1.5.2 Operator errors 13 1.6 Applications 14 1.6.1 Clinical, food and organic samples 14 1.6.2 Petrochemicals 14 1.6.3 Agricultural samples 15 1.6.4 Waters and effluents 15 1.6.5 Geochemical and mineralogical samples 15 1.6.6 Metals 15