Uncertainty in the quantification of pentachlorophenol in wood processing wastewaters by SPME-GC-MS

Abstract

Pentachlorophenol is a trace contaminant with toxicological effects in environment. When dealing with the analysis and quantification of trace amounts in complex matrices, procedures such as extraction/pre-concentration are often needed and chromatographic determination are often operated close to the limit of detection, which contribute to the increase of the uncertainty of the measurement. This matter is of crucial importance when the results obtained approach the legal limits and is frequently ignored in scientific work. The aim of this study was the estimation of the global uncertainty associated to the determination of pentachlorophenol (PCP) in aqueous samples, by gas chromatography with mass spectrometric detection (GC-MS), after solid-phase microextraction (SPME). It was concluded that, while in the range of 5 to 40 μg/L the uncertainty did not exceed 20%, in the vicinity of the limit of detection (0.75 μg/L) it raised up to 64%.