Trace Elements Detection in Urine by Atomic Absorption Spectroscopy

A technique has been developed to minimize matrix effects in urine for the estimation of trace elements by atomic absorption spectrophotometer using Flame or electro thermal atomization. The matrix and pH effects are known to change the absorption. This study may be useful for the determination of trace elements in the absence of standard/certified reference materials of urine. Our interest was the determination of trace elements in urine. For this purpose a standard urine solution was made up for the estimation of elements. At least 3-5 standard calibration curves were taken for each element. Percentage recoveries were also determined and found satisfactory. The following percentage recoveries for different elements were found; Ca (101.5 %), Mg (102.9 %), Fe (101.6 %), Zn (102.8 %), Cu (99.05 %), Cr (100.6 %) and for Ni (105.3 %).The same elements in aqueous standards were also determined against the above calibration curves to see if they could be used instead of the stock standards. The observed concentration of aqueous standards was found to be different from actual values except copper, e.g. 4.0 µg/ ml Ca was found to be 4.67, 0.30 µg/ ml Mg was 0.32, 0.40 µg/ ml Fe was 0.47, 0.50 µg/ ml Zn was 0.52, 40 ng/ mg Cr was 39.15 and 80 ng/ ml Ni was found 98.76.  No difference between the actual and observed values of copper was found. Values of observed aqueous standards may be taken as standard concentration against which respective elements can be estimated.

SHERAZ SHAFIQ ,S.ARIF KAZMI ,KHAULA SHIRIN ,