Solid waste. Determination of lead and cadmium. Graphite furnace atomic absorption spectrophotometry (1)

(1) Scope of application

This method is suitable for the determination of lead and cadmium in solid waste samples and solid waste leachate

(2) Method principle

The solid waste sample or solid waste leachate is digested by acid, and then injected into the graphite furnace atomizer.

(3) Reagents and materials

(1) Sulfuric acid , nitric acid , hydrochloric acid , hydrofluoric acid , perchloric acid , hydrogen peroxide , and ammonium dihydrogen phosphate are class pure

(2) Metal lead and metal cadmium are spectrally pure

(3) Nitric acid solution (1+9), nitric acid solution (1+99), hydrochloric acid solution (1+1)

(4) Matrix improver: ammonium dihydrogen phosphate solution

Accurately weigh 13.

(5) Lead standard stock solution; p=1000mg/L

Accurately weigh 1.

(6) Cadmium standard stock solution: p=1000mg/L

Accurately weigh 1.

(7) Lead standard intermediate solution: p=100mg/L

Accurately pipette 10.

(8) Cadmium standard intermediate solution: p=100mg/L

Accurately pipette 10.

(9) Lead standard liquid: p=1.

Accurately pipette 1.
00 mL of the lead standard intermediate solution into a 100 mL volumetric flask, dilute to the mark with a nitric acid solution (1+99), and shake well
.
Now equipped for temporary use
.

(10) Cadmium standard liquid: p=1.
00mg/L
.

Accurately pipette 1.
00 mL of the cadmium standard intermediate solution into a 100 mL volumetric flask, dilute to the mark with a nitric acid solution (1+99), and shake well
.
Now equipped for temporary use
.

(4) Instruments and equipment

(1) Graphite furnace atomic absorption spectrophotometer with background correction function
.

Different types of graphite furnace atomic absorption spectrophotometers have different optimal measurement conditions, and the test conditions can be optimized according to the requirements of the instrument manual
.

Table 5-8 Reference measurement conditions of the instrument

(2) Lead hollow cathode lamps, cadmium hollow cathode lamps
.

(3) Electric heating plate or graphite digestion instrument: with temperature control function (temperature stable ±5℃), the maximum temperature can be set to 200℃
.

(4) Microwave digestion instrument: output power 1000～1600W
.
With programmable control function, temperature, pressure and time (heating time and holding time) can be monitored in the whole process; with safety protection function
.

(5) Analytical balance: accuracy of 0.
1mgn

(6) PTFE crucible: 50mL
.

(7) Sieve: non-metallic sieve, 100 mesh
.

(8) High-purity argon: the purity is not less than 99.
999%
.

Related Links: Atomic Absorption Spectrometry (3)