Spectral interferences of oxygen and water molecules in hydride generation atomic absorption spectrometry with quartz atomizers: Comparison of preconcentration and on-line atomization modes for As and Se determination

Absorption by molecular oxygen and gaseous water in the vicinity of As 193.7 nm and Se 196.0 nm analytical lines in quartz atomizers was studied by both line source atomic absorption spectrometry and high-resolution continuum source absorption spectrometry. Oxygen absorption has a structured spectrum whereas water has a pseudo-continuum structure in the studied range. The influence of relevant experimental parameters such as atomizer temperature, carrier gas flow rate, and oxygen/water concentration on absorption by oxygen/water molecules was investigated. Effect of molecular oxygen and water absorption on background correction and thus their influence on determination of As and Se by hydride generation atomic absorption spectrometry is discussed comparing two modes of operation: (i) conventional mode of hydride generation in absence of preconcentration and (ii) preconcentration (trapping) mode.