CN105548115A - Method for assaying total mercury in soil - Google Patents

Abstract

The invention discloses a method for assaying total mercury in soil. The method comprises the following steps that firstly, 0.2g of soil samples are weighed and put into a high-pressure microwave digestion tank, 6ml of HCl and 2ml of HNO3 are added into the high-pressure microwave digestion tank, standing is carried out for 5min to 10min, the high-pressure microwave digestion tank is put into a microwave digestion instrument, microwave digestion is conducted, after digestion is finished, the microwave digestion tank is taken out and cooled, after becoming cool, the microwave digestion tank is immediately leached by 5% HCl and transferred to a 50ml centrifuge tube, 10ml of 5% thiourea and 10ml of 5% ascorbic acid are added into the centrifuge tube, and a 5%HCl solution is metered to the scale; secondly, a standard series solution is prepared; thirdly, an AFS-9700 type bi-channel atomic fluorescence spectrophotometer is used for measuring the total mercury content in the first step and the second step, and the total mercury content in the soil samples is obtained. By means of the method, the assayed total mercury content conforms to the assay requirement, and the result still conforms to the assay requirement when the soil samples are detected by a machine after being preserved for 1h to 18h at the temperature of 4 DEG C. The method effectively solves the problem that detection of the heavy metal mercury in the soil is unstable.

Description

The assay method of Mercury In Soil

Technical field

The present invention relates to a kind of assay method of chemical substance, specifically the assay method of Mercury In Soil.

Background technology

Total mercury in soil less stable in mensuration, assay method is also a lot, but its all multi-method less stable.During total mercury in current employing Soil by Atomic Fluorescence Spectrometry, if machine testing on constant volume immediately after clearing up, phenomenon is forbidden on time when its result also there will be, measure again if cleared up after constant volume liquid preserves 1-18 hour at 4 DEG C, the result of many methods is had just to be difficult to accurately, through studying for many years, the larger problem of this error can be thought mainly because the stability of total mercury is closely related with the reagent of constant volume when detecting.

Summary of the invention

The object of the present invention is to provide a kind of mensuration accurately, and after preserving 0-18 hour at 4 DEG C, still can keep the assay method measuring Mercury In Soil accurately.

This method is applicable to the total mercury in Soil by Atomic Fluorescence Spectrometry, and the detectability of method is 0.002mg/kg.

The present invention is achieved in that

An assay method for Mercury In Soil, comprises the steps:

Step one, take soil sample 0.2g in high pressure micro-wave diminishing pot, add 6mlHCl, 2mlHNO ₃leave standstill 5-10min, high-pressure microwave counteracting tank is put into microwave dissolver micro-wave digestion, clear up end, take out the cooling of high-pressure microwave counteracting tank, transfer in 50ml centrifuge tube with 5%HCl drip washing immediately after cooling, add 5% thiocarbamide 10ml, 5% ascorbic acid 10ml, be settled to scale with 5%HCl solution;

Step 2, to get 160 μ l content be 1 μ g/ml Standard Reserving Solution, in 100ml volumetric flask, add 5% thiocarbamide 20ml, 5% ascorbic acid 20ml, use 5%HCl solution constant volume to 100ml, obtained 1.6ng/ml standard solution, 1.6ng/ml mercury standard solution is the peak concentration of typical curve, corresponding point is 0 by instrument automatic dilution, 0.1,0.2,0.4, the standard serial solution of 0.8,1.6ng/ml.

Step 3, the total mercury content utilized in AFS-9700 type dual channel atomic fluorescence photometers measuring process one and step 2, thus obtain the total mercury content in soil sample.

Utilize method of the present invention, the total mercury content of mensuration meets mensuration requirement, and upper machine testing after 4 DEG C of preservation 1h to 18h, result still meets mensuration requirement.Method of the present invention efficiently solves heavy metal in soil mercury and detects unstable problem.

Embodiment

In order to verify implementation result of the present invention, test as follows:

1, liquid preparation to be measured

Accurately take GSS-13 standard soil sample 0.2000g (being accurate to ± 0.0001g), 5 repetitions of often kind of method, respectively in high pressure micro-wave diminishing pot, add 6mlHCl, 2mlHNO respectively ₃, leave standstill 5-10min, micro-wave digestion in microwave dissolver is placed in tinning.Clear up end, take out cooling, add following solvent constant volume respectively immediately.

A transfers in 50ml centrifuge tube with 5%HCl drip washing after clearing up cooling immediately, adds 5% thiocarbamide 10ml, 5% ascorbic acid 10ml, to be settled to scale with 5%HCl solution to be measured.(being method of the present invention).

B transfers in 50ml centrifuge tube with deionized water drip washing after clearing up cooling immediately, is settled to scale to be measured.

C transfers in 50ml centrifuge tube with 5%HCl drip washing after clearing up cooling immediately, is settled to scale to be measured.

D uses 5%HNO after clearing up cooling immediately ₃drip washing is transferred in 50ml centrifuge tube, is settled to scale to be measured.

E transfers in 50ml centrifuge tube with containing 5%HCl, 2% thiocarbamide 10ml, 2% ascorbic acid solution 10ml drip washing after clearing up cooling immediately, is settled to scale to be measured.

F uses immediately containing 5%HNO after clearing up cooling ₃, 2% thiocarbamide 10ml, 2% ascorbic acid solution 10ml drip washing transfers in 50ml centrifuge tube, is settled to scale to be measured.

G uses 5%HNO after clearing up cooling immediately ₃drip washing is transferred in 50ml centrifuge tube, adds 5% thiocarbamide 10ml, 5% ascorbic acid 10ml, uses 5%HNO ₃it is to be measured that solution is settled to scale.

H transfers in 50ml centrifuge tube with the drip washing of potassium chromate dilution after clearing up cooling immediately, adds 10ml potassium dichromate conserving liquid, is settled to scale to be measured with potassium dichromate dilution.

Containing HNO in solvent ₃, use 5%HNO ₃make current-carrying, other all make current-carrying with 5%HCl.

2, typical curve

Getting 160 μ l content is 1 μ g/ml Standard Reserving Solution, and in 100ml volumetric flask, constant volume obtains 1.6ng/ml standard solution to 100ml, for the sample application corresponding solvent constant volume standard solution of the different solvents constant volume that aforementioned a-h uses.Such as correspond to a, use 5% thiocarbamide 20ml, 5% ascorbic acid 20ml, be settled to 100ml with 5%HCl solution, corresponding to f, use 2% thiocarbamide 20ml, 2% ascorbic acid solution 20ml, use 5%HNO ₃be settled to 100ml; By that analogy.1.6ng/ml mercury standard solution is the peak concentration of typical curve, and corresponding point is the standard serial solution of 0,0.1,0.2,0.4,0.8,1.6ng/ml by instrument automatic dilution.

3, instrument condition of work

3.1AFS-9700 type dual channel atomic fluorescence photometers

3.2MultiwavePRO/24HVT50 high-pressure microwave counteract appearance

Start	Counteract appearance rises to temperature (DEG C)	Retention time (min)
			Normal temperature	120	15
120	180	10
			180	65	25

4, laboratory environment condition

5, result calculates and detects data summarization

The calculating of 5.1 pedotheque total mercury contents

Pedotheque total mercury content ω is in massfraction, and numerical value represents with milligrams per kilogram (mg/kg), as follows:

ω＝(C-C ₀)×V/【m(1-f)×1000】

In formula: C---check in mercury element content from calibration curve, unit is nanograms per milliliter (ng/ml);

C ₀---reagent blank liquid measures concentration, and unit is nanograms per milliliter (ng/ml);

V---after Specimen eliminating, constant volume unit is milliliter (ml);

M---sample mass, unit is gram (g);

F---soil moisture content;

Directly sample weighting amount during practical operation, constant volume, calibration curve concentration point, is input to instrument, and instrument conversion can draw the data that will detect automatically.

The testing result after rear different time different solvents constant volume cleared up by 5.2 total mercuries measured in soil: (unit mg/kg)

A-h is sample corresponding to aforementioned employing different solvents constant volume method.GSS-13-1, GSS-13-2, GSS-13-3, GSS-13-4, GSS-13-5 are respectively the code name of 5 repeat samples.

5.3 preci-sion and accuracy

The data analysis of the inventive method

From in upper table, no matter be between parallel experiment or same test different time replication, its relative absolute value error is all less than 5%, and relative deviation is all less than 12%, meets the preci-sion and accuracy of the mensuration of GB/T22105.1-2008 Mercury In Soil.

The full mercury right value of GSS-13 standard substance be 0.052 ± 0.006mg/kg namely: 0.046 ~ 0.058mg/kg, as can be seen from table above, disposal route a, b, machine testing is gone up immediately after the clearing up of c process, result is all in correct scope, through 1 hour, 12 hours later upper machine testings, only has the testing result of a disposal route still in correct scope, other disposal routes are most of inaccurate, have also occur time inaccurate phenomenon on time, as can be seen here, a disposal route not only testing result is accurate, and Comparison between detecting methods is stablized, detecting the method in the method for full mercury in soil in current grasp is a not only accurate but also stable method, solve heavy metal in soil mercury and detect unstable problem.I.e. detection method of the present invention, 4 DEG C of preservations, machine testing in 0-18 hour, result is all very accurate, is the good method detecting full mercury in soil at present.

Claims (1)

1. an assay method for Mercury In Soil, is characterized in that comprising the steps:

Step one, take soil sample 0.2g in high pressure micro-wave diminishing pot, add 6mlHCl, 2mlHNO ₃leave standstill 5-10min, high-pressure microwave counteracting tank is put into microwave dissolver micro-wave digestion, clear up end, take out the cooling of high-pressure microwave counteracting tank, transfer in 50ml centrifuge tube with 5%HCl drip washing immediately after cooling, add 5% thiocarbamide 10ml, 5% ascorbic acid 10ml, be settled to scale with 5%HCl solution;

Step 2, to get 160 μ l content be 1 μ g/ml Standard Reserving Solution, in 100ml volumetric flask, add 5% thiocarbamide 20ml, 5% ascorbic acid 20ml, use 5%HCl solution constant volume to 100ml, obtained 1.6ng/ml standard solution, 1.6ng/ml mercury standard solution is the peak concentration of typical curve, corresponding point is 0 by instrument automatic dilution, 0.1,0.2,0.4, the standard serial solution of 0.8,1.6ng/ml;

Step 3, the total mercury content utilized in AFS-9700 type dual channel atomic fluorescence photometers measuring process one and step 2, thus obtain the total mercury content in soil sample.