On-line microwave sample pre-treatment for hydride generation and cold vapour atomic absorption spectrometry. Part 1. The manifold

Abstract

An analytical system for automated on-line pre-treatment of liquid samples in a microwave oven for flow injection cold vapour and hydride generation atomic absorption spectrometry has been designed and evaluated. The system is based on a focused microwave oven and a new manifold with two coils. A reaction coil and a ballast-load coil are placed and oriented within the digestor in a manner providing a reliable long-term operation and increased reaction time. Samples are mixed with an appropriate oxidation reagent and loaded on an autosampler; all further operations of sample uptake, digestion, measurement, calibration and data processing are performed automatically with a sample throughput rate of 20–40 h^–1. For the determination of mercury at ng l^–1 levels using amalgamation the sample throughput decreased to 7–20 h^–1. Introducing hot sample digests into the mercury/hydride system resulted in an increased sensitivity, particularly for peak height absorbance.