Abstract: Flow-injection anal. (FIA), well known for high sampling rates and good precision, is coupled with AAS. The sample capillary tube of the injection valve is replaced by a column filled with Chelex-100 ion exchanger. In the sample insert position of the valve, heavy metals are retained by the ion-exchange column. After changing the position of the valve, HNO3 (2 mol/L) elutes the heavy metal ions directly into the atomic absorption spectrometer. The various parameters, such as, flow rate, volume of enrichment, inner diameter of column, and amt. of Chelex-100 are optimized. To analyze at least 4 samples at a time, a small plastic cylinder-type device is used, which contains 6 microcolumns. The enrichment takes place in 4 microcolumns, and, at the same time, heavy metals are eluted by HNO3 from one column and the exchange resin of another column is regenerated. Thus, the device developed allows 34 samples/h to be analyzed, and sensitivity is improved 100-fold. (SFS)

Abstract: Trace metals were determined in natural waters by inductively coupled plasma atomic emission spectroscopy (ICP-AES) after pre-concentration by ion exchange or solvent extraction Chelex 100 [11139-85-8] gave better recoveries of Mn, Co, Ni, Cu, Zn, Cd, and Pb than Amberlite IR 120 [9002-23-7] or 8-hydroxyquinoline [148-24-3] immobilized on SiO2. However, CHCl3 extraction with 4-ethyl-1,2,4-triazole [43183-55-7]/Na diethyldithiocarbamate (I) [148-18-5] or ammonium pyrrolidinedithiocarbamate [5108-96-3]/I gave better results. (SFS)