered the detection level of the MC-ICP-MS, making it capable of

competing with PTIMS and NTIMS.

2011 Elsevier B.V. All rights reserved.

Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

1.1. Boron: its occurrence and toxicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

1.2. Boron removal in desalination plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2. Techniques for boron and boron isotopes analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.1. Available techniques and their principles of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.1.1. Plasma-based techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2 .1.2. Thermal ionization mass spe ctrome try (TIMS)-based te chnique s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.1.3. Non-MS-based techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.2. Precision and detection limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.3. Complexity of operation and sample preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.4. Compliance with regulatory levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.5. Interferences and limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.5.1. Spectral and isobaric interferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.5.2. Mass fractionation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.5.3. Memory effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

2.5.4. Other limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 03. Boron isotope tracer analysis in applications related to desalination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

4. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

1. Introduction

1.1. Boron: its occurrence and toxicity

Boron is a nonmetallic element, which has five protons in its nu-

cleus along with five to six neutrons, resulting in two stable isotope

Desalination xxx (2012) xxxxxx

Corresponding author.

E-mail address:[email protected](H. Arafat).

DES-11194; No of Pages 9

0011-9164/$ see front matter 2011 Elsevier B.V. All rights reserved.

doi:10.1016/j.desal.2011.12.020

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Please cite this article as: A. Farhat, et al., Analytical techniques for boron quantification supporting desalination processes: A review, Desalination(2012), doi:10.1016/j.desal.2011.12.020
http://dx.doi.org/10.1016/j.desal.2011.12.020http://dx.doi.org/10.1016/j.desal.2011.12.020http://dx.doi.org/10.1016/j.desal.2011.12.020mailto:[email protected]://dx.doi.org/10.1016/j.desal.2011.12.020http://www.sciencedirect.com/science/journal/00119164http://dx.doi.org/10.1016/j.desal.2011.12.020http://dx.doi.org/10.1016/j.desal.2011.12.020http://www.sciencedirect.com/science/journal/00119164http://dx.doi.org/10.1016/j.desal.2011.12.020mailto:[email protected]://dx.doi.org/10.1016/j.desal.2011.12.020


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forms: 10B (abundance of 19.8%) and 11B (abundance of 80.2%), aver-

aging its atomic weight at 10.81 Da[1]. Boron exists in nature in the

form of boric acid (H3BO3) or borates, mainly sodium borate (Na2B4-O710H2O), also known as borax. Boric acid and sodium borates are

considered to be medicinally important compounds and they are clas-

sified by the United States Pharmacopeia-National Formulary[2]and

the British Pharmacopeia [3] as two pharmaceutical necessities,

where they are used as antibacterial[4]and antifungal agents[57],

as well as components of dental cement [8]. Despite the fact thatboron exists in fertilizers, where it is described as an essential constit-

uent for the growth of plants and vegetation, boron contamination is

a serious threat to crops, because they are very sensitive to high levels

of boron in the irrigation waters [9]. In animals, high boron concen-

trations have been observed to affect male reproductive capabilities

[10], unlike in humans where no such negative findings have been

reported[11].

Boron is detected in surface water and groundwater in various lo-

cations around the world, including sea and river waters, where it is

present mainly in the form of boric acid. In seawater, the boron con-

centration ranges from 0.5 to 9.6 ppm [12], averaging at a value of

4.5 ppm[13,14]to 4.6 ppm[1]. Geographical location and seasonal

effects play a significant role in the boron concentration in the oceans

and seas. Boron levels in the Arabian Gulf have been reported at

7 ppm [14]. In freshwater, concentrations of boron have been

reported ranging from b0.01 to 1.5 ppm [1] in most cases. For in-

stance, boron levels measured in many US and Canadian surface

water bodies range from 0.01 to 0.4 mg/L, and in UK and Italy river

waters reach 0.9 mg/L. Meanwhile, studies measuring boron levels

in potable water supplies in northern Chile report values from

0.31 mg/L to 15.2 mg/L due to nearby boron-containing soil deposits

[15]. In brackish water, boron levels are generally lower than 5 ppm.

Yet, concentrations might get as high as 23.5 ppm, as in the case

reported by Rahardianto et al. [16].Hence, the geographic source of

water is the major determinant of these widely variable levels of

boron in the drinking waters.

The 4.5 ppm mean boron level in ocean waters is higher than the

USEPA Health Advisory Committee's maximum boron concentration

of 0.6 ppm in drinking water[17]. In the same vein, the World HealthOrganization (WHO, 2004) recommends a stricter goal for the boron

concentration. WHO defines the guideline value of boron concentra-

tion in drinking water as 0.5 ppm with the non-observed adverse ef-

fect level (NOAEL) of boron in drinking water at 0.3 mg/L[18].In this

recommendation, WHO considered the maximum tolerable intake in

one day as 0.16 mg of boron per kg body weight [13]. The WHO

guideline value of 0.5 ppm is provisional owing to the lack of detailed

toxicological studies on boron. Thus, it is not a mandatory water qual-

ity parameter in the US and it is not yet enforced in the Safe Drinking

Water Act, despite the fact the Boron is classified as a U.S. EPA's

Drinking Water Contaminant Candidate[1]. In the US, only the state

of California issued a regulation with a notification level of Boron ex-

ceeding 1 ppm, the same value adopted by the European Union (EU)

[19]. Thus, countries relying on seawater desalination must reducethe high levels of boron in seawater to below 0.6 ppm before any

water usage by humans and animals, as well as any usage for crop

irrigation.

1.2. Boron removal in desalination plants

In thermal desalination processes, such as Multi-Stage Flash Desali-

nation (MSF) and Multi-Effect Desalination (MED), where the product

water is reported with Total Dissolved Solids (TDS) values between

5 ppm and 50 ppm[20], the boron problem has never been reported.

The boron problem is exclusively reported in membrane technologies

[21,22], where the membrane rejects most ionic species but fails to pre-

vent the boron from passing through because it is present in its un-

charged boric acid form (pKa=9.2 at 25 C[23]). Thus, boron removal

is gaining significant attention in membrane desalination where several

specialized boron removal processes and plant configurations have

been tested. Plant configurations evaluated include those using a

second-pass Reverse Osmosis (RO)unit following pH increase to values

above the boric acid pKa[24,25], as well as the ones employing a post-

RO ion-exchange process with boron-specific resins [26]. Non-RO plant

configurations evaluated for boron removal include electrodialysis de-

salination using specialized membranes [27] and adsorption membrane

filtration (AMF) [28]. Readers interested in boron removal technologiesfrom saline water are referred to a recently published detailed review

on this topic[28].

The analysis of boron in feed waters and desalinated waters is of

crucial importance to assessing the effectiveness of boron removal

in desalination. Consequently, this requires the availability of robust

instrumental techniques and analytical methods for monitoring

and quantifying boron and its isotopic composition with significant

sensitivity, precision, as well as convenience.This paper reviews the dif-

ferent contemporary boron measurement and instrumentation tech-

niques, which include plasma-based techniques, thermal ionization

mass spectrometry (TIMS), and other MS-based and non-MS based

techniques. A comparison of the precision, detection levels, complexity

of operation, sample preparation, and major limitations and interfer-

ences among these analytical techniques is detailed. Moreover, the

paper explores boron isotopic ratio analysis as an emerging technique

for evaluating the performance of membrane-based boron removal

processes, and the mixing of waters containing different isotopic ratios

of boron in cases such as aquifer recharge and brine discharge.

2. Techniques for boron and boron isotopes analysis

2.1. Available techniques and their principles of operation

The detection and quantification of boron and its stable isotopes

have been conducted using several different techniques reported in

literature. These techniques are summarized in Table 1. The most

widespread of these are plasma-based techniques, mainly the induc-

tively coupled plasma (ICP) technique[29

39], which has recentlybeen coupled to different types of mass spectrometers (MS) to im-

prove method sensitivity and reliability. Positive thermal ionization

mass spectrometry (PTIMS)[4050]is recognized as the most precise

technique, whereas negative thermal ionization MS (NTIMS)[5160]

is reported for being the most sensitive one. Other non-MS-based

Table 1

Principle of the major boron analyses techniques.

Technique Principle of the technique

Plasma-

based

ICP-OES Ionizing boron into B+ ions then monitors

the wavelength emissions from these excited

ions at its corresponding wavelengths

ICP-MS Ionizing boron into B+ ions, then measuring

B isotopes abundance based on theirmass-to-charge ratio (m/z 10 and 11)

TIMS PTIMS Converting boron into alkali or metal

metaborate cations such as Na2BO2+

(m/z 88 and 89), and Cs2BO2+ (m/z 308

and 309) then measuring their

corresponding m/z

NTI MS Conver ting b or on int o metab or at e anions

of BO2 (m/z 42 and 43) then measuring

their corresponding m/z

Non-MS-

based

Spectrophotometry Adding specific reagents to the boron

samples for color development, then

measuring the absorbance at

wavelengths, respective of the reagent

Nuclear Bombarding boron with neutrons causing

the production of a-particles and g-particles

that are monitored to measure 10B isotope

abundance

2 A. Farhat et al. / Desalination xxx (2012) xxxxxx

Please cite this article as: A. Farhat, et al., Analyticaltechniques for boron quantification supporting desalination processes: A review, Desalination(2012), doi:10.1016/j.desal.2011.12.020
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techniques [6165], such as spectrophotometry, are also employed

for boron analysis.

2.1.1. Plasma-based techniques

Plasma is a state of matter similar to gas, described to be an elec-

trically conducting gaseous mixture that is ionized into cations, an-

ions, and electrons with a net charge of zero [66]. Inductively

coupled plasma (ICP) technique is the most widely used plasma-

based techniques for boron analysis. ICP is a type of plasma source

formed from electric currents that are caused by electromagnetic in-

duction on a rarefied gas such as Argon. Samples are usually prepared

in aqueous phase using steps involving extraction and purification,

and are then introduced into the plasma of the instrument via a neb-

ulizer and spray chamber [67]. The nebulizer is responsible for the

aerosolization of the aqueous sample into fine droplets. However,

since any large droplets formed cannot be further dissociated by the

plasma discharge, a spray chamber is utilized to permit the entrance

of only small droplets into the plasma torch. Other plasma-basedtechniques besides ICP, include direct current plasma (DCP) [68,69],

which is less sensitive and requires more maintenance compared to

ICP, as well as microwave induced plasma (MIP)[70]and glow dis-

charge plasma (GDP)[71], which are less commercially available for

general elemental analysis and not widely reported for boron

analysis.

In the ICP method, the boron-containing liquid sample is purified

and pre-concentrated, then atomized (i.e. converting boric acids and

other borates into elemental boron (B)), and ionized into B+, which

is analyzed via different types of detectors. The ICP optical emission

spectroscopy (ICP-OES), also known as ICP atomic emission spectros-

copy (ICP-AES), is one type of ICP that detects boron and was pub-

lished as standard method ISO 11885:1996 (E) [72]. This type of

emission spectroscopy detects electromagnetic radiation emitted

from excited atoms and ions produced by the plasma source, where

the wavelength of the radiation emitted is characteristic of an ele-

ment. The wavelengths typically monitored for the boron analysisare 249.678 nm, 249.773 nm [59], and 182.52 nm[73]. This method

was reported for aqueous samples including fresh and saline water

[31,45], as well as solid samples[40,59] including soil, rocks, plant,

and biological samples. The coupling of ICP with a mass spectral de-

tector (ICP-MS), introduced by Gregoire [39], revolutionized the

boron determination with its simultaneous measurement of boron

concentration and its isotope abundance (11B and 10B) leading to

lower detection limits and higher sensitivity[67]. Instead of monitor-

ing wavelength-specific emissions of the excited ions as in ICP-OES,

the ICP-MS method measures the ions based on their mass-to-

charge ratio (m/z), thus simultaneously measuring boron concentra-

tion and its stable isotope abundance.

Configurations involving different types of MS have been developed

to enhance the performance of the ICP-MS instrumental analysis tech-

nique. One configuration comprises of combining ICP with a quadruple

MS (ICP-qMS) [38], where the qMS provides higher precision than nor-

mal MS. Others include double-focusing magnetic sector ICP-MS, also

referred to as high resolution ICP-MS[34], which reduces the effect of

interferences induced from any mass overlaps, but is complex to oper-

ate and maintain and requires a higher capital cost compared to the

ICP-qMS. The configuration utilizing a multi collector MS, known as

multi-collector ICP-MS (MC-ICP-MS) [33], is described as the most

promisingICP-MS technique combining the advantages of superior ion-

ization of ICP with the precision of a double focusing magnetic sector

mass spectrometer with multiple Faraday cups and ion counters[30].

MC-ICP-MS (Fig. 1) overweighs other ICP configurations by its preci-

sion, sensitivity and ability to analyze a broader range of elements. Re-

cently, Le Roux et al. [29] and Fietzke et al. [32]used the multiple-

multiplier laser-ablation ICP-MS (MM-LA-ICP-MS) and laser-ablationMC-ICP-MS (LA-MC-ICP-MS), respectively, for in-situ boron isotope

analysis, but these techniques were primarily used for solid samples.

In fact, the different ICP-MS instruments for boron measurement have

been applied to samples ranging from surface and ground water

[3436]to volcanic fluids[74], marine carbonates [75,76], and other

geological materials[39].

The ICP techniques are characterized by their fast analyses and

high sample throughput[30,76,77] compared to thermal ionization

MS techniques. In fact, MC-ICP-MS is the most preferred among the

plasma-based technologies due to its high precision and the relatively

small sample size requirements[35,36], allowing it to potentially

compete with the very precise positive thermal ionization mass spec-

trometry (PTIMS) and the sensitive negative TIMS (NTIMS) boron

analysis techniques [76], albeit at a significant capital investmentcost.

2.1.2. Thermal ionization mass spectrometry (TIMS)-based techniques

Positive TIMS (PTIMS): PTIMS, which is considered to be the most

precise instrumental analysis technique for measuring boron isotopic

ratios [78], is an MS detection technique working in positive ionmode

to analyze for boron ions generated by a thermal ionization source

(Fig. 2). In PTIMS, the boron in the sample is converted into positively

charged metaborate ions (BO2+) that are not solely present as BO2

+,

but exist in the form of alkali or metal metaborate cations (M2BO2+)

[44,79,80].In fact, this technique requires boron separation from the

sample and this step should be preceded by offline sample prepara-

tion. Subsequent to the separation, an alkali salt (carbonate or hy-

droxide) is added to form the alkali or metal metaborate complex,

Fig. 1. Schematic drawing of MC-ICPMS with its different components: plasma torch,

electrostatic analyzer (ESA), magnet, and the multi-collector.

Fig. 2.Schematic drawing the thermal ionization source of PTIMS.

3A. Farhat et al. / Desalination xxx (2012) xxxxxx



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which is then thermally ionized before being introduced into the

mass spectrometer for m/z filtering and measurement [67,81].The

various types of alkali metaborate ions analyzed depend on the alkali

salt used in preparing them. Such alkali or metallic metaborate ions

reported in literature include K2BO2+ [77], Na2BO2

+ [79,80,82,83],

Cs2BO2+ [4145,78,8486], Rb2BO2

+ [87], and Li2BO2+ [88]. PTIMS is

different from ICP-MS because it analyzes boron in the form of

M2BO2+, rather than an elemental form of boron (B+) as analyzed

by ICP-MS[34]. Initially, sodium metaborate (Na2BO2+

of m/z 88 and89) was widely used; in fact, two National Institute of Standards

and Technology (NIST) standards, SRM951 and SRM952, were both

certified via monitoring Na2BO2+ in PTIMS[89]. The same is true for

the Central Bureau for Nuclear Measurement (CBNM) standard of

boric acid [90]. However, Na2BO2+ has since been substituted by

Cs2BO2+ (of m/z 308 and 309)[4144]because the latter is more pre-

cise and sensitive compared to Na2BO2+, K2BO2

+, and Rb2BO2+, all of

which suffer from spectral interferences[67,77,81]. The PTIMS instru-

mental technique has been applied to aqueous samples[44](includ-

ing seawater[63], groundwater[47,82], and volcanic thermal water

[45]), geological samples [45,51,55,91], as well as crop plants [85]

and nuclear materials[83].

Negative TIMS (NTIMS): NTIMS operates in a similar way to PTIMS

but produces and analyzes for metaborate anions (BO2) in a negative

ion mode of operation. At variance with PTIMS, NTIMS requires no al-

kali salts or metals to be added to the sample as no alkali or metal

metaborate anions are required for mass measurement. Thus, simpler

mass measurements are conducted for 10BO2 and 11BO2

, at m/z of 42

and 43, respectively. Developed by Zeininger and Heumann[91]and

Duchateau and De Bievre[92], this technique is characterized by an

ion yield that is 1000 times higher than yields in PTIMS, leading to

higher sensitivity and less sample purification requirements [77].

Barth[55,56]reported a boron isotopic analysis of fresh and saline

water using NTIMS. Furthermore, Barth [57], along with other re-

searchers[52,60], used NTIMS to investigate boron in groundwater

as a tracer, showing that NTIMS is more suitable for aqueous samples

when precision is not of significance. Other applications of NTIMS

were reported on solid carbonate samples[51,53,58,93], and air sam-

ples[54].

2.1.3. Non-MS-based techniques

Spectrophotometric methods for boron determination are simply

based on the addition of specific reagents to aqueous samples for

the development of colored boron complexes, which are then mea-

sured using light absorbance at wavelengths corresponding to the

chromophore of the reagent used. These reagents include the red cur-

cumin, measuring its absorbance at 550 nm [94], blue carmine at

605 nm[95], and yellow azomethine-H at 410 nm[96]. USEPA Meth-

od 212.3, ASTM Method D3082-03 and AWWA Method 4500-B B are

published standardized methods for boron analysis using the curcu-

min [97], while AWWA Method 4500-B C and ISO 9390:1990 [98]

are for carmine and azomethine-H respectively. Azomethine-H meth-

od is the most commonly employed boron spectrophotometric method,mainly because it is fast, simple, sensitive, andreported to have the least

interferences among all spectrophotometric methods [67]. This method

has been employed to investigate boron geochemistry in groundwater

[47], seawater [61,63], and geothermal waters [64]. In addition, the

curcumin colorimetric method forms the basis of the American Society

of Testing and Materials (ASTM) method D3082 and Standard Methods

4500-B, which measure boron dissolved in aqueous samples. Thecurcu-

min method is prone to interferences from nitrate ions and hardness

constituents, even though it can detect boron concentrations as low as

0.1 mg/L or at minimum loading of 0.2 g boron [99]. Furthermore,

other spectrophotometric methods such as the fluorimetric methods

are also available to measure thefluorescence of samples after the addi-

tion of reagents that cause the formation of fl

uorescent boroncompounds.

Non-spectrophotometric methods include the ionometric method,

where boron in the sample is converted into tetrafluoroborate (BF4)

which is then measured viaselective ion selectiveelectrode. In addition,

boron analysis is of interest in nuclear industry, where boric acid is used

in the primary coolant to control the nuclear reaction, and high boron

concentrations might cause metal oxides to deposit on the fuel rods

[100]. In order to monitorthe boron concentration,several nuclear reac-

tion analytical (NRA) methods were reported as powerful independent

measurement technique that can be employed at nuclear reactor sites

withminimal sample preparation. Boron samplesin nuclear techniques

are bombardedwith neutrons causing theproduction of-particles and-particles, oneor bothof which aremonitoredto correlate to 10B stable

isotope abundance.

2.2. Precision and detection limits

Table 2 summarizes detection limits and precisions for all men-

tioned techniques. PTIMS has been widely reported as the most precise

among all instrumental techniques for boron isotope ratio analysis. The

Cs2BO2+ PTIMS method is considered to be the most precise with rela-

tive standard deviation (RSD) precisions in the range of 0.2 0.5

[40,4447,50,59,63,77,86] at detection levels of 0.15 g. Rao et al.

[79,80,83,87]reported boron isotopic ratio with RSD precision values

of 0.242.0for Na2BO2+ and 0.22.5for Rb2BO2

+. On the other

hand, NTIMS is described as the most sensitive technique, able to detect

boron at concentrations of 110 ng, while PTIMS detection levels are

higher in the range of 0.15 g. Further improvements applied on the

Cs2BO2+ PTIMS method by Nakano and Nakamura [43] and Deyhle[78]increased the precision and detection by 10-fold, reaching preci-

sion values of 0.070.25(2mean) for 1 g of B, and 0.150.32

(2mean) for 0.1 g of B by the former [43], and 0.06 for 0.1 g

boron by the latter [78]. Below 0.1 g boron, Ishikawa et al. [42]

reported 0.1 precision for 0.050.1 g, and 0.2 for 0.01 g

boron samples [42]. Nonetheless, PTIMS is not yet able to compete

with the sensitive detection capabilities of NTIMS, where 110 ng

boron loadings are reported with comparable precisions of

0.240.8 (2)[5557,93]. ICP-MS, ICP-qMS, and double-focusing

magnetic sector ICP-MS are less precise than PTIMS and NTIMS, with

reported precisions for the plasma-based techniques in the range of

714for ICP-MS[39,77], 310for ICP-qMS[80], and 12for the

double-focusing magnetic sector ICP-MS[34]. However, the introduc-

tion of the MC-ICP-MS improved the precision of the plasma-basedtechniques. In fact, the most recent publications report precision values

for MC-ICP-MS in the range of 0.20.4 (for 250 ng B [30], for 100 ngB

[35,36], and for 1050 ng B[7476]). This precision range at such low

detection levels (10100 ng) has made MC-ICP-MS very competitive

Table 2

Precision and detection levels of the major boron analyses techniques.

Precision and detection levels

1000 ng 100250 ng 50100 ng 1050 ng 110 ng

MC-ICP-MS 0.20.4for 250 ng[30] 0.20.4for 100 ng[35] 0.20.4[7880]

PTIMS (Cs2BO2+ method) 0.070.25[43] 0.06for 100 ng[83] 0.1for 50100 ng[42] 0.2for 10 ng[42]

NTIMS 0.240.8[5557]




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compared to both TIMS (0.240.8 for 110 ng) and PTIMS

(0.10.2for 10100 ng), especially since MC-ICP-MS is a relatively

faster technique that is characterized by its higher sample throughput.

The major non-MS based technique, ICP-OES, reported 10% pre-

cision in quantifying boron concentrations of solid samples[40], and

only 12% for aqueous samples[74]. Furthermore, the spectrophoto-

metric azomethine-H method reported a precision of 210% in the

aqueous samples[47,63]and 5% for the solid samples [45]. Where-

as, the nuclear reaction analytical (NRA) method, prompt-gammaneutron activation, determined boron concentrations with even

higher analytical precision of 515%[46]. The detection limits for

these techniques range from 13 ppb-B for spectrophotometric

methods to 10100 ppb-B in ICP-OES, and 1 ppm-B in the NRA method

[67], depending on type of the reagent and the sample matrix.

2.3. Complexity of operation and sample preparation

MC-ICP-MS outperforms PTIMS, NTIMS, and all other MS-based

techniques in terms of simplicity of operation because of its fast analysis

times and high sample throughput (up to 100 samples per day)[77].

The speed of sample acquisition in MC-ICP-MS has been reported with-

in 4 min per sample for samples containing 250 ng-B to a 0.2 preci-

sion [30], compared to 0.254.0 h reported for the TIMS technique

[44,59,80]. Improvements in NTIMS[93]have shortened its sample ac-

quisition time to 20 min, which is still longer than MC-ICP-MS, yet sim-

pler with itsfewer samplepreparation requirements. As a matter of fact,

to achieve high precision and low detection levels for the aforemen-

tioned boron analysis techniques, extensive and laborious sampleprep-

aration steps are required for almost all techniques. Samplepreparation

procedures involve boron extraction and separation/purification, pri-

marily by ion-exchange resins in order to pre-concentrate boron and

eliminate the effects of the samplematrix [30,50,76,78]. NTIMS isan ex-

ception and only requires minimal sample preparation especially for

aqueous samples [56,57], where it entails the addition of free-

seawater or Ba(OH)2+MgCl2to enhance BO2 formation[80]. Hence,

NTIMS has been recognized as the most suitable technique for water

samples.

2.4. Compliance with regulatory levels

As can be observed, with the exception of the nuclear reaction ana-

lytical methods, whose detectionlimit is 15 ppm witha 15% precision

[67], almost all the above reported techniques for the determination of

boron have their detection limits significantly below the seawater

boron levels of 4.5 ppm [14] and possess relatively high precision.

More importantly, these detection limits are well below the regulatory

guidance levels for boron of 0.5 and 0.6 ppm [13], as advised by the

WHO and USEPA. Hence, all of the aforementioned techniques can be

applied to ascertain regulatory compliance of aqueous samples.

2.5. Interferences and limitations

Each of the techniques discussed so far for Boron analysis suffers

one or more limitations (Table 3), although in most cases, there are

ways to deal with these limitations. Below is a discussion of these

limitations.

2.5.1. Spectral and isobaric interferences

Each of the MS based techniques described earlier is prone to iso-

baric interferences owing to the absence of an inline compound sep-

aration procedure (e.g., chromatography) prior to mass spectral

analysis. Isobaric interferences occur when the m/z ratios of the tar-

get ion and an interfering ion have a difference of less than one unit[66], making it difficult to separate ions given the resolution of the

mass spectral filter. ICP-MS measuring elemental boron abundance

at m/z 10 and 11 suffers from interference with 12C due to spectral

overlap with 11B [67]. It is not widely reported in MC-ICP-MS, but

others such as 40Ar4+ (m/z of 10) and 10BH+ (m/z of 11) interfering

with 10B and 11B, respectively, are noted [76]. Furthermore, NTIMS

suffers from isobaric interferences of BO2+ at m/z 42 with cyanogens

(CNO) formed when the samples contain organic materials

[53,80]. In PTIMS, the following isobaric interferences have been

identified: Cs2CNO+ with Cs2BO2

+ (m/z 308), when HNO3is present

in the sample, and 88Sr with Na2BO2+ (m/z 88) [77,80]. Wei et al.

[41]used an ionization depressor, 1% H3PO4, to effectively eliminate

isobaric interferences by preventing the formation of Cs2CNO+ and

CNO. The CNO interference was also corrected by applying an ex-

trapolation technique described by Kasemann et al. [59].

In techniques measuring light absorbance, several spectral inter-

ferences occur with a number of elements because the wavelength

of the investigated boron is near the wavelength of these elements.

Interferences with Fe, Al, Cu, Zn, and Mo are reported in spectropho-

tometric techniques utilizing the measurement of colored complexes

[101], whereas, in ICP-OES, interferences with Fe, Al, Ni, Cr, Si, and V

are observed[67].

2.5.2. Mass fractionation

This phenomenon occurs due to space-charge effects, which result

in unequal and preferential transmission of the heavier isotope

through the machine parts[80,81]. When the heavier isotopes pass

through the interface, skimmer cone, quadruple mass filter, and the

detector, they are slightly delayed compared to the lighter isotopes.Therefore, the concentration of the heavier isotope in the measured

results will be reported lower; causing a substantial alteration in the

ratio of the heavier isotope to the lighter isotope. ICP-MS techniques

measure boron by monitoring m/z 10 and 11, while NTIMS monitors

m/z 42 and 43, and with such low masses monitored, mass fraction-

ation is inevitable[30,81]. This is also observed in PTIMS monitoring

Na2BO2+ (m/z 88 and 89) but not in Cs2BO2

+ (m/z 308 and 309)

[80]. Yet, the measurement of the total boron concentration in the sam-

ple is not significantly affected by this phenomenon. In any case, such

limitations are corrected by using defined boron isotopic standards

such as SRM 951 and SRM 952 available from NIST, where the drift of

the results of themeasured standards from thepre-definedboron isoto-

pic ratios is quantified and corrected to all experimental runs. This is at

variance with matrix induced mass fractionation, which is another typeof mass discrimination effect caused by the sample preparation proce-

dure employed. This is especially observed when using ion-exchange

Table 3

Summary of the major advantages and disadvantages on the boron analyses techniques.

MC-ICP-MS PTIMS NTIMS

Convenienc e of analysis V er y f ast

[34,76]

Slow

[30]

Fast

[53]

Limitations Memory effect and mass fractionation

[30,67]

Mass fractionation

(Na-PTIMS)

[77,81]

Mass fractionation

[42,53]

Interferences 40Ar4+ and 10BH+

[53,76]

Cs2CNO+ (with Cs-PTIMS) and 88Sr (with Na-PTIMS)

[77,80]

CNO

[53,59]




6/9

Amberlite IRA-743 resin[76], and cannot be corrected for by using a

defined boron isotopic standard. An exception is NTIMS, which was ap-

plied to water samples without the need for ion exchange preparatory

procedure[56].

2.5.3. Memory effect

In spectrometric instruments, boron adheres to the instrumental

components and is retained in the system. This affects the reading of

the instrument for subsequent sample runs, and is defi

ned in literatureas thememory effect[65]. The memory effect is exclusively reported

in plasma-based techniques and causes substantial suppression of 10B

relative to 11B. The memory effect presents a major problem in boron

analyses[67]despite several attempts to minimize it by performing

washouts between runs using NH3, NaF, and Mannitol blanks [80].

The ICP spray chamber is one of the major instrumental components

to which boron adheres to cause the memory effect. Aggarwal et al.

[30]reported using direct injector nebulizer instead of spray chamber

in their ICPto introduce thesample directly into theplasmato minimize

the memoryeffect, but this approach causedsignal intensity to decrease

in half.

2.5.4. Other limitations

Other general limitations are reported in PTIMS which is charac-

terized by its low ionization efficiency, requiring laborious sample

preparation for purification[55]. It is also limited by its generation

of its alkali or metallic metaborate (M2BO2+) ion, which is dependent

on the ratio of the metal (M) to the boron (M/B ratio) in the prepared

sample, especially in the case of Cs2BO2+ [80].

3. Boron isotopetracer analysis in applications related to desalination

The removal of boron from seawater or brackish water using

membrane desalination is not a straightforward process. Under neu-

tral feed water pH, boron exists in the form of boric acid, which is a

small and uncharged molecular compound that is poorly rejected by

membranes. However, one of the merits of boron's complicated

chemistry is that the rejection of boron by Reverse Osmosis (RO)

membranes increases with the increase of the pH of the systemabove a value significantly higher than the acid dissociation constant

(pKa) of boric acid (Eqs. (1) and (2)). The elevated pH shifts boric

acid's dissociation equilibrium in the direction of the ionized borate

anion[22], where the borate anion is efficiently removed by the mem-

brane because the negatively charged membrane rejects the negatively

charged borate via charge repulsion and prevents its penetration

through the membrane[1].

B OH 3 H2OH

B OH 4

1

pKa log Ka log H

h i B OH 4

= B OH 3

2

Boron speciation in the form of boric acid and borate as a functionof pH is displayed inFig. 3. The point where the concentration of boric

acid equals the borate concentration is the pKa, and its value, ranging

from 8.4 to 9.5, is affected by the temperature and the ionic strength

or salinity of the feed water [22,102]. As temperature and ionic

strength (salinity) increase, the borate fraction increases and thus

the boron rejection increases.

The RO systems, used for the treatment of seawater and brackish

water, operate traditionally at low pH (66.5) to inhibit scaling, but

since the boric acid penetrates undissociated through these RO mem-

branes, an innovative system of high pH in RO plants has been devel-

oped [21,24,25], where a two-pass system of pH adjustment is

installed. The first pass is operated without pH adjustments to treat

the high salinity water with limited scaling, followed by a second

pass at a pH of 9.510. The second pass RO effectively rejects boron

to a range of 8095%[22], as it is predominantly in the form of borate,

which can easily be removed by RO membranes because it is a

charged, polar molecular molecule[103]. Once the borate is removed,

the permeate is neutralized or blended before distribution to the end

user.

Kloppmann et al. [103] studied the variation of boron isotopic

composition throughout several stages of membrane desalination

plants and reported that boron fractionation is observed in the second

passes (high operating pH at around 9.5), where permeate is enriched

in 11B(Fig. 4). The study observed that no significant boron fraction-

ation is reported for the first passes, operating at relatively low pH

values of 66.5, concluding that these isotopic variations are depen-

dent on the pH induced variations of the boron species concentra-

tions. However, the behavior and mechanism of boron speciation

and fractionation related to its removal in second-pass RO still require

deeper investigation. One toolbox for such investigation would be the

stable isotope analysis of boron (11B and 10B) to gain a clearer insight

into the chemical separation and isotopic fractionation occurring during

the boron removal process.

Moreover, this enrichment in 11B of the desalted water causes anexpected depletion of 11B in the produced brine due to mass balance

considerations. These reported fractionations are advantageous in

terms of creating a fingerprinting signature of the desalted water

and the discharged brine.

The importance of water fingerprinting emerges potential contri-

bution of the man-made fresh water to the global water balance.

The desalted water, with its wide utilization including domestic

usage, drinking purposes, and irrigation, is being introduced into

natural systems such as soils, groundwater bodies via artificial

Fig. 3.Distribution of aqueous boron species versus pH in saline water[102].

Fig. 4.Stable isotope fractionation between B(OH)3and B(OH)4 in terms of11B () as a

functionof operationalpH conditions [103]. Thevalueof11B forboth boron speciesincreases

as the pH increases showing a strong fractionation in the heavy isotope of boron while the

average of11

B in seawater is around 39.




7/9

recharge and leaching from irrigation, as well as surface water bodies,

eventually causing changes in the water chemistry and thus in the

ecology. Therefore, backtracking the water origin using the chemical

and isotopic fingerprinting would be of great value, especially in the

case of artificial recharge (AR) of the seawater RO (SWRO) desalted

waters into coastal or continental aquifers, where mixing between

desalinated and natural waters is likely occurring [104]. The stable

isotope analysis of boron in water potentially enables the evaluation

of the natural and anthropogenic proportions in groundwater systemsand determination of the source of aquifer water recharge as well as

the salinity origin and the water residence time[60]. As a matter of

fact, the SWRO desalted waters are characterized by a distinctive

boronisotopic composition that can differentiate theseSWROpermeate

waters from surface water and meteoric rainwater, where boron iso-

topes have been reported as useful artificial tracers in stressed aquifers

[82]. Therefore, boron isotopes monitoring is considered a successful

tool for evaluating the performance of the artificial recharge systems

and assessing the mixing of the man-made fresh waters with the natu-

ral water in terms of mixing proportions of the SWRO desalted water

and the degree of its penetration into the groundwater bodies [104].

In addition, this fingerprinting tool can also be applied on the

brine discharged back into the seas or oceans, making use of the de-

pletion of 11B. Since the desalination plants discharge their brine at

relatively short distances from their pumped feed water, the mixing

of the discharge brine with the sea feed water is inevitable. Thus,

studying the boron isotopic composition of these brines as well as

the mixed water in the sea will provide a reliable estimation of the

mixed proportions. Hence, this tool would be of great potential to as-

sess the brine discharge processes and predict the most suitable loca-

tions for discharging the brine in SWRO plants.

4. Conclusions

Boron analysis is of interest to numerous areas of research ranging

from nuclear technology, marine biochemistry, and geochemistry, to

environmental sciences, hydrology, and desalination. In seawater de-

salination, the removal of boron is of paramount concern because itexists in uncharged form under ambient conditions, allowing it to

pass through desalination membranes. Furthermore, boron has been

shown to be toxic to a number of plant species. Thus, the removal of

boron from saline waters is critical and entails the availability of ro-

bust instrumentation and analytical techniques for monitoring

boron levels with considerable sensitivity and precision, as well as

ease of use. The prevailing instrumentation and analytical methods

for boron determination along with their isotopic composition have

been detailed in this study.

NTIMS is recognized as the most suitable for aqueous samples,

especially when theprecisionof such samples is not of high importance.

Yet,it isdifficult to choose a most suitable method because each one is

characterized by its characteristic advantages and disadvantages. Each

of these boron analysis techniques endures several limitations, primar-

ily those associated by the sample matrix, and spectral and isobaric in-

terferences, which render the choice of technique dependant on the

sample type and the degree of complexity acceptable for sample prep-

aration. Several recent developments in MC-ICP-MS have made this

instrumental analysis method competitive with the very precise

PTIMS and very sensitive NTIMS, especially since MC-ICP-MS analysis

is relatively faster and is characterized by a high sample throughput.

References

[1] J. Kim, H. Hyung, M. Wilf, J.S. Park, J. Brown, Boron rejection by reverse osmosismembranes: National Reconnaissance and Mechanism Study, US Department ofthe Interior Bureau of Reclamation, Denver Colorado, 2009.

[2] United-States-Pharmacopeia-30/National-Formulary-25, United States Pharmaco-peial Convention, Rockville, MD, 2007 Electric Version.

[3] British-Pharmacopoeia, Her Majesty's Stationery Office, London, 2007 Electronicversion 11.0.

[4] M. Chung, Handbook on Borates: Chemistry, Production, and Application, NovaScience Publishers Inc, New York, 2010.

[5] L. Romano, F. Battaglia, L. Masucci, M. Sanguinetti, B. Posteraro, G. Plotti, S.Zanetti, G. Fadda, In vitro activity of bergamot natural essence andfurocoumarin-free and distilled extracts, and their associations with boric acid,against clinical yeast isolates, J. Antimicrob. Chemother. 55 (2005) 110.

[6] R. Jovanovic, E. Congema, H. Nguyen, Antifungal agents vs. boric acid for treatingchronic mycotic vulvovaginitis, J. Reprod. Med. 36 (1991) 593.

[7] K. Van Slyke, V. Michel, M. Rein, Treatment of vulvovaginal candidiasis with

boric acid powder, Am. J. Obstet. Gynecol. 141 (1981) 145.[8] L. Prentice, M. Tyas, M. Burrow, The effects of boric acid and phosphoric acid onthe compressive strength of glass-ionomer cements, Dent. Mater. 22 (2006) 94.

[9] K.V. Peinemann, S.P. Nunes, Membranes for Water Treatment, Wiley-VCH VerlagGmbH & Co. KGaA, Weinheim, 2010.

[10] WHO, Guidelines for drinking-water quality, Second edition, Health Criteria andOther Supporting Information Addendum, vol. 2, 1998.

[11] M. Korkmaz, M. Yenign, S. Bakirdere, O.Y. Ataman, S. Keskin, T. Mezzinoglu,M. Lekili, Effects of chronic boron exposure on semen profile, Biol. Trace Elem.Res. (2010) 113.

[12] W. Woods, An introduction to boron: history, sources, uses, and chemistry, Environ.Health Perspect. 102 (1994) 5.

[13] Y. Xu,J. Jiang,Technologies forboron removal, Ind. Eng. Chem.Res. 47(2008) 1624.[14] M. Busch, W. Mickols, S. Jons, J. Redondo, J. De Witte, Boron removal in sea water

desalination, Int. Desalin. Water Reuse Q. 13 (2004) 25.[15] J. Coughlin, Sources of human exposure: overview of water supplies as sources

of boron, Biol. Trace Elem. Res. 66 (1998) 87.[16] A. Rahardianto, B. McCool, Y. Cohen, Reverse osmosis desalting of inland

brackish water of high gypsum scaling propensity: kinetics and mitigation of

membrane mineral scaling, Environ. Sci. Technol. 42 (2008) 42924297.[17] J. Moore,An assessmentof boric acid andborax using theIEHRevaluativeprocessfor

assessing human developmental and reproductivetoxicity of agents. Expert ScientificCommittee, Reprod. Toxicol. 11 (1997) 123160.

[18] B. Tural, Separation and preconcentration of boron with a glucamine modifiednovel magnetic sorbent, Clean-Soil, Air, Water 38 (2010) 321 327.

[19] E. Weinthal, Y. Parag, A. Vengosh, A. Muti, W. Kloppmann, The EU drinkingwater directive: the boron standard and scientific uncertainty, Eur. Environ. 15(2005) 112.

[20] E. Drioli, L. Giorno, Membrane Operations, Wiley-VCH Verlag GmbH & Co. KGaA,Weinheim, 2009.

[21] Y. Magara, T. Aizawa, S. Kunikane, M. Itoh, M. Kohki, M. Kawasaki, H. Takeuti,The behavior of inorganic constituents and disinfection by products in reverseosmosis water desalination process, Water Sci. Technol. 34 (1996) 141 148.

[22] M. Wilf, Membrane Desalination Technology, Balaban Publications, 2007.[23] N. Greenwood, Boron, Compr. Inorg. Chem. 1 (1973) 665991.[24] J. Redondo, M. Busch, J. De Witte, Boron removal from seawater using FILM-

TECTM high rejection SWRO membranes, Desalination 156 (2003) 229 238.[25] Y. Magara, A. Tabata, M. Kohki, M. Kawasaki, M. Hirose, Development of boron

reduction system for sea water desalination* 1, Desalination 118 (1998) 25 33.[26] X. Ying Kai, L. Bu Yong, L. Wei Guo, X. Yun, H. George, Ion exchange extraction of

boron from aqueous fluids by amber lite IRA 743 resin, Chin. J. Chem. 21 (2003)10731079.

[27] L. Melnik, O. Vysotskaja, B. Kornilovich, Boron behavior during desalinationof sea and underground water by electrodialysis* 1, Desalination 124 (1999)125130.

[28] N. Hilal, G. Kim, C. Somerfield, Boron removal from saline water: a comprehensivereview, Desalination (2010).

[29] P. Le Roux, S. Shirey, L. Benton, E. Hauri, T. Mock, In situ, multiple-multiplier,laser ablation ICP-MS measurement of boron isotopic composition ([delta]11B) at the nanogram level, Chem. Geol. 203 (2004) 123138.

[30] J.K. Aggarwal, D. Sheppard, K. Mezger, E. Pernicka, Precise and accurate determi-nation of boron isotope ratios by multiple collector ICP-MS: origin of boronin the Ngawha geothermal system, New Zealand, Chem. Geol. 199 (2003)331342.

[31] S. Barth, Comparison of NTIMS and ICP-OES methods for the determination ofboron concentrations in natural fresh and saline waters, Fresenius J. Anal.

Chem. 358 (1997) 854855.[32] J. Fietzke, A. Heinemann, I. Taubner, F. Bohm, J. Erez, A. Eisenhauer, Boron

isotope ratio determination in carbonates via LA-MC-ICP-MS using soda-limeglass standards as reference material, J. Anal. At. Spectrom. 25 (2010)19531957.

[33] G. Foster, T. Elliott, C. Coath, Boron isotope determinations by direct injectionMC-ICPMS, Geochim. Cosmochim. Acta Suppl. 70 (2006) 182.

[34] H.E. Gabler, A. Bahr, Boron isotope ratio measurements with a double-focusingmagnetic sector ICP mass spectrometer for tracing anthropogenic input intosurface and ground water, Chem. Geol. 156 (1999) 323 330.

[35] C. Guerrot, R. Millot, M. Robert, P. Ngrel, Accurate and high-precision determinationof boron isotopic ratios at low concentration by MC-ICP-MS (Neptune), Geostand.Geoanal. Res. 35 (2011) 275284.

[36] P. Louvat, J. Bouchez, G. Paris, MC-ICP-MS isotope measurements with directinjection nebulisation (d-DIHEN): optimisation and application to boron in sea-water and carbonate samples, Geostand. Geoanal. Res. 35 (2011) 75 88.

[37] J. Vogl, M. Rosner, W. Pritzkow, Development and validation of a single collectorSF-ICPMS procedure for the determination of boron isotope ratios in water andfood samples, J. Anal. At. Spectrom. 26 (2011) 861 869.




8/9

[38] A. Al-Ammar, E. Reitznerov, R.M. Barnes, Improving boron isotope ratio measure-ment precision with quadrupole inductively coupled plasma-mass spectrometry,Spectrochim. Acta, Part B: At. Spectrosc. 55 (2000) 18611867.

[39] D.C. Gregoire, Determination of boron isotope ratios in geological materials byinductively coupled plasma mass spectrometry, Anal. Chem. 59 (1987)24792484.

[40] S. Tonarini, W. Leeman, G. Ferrara, Boron isotopic variations in lavas of the Aeolianvolcanic arc, South Italy, J. Volcanol. Geotherm. Res. 110 (2001) 155170.

[41] H. Wei, Y. Xiao, A. Sun, C. Zhang, S. Li, Effective elimination of isobaric ionsinterference and precise thermal ionization mass spectrometer analysis forboron isotope, Int. J. Mass spectrom. 235 (2004) 187 195.

[42] T. Ishikawa, K. Nagaishi, High-precision isotopic analysis of boron by positivethermal ionization mass spectrometry with sample preheating, J. Anal. At.Spectrom. 26 (2010) 359365.

[43] T. Nakano, E. Nakamura, Static multicollection of Cs2BO2+ ions for preciseboron isotope analysis with positive thermal ionization mass spectrometry,Int. J. Mass spectrom. 176 (1998) 1321.

[44] A.J. Spivack, J.M. Edmond, Determination of boron isotope ratios by thermal ion-ization mass spectrometry of the dicesium metaborate cation, Anal. Chem. 58(1986) 3135.

[45] W. Leeman, S. Tonarini, M. Pennisi, G. Ferrara, Boron isotopic variations in fuma-rolic condensates and thermal waters from Vulcano Island, Italy: implicationsfor evolution of volcanic fluids, Geochim. Cosmochim. Acta 69 (2005) 143163.

[46] W.P. Leeman, S. Tonarini, L.H. Chan, L.E. Borg, Boron and lithium isotopic varia-tions in a hot subduction zonethe southern Washington Cascades, Chem. Geol.212 (2004) 101124.

[47] M. Pennisi, W. Leeman, S. Tonarini, A. Pennisi, P. Nabelek, Boron, Sr, O, and Hisotope geochemistry of groundwaters from Mt. Etna (Sicily)hydrologic impli-cations, Geochim. Cosmochim. Acta 64 (2000) 961974.

[48] S. Tonarini, M. Pennisi, R. Gonfiantini, Boron isotope determinations in waters

and other geological materials: analytical techniques and inter-calibration ofmeasurements, Isotopes Environ. Health Stud. 45 (2009) 169 183.

[49] F. Vils, S. Tonarini, A. Kalt, H.M. Seitz, Boron, lithium and strontium isotopes astracers of seawaterserpentinite interaction at Mid-Atlantic ridge, ODP Leg209, Earth Planet. Sci. Lett. 286 (2009) 414 425.

[50] S. Tonarini, M. Pennisi, W.P. Leeman, Precise boron isotopic analysis of complex sili-cate (rock) samples using alkali carbonate fusion and ion-exchange separation,Chem. Geol. 142 (1997) 129137.

[51] S.K. Aggarwal, B.-S. Wang, C.-F. You, C.-H. Chung, Fractionation correctionmethodology for precise and accurate isotopic analysis of boron by negativethermal ionization mass spectrometry based on BO2 ions and using the18O/16O ratio from ReO4 for internal normalization, Anal. Chem. 81 (2009)74207427.

[52] S. Eisenhut, K. Heumann, A. Vengosh, Determination of boron isotopic variationsin aquatic systems with negative thermal ionization mass spectrometry as atracer for anthropogenic influences, Fresenius J. Anal. Chem. 354 (1996)903909.

[53] N. Hemming, G. Hanson, A procedure for the isotopicanalysis of boron by negativethermal ionization mass spectrometry, Chem. Geol. 114 (1994) 147156.

[54] Y. Miyata,T. Tokieda, H. Amakawa, M. Uematsu,Y. Nozaki,Boron isotopevariationsin the atmosphere, Tellus B 52 (2000) 10571065.

[55] S. Barth, Boron isotopic analysis of natural fresh and saline waters by negativethermal ionization mass spectrometry, Chem. Geol. 143 (1997) 255 261.

[56] S. Barth, 11B/10B variations of dissolved boron in a freshwater-seawater mixingplume (Elbe Estuary, North Sea), Mar. Chem. 62 (1998) 114.

[57] S. Barth, Application of boron isotopes for tracing sources of anthropogeniccontamination in groundwater, Water Res. 32 (1998) 685690.

[58] N. Hemming, G. Hanson, Boron isotopiccomposition and concentration in modernmarine carbonates, Geochim. Cosmochim. Acta 56 (1992) 537543.

[59] S. Kasemann, A. Meixner, A. Rocholl, T. Vennemann, M. Rosner, A.K. Schmitt, M.Wiedenbeck, Boron and oxygen isotope composition of certified referencematerials NIST SRM 610/612 and reference materials JB 2 and JR 2, Geostand.Geoanal. Res. 25 (2001) 405416.

[60] L. Bouchaou, J. Michelot, A. Vengosh, Y. Hsissou, M. Qurtobi, C. Gaye, T. Bullen, G.Zuppi, Application of multiple isotopic and geochemical tracers for investigationof recharge, salinization, and residence time of water in the Souss-Massaaquifer, southwest of Morocco, J. Hydrol. 352 (2008) 267 287.

[61] K. Klochko, A.J.Kaufman,W. Yao,R.H. Byrne, J.A.Tossell, Experimental measurementof boron isotope fractionation in seawater, Earth Planet. Sci. Lett. 248 (2006)276285.

[62] C. Rollion-Bard, D. Blamart, J. Trebosc, G. Tricot, A. Mussi, J.P. Cuif, Boron isotopesas pH proxy: a new look at boron speciation in deep-sea corals using 11B MASNMR and EELS, Geochim. Cosmochim. Acta 75 (2011) 1003 1012.

[63] Y. Xiao, S. Li, H. Wei, A. Sun, W. Liu, W. Zhou, Z. Zhao, C. Liu, G. Swihart, Boronisotopic fractionation during seawater evaporation, Mar. Chem. 103 (2007)382392.

[64] P. Trujillo, E.Gladney, D.Counce,E. Mroz,D. Perrin, J.Owens, L.Wangen,A comparisonstudy for determining dissolved boron in natural water and geothermal fluid, Anal.Lett. 15 (1982) 643655.

[65] R.G. Downing, P.L. Strong, B.M. Hovanec, J. Northington, Considerations in thedetermination of boron at low concentrations, Biol. Trace Elem. Res. 66 (1998)321.

[66] D.A. Skoog, F.J. Holler, S.R. Crouch, Principles of Instrumental Analysis, ThomsonBrooks/Cole, 2007.

[67] R. Sah,P. Brown, Boron determinationa review of analytical methods, Microchem.J. 56 (1997) 285304.

[68] I.T. Urasa, Determination of arsenic, boron, carbon, phosphorus, selenium, andsilicon in natural waters by direct current plasma atomic emission spectrometry,Anal. Chem. 56 (1984) 904908.

[69] M. Brennan, G. Svehla, Flow injection determination of boron, copper, molybde-num, tungsten and zinc in organic matrices with direct current plasma opticalemission spectrometry, Fresenius J. Anal. Chem. 335 (1989) 893 899.

[70] E.H. Evans, J.A. Caruso, Low pressure inductively coupled plasma source for massspectrometry, J. Anal. At. Spectrom. 8 (1993) 427431.

[71] B.S. Sheppard, J.A. Caruso, Plasma mass spectrometry: consider the source. Invitedlecture, J. Anal. At. Spectrom. 9 (1994) 145149.

[72] ISO, Water QualityDetermination of 33 Elements by Inductively Coupled

Plasma Atomic Emission Spectroscopy, International Organization for Standard-ization, Geneva, 1996 [ISO 11885:1996 (E)].[73] M. Duffy, R. Thomas, Benefits of a dual-view ICP OES for the determination

of boron, phosphorus, and sulfur in low alloy steels, Atomic Spectroscopy Norwalk Connecticut-, 17, 1996, pp. 128132.

[74] H.C. Chao, C.F. You, B.S. Wang, C.H. Chung, K.F. Huang, Boron isotopic composi-tion of mud volcano fluids: implications for fluid migration in shallow subduc-tion zones, Earth Planet. Sci. Lett. 305 (2011) 3244.

[75] J.W.B. Rae, G.L. Foster, D.N. Schmidt, T. Elliott, Boron isotopes and B/Ca in benthicforaminifera: proxies for the deep ocean carbonate system, Earth Planet. Sci.Lett. (2011).

[76] G. Foster, Seawater pH, pCO2 and [CO2-3] variations in the Caribbean Sea overthe last 130 kyr: a boron isotope and B/Ca study of planktic foraminifera, EarthPlanet. Sci. Lett. 271 (2008) 254266.

[77] J.K. Aggarwal, M.R. Palmer, Boron isotope analysis. A review, Analyst 120 (1995)13011307.

[78] A. Deyhle, Improvements of boron isotope analysis by positive thermal ioniza-tion mass spectrometry using static multicollection of Cs2BO2+ ions, Int. J.Mass spectrom. 206 (2001) 7989.

[79] R. Rao, A. Parab, K. Sasibhushan, S. Aggarwal, Studies on the isotopic analysis ofboron by thermal ionisation mass spectrometry using NaCl for the formation ofNa2BO2+ species, Int. J. Mass spectrom. 273 (2008) 105110.

[80] R.M. Rao, A.R. Parab, K. Sasibhushan, S.K. Aggarwal, A robust methodologyfor high precision isotopic analysis of boron by thermal ionization mass spec-trometry using Na2BO2+ ion, Int. J. Mass spectrom. 285 (2009) 120125.

[81] R.N. Sah, P.H. Brown, Isotope ratio determination in boron analysis, Biol. TraceElem. Res. 66 (1998) 3953.

[82] K.W. Quast,K. Lansey, R. Arnold, R.L. Bassett,M. Rincon, Boron isotopes asan artificialtracer, Ground Water 44 (2006) 453466.

[83] R.M. Rao, A.R. Parab, K.S. Bhushan, S.K. Aggarwal, Determination of ultratraceboron concentrations in uranium oxide by isotope dilution-thermal ionizationmass spectrometry using a simplified separation procedure, Microchim. Acta169 (2010) 227231.

[84] Y. Liu, W. Liu, Z. Peng, Y. Xiao, G. Wei, W. Sun, J. He, G.Liu, C.L. Chou, Instability ofseawater pH in the South China Sea during the mid-late Holocene: evidencefrom boron isotopic composition of corals, Geochim. Cosmochim. Acta 73(2009) 12641272.

[85] M. Rosner, W. Pritzkow, J. Vogl, S. Voerkelius, Development and validation of amethod to determine the boron isotopic composition of crop plants, Anal.Chem. (2011).

[86] E. Lemarchand, J. Schott, J. Gaillardet, How surface complexes impact boron iso-tope fractionation: evidence from Fe and Mn oxides sorption experiments, EarthPlanet. Sci. Lett. 260 (2007) 277296.

[87] R.M. Rao, A.R. Parab, K.S. Bhushan, S.K. Aggarwal, High precision isotope ratiomeasurements on boron by thermal ionization mass spectrometry usingRb2BO2+ ion, Anal. Methods 3 (2010) 322327.

[88] S.K. Sahoo, A. Masuda, Simultaneous measurement of lithium and boron isotopesas lithium tetraborate ion by thermal ionization mass spectrometry, Analyst 120(1995) 335339.

[89] E. Catanzaro, C. Champion, E. Garner, G. Marinenko, K. Sappenfield, W. Shield,Boric acid: isotopic and assay standard reference materials, US Natl. Bur.Stand. Spec. Publ. 260 (1970) 1770.

[90] P.J. De Bivre, G.H. Debus, Absolute isotope ratio determination of a naturalboron standard, Int. J. Mass Spectrom. Ion Phys. 2 (1969) 15 23.

[91] H. Zeininger, K. Heumann, Boron isotope ratio measurement by negative ther-mal ionization mass spectrometry, Int. J. Mass Spectrom. Ion Phys. 48 (1983)

377380.[92] N.L. Duchateau, P. de Bivre, Boron isotopic measurements by thermal ioniza-

tion mass spectrometry using the negative BO2-ion, Int. J. Mass Spectrom. IonProcess. 54 (1983) 289297.

[93] B. Honisch, N.G. Hemming, Surface ocean pH response to variations in pCO2through two full glacial cycles, Earth Planet. Sci. Lett. 236 (2005) 305 314.

[94] J.W. Mair Jr., H.G. Day, Curcumin method for spectrophotometric determinationof boron extracted from radio frequency ashed animal tissues using 2-ethyl-1, 3-hexanediol, Anal. Chem. 44 (1972) 20152017.

[95] S. Ammar, R. Abdelhedi, C. Flox, C. Arias, E. Brillas, Electrochemical degradationof the dye indigo carmine at boron-doped diamond anode for wastewatersremediation, Environ. Chem. Lett. 4 (2006) 229 233.

[96] R.R. Spencer, D.E. Erdmann, Azomethine H colorimetric method for determiningdissolved boron in water, Environ. Sci. Technol. 13 (1979) 954956.

[97] Protocol of Accepted Drinking Water Testing Methods. Version 2.0. LaboratoryServices Branch. Ministry of the Environment. Ontario, in, 2010.

[98] ISO, Water QualityDetermination of BorateSpectrometric Method UsingAzomethine-H, International Organization for Standardization, Geneva, 1990[ISO 9390:1990].




9/9

[99] A.D. Eaton, M.A.H. Franson, Standard Methods for the Examination of Water &Wastewater, Amer Public Health Assn, 2005.

[100] F. Nordmann, Aspects on chemistry in French nuclear power plants, 14th Interna-tional Conference on the Properties of Water and Steam in Kyoto, 2004.

[101] M. Arruda, E. Zagatto, A simple stopped-flow method with continuous pumpingfor the spectrophotometric flow-injection determination of boron in plants,Anal. Chim. Acta 199 (1987) 137145.

[102] J. Hoefs, Stable Isotope Geochemistry, sixth edition Springer, Berlin, 2009.

[103] W. Kloppmann, A. Vengosh, C. Guerrot, R. Millot, I. Pankratov, Isotope and ionselectivity in reverse osmosis desalination: geochemical tracers for man-madefreshwater, Environ. Sci. Technol. 42 (2008) 47234731.

[104] W. Kloppmann, E. Van Houtte, G. Picot, A. Vandenbohede, L. Lebbe, C. Guerrot, R.Millot, I. Gaus, T. Wintgens, Monitoring reverse osmosis treated wastewaterrecharge into a coastal aquifer by environmental isotopes (B, Li, O, H), Environ.Sci. Technol. 42 (2008) 87598765.


Please cite this article as: A. Farhat, et al., Analytical techniques for boron quantification supporting desalination processes: A review, Desalination(2012) doi:10 1016/j desal 2011 12 020

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