Method for measuring mercury content by using gas-phase molecular absorption spectrometer

Abstract

The invention relates to a method for measuring mercury content by using a gas-phase molecular absorption spectrometer. The method comprises the following steps of diluting a mercury standard stock solution step by step by using a hydrochloric acid solution to prepare a mercury standard working solution; detecting the mercury standard working solution by using a gas-phase molecular absorption spectrometer, and correspondingly drawing a standard curve by using the detection data and the concentration; detecting a to-be-detected water sample by adopting a gas-phase molecular absorption spectrometer, and finding the concentration of mercury according to the drawn standard curve by adopting detection data of the to-be-detected water sample; wherein the gas-phase molecular absorption spectrometer adopts two paths of sample injection, one path of sample injection being a mercury standard working solution or a to-be-detected water sample and a potassium dichromate-hydrochloric acid solution,the other path of sample injection being a KBH4 solution, and the two paths of sample injection being performed at the same time and being mutually converged. Compared with the prior art, the method is advantaged in that the standard solution is very stable and can be stored for a long time, detection sensitivity of the method is high, the determination result is accurate and stable, and operationis convenient.

Description

technical field

[0001] The invention relates to a method for measuring mercury in sewage, in particular to a method for measuring mercury content by using a gas-phase molecular absorption spectrometer. Background technique

[0002] HNO 3 +K 2 Cr 2 o 7 Preparation, the assay medium is NH 2 OH.CL reduces excess KMnO 4 , then use SnCL 2 Reduction of divalent Hg 2+ as elemental Hg 0 The absorbance of mercury atom gas was measured. However, HNO 3 +K 2 Cr 2 o 7 medium does not guarantee divalent Hg 2+ stable, and often volatile elemental Hg 0 , so that the concentration of the standard solution gradually decreases. SnCL 2 Reduction of divalent Hg 2+ as elemental Hg 0 , only suitable for low concentration 1mol / L HCL medium, higher concentration HCL medium SnCL 2 The reduction efficiency is very low, but when the hydrochloric acid medium is lower than 1mol / L, SnCL 2 It will also be hydrolyzed and precipitated to block the liquid path, or even impossible to measur...

Examples

Embodiment 1

[0028] A method for measuring mercury content by cold atomic absorption, the measured water sample is groundwater, comprising the following steps:

[0029] (1) Dilute the mercury standard stock solution step by step with a hydrochloric acid solution with a concentration of 0.5mol / L to make a mercury standard use solution, wherein the mercury standard stock solution contains HgCl 2 , hydrochloric acid and water, wherein the concentration of hydrochloric acid is 1mol / L, Hg 2+ The concentration of the mercury standard solution is 10 μg / ml; the preparation method of the mercury standard solution is to use a micropipette to draw 50 μl, 100 μl, 150 μl, 200 μl, and 250 μl of the mercury standard stock solution into a 100ml volumetric flask respectively, and dilute it with 0.5mol / L HCl to scale and shake well to obtain a set of mercury standard solutions with different concentrations;

[0030] (2) Use AJ-3610 gas-phase molecular absorption spectrometer to detect the mercury standard ...

Embodiment 2

[0033] This embodiment only detects mercury standard stock solutions with different concentrations of hydrochloric acid. 4 After reduction, the absorption peak measured by the gas-phase molecular absorption spectrometer is 35mm; when the concentration of hydrochloric acid in the mercury standard stock solution is 0.5mol / L, the KBH 4 After reduction, the absorption peak measured by the gas-phase molecular absorption spectrometer is 34mm; when the concentration of hydrochloric acid in the mercury standard stock solution is 1mol / L, the KBH 4 After reduction, the absorption peak measured by the gas-phase molecular absorption spectrometer is 36mm; when the concentration of hydrochloric acid in the mercury standard stock solution is 5mol / L, the KBH 4 After reduction, the absorption peak measured by the gas-phase molecular absorption spectrometer is 36 mm, and the maximum error of the absorption peak is 2 mm; it shows that the method of the present invention can withstand a larger co...

technical field

[0001] The invention relates to a method for measuring mercury in sewage, in particular to a method for measuring mercury content by using a gas-phase molecular absorption spectrometer. Background technique

[0002] HNO 3 +K 2 Cr 2 o 7 Preparation, the assay medium is NH 2 OH.CL reduces excess KMnO 4 , then use SnCL 2 Reduction of divalent Hg 2+ as elemental Hg 0 The absorbance of mercury atom gas was measured. However, HNO 3 +K 2 Cr 2 o 7 medium does not guarantee divalent Hg 2+ stable, and often volatile elemental Hg 0 , so that the concentration of the standard solution gradually decreases. SnCL 2 Reduction of divalent Hg 2+ as elemental Hg 0 , only suitable for low concentration 1mol / L HCL medium, higher concentration HCL medium SnCL 2 The reduction efficiency is very low, but when the hydrochloric acid medium is lower than 1mol / L, SnCL 2 It will also be hydrolyzed and precipitated to block the liquid path, or even impossible to measur...

Examples

Embodiment 1

[0028] A method for measuring mercury content by cold atomic absorption, the measured water sample is groundwater, comprising the following steps:

[0029] (1) Dilute the mercury standard stock solution step by step with a hydrochloric acid solution with a concentration of 0.5mol / L to make a mercury standard use solution, wherein the mercury standard stock solution contains HgCl 2 , hydrochloric acid and water, wherein the concentration of hydrochloric acid is 1mol / L, Hg 2+ The concentration of the mercury standard solution is 10 μg / ml; the preparation method of the mercury standard solution is to use a micropipette to draw 50 μl, 100 μl, 150 μl, 200 μl, and 250 μl of the mercury standard stock solution into a 100ml volumetric flask respectively, and dilute it with 0.5mol / L HCl to scale and shake well to obtain a set of mercury standard solutions with different concentrations;

[0030] (2) Use AJ-3610 gas-phase molecular absorption spectrometer to detect the mercury standard ...

Embodiment 2

[0033] This embodiment only detects mercury standard stock solutions with different concentrations of hydrochloric acid. 4 After reduction, the absorption peak measured by the gas-phase molecular absorption spectrometer is 35mm; when the concentration of hydrochloric acid in the mercury standard stock solution is 0.5mol / L, the KBH 4 After reduction, the absorption peak measured by the gas-phase molecular absorption spectrometer is 34mm; when the concentration of hydrochloric acid in the mercury standard stock solution is 1mol / L, the KBH 4 After reduction, the absorption peak measured by the gas-phase molecular absorption spectrometer is 36mm; when the concentration of hydrochloric acid in the mercury standard stock solution is 5mol / L, the KBH 4 After reduction, the absorption peak measured by the gas-phase molecular absorption spectrometer is 36 mm, and the maximum error of the absorption peak is 2 mm; it shows that the method of the present invention can withstand a larger co...