STATISTICAL EVALUATION AND VALIDITY OF TWO ATOMIC-ABSORPTION SPECTROMETIC TECHNIQUES FOR THE DETERMINATION OF LEAD IN TOOTHPASTE SAMPLES

Abstract

Two methods for the determination of lead in toothpaste were tested and compared. In the developed method (ETAAS), the toothpaste samples were dry-ashed with %10 magnesium nitrate and the resulting solution was injected directly into the graphite furnace using a combined platform and matrix-modification techniques for the determination of Pb in these samples. In British standard method, the toothpaste was slurred with ethanol, evaporated to dryness, dry-ashed and the resulting solution was extracted with APDC/MIBK system. The organic layer was aspirated into the FAAS. Several statistical tools were carried out for the developed method to evaluate its analytical performance (LDR, MDL, LOQ, and RSD) and ANOVA Results for the calibration graph have shown that the regression line was statistically valid. With a %95 CL there was no significant difference in mean between the two methods by applying a paired t-test. Two procedures (direct and standard additions) of the developed ETAAS method were compared and tested statistically with British standard method based on RBD using two way ANOVA. The results were revealed that all these methods have no significant difference and statistically valid.