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eichrom
expertise. commitment. results.
The Separation of Beryllium from Spectral Interfering Elements in Inductively Coupled
Plasma – Atomic Emission Spectroscopic Analysis
Daniel R. McAlister and E. Philip HorwitzPG Research Foundation, Inc.
8205 S Cass Avenue, Suite 109
Darien, IL 60561
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expertise. commitment. results.
Problems with Current Method
Interfering elements in the AES spectrum of Beryllium
Analyte Peak (nm) Intensity Analyte Peak (nm) IntensityCr 312.870 15.0 Nb 313.079 2200.0U 312.879 6.0 Ti 313.080 6.0Zr 312.918 400.0 Ce 313.087 65.0Nb 312.964 22.0 Th 313.107 27.0
U 312.973 15.0 Beb 313.107 41000.0Zr 312.976 550.0 Tm 313.126 2300.0Th 312.997 10.0 U 313.132 8.0V 313.027 1020.0 Hf 313.181 20.0
OH 313.028 0.0 U 313.199 15.0Ce 313.033 50.0 Cr 313.206 1000.0
Beb 313.042 64000.0 Zr 313.207 7.0U 313.056 6.0 Th 313.226 5.0
OH 313.057 0.0 Mo 313.259 1800.0U 313.073 0.0 Ce 313.259 30.0
Table 1. Potential Spectral Interferences for Be determination by ICP-AESa
aAs listed in Varian Plasma96 software version 1.12bCommonly used peaks for beryllium determination by ICP-AES
Beryllium lines very intense method is very sensitive for the determination of beryllium
Interfering lines from other elements could lead to false positives.
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expertise. commitment. results.
10-2 10-1 100 101
10-1
100
101
102
103
104
105
a
Cr
V
Be
Ce
Nb
Be(II) Ce(III) Zr(IV) Nb(V) Cr(III) V(V)
k'
[HNO3]
k' for U(VI) and Th(IV)
> 104 for all HNO3
Zr
Uptake of Selected Elements on Dipex Resin
Several EXC materials evaluated
Dipex offered the most promising beryllium retention characteristics
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expertise. commitment. results. 10-2 10-1 100 101
10-1
100
101
102
103
104
105
b
Hf
Be
Tm
Ti
Be(II) Mo(VII) Ti(IV) Hf(IV) Tm(III)
k'
[HNO3]
Mo
Uptake of Selected Elements on Dipex Resin
Single column should remove all ICP-AES interferences
Load pH 2-4
Rinse 0.2 M HNO3
Strip Be with 4 M HNO3
Potential for 2-10 x concentration of Be depending on sample size
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expertise. commitment. results.
10-2 10-1 100 101
10-1
100
101
102
103
104
105
Mg
Sr
Ba
Ca
Be(II) Mg(II) Ca(II) Sr(II) Ba(II)
k'
[HNO3]
Be
a
Uptake of Selected Elements on Dipex Resin
Resin selective for Be over other alkaline earth metal ions
Ca and Mg common matrix impurities
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expertise. commitment. results.
10-2 10-1 100 101
10-1
100
101
102
103
104
105
Be(II) Fe(III) Cu(II) Pb(II) Al(III)
Pb
Cu Al
Fe
Be
k'
[HNO3]
b
Uptake of Selected Elements on Dipex Resin
Fe(III) strongly retained
Al(III) and Pb(II) have similar retention to Be(II)
Cu(II) more weakly retained
Large amounts of Fe(III) could interfere with Be(II) uptake
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expertise. commitment. results.
10-2 10-1 100 101
10-1
100
101
102
103
104
105
Mn
Be(II) Cd(II) Zn(II) Hg(II) Mn(II)
Hg
Zn
CdBe
k'
[HNO3]
c
Uptake of Selected Elements on Dipex Resin
Resin selectively retains Be(II) over most other divalent metal ions
Be(II) can be separated from samples containing large quantities of divalent metal ion impurities
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expertise. commitment. results.
Proposed Method for Beryllium Purification
Prepare samples as before (Digest with H2SO4/H2O2, dilute with HNO3)
Neutralize samples to pH 1-2 with sodium aceate
Buffers to maximum pH of 4.5
Monitor pH with methyl violet or crystal violet or pH strip
pH
0.0 0.3 0.5 1.1 1.6 2.8 3.4 4.0 4.5
pH Range over which separation is effective
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expertise. commitment. results.
Elution of Be and Selected Elements on Dipex Resin
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 4010-3
10-2
10-1
100
101
102
103
Load 5.5 cm digested ashless filter + 140 g Be, Al, V and Cr neutralized to pH 2.0 with 3.4 M Sodium Acetate
Cr mL %Be 6 66 8 79 10 92 12 95 14 97 16 97
V
Strip4.0 M HNO
3
1 mL/min
Background
Be
Al
Rinse0.2 M HNO
3
ppm
Bed Volumes
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expertise. commitment. results.
Elution of Be and Selected Elements on Dipex Resin
0 5 10 15 20 25 30 35 40 45 5010-3
10-2
10-1
100
101
102
103
Strip0.2 M
Na4EDTA
U
Load 5.5 cm digested ashless filter + 140 g Be, Ce, Nb, U and Zr neutralized to pH 1.0 with 3.4 M Sodium Acetate
Zr
mL %Be 6 86 8 90 10 91 12 93 14 94 16 94
Nb
Strip4.0 M HNO
3
Background
Be
Ce Rinse0.2 M HNO
3
ppm
Bed Volumes
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expertise. commitment. results.
Elution of Be and Selected Elements on Dipex Resin
0 5 10 15 20 25 30 35 40 45 5010-3
10-2
10-1
100
101
102
103
Ti
Strip0.2 M
Na4EDTA
Tm
Load 5.5 cm digested ashless filter + 140 g Be, Hf, Mo, Ti, Tm and Th neutralized to pH 1.0 with 3.4 M Sodium Acetate
Th
mL %Be 6 84 8 89 10 91 12 94 14 94 16 97
Mo
Strip4.0 M HNO
3
Background
Be
Hf
Rinse0.2 M HNO
3
ppm
Bed Volumes
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expertise. commitment. results.
Simulated Sample Results
Successfully separated Be from samples digested with H2SO4/H2O2
Several different digested methods employed in Be analyses (HCl, H2SO4, HNO3, HF, H2O2, HClO4)
High levels of impurities
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expertise. commitment. results.
Digestion Methods using HF
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
10-3
10-2
10-1
100
101
102
103
98% of Be
2% of Be
0.1 M Boric Acid
No Boric Acid
Load Strip
4.0 M HNO
3
(1 mL/min)
Background
Rinse0.2 M HNO
3
ppm
Bed Volumes
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expertise. commitment. results.
Separation of Be from Large Amounts of Interferences
Dipex® capacity mg to reduce
mg/2 mL bed Be yeild to 90%c
Cr(VI) N/A > 100Mo(VI) N/A 25
U(VI) 102.6a 25
Ti(IV) 12.5b 7.5
Th(IV) 60.6a 10
Fe(III) 22.6a 10
Pb(II) 53.8b 50
Ca(II) 10.4a >100
Be(II) 0.9b 0.5
Capacity of Dipex® Resin for Selected Metal Ions
Metal Ion
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expertise. commitment. results.
Separation of Be from Large Amounts of Interferences
100 mg Cr 50 mg Fe 10 mg Ti 100 mg U
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expertise. commitment. results.
10-4 10-3 10-2 10-1
10-1
100
101
102
103
104
105
10-4 10-3 10-2 10-1
k' for U, Th, Ti, Fe
>103 for all [HNO3]
k' Ca
Be
[HNO3]
k' for Mg, Sr, Ba<1 for all [HNO
3]
k' for U, Th, Ti
>103 for all [HNO3]
k' for Mg, Ca, Sr Ba<1 for all [HNO
3]
Be
LN3
[HNO3]
LN2
Uptake of Selected Metal Ions on LN2 and LN3 Resins
U(VI), Th(IV), Ti(IV) retained from all [HNO3]
LN2: Strongly retains Fe(III)
LN3: Be not retained from pH < 2
Choice of LN2/LN3 depends on desired operating conditions and amount of Fe in samples
O
OHP
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expertise. commitment. results.
Elution of Be on LN2 and LN3 Guard Columns
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
10-3
10-2
10-1
100
101
102
103
LN2
LoadpH 2
1 % Be
85% Be
6 % Be
10% Be
Strip4.0 M HNO
3
(1 mL/min)
Background
LN3
Rinse0.2 M HNO
3
2.0 mL Resin, 50-100 m, Assisted Gravity Flow 2.0 mL/min, 22(2) oC
ppm Be vs. Bed Volumes of Eluate
ppm
Bed Volumes
93 % Be
5% Be
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expertise. commitment. results.
Effect of Large Quantities of Uranium
% Be g U in % Be g U in % Be g U in
mg U in 12 mLb Be fraction in 12 mLb Be fraction in 12 mLb Be fraction
0.14 90 < 1.5c 85 < 1.5 N/A N/A10 92 < 1.5 N/A N/A N/A N/A25 86 < 1.5 87 < 1.5 97 < 1.550 61 < 1.5 88 < 1.5 97 < 1.575 N/A N/A 81 < 1.5 93 < 1.5
100 29 580 88 < 1.5 79 < 1.5
sodium acetate to pH 1.8bBeryllium Resin Strip Solution 4.0 M HNO3
cDetection limit for Uranium by ICP-AES under the experimental conditions
2 mL Beryllium Resin Beryllium Yields and Uranium Impurity vs mg Uranium in Load Solutiona
+ 2 mL LN2 + 2 mL LN32 mL Beryllium Resin2 mL Beryllium Resin
aWhatman filter paper spiked with 0.14 mg Be, digested with H2SO4/H2O2, and neutralized with
LN2 and LN3 Resins effectively increase the capacity for Uranium
With LN2, the GC remains connected through the load, rinse and strip
With LN3, the GC can be removed following the rinse
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expertise. commitment. results.
ConclusionsEfficient, Reliable method for purifying Be from all ICP-AES spectral interfering elements has been found using a single column
Method is compatible with current monitoring and sample digestion methods
Method is robust and performs over a wide pH range
Inserting a LN2 or LN3 Resin guard column increases U capacity without changing the chemistry or significantly decreasing Be yields.
Working to develop methods to isolate Be from high levels of other impurities