Determination of Alkyl Mercury in Solid Waste Leachate Purge and Trap/Gas Chromatography-Cold Atomic Fluorescence Method (1)

1.

This method is applicable to solid waste leachate methylmercury and ethylmercury assay containing the wall

When the sampling volume of the extract is 45 mL, the detection limits of methyl mercury and ethyl mercury are 0.

Second, the principle of the method

The extract was distilled with a distillation apparatus, and the distillate was derivatized with sodium tetrapropyl boride and measured by an alkyl mercury analyzer

3.

Unless otherwise specified, analytical reagents conforming to national standards are used for analysis, and the experimental water is newly prepared ultrapure water or distilled water

(1) Hydrochloric acid : pure superior grade

(2) Copper sulfate : analytically pure

(3) Acetic acid : pure superior grade

(4) Sodium acetate : excellent grade pure

(5) Sodium tetrapropyl boride: analytically pure

Dissolve 1.

(6) Standard solution: standard solution of methylmercury and ethylmercury, ρ=1.

(7) Concentrated sulfuric acid: pure superior grade

(8) Concentrated nitric acid: pure superior grade

(9) Extractant: Add a mixture of concentrated sulfuric acid and concentrated nitric acid with a mass ratio of 2:1 to ultrapure water (about 2 drops of 1L water) to make the pH 3.

Four, instruments and equipment

(1) Alkyl mercury analyzer: It consists of a purge and trap system, a gas chromatograph, a thermal cracking system, and a cold atomic fluorescence spectrometer
.

(2) Distillation instrument: fraction collection device with ice bath
.

(3) Flip the oscillator
.

Five, pre-treatment

(1) Preparation of leaching solution

"Semi-Volatile Organic Compound Analysis Technology-Preparation of Sulfuric Acid and Nitric Acid from Leachate"

(2) Steaming letter

Accurately measure 45mL pure water (or sample, need to add 0.
4% HC1) in a distillation flask, add 100mL saturated CuSO ₄ solution, add 4.
4mL ultrapure water and 0.
6mL acetic acid/sodium acetate buffer solution with pH 6.
0 to the receiving flask ( 2mol/L), distill at 125°C for 3.
5~4h, distill out about 80% of the distillate (35~36mL), the distillate receiving flask should be placed in a water tank with an ice bath
.

(3) Derivative

Pour all the distillate into a 42 mL sample bottle, then add 50 μm of sodium tetrapropyl boride for derivatization, and analyze it on the machine after 20 minutes
.

Related links: Semi-volatile organic compounds analysis technology-leaching solution preparation sulfuric acid and nitric acid method