Analysis of primary aliphatic short-chain monoamines by LC in water samples.
Several derivatization procedures with o-phthaldialdehyde-N-acetylcysteine (OPA-NAC) were compared for a rapid analysis of primary aliphatic short-chain monoamines in water samples by HPLC using a LiChorospher analytical separation column (100RP(18)125 mm x4 mm i.d., 5mum). Both the solution and the solid-support assisted off-line derivatization on C(18) SPE cartridges were inadequate options because of beginning degradation processes of the instable isoindol derivatives during their transfer to the analytical column. This problem was precluded with the on-column or solid-support assisted on-line derivatization. In the last mentioned procedure, the derivatization took place in a Hypersil C(18) precolumn (20 mm x2.1 mm i.d., 30mum) connected with an additional preconcentration step resulting in better detection limits (0.002-0.040mugml(-1) requiring only 150mul of water sample) than in the on-column procedure (0.08-0.16mugml(-1)). The improved sample handling, the better control of parameters affecting reaction rates, the fully automation of this method with only 10min analysis time for each sample are further advantageous. The potential of the solid-support assisted on-line derivatization was outlined and applied to water samples from several sources. Recovery values near 100% were obtained.
Moliner Martinez
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Department of Analytical Chemistry, University of Valencia, Dr. Moliner 50, 46100-Burjassot, Valencia, Spain.
Molins Legua
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Campíns Falcó
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