DETERMINATION OF AMPHETAMINE AND METHAMPHETAMINE IN URINE WITH SODIUM 1,2-NAPHTHOQUINONE 4-SULFONATE USING THE H-POINT STANDARD ADDITION METHOD

The determination of amphetamine and methamphetamine in urine by the H-point standard additions method (HPSAM) is described. An extraction-spectrophotometric method for the determination of these drugs with sodium 1,2-naphthoquinone 4-sulphonate using n-hexane-ethyl acetate (1:1) as the extraction solvent is proposed. The analytes are previously extracted into n-hexane. Although their spectra are very similar and overlap, the H-point standard additions method provides good results for both amines. The applicability of the method when the total Youden blank is present is demonstrated. The relative errors found were less than 10%.