Comparison of four methods for digesting food samples for determination of trace levels of cadmium by flameless atomic absorption spectrophotometry.
We compared 4 digestion procedures, namely, sulfuric-nitric acid in an open flask, nitric acid under pressure, sulfuric-nitric acid with refluxing, and nitric-hydrochloric-peroxide with refluxing, for the determination of cadmium by flameless atomic absorption spectrophotometry in 3 foodstuffs: rice, beef, and cream cheese. The foodstuffs were homogenized and divided into several batches for analysis. The results were evaluated using a 2-way cross analysis of variance. The study revealed that the digestion procedure was a highly significant factor (P less than 10(-4] in the analysis of the 3 foods; whereas the nature of the foodstuffs was not significant for rice and meat and only slightly significant (P less than 10(-2] for cream cheese. When the foodstuffs were spiked with a known amount of cadmium, we observed a loss of the metal when the sulfuric-nitric acid procedure in an open flask and the nitric-hydrochloric-peroxide digestion procedure were used. Taken together, the results of the present study indicate that the choice of the reagents used for digestion of foodstuffs is a crucial factor for cadmium determination by flameless atomic absorption spectrophotometry.
Cabanis
M T
MT
Laboratory of Analytical Chemistry and Industrial Physics, Faculty of Pharmacy, Montpellier, France.
Cassanas
G
G
Cabanis
J C
JC
Brun
S
S
D000818:Animals; D002104:Cadmium / Q000032:analysis*; D002417:Cattle; D002611:Cheese / Q000032:analysis; D005504:Food Analysis; D007202:Indicators and Reagents; D008460:Meat / Q000032:analysis; D012275:Oryza / Q000032:analysis; D013054:Spectrophotometry, Atomic; D013696:Temperature
D007202:Indicators and Reagents; D002104:Cadmium