US EPA

4119817 

Journal Article 

Performance of Diammonium Hydrogen Phosphate-Nitric Acid-Graphite Furnace Atomic Absorption Spectrometric Method for Urinary Cadmium Determination 

Subramanian, KS 

1987 

Yes 

Clinical Chemistry
ISSN: 0009-9147
EISSN: 1530-8561 

NIOSH/00171808 

33 

7 

The results of validation studies of a newly developed procedure for determining cadmium (7440439) in urine samples were summarized. The method involved processing the samples in a matrix with diammonium-hydrogen-phosphate and nitric-acid, followed by graphite furnace atomic absorption spectrometric analysis. When validated with 38 reference urine samples containing 1 to 21 nanograms per milliliter cadmium, 25 samples (66 percent) came within 15 percent of the known values and 36 samples (95 percent) came within 30 percent of the known values. In other laboratories using different methods, 79 percent of the samples came within 15 percent and 84 percent came within 30 percent of the reference values. The regression curves of the data were linear and had a mean correlation coefficient of 0.9762. The correlation coefficients of the regression lines for two alternative methods, dilution of the sample with water or acid digestion of the sample followed by dilution with water, were 0.9473 and 0.9771, respectively. The author concludes that the dilution method is faster and simpler, but less accurate than the new method. The acid digestion method has comparable accuracy but is slower and more labor intensive than the new method. The new method can be considered a reliable technique for determining cadmium in urine.