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GB/T 17141-1997 (GB/T17141-1997)

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GB/T 17141-1997English70 Add to Cart 0--3 minutes. Auto-delivery. Soil quality. Determination of lead, cadmium. Graphite furnace atomic absorption spectrophotometry  


GB/T 17141-1997: PDF in English (GBT 17141-1997)
GB/T 17141-1997
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 13.080
Z 18
Soil quality - Determination of lead, cadmium –
Graphite furnace atomic absorption spectrophotometry
ISSUED ON. DECEMBER 8, 1997
IMPLEMENTED ON. MAY 1, 1998
Issued by. Ministry of Environmental Protection of the People’s Republic
of China;
General Administration of Quality Supervision, Inspection and
Quarantine of the People’s Republic of China.
Table of Contents
1 Subject content and scope of application ... 3 
2 Principle... 3 
3 Reagents ... 3 
4 Instruments ... 4 
5 Samples ... 5 
6 Analysis procedures ... 5 
7 Result representation ... 7 
8 Precision and accuracy ... 7 
Annex A (Normative) Determination of the water content in soil sample ... 8 
Additional information... 9 
Soil quality - Determination of lead, cadmium –
Graphite furnace atomic absorption spectrophotometry
1 Subject content and scope of application
1.1 This Standard specifies the graphite furnace atomic absorption
spectrophotometry for determining the lead and cadmium in the soil.
1.2 The detection limit (calculated by digesting 0.5g of test piece to the
constant volume of 50mL) of this Standard is as follows. 0.1 mg/kg, for both
lead and cadmium.
1.3 USE the Zeeman method, self-absorption method and deuterium lamp
method to deduct the background. In the presence of a matrix modifier such as
diammonium hydrogen phosphate or ammonium chloride, directly
DETERMINE the trace lead and cadmium in test solution. There is no
interference.
2 Principle
USE the hydrochloric acid - nitric acid - hydrofluoric acid - perchloric acid full
digestion method to completely destroy the mineral lattices in soil so that all the
elements to be tested in the test pieces can enter into the test solution. INJECT
the test solution into a graphite furnace afterwards. EVAPORATE and REMOVE
the coexisting matrix components by a predetermined temperature rising
program such as drying, ashing and atomization. In the meantime,
DISSOCIATE the lead and cadmium compounds into ground-state atomic
vapors at high temperature in the atomization phase. Furthermore, the selective
emission of the characteristic spectrum of the hollow cathode lamp is induced.
Under the optimal determination condition, DETERMINE the absorbance of the
lead and cadmium in test solution by means of background subtraction.
3 Reagents
Unless otherwise specified, the analytical reagents and deionized water or
water of equivalent purity, complying with national standards, are used as
reagents in this Standard.
3.1 Hydrochloric acid (HCl), ρ = 1.19 g/mL, guaranteed reagent.
remove silicon. In order to achieve a good silicon flying effect, it is necessary to
frequently SHAKE the crucible. KEEP on heating until there is white and dense
perchloric acid smoke coming out of the crucible. COVER the lid so that black
organic carbides can fully decompose. WAIT until the black organics on the
crucible disappear. OPEN the lid. DRIVE the white smoke. EVAPORATE until
the contents become viscous. Based on the digestion condition, it is allowed to
add 2mL of nitric acid (3.2), 2mL of hydrofluoric acid (3.5) and 1mL of perchloric
acid (3.6) again. REPEAT the above-mentioned digestion process. When the
white smoke basically exhausts and the contents become viscous again,
REMOVE the crucible for slight cooling. USE water to flush the crucible cover
and inner wall. ADD 1mL of nitric acid solution (3.3) to warm the dissolved
residuals. TRANSFER the solution into a 25mL volumetric flask. ADD 3mL of
aqueous diammonium hydrogen phosphate solution (3.7) afterwards. After
cooling, DETERMINE the constant volume. SHAKE evenly for standby
measurement.
Since there are various kinds of soil, there are major differences between the
contents of organic matters. During digestion, PAY attention to observe. It is
allowed to increase and decrease the dosage of various kinds of acid according
to the digestion condition. The soil digestion solution shall be white or faint
yellow (soil with higher iron content). There shall be no significant precipitates.
Note. The temperature of the electric hot plate shall not be too high. Otherwise, the teflon crucible will be
out of shape.
6.2 Determination
ADJUST the instrument to optimal operating conditions according to the
instrument instruction manual. DETERMINE the absorbance of the test solution
afterwards.
6.3 Blank test
USE water to replace the test pieces. USE the same procedures and reagents
as Section (6.1). PREPARE the whole process blank solution. DETERMINE in
accordance with the procedure (6.2). PREPARE at least two portions of blank
solution in each batch of samples.
6.4 Calibration curve
Respectively TRANSFER 0.00mL, 0.50mL, 1.00mL, 2.00mL, 3.00mL and
5.00mL of standard lead and cadmium working mixture (3.10) into a 25mL
volumetric flask. ADD 3.0mL of aqueous diammonium hydrogen phosphate
solution (3.7) afterwards. USE nitric acid solution (3.4) to determine the
constant volume. The lead contents in this standard solution shall be
respectively 0μg/L, 5.0μg/L, 10.0μg/L, 20.0μg/L, 30.0μg/L and 50μg/L. The
......
 
(Above excerpt was released on 2016-11-24, modified on 2021-06-07, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT17141-1997