Leistungsvergleich von hocheffektiven Zerstäubern mit thermischer Abscheidung der Matrix für die Analytik korrosiver Proben im Halbmikromaßstab durch ICP-Massenspektrometrie

Comparison of Nebulizer Efficiencies with Thermal Trace-Matrix-Separation for the Analysis of Corrosive Samples by ICP-MS on the Semi-Micro-Scale New, highly efficient aerosole generating techniques such as ultrasonic nebulization (USN), hydraulic high pressure nebulization (HHPN) and Meinhard high efficiency nebulization (HEN) are adapted for the on-line analysis of corrosive samples by ICP-MS. Nebulization efficiencies range from 10 to 60%. A desolvation and condensation assembly is described. It allows on-line thermal trace-matrix separation and ensures reduction of all major acid components (HF, HCl, HNO₃,H₂SO₄, H₃PO₄) and of methanol by 90 to 98%. Non-metals (B, Si, Se, Br, I) are washed out and could not be analyzed in the ng/g range. For 68 other analytes recoveries are 95%. The analyte-matrix ratio is increased by a factor of 5 to 25 and detection limits improved by a factor of 2 to 20. Most polyatomic interferences are reduced. Using this system, HPLC, IC, and other trace-matrix separation techniques developed for ICP-AES can, in many cases, be directly applied to ICP-MS. The selective condensation of acids avoids evaporation and its risk of contamination. The entire assembly fits into the torch box of the VG Plamaquad 2+. The system requires sample volumes of less than 1 mL, which allows applications of semi-micro techniques. The total improvement of the detection limits amounts to a factor of 5 to 100 in the ng-range. All results are compared to standard nebulizers and FIA.