Solid waste. Determination of lead, zinc and cadmium. Flame atomic absorption spectrophotometry (1)

(1) Scope of application

This method is suitable for the detection of lead, zinc and cadmium in solid waste and solid waste leachate

(2) Method principle

After the solid waste sample or solid waste leaching solution is digested with acid, the test element in the sample is dissociated into ground state atoms in the flame atomizer.

(3) Reagents and materials

(1) Sulfuric acid , nitric acid, hydrochloric acid , hydrofluoric acid , perchloric acid , hydrogen peroxide , and lanthanum nitrate are all top grade pure

The experimental water was newly prepared deionized water

(2) Metal lead, metal zinc, and metal cadmium are all spectrally pure

(3) Nitric acid solution: 1+9, 1+99

(4) Hydrochloric acid solution: 1+1

(5) Matrix improver: lanthanum nitrate solution, [La(NO ₃ ) ₃ 6H ₂ O]

Accurately weigh 5.

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

Accurately weigh 1.

(7) Zinc standard stock solution: p=1000mg/L

Accurately weigh 1.

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

Accurately weigh 1.

(9) Lead, zinc, and cadmium standard liquid: p=100mg/L

Accurately pipette 10.
00mL each of the lead, zinc, and cadmium standard stock solutions into a 100mL volumetric flask, dilute to the mark with a nitric acid solution, and shake well
.

(10) Acetylene: The purity is higher than 99.
5%
.

(11) Air: It can be provided by an air compressor or a compressed air cylinder
.

(4) Instruments and equipment

(1) Flame atomic absorption spectrophotometer
.

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

(3) The air compressor should be equipped with water removal, oil removal and dust removal devices
.

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

(5) 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
.

(6) Analytical balance: the accuracy is 0.
1mg
.

(7) PTFE crucible: 50mL
.

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