Determination of Trace Elements in Manganese Salts after Preliminary Matrix Separation

Abstract

The analytical procedure for trace elements (Co, Cr, Cu, Fe, Pb and Zn) determination in
various manganese salts (manganese sulfate, manganese chloride) is described. Preliminary
separation of matrix element is based on the different kinetics of reextraction of dithiocarbamate
complexes of the trace elements and manganese. Analytical procedure consists of following
steps: simultaneous extraction of dithiocarbamate complexes of analytes and matrix element in
isobutylmethyl ketone (IBMK), reextraction of manganese dithiocarbamate in aqueous phase
and FAAS or ETAAS measurement of trace elements in the organic phase. The method is
adapted also for ICP-AES measurements by using the second step of reextraction of the trace
analytes (after manganese reextraction) in 4 mol L
-1 HNO3. Several parameters which are the
most important for quantitative separation of matrix element without losses of trace elements
were optimized by using model experiments. Optimal instrumental parameters for ETAAS/FAAS
measurements in IBMK are presented. The accuracy and precision of the proposed analytical
procedure was verified by the method of standard additions and by comparative analysis using
routine ETAAS after sample dissolution in H2O. Detection limits achieved are 0.01 μg g
-1 for Co,
Cr, Cu (ETAAS determination) and Zn (FAAS determination) and 0.02 μg g
-1
for Fe (ETAAS
determination) and Pb (ETAAS determination). Relative standard deviation varied in the range
from 2 to 12% for all studied elements at levels of content from 0.04 to 1 μg g
-1