LAAN-A-AA-E035
Application
News
A446
Spectrophotometric Analysis
Measurement of Cesium in Tap Water and Soil by
Atomic Absorption Spectrometry
No.
Table 2 Atomization Parameters by ETAAS
n Introduction
Recently, technologies that can efficiently remove
radioactive cesium (chiefly Cs-137) from water and soil
have been actively researched.
The study and evaluation of these removal technologies
can be conducted using Cs-133, an easy-to-handle,
stable substance, yet chemically similar to Cs-137.
Cesium can be analyzed using atomic absorption
spectrometry and ICP emission spectroscopy, which are
therefore effective for researching and evaluating the
various removal technologies.
Here, we introduce examples of analysis of cesium in
tap water and soil using the AA-7000 atomic
absorption spectrophotometer.
n Sample Preparation
The tap water was used as is, without pretreatment.
As for the soil, 1 g of sample was accurately weighed
into a beaker, and after adding aqua regia and heating
on a hot plate to decompose, the mixture was filtered
through 5B filter paper, and 50 mL of the filtrate was
used as the process solution.
n Analytical Method and Conditions
(1) Tap Water
Measurement was conducted by the calibration curve
method using the furnace technique (electric furnace,
ETAAS). The measurement samples consisted of tap
water and tap water spiked with 1 µg/L cesium. In
addition, a solution containing a mixture of Na, Ca, and
Mg was added as an interference suppression agent.
(2) Soil
The soil was measured by the calibration curve method
using both the flame and furnace techniques. With the
flame technique, the process solution and standard
solution were measured after sodium was added as an
interference suppression agent to both at a final
concentration of approximately 0.1 %.
W ith the fur nace technique, measurement was
conducted after diluting the process solution by a factor
of 10. A solution containing a mixture of Na, Ca, and
Mg was added as an interference suppression agent.
The main spectrometer parameters are shown in Table
1, and the main atomization conditions using the
furnace and flame techniques are shown in Table 2 and
3, respectively.
Table 1 Optics Parameters
Analysis wavelength
Slit width
Current value
Lighting mode
852.1 nm
0.7 nm
16 mA
NON-BGC
Gas
Temperature Time
Mode Sensitivity Flowrate
°C
sec
L/min
0.1
20 Ramp Reguler
120
1
0.1
10 Ramp Reguler
250
2
0.2
10 Ramp Reguler
600
3
Temperature program
0.2
Step Reguler
10
600
4
0.0
High
Step
3
600
5
0.0
High
Step
3
2000
6
0.5
Step Reguler
2
2500
7
Atomization stage: 6
Tube type
Pyrolytic graphite tube
Interference suppressant Mixture of Na, Ca, Mg
Sample injection volume 20 µL (tap water), 10 µL (soil)
Table 3 Atomization Parameters by Flame AAS
Flame type
Burner height
Interference suppressant
Air-C2H2
7 mm
Na 0.1 %
n Measurement Results
(1) Tap Water
The calibration curve and peak profiles are shown in
Figs. 1 and 2, respectively.
The measurement results for the unspiked and spiked
samples are shown in Table 4.
Cesium was not detected in the unspiked tap water,
and excellent recovery was obtained for the cesiumspiked tap water.
(2) Soil
The calibration curve obtained by the flame technique
is shown in Fig. 3.
Figs. 4 and 5 show the calibration curve obtained by
t h e f u r n a c e t e c h n i q u e , a n d t h e p e a k p ro f i l e s ,
respectively.
The measurement results for the soil sample are shown
in Table 5. The lower limit of quantitation was 3 µg/g
(ppm) by the flame technique, and 0.2 µg/g (ppm) by
the furnace technique, converted to the concentration
in solid soil.
The flame technique offers rapid analysis, while high
sensitivity measurement is possible with the furnace
technique, thus permitting selection of the type of
analysis depending on the purpose. The AA-7000
permits automatic switching between the flame and
fur nace measurement techniques, and because
t ro u b l e s o m e a d j u s t m e n t o f t h e o p t i c a l a x i s i s
eliminated, switching between atomization methods is
quickly accomplished. Moreover, space-saving is
achieved by the back-to-front placement of the two
atomizers.
Application No. A446
News
Abs
Abs
0.200
0.400
0.150
0.300
0.100
0.200
0.050
0.100
0.000
0.000
0.000
1.000
2.000
3.000
Conc (µg/L)
4.000
0.000
10.000
Conc (µg/L)
15.000
Fig. 4 Calibration Curve by ETAAS (Soil)
Fig. 1 Calibration Curve by ETAAS (Tap Water)
Abs
5.000
Abs
0.500
0.250
4 µg/L standard solution
16 µg/L standard solution
0.400
0.200
0.300
0.150
0.100
Tap water + 1 µg/L
0.050
Tap water
Soil process solution
(10:1 dilution)
0.200
0.100
0.000
0.000
0
0
2 sec
2 sec
Fig. 2 Peak Profiles of Standard Solution and Tap Water Samples by ETAAS
Fig. 5 Peak Profiles of Standard Solution and Soil Sample by ETAAS
Table 4 Measurement Results for Tap Water by ETAAS
Table 5 Measurement Results for Soil by Flame AAS and ETAAS
Tap Water (Unspiked)
< 0.2 µg/L
Tap Water (Spiked)
0.97 µg/L
Spike Recovery
97 %
Flame Technique
3 µg/g
Furnace Technique
3.1 µg/g
Values are converted to concentration in the solid.
Abs
0.015
0.013
0.010
0.007
0.005
0.003
0.000
0.000
0.050
0.100
0.150
Conc (mg/L)
0.200
Fig. 3 Calibration Curve by Flame AAS (Soil)
First Edition: Sep, 2012
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