Hu Weiyang
(Nanjing Fisheries Research Institute, Nanjing 210036, Jiangsu)
Abstract Determination of cadmium in aquaculture water by graphite furnace atomic absorption spectrometry is more sensitive and lower detection limit than flame method. However, due to the complexity of the matrix in aquaculture water, the background absorption caused by the matrix in the determination of graphite furnace atomic absorption spectrometry The interference is often more serious. Therefore, the background correction is performed with a deuterium lamp, and the detection limit of the method is verified by the US EPA method. The detection limit is 3.1 × 10-4 mg / L, which is less than 1.0 × 10-3 mg / L of the national standard method. At the same time, the recovery of high and low concentration spiked was measured. The average recovery rate of low concentration spiked was 97% and the precision was 1%. The average recovery rate of high concentration spiked was 88% and the precision was 1%. It proves that this method can fully meet the needs of the detection work.
Keywords detection limit plus standard recovery graphite furnace deuterium lamp buckle background cadmium
1 Experimental part
1.1 Instrument
1.1.1 Atomic absorption spectrophotometer Product of Beijing General Analysis General Instrument Co., Ltd., type TAS-986 (with deuterium lamp buckle background mode).
1.1.2 Adjustable electric heating plate: Dongtai Electric Appliance Factory.
1. 2 reagents
1.2.1 Cadmium standard solution: the concentration is 500mg / L;
1.2.2 Excellent grade pure HNO3, Nanjing Chemical Reagent Factory;
1.2.3 Excellent grade pure HClO4, Shanghai Jinlu Chemical Co., Ltd .;
1.2.4 0.2% HNO3, formulated with superior grade pure HNO3;
1.2.5 The experimental water is ultrapure water (resistance greater than 18 ohms).
1.3 Measurement conditions
Table 1. Instrument operating conditions
Element wavelength
/ nm lamp current / mA spectral bandwidth
/ nm injection volume
/ μL
Element lamp deuterium lamp
Cd 228.8 2.1 15.1 0.4 10
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