Atomic Fluorescence Method of Soil Mercury (2)

(5) Analysis steps

1.

Weigh 0.

2.

Accurately pipette 0.

3.

Adjust the instrument to the best working conditions, and measure the fluorescence intensity of each point in the standard series (the calibration curve is the calibration curve drawn by the fluorescence intensity after subtracting the standard blank against the mass concentration) under the drive of the reducing agent and the carrier liquid, and then determine Sample blank, the fluorescence intensity of the sample

(6) Result expression and calculation

The total mercury w of the soil sample is expressed in milligrams per kilogram (mg/kg), and the results of repeated tests are expressed as the arithmetic average value, with three significant figures reserved

In the formula, p——the mass concentration of mercury element obtained from the calibration curve, ng/mL;

p _o ——measured mass concentration of reagent blank solution, ng/mL;

V——The constant volume of the sample after digestion, mL;

m—the mass of the sample, g;

wH ₂ O-- soil moisture;

1000——The coefficient for converting "ng" to "ug"

(7) Quality assurance and quality control

(1) Prepare at least 2 blank solutions for each batch of samples

(2) For the measured value of the standard substance of total mercury in the soil, the absolute value of the relative error shall not exceed 5%

(3) Under repeated conditions, the relative deviation of the two independent measurement results obtained shall not exceed 12%

(8) Matters needing attention

(1) During the operation, pay attention to checking the reagent blanks of the whole procedure.

(2) The nitric acid-hydrochloric acid digestion system not only decomposes a large amount of organic matter in the sample due to its strong oxidizing ability, but also can extract various inorganic forms of mercury

(3) Due to the influence of environmental factors and the limitation of instrument stability, a calibration curve must be drawn during the determination of each batch of samples

(4) After the sample is digested, the preservation solution is usually added and the diluent is used to make the volume constant to prevent the loss of mercury

Related Links: Atomic Fluorescence Method of Soil Mercury (1)