Slurry Sampling Graphite Furnace Atomic Absorption Spectrometry Determination Of Cadmium In Rice

Slurry sampling,both with the advantage of liquid sampling and solid injection, appear to reduce the impact of these factors on the analysis,which in the field of elemental analysis has very broad prospects。However, due to the large amounts of organic reagents in the graphite furnace, it is easy to build up carbon deposition Interfer analysis.Based on predecessors, this paper established the new methord determinate the cadmium in rice,use colloidal palladium and magnesium nitrate as mixed Chemical Modifier, while the use of hydrogen peroxide decrease the formation of carbon deposits。The optimized of the slurry stability,acid extraction, and sample processing,is also studied。The test do some research about the combination of slurry sampling and GFFS。The major conclusion of this thesis as follows:1) When the sample particle size is between 300 to 500 mesh, the test get the better results and the suspension stability.2) Agar have the best effect own to the long time stability and uniform sample distribution. the effection of acid is also studied,the research show that the 1%HNO3 promote the extraction of the Cd3) Use ultrasonic bath dispersing the sample to prevent sample particle aggregation, precipitation. It was found the slurry is almost the Homogeneous sample after ultrasonic dispersion within 3min.4) Use the colloidal palladium and magnesium nitrate (9:1) as a mixed matrix modifier, with the ashing temperature 600℃, atomization temperature of 1600 ℃ as the optimum conditions.5) In order to prevent carbon deposition impact analysis, the graphite tube was added 20μL of hydrogen peroxide, for inhibiting the formation of carbon deposition and achieved satisfactory results.6) The recovery are 89%～95%, the relative standard deviation was 3.1%(n= 6)7) Compared with traditional digestion (HNO3+HCLO4),the two methods have the same measurement results.