DEVELOPMENT OF A TECHNIQUE FOR DETERMINING CADMIUM, LEAD, ARSENIC WITH THE ETAAS METHOD IN MEDICINAL PLANT RAW MATERIALS

Electrothermal atomic absorption spectrometry (ETAAS) is one of the most well-known methods for determining trace amounts of elements in natural objects, since it is simple in instrumentation and rather cheap. It is especially promising for the pharmaceutical analysis of medicinal plant raw materials for quality control purposes. A new unified ETAAS technique for the determination of cadmium, lead and arsenic in solutions obtained after acid decomposition (with HNO3) of plant raw material under microwave heating conditions has been developed. It was shown that cadmium can be determined without a modifier, while for lead and arsenic the presence of a modifier is necessary. Inexpensive and widely available substances were proposed as modifiers: 1% solution of ascorbic acid (for lead), 1% solution of Ni(NO3)(2) (for arsenic), which were previously used in the Russian Federation exclusively in geochemical studies. The conditions for the preparation of the analysed samples are proposed. The using prospects of the developed technique for the natural substances quality control, as well as its universality for the analysis of plant raw material of various morphological groups have been demonstrated. The technique was validated in terms of specificity, accuracy, precision, repeatability, linearity, range, robustness. The technique can be recommended for determination of these ecotoxicants accumulation in wild-growing and cultivated medicinal plants.