Oxisolv® plus microwave — a new way for sample pretreatment and sample preparation
A new sample pretreatment procedure for water and waste water samples is presented. Complexing agents inhibit the determination of metals in instrumental analysis. These reagents often contain nitrogen or organic phosphate. During digestion with peroxodisulphate/alkali = Oxisolv® in combination with microwave heating in a closed Teflon-vessel, all N and P react to nitrate and phosphate. The resulting ions can be determined with photometric, AAS, voltammetric or other methods. NTA, EDTA, DTPA, TMT, TEA, CN− and Tetra ToruMin as complexing agents were tested. In the case of Cr, Cu, Fe, Ni and Zn higher recoveries were obtained in comparison with the DIN-method (NTA as complexing agent). Due to MnO2 precipitation for Mn no values could be found.