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Gamal A. Hamid1
DMADirect Mercury Analyzer
Gamal A. Hamid
Gamal A. Hamid2
DMA
ThanksTo everyone who has helped us with
support,
new books, hard/soft ware And over the internet
Special thanks for MILESTONE
http://www.milestonesrl.com/
Gamal A. Hamid3
DMA
Contents
• Introduction
• Hardware
• System initialization
• Software
• Analysis
• Applications
Gamal A. Hamid4
Introduction
Gamal A. Hamid5
DMA
DMA-80
• DMA which uses the principle of thermal
decomposition, amalgamation and atomic
absorption.
• The DMA-80 can analyze solid, liquid and gas
matrices with equal precision.
• All mercury is released from the sample through
thermal decomposition.
• This eliminates the need for any sample
preparation.
Direct Mercury Analyzer for analysis of liquid, solid and gaseous samples
Gamal A. Hamid6
DMA
DMA – 80 Advantage
• Results in 5 minutes.
• Results are matrix independent.
• Small footprint ideal for laboratory and
field analysis.
• No sample digestion step.
• No chemical pretreatment step.
• Eliminates use of reagents and their disposal.
• Validated results for both solid and liquid
matrices.
• Autosampler allows unattended operation.
Gamal A. Hamid7
DMA
Mercury
• Elemental mercury
• Most toxic in its vapor form, slowly vaporizes
at room temperature and more quickly when
heated.
• Organic mercury (methyl-mercury)
• Elemental and inorganic mercury salts are
transformed into organic mercury by
bacteria and it concentrates by bio-
accumulation.
• Readily absorbed in humans
• Exposure can result in long term damage to
the kidney, liver and central nervous system.
Gamal A. Hamid8
DMA
Principle of Operation
Gamal A. Hamid9
DMA
Sequence of Analysis
• Solid, liquid or gas samples are weighed and
introduced in the DMA-80.
• The sample is initially dried and then thermally
decomposed in a oxygen/air flow.
• Combustion products are carried off and further
decomposed in a hot catalyst bed.
• Mercury vapors are trapped on a gold amalgamator
and subsequently desorbed for quantitation.
• The mercury content is determined using atomic
absorption spectrophotometry at 254 nm.
Gamal A. Hamid10
DMA
Accuracy
The DMA-80 produces accurate results over a wide dynamic range and on a variety of different matrices.
Gamal A. Hamid11
DMA
Sample matrix
• The DMA-80 produces matrix independent results.
• The instrument is calibrated with aqueous standards and analyzes organic and inorganic solid samples.
Gamal A. Hamid12
Hardware
Gamal A. Hamid13
DMA
Hardware
Back View
Front View
Gamal A. Hamid14
DMA
The System
Gamal A. Hamid15
DMA
Instrument Hardware
1. Sample dosing system.
2. Thermal process furnaces.
3. Atomic absorption spectrophotometer.
4. T660 or T1660 or PC controller.
Gamal A. Hamid16
DMA
1. Sample Dosing System
• The DMA-80 has a built-in 40 positions
auto-sampler plate for high throughput
unattended operation, for solid and liquid
samples.
• This auto-sampler system is composed of a
pneumatic and an electrical section.
• Maximum sample weight 500 mg.
• Maximum sample volume 1,5 ml.
• Possibility of multiple sample dosing for Hg
pre-concentration on amalgamator.
Gamal A. Hamid17
DMA
Pneumatic Section
• Purpose of the pneumatic section is to take
the sample boat from the auto-sampler
plate, to place it in the catalyst tube and, at
the end of the sample analysis, to locate it
back on the plate.
• The movement of the pneumatic cylinders
is activated by the opening and closing of
the corresponding electro-valve placed on
the valves block.
• The position of each pneumatic cylinder is
controlled by two electrical end-run
switches.
Gamal A. Hamid18
DMA
Electrical Section
Auto-sampler motor
• Purpose of the electrical section of the
dosing system is to move, controlled by the
software, the auto-sampler plate in the
correct position for the loading and
analysis of each sample.
• It is based on a step motor with encoder
installed underneath the autosampler
plate.
Gamal A. Hamid19
DMA
Boat Types
• The samples are weighed and carried for
measurement in special sample boats be
made of Nickel or Quartz.
• To clean metal boats, it is possible to bake
out them in a muffle furnace or they can be
run without sample in the DMA-80 at 650°C
(decomposition) for 180 seconds.
• Repeat this cleaning procedure until the
absorbance is stable and lower than 0.003
running blank analysis.
Gamal A. Hamid20
DMA
2. Thermal Process Furnaces
• After the loading and positioning steps the
sample is submitted to three different furnace
systems and a thermal process with four distinct
thermal phases: drying, decomposition,
catalyzing and amalgamating.
• Heating in the furnace is produced through an
electrical resistance under the control of power
values and thermocouple sensors.
• All thermal processes are performed under
oxygen flow or air compressed with the purpose
of carrying the sample and its residuals to all the
sections, as well as to aid decomposition.
Gamal A. Hamid21
DMA
a. Drying & Decomposition
• Moisture removal from solid samples, bulk
evaporation from liquid samples and final
decomposition.
• Temperature is controlled by a thermocouple
connected to the mother board.
• If a new catalyst or amalgamator tube is replaced,
conditioning procedure has to be followed and a
new calibration curve is required.
• This process is not necessary for new DMA80 it
already done during final quality control testing.
• After drying the sample is decomposed at high
temperature (burned in the oxygen flow).
Gamal A. Hamid22
DMA
b. Catalyzing
• keep the temperature of the catalyst tube
stable at around 565°C, which is necessary
for its optimal functioning.
• Inside the catalyst tube, mercury coming
from the sample is converted in metallic
mercury and the reaction products
generated during the sample
decomposition are neutralized.
Gamal A. Hamid23
DMA
c. Amalgamator
• Hg is trapped in the amalgamator and all the other gases
are flushed out of the system before Hg is measured in
the cuvette.
• The amalgamator coil has a double purpose: to keep the
amalgamator tube at the stand-by temperature of
around 170°C/150°C and then to quickly heat it up to
850°C.
• The temperature is measured with an infrared sensor.
• The first stand-by temperature is necessary to avoid
water condensation and retain of organic residues in the
amalgamator tube.
• The grove on the quartz must be placed close to the
cuvette.
Gamal A. Hamid24
DMA
3. Atomic Absorption Spectrophotometer
• The spectrometer works with a single beam
system with sequential flow through
measurement cells.
• It is composed of:
A low pressure Hg lamp with relative
power supplier,
A cuvette system with quartz
window,
A detector based on a Si-photodiode
sensor.
Gamal A. Hamid25
DMA
Normal System
• Normal system: The spectrometer works
with a single beam system with sequential
flow through measurement cells.
• It is composed of a low pressure Hg lamp
with relative power supplier, a cuvette
system with quartz window and a detector
based on a Si-photodiode sensor.
• The cuvette block is also provided with an
heating system, controlled by thermocouple,
with the purpose of avoiding moisture
condensation.
Gamal A. Hamid26
DMA
Tricell System
• Tricell system: The spectrometer
works with a dual beam system
with sequential flow through
measurement cells.
• It is composed of an high power Hg
lamp with relative power supplier, a
cuvette system with quartz window
and two detectors based on a Si-
photodiode sensor.
Gamal A. Hamid27
DMA
Lamp
• Light source is a low pressure mercury
vapor lamp.
• The lamp is not subjected to temperature
changes and its voltage is stable in the
time.
• The cooling fan and the temperature
sensor ensure a full control of the lamp
temperature.
Gamal A. Hamid28
DMA
Cuvette “Cell”
• Cuvette system with quartz window.
• The cuvette block is provided with an heating system, controlled
by thermocouple, with the purpose of avoiding moisture
condensation.
• Clean the windows using a very soft tissue and some acetone.
• Dry them very well, in order not to left any mark on the quartz.
• Tricell DMA-80: The first and long one cuvette is used for
measuring low Hg content (up to approx. 10 ng),
• The second medium one (10-20ng), the third and short one for
measuring high Hg content (up to approx. 1200 ng).
Gamal A. Hamid29
DMA
Detector
• Detector is UV enhanced Si- photodiodes.
• Wavelength is 253.65 nm.
• Tricell system detectors.
• Normal system detector.
• Detection limit:
0.005 ng of Hg (dual-cell)
0.0015 ng of Hg (tri-cell)
Gamal A. Hamid30
DMA
4. Terminal / PC
Terminals 660 ( 1660)
• Touch-screen 6.5” (12”)with 65.000 colors; VGA resolution
640x480 for sharp process graphic.
• 5 USB port, 1 LAN connection for network, 2 RS 232 ports for
external devices, 2 video port.
• Methods and runs saved on PC-compatible USB pen-drive.
Personal Computer (minimum requirements)
• CPU Pentium III 800, RAM 256 MB.
• 20 MB free space on hard disk.
• 1 USB port, 1 CD-ROM reader, operating system Windows 7, XP
or Vista.
Gamal A. Hamid31
DMA
Oxygen / Air
Function Carrier and decomposition gas
Inlet pressure 4 bar (60 psig)
Flow rate 200 ml/minute
Purity“Research” grade
(O2 > 99,95%)
Internal oxygen pressure 3.1 bar
Gamal A. Hamid32
DMA
Flow Measurement
• The required Oxygen must have a flow rate
of approximately 160ml/minute (6-8 l/h)
and an inlet pressure of 4 bar (60 psig).
• To avoid damages to the pressure regulator
diaphragm, open the tank valve only when
the DMA-80 unit and the Terminal are
communicating, then adjust the pressure
from 0 to 4 bar.
• The internal Oxygen pressure must be set
at 3,1 bar.
Gamal A. Hamid33
DMA
Air Compressor
• Oxygen/Air connection,
• The DMA can run using Oxygen or Air with
the same pressure.
• The Oxygen or Air required for DMA-80
working must be at “research” grade (O2
/Air purity > 99,95%).
• A flow rate must have of approximately
160ml/minute (6-8 l/h) and an inlet
pressure of 4 bar (60 psig).
Gamal A. Hamid34
DMA
Mercury Trap
• Mercury trap to be located at
DMA-80 outlet.
• Activated charcoal.
• Safe operation.
• Easy and ready to install.
Gamal A. Hamid35
System initialization
Gamal A. Hamid36
DMA
Setup the System
• The DMA-80 system must be installed in a
well ventilated, dust free room, free from
acid vapors or highly corrosive chemical
atmosphere.
• Aggressive vapors can attack the system
through its ventilation openings and cause
heavy damage to the electronic boards,
plugs, etc.
• The optimal placement is in an air-
conditioned room with approx. 20 °C (± 3 °C).
Gamal A. Hamid37
DMA
Preparing the system
System initialization steps:
1. Warm up of the unit.
2. Initialization of the Catalyst tube.
3. Calibration of the unit Load one of the original .
4. Conditioning the catalyst tube.
5. Stability of 100ul of aqueous standard solution.
6. Verification of stability test.
Gamal A. Hamid38
DMA
1. Warming Up
• Click on DMA-80 Measurement icon and wait
the complete warm up of the unit.
• After approx. 15 minutes the message
“START” of the software will indicate that the
DMA-80 is ready to work.
• At this point it would be possible to install
the amalgamator.
• If a trace of condensation on the tip of the
catalyst, switch ON the unit again, wait some
minutes to remove this condensation.
Gamal A. Hamid39
DMA
2. Initialization of the Catalyst tube
Create a new working method (sample path and temperatures) in according to the
information you can find in the table.
Gamal A. Hamid40
DMA
3. Calibration
• In the calibration page load the
original calibration of the unit
performed during the QC of the
instrument.
• You can find the file saved in the
USB key or CD-ROM (calibration).
• If any calibration is not selected the
analysis can not start.
Gamal A. Hamid41
DMA
4. Conditioning the catalyst tube
Proceed with this method:
• 2 times B/V amalgamator
• 3 boats without boats
• 1 boat flour 0,3g + water 50µl
• 2 boats without boats
• 1 boat flour 0,3g + water 50µl
• n° blanks without boats (it must give an
absorbance value, (height) < 0,0030 in cell
1).
• If the conditions above are not verified it
is necessary to run further cleaning.
Gamal A. Hamid42
DMA
5. Stability of 100ul of aqueous standard solution.
• The solution (100 µl of 100ppb) must be fresh
and stabilized with 1-2% of HCL(ultrapure).
• Create a new working method
1) 00:00:10 200°C
2) 00:01:00 200°C
3) 00:01:30 650°C
4) 00:01:30 650°C
• Max start: 250°C
• Purge time P: 60 s
• Amalgamator heating time H: 12 s
• Signal recording time R: 30 s
• Use this method for the test that will follow
• Go to Meas. Page and press the white paper to
create a new measurement file and save it as
“stability”.
• Quartz sample boat required.
• In case of metal boats usage, they must be
deeply cleaned before to run a stability test.
Gamal A. Hamid43
DMA
6. Verification of stability test
• Once the analyse has ended, you have to verify:
• The absorbance values (Height) are between 0,4200
and 0.5700.
• Select all samples (green circle) in order to verify the
correct value of RSD(% error between selected
readings). It must be <3%.
• If one of this conditions is not verified, try to run the
test again.
• If both conditions are verified, then the test is passed.
• Now, it is possible proceed with the calibration of the
unit if the customer needs or start to work with the
original calibration.
Gamal A. Hamid44
Software
Gamal A. Hamid45
DMA
EasyCONTROL Software
• Evolution of previous Windows™ based
DMA-80 software.
• Selectable calibration algorithm.
• Virtually unlimited memory for programs
and actual data storage.
• Built-in service and diagnosis functions
• CFR-21 part 11 compliant.
• All sample parameters, including furnace
temperatures, method profiles, absorbance
signals, results , and calibrations are saved.
Gamal A. Hamid46
DMA
Desktop
Item Symbol Function
Dma-80 Measurements
The actual control program
Balance Set-up The communication settings for the balance. These must be adjusted only when switching over to a new type of balance.
History Trail All changes in the system are automatically documented, e.g. login, logout, etc
Panel Administration This area is dedicated to the basic adjustments/settings and to the user administration. The basic settings to a major extent are reserved to Service.
Logout With Logout you go out of the system. The Login window appears where the next user can log in with his own password.
Gamal A. Hamid47
DMA
DMA - 80
DMA-80 MEASUREMENTS
• The actual control program is opened.
• This is divided into four main registers.
1. Method
2. Calibration
3. Measurement
4. System
Gamal A. Hamid48
DMA
1. Methods
• To create a new method its Program
steps must be defined, as well as the
related parameters (temperature,
heating ramp, decomposition time,
amalgam heating time, purge time of
the process.
• Here methods can be created, stored,
changed, deleted and loaded.
Gamal A. Hamid49
DMA
Method Symbols
Item Symbol Function
Create new file Provides a new, empty file
Go back Go back to the start screen, save any changes before quitting.
Break Terminated without saving and the input window is quitted.
Delete File is deleted.
Start If there is a sand clock on, this means that a Current procedure must first be accomplished (e.g. Heating of furnace and cuvette).
Stop The current measurement is interrupted and the sample boats are taken back to the auto sampler tray.
Restart The stop-button must then be re-set Touching the red-green stop-button.
Gamal A. Hamid50
DMA
Method parameters
No. Function Meaning
1 Steps 1-2 Drying time 00:00:10 to 00:02:00
2 Steps 3-4 Decomposition time 00:0 0:10 to 00:04:00
3 Max. Start-T Measurement starts only when temperature T1 (drying- unddecomposition furnace) is under the maximum Start-Temperature.
4 Purge time The time elapsing between the end ofdrying/decomposition and the start of the Hg measurement.
5 Amalgam Heater Time The time required by the amalgam heater to completely release the Hg collected in the absorption cell.
6 Recording Time Time for Noted and evaluated the measuring signal of the spectrometer.
Gamal A. Hamid51
DMA
Parameters ranges
STEP TEMPERATURE RANGE
TYPICAL TEMPERATURE TIME RANGE TYPICAL TIME
Drying 20-300°C 200°C 0-300 s 60 s
Decomposition 500-1000°C 650°C 0-420 s 180 s
Catalyst 550-650°C 565°C 0-420 s 180 s
Amalgamator 850-950°C 850°C 0-30 s 12 s
Gamal A. Hamid52
DMA
2. Calibration
• Purpose is to administer the calibration files.
• From a calibration file you can select the
used measuring points and specify the
regression curves for each cuvette.
• Different calibration files can be opened,
created and saved.
• All cuvettes are always used for
measurement.
• If the maximum peek of the first signal is
over 1.0 A (standard setting), the maximum
of the second signal will be used to calculate
the result.
Gamal A. Hamid53
DMA
Calibration Symbols
Item Symbol Function
ΔE or δ Hg Value by which the measured value deviates from the calibration curve
The R² Is calculated from the deviations of the measured values that have been calculated
Zero point setting
The curve is placed across the zero point
Ultratrace range
The calibration curve can be adapted to measuring for ultratrace analysis.
Calibration methods
It is possible to determine the type of calibration curve. If „undefined“ is selected, then only the measured points will be shown and not curve.
Gamal A. Hamid54
DMA
Cell 1
Low value used for 1st cell
calibration 0 – 35 ng.
• The working standards solution
must be freshly prepared before
every calibration.
• Diluted liquid standard solution
can be stored for one month if
maintained in its original tightly
sealed bottle away from sunlight
and intense sources of radiation,
in a refrigerator at 10°C.
Standardsolution
From 5 ppmin ml
HCl 36% in ml
Deionizedwater in ml
Blank 0 1 Up to 100
0.05 ppm 1 1 Up to 100
0.1 ppm 2 1 Up to 100
0.2 ppm 4 1 Up to 100
0.3 ppm 6 1 Up to 100
Gamal A. Hamid55
DMA
Cell 2
High value used for 2nd cell of
calibration35 – 600 ng.
• Stock solution of 1000 ppm (1mg/ml)
of HgCl2 stabilized in diluted HCl.
• Standard for atomic absorption.
• Stock solution of 1000 ppm can be
stored for one year if maintained in
its original tightly sealed bottle away
from sunlight and intense sources of
radiation, in a refrigerator at 10°C.
Standardsolution
1000 ppmin ml
HCl 36% in ml
Deionizedwater in ml
1 ppm 0.1 1 Up to 100
2 ppm 0.2 1 Up to 100
5 ppm 0.3 1 Up to 100
Gamal A. Hamid56
DMA
3. Measurement
• The extinction process can be monitored in
real time.
• Previously measured data can be recalled
and displayed at any time.
• Results and statistics (over selected data)
are calculated and can be printed out.
Gamal A. Hamid57
DMA
Measurement Symbols
Item Symbol Function
Add data A new line is added to the table.
Simple mode Each sample is measured individually. Each measurement has to be manually started.
Automatic mode Samples are automatically measured in sequence one after the other.
Only one sample Only a defined maximum volume can be loaded into the sample boat.
Concentrate over several samples
With the concentrate function a large sample can be distributed and measured in several sample boats.The divided samples are thermally decomposed and the total Hg of all subsamples is collected successively in the amalgamator.
Gamal A. Hamid58
DMA
Sample
• Sample name, The Name is taken over from the selected record and can be changed/modified.
• Pos, Consists of two numbers: If Simple sample processing is activated, and a sample is added,
the number over the selected record will be taken, alternatively the sample can be selected
(from pos. 1 to 40), as in this operating mode each sample can be measured individually.
• n, the number of samples.
• Amount , A weight must always be entered.
• Remarks, It is possible to enter comments on the corresponding samples.
Gamal A. Hamid59
DMA
Links
In this Register you can select the calibration file (Cal-Date) and Methods to be used for the
process.
Gamal A. Hamid60
DMA
Signal
• On the left of the screen there is a
listing of the samples.
• If one sample is check-marked, its
curve is shown in the graphic on the
right.
• Each measurement is shown in real
time and can be observed during
process run.
• During a current measurement you
can also look at earlier runs.
Gamal A. Hamid61
DMA
Signal “peak” testing
• Check the signal for a typical good
peak:
• The shape of the peak is regular
• The distance between Peak Cell 1
and Peak Cell 2 is between 11 to 15
seconds.
• In this picture: T2 (21,85s) – T1
(6,85s) = 15 seconds
• Remember, Oxygen flow rate is
from 5 to 8 L/h.
Gamal A. Hamid62
DMA
System correct profiles
Gamal A. Hamid63
DMA
Results
• The average final result with the relative standard deviation is shown in the headline of the
multiple measurements. Individual values can be disabled removing the sigma sign.
• Hg [ng], Absolute quanty of Hg in the sample (calculated from active calibration) c[μg/kg] or
c[mg/kg],Concentration of Hg in the sample (calculated from active calibration and sample
weight).
Gamal A. Hamid64
DMA
4. System
Here the system is supervised (Autosampler, heating elements, spectrometer)
Gamal A. Hamid65
DMA
Startup conditions of the system
After the start of the system all Standby functions are activated:
• The Hg lamp of the spectrometer is switched on
• The catalyst tube is locked by the pneumatic cylinder.
• Oxygen flushes the catalyst, as long as there is gas pressure.
• Catalyst, amalgamator unit and absorption cells are heated up to Standby temperatures.
• After reaching these temperatures the Start button is released.
• HEATING 1: for drying and decomposition of the sample. Here also the oxygenation takes place.
• HEATING 2: Heating of the catalyst zone at constant temperature.
• HEATING 3: Heating of the amalgamator: at constant temperature to prevent separation of
condensation water. Heating to high temperature is then used to release very rapidly the
accumulated Hg.
• HEATING 4: Heating of the cuvette block at constant temperature, to avoid condensation.
Gamal A. Hamid66
Analysis
Gamal A. Hamid67
DMA
Tips and Techniques 1
• Working range: from 0.05 ng up to 600 ng absolute value of Hg.
• That means for 100 mg of sample, 0.5 ppb up to 6 ppm.
• Eliminate any source of contamination coming from environmental dust or from the
samples.
• Cleaning boats—in the DMA-80 or a muffle at 800°C for a few minutes.
• Clean the laboratory tools such as spatula, balance plate, tweezers, etc.
• The working standards solution must be freshly prepared before every calibration.
• Stock solution of 1000 ppm can be stored for one year if maintained in its original tightly
sealed bottle away from sunlight and intense sources of radiation, in a refrigerator at 10°C.
• Note: It is recommended to measure liquid samples only in Single mode using metal boat.
Gamal A. Hamid68
DMA
Tips and Techniques 2
• Diluted liquid standard solution can be stored for one month.
• The curve comprises the entire range of interest, working range 0.5– 600 ng.
• The quality of the calibration curve can be also improved by using quartz boats,
because quartz is completely inert.
• A method blank is prepared by using a volume or weight of reagent water at the
volume or weight specified in the preparation method.
• For solids (special for inorganic matrix), it is extremely important to have
homogeneous distribution of mercury and uniform sample sizes with a maximum
particle size of 100 um.
• Quartz boat are completely inert; they have no memory effect, and do not interact
with the acid used for stabilizing the samples.
Gamal A. Hamid69
DMA
Tips and Techniques 3
• Increase the decomposition time will reduce the memory effect.
• Increase the recovery from difficult inorganic sample matrices, such as metal oxide, by
increasing its decomposition temperature and time.
• Reduce the drying temperature and extend the time if strong exothermic reaction
persists.
• Use pre-concentration step to increase signal of low Hg amount.
• Longer drying step allows a pre-combustion of sample before rapid decomposition at
high temperature, reducing the exothermic reaction.
• With liquid samples, metal boats can be used only in single mode, to minimize the loss
of mercury due to chemical interaction between the acid matrix and the metal boat.
Gamal A. Hamid70
DMA
Tips and Techniques 4
• Drying time (sec) = Sample Volume (μL) × 0.6 or
• Drying time (sec) = Sample weight (mg) × 0.6 x % H2O.
• For dry inorganic samples, Drying time =10 sec
• Drying temperature = 200°C for most samples.
• Reduce the drying temperature if you are working with flammable sample
• Decomposition time is 3 min. for most samples.
• Increase decomposition time if analysis resulted in high RSD (> 5 %)
• Add 30 sec and analyze samples determining RSD again.
• For Example, coal requires 300 sec(for others see application notes).
• Decomposition temperature = 650°C for most samples
• Purge time is 60 sec for most samples
Gamal A. Hamid71
DMA
Standards Preparation
• To calibrate the instrument for its full
range, prepare 5 ppb up to 10 ppm Hg
working standards.
• Don’t leave the solution bottles open on
the bench and at the end store them into
a fridge at 5-10°C.
• The instrument does not have to be re-
calibrated every time, but the calibration
curve must be checked every morning
prior to analyze unknown samples.
Working standard (ppm) = Stock solution (ppm) x (Volume of the stock solution (mL) Total volume (mL).
Gamal A. Hamid72
DMA
Different preparation techniques
Different volumes of same standard solution
• 1 ml of 1000 ppm in 100 ml measuring 10 ppm
• 1 ml of 10 ppm in 100 ml measuring 100 ppb
Different volume of this solution (100ppb) and put it in 100 ml
measuring flask will give different concentration:-
( 50 μL, 100 μL and 200 μL) give ( 5 ng, 10 ng and 20 ng mercury).
Same volume but different standards solutions (most used)
• 1 ml of 1000 ppm in 100 ml measuring 10 ppm
• 0.5 ml of 10 ppm in 100 ml measuring 50 ppb
• 1 ml of 10 ppm in 100 ml measuring 100 ppb
• 2 ml of 10 ppm in 100 ml measuring 200ppb
Same volume (100 μL) of above 3 solutions in three 100 ml measuring flask gives
different concentrations ( 5 ng, 10 ng and 20 ng mercury).
( 50 μL, 100 μL and 200 μL) give ( 5 ng, 10 ng and 20 ng).
Gamal A. Hamid73
DMA
Working ranges
For solids and liquids Automatic switch-over.
Dual-cell:
Low range: 0 to 20 ng.
High range: 20 to 1500 ng.
Tri-cell:
Low range: 0 to 10 ng
Medium range: 10 to 20 ng.
High range: 20 to 1500 ng.
• Use 0.5 % - 5 % (1 % suggested) dilute
hydrochloric for the dilutions.
Gamal A. Hamid74
DMA
Sample Amount
• The instrument is calibrated using aqueous
standards and then analyzes organic and
inorganic solid samples.
• One method is used to analyze a variety of
different matrices .
Up to 1,5 grams of solid,
1,5 mL of liquids
0.05-100 l. of gas can be analyzed.
• For solid sample, we need to reduce the
sample’s particle size to a powder form,
normally below 100 um.
Gamal A. Hamid75
DMA
Rapid determination of Hg in Samples
Gamal A. Hamid76
DMA
Gas Analysis
• Simply sample the gas, through a dedicated
mass flow controller, using the Sorbent
Traps, and load them onto the DMA.
• Total mercury (elemental and oxidized
forms) is quantitatively measured in 5
minutes.
• Sorbent Traps are reusable and extremely
easy to operate.
Gamal A. Hamid77
DMA
Gas sample collection
• More adsorption tubes can be tied up,
according to requirement.
• With two adsorption tubes, the sample gas
is collected on the first tube, while the
second is used to control the blank value.
• Upgrading kit for direct mercury
determination at trace level in gases.
Gamal A. Hamid78
DMA
Sample measurements 1
• Switch on the DMA-80 System it requires approx. 15 minutes of pre-heating time before run.
• Open the “Methods - parameter”, type a new method name, description and assign the working
parameters of the instrument, such as drying and decomposition time and save the new method
file.
• Open the “DMA-80 Measurement - sample ” click the button to obtain a new empty data file, type a
new data name, number of sample and weight, description and save new data file, Select the
operating mode, either automatic or simple.
• Open the “DMA-80 Calibration”, click the button for provide new empty calibration file, type a new
data name, description and save the new calibration file.
• Return to the “DMA-80 Measurement ”, and load the data file saved. Open “Sample” table of
“Data”. Click “magic wand” button to build a new line, fill the data.
• Open “ Measurement - Result” table and clicking the “Calibration” button appears under State “C”.
Enter with the concentration of your working standard solution.
Gamal A. Hamid79
DMA
Sample measurements 2
• Carry on an blank (several empty boats) measurement to make sure that the system is free
from Hg contaminations, (this cleans the system and the boats).
• Then, follow the calibration procedure that has been described above, running one of the
clean empty boats. In the “Result” table, enter 0.0000 in the “C (μg/Kg)” column and 0.1 g in
the “Weight” column.
• Check calibration of the system measuring a reference sample. At the end also the signal
curve can be tested in the Measurement/Signal menu.
• Add the data necessary for the measurement. Be careful that measurement can be started
only when weight is indicated for all data records.
• Enter the sample weight, put the sample in the Autosampler and start measurement.
• Verify the results, If the samples show heavily different Hg values, it is recommended to carry
out blank measurements after samples with high values.
Gamal A. Hamid80
DMA
QC during analysis
• An initial calibration verification standard is checked once per run after calibration.
• An initial calibration verification blank is checked once per run after calibration.
• Verification standard for instrument calibration and standardization:
• checked every 10 samples and at end of run.
• A method blank is analyzed with each sample batch, or one per
20 samples (5%), for each matrix.
• An external reference sample (laboratory control standard) is analyzed with
each batch, or one of 20 samples (5%) for each matrix.
• A matrix spike is analyzed with each sample batch, or one per 20 samples (5%)
for each matrix.
• A sample in replicates (spike in replicates) is analyzed with each sample batch,
or one per 20 samples (5%), for each matrix.
Gamal A. Hamid81
DMA
Acceptance Criteria for QC
• Control standards for checking the stability of the instrument
calibration within ±10% of their true value.
• blank should be less than 10% of the lowest sample
concentration for each analyte.
• The acceptable criteria in absence of historical analysis is set at
±10%.
• Matrix Spike/Matrix Spike duplicated at ± 20% of the spiked for
precision and ≤ 20 relative percent difference.
• For samples processed, The acceptable criteria in absence of
historical analysis is set at ±10%.
Gamal A. Hamid82
Applications
Gamal A. Hamid83
DMA
Major Applications
• Biological
Blood, urine, hair, tissue, plankton
• Liquids
Waste water, crude oil, heavy oil, detergents, paints
• Solids
Coal, fly ash, soil, sediment, sludge, minerals, food, feed,
plastic, wood, vegetables, leaves, waxes
• Medicinal
Pharmaceuticals, gelatin capsules, lipstick, lotions
• Gas
natural gas, biogas, gases processing, safety and health
occupational hygiene, hazardous waste inspection
Gamal A. Hamid84
DMA
Application Book
• Clinical, 6 applications .
• Chemicals, 8 applications .
• Beverage, 4 applications .
• Cosmetic, 4 applications .
• Environment, 14 applications .
• Foods, 29 applications.
• Pharmaceutical , 11 applications .
• Petroleum, 10 applications .
• Geochemistry, 25 applications .
• Industrial, 3 applications .
• Energy, 1 applications .
• Plastic, 20 applications .
Gamal A. Hamid85
DMA
DMA Selection
Gamal A. Hamid86
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