Potential of microbore HPLC within a multiresidue method for the trace analysis of plant-protective substancees in water

摘要

The performance of microbore HPLC as a "mea- surement channel" within a true multiclass/multiresidue method for monitoring plant protectants in raw and potable water is demonstrated. The method has a modular design and consists of a non-selective sampling and preparation line generating 250 ~L of an "extract" from a 100-mL wa- ter sample; this extract can be introduced to up to four measurement channels, as required by the analytical task. The microbore HPLC channel can be used to quantify 34 plant protectants in the 0.1 ~g L -I concentration range by use of diode-array detection at seven different wavelengths. A solvent change is necessary to link sample preparation to microbore HPLC; this uses 50 ~L of the "extract" and is accomplished directly in an autosampler vial. Perfor- mance characteristics were evaluated for tap water spiked at 0.2 ~g L -1. Average recoveries were between 65 and 100% and method detection limits were 0.07 ~g L -lor better. The ability to provide comparable and accurate re- sults was proven by participation in an interlaboratory comparison trial. The procedure for preparing microbore columns from 750 ~m i.d. PEEK tubing is described in detail to enable the reader to prepare his own columns. The reproducibility of this preparation procedure was proven by an analysis-of-variance test.