Determination of lead in natural herbal medicines by flame atomic absorption spectrometry with a slotted, sputtered quartz tube

Abstract

An AAS method was used for the determination of lead in natural herbal medicines. A pretreatment method of the samples, digesting the analyte with a mixed acid solution, and using a slotted quartz tube pre-sputtered with a vanadate solution were used for the determination.The reason for the increase in sensitivity and the resistance to corrosion of the tube at high temperature, were thus investigated. The results indicated that a clear sample solution was attained by the digestion method without loss of lead. The increase in sensitivity was almost three-fold. The detection limit was 8.37×10^–3 µg mL^–1(s=3). The RSD was 0.9–1.2%. The correlation coefficient using the standard additions calibration technique was better than 0.999. The recovery was 97.2–103.5%.