Optimization of a Solid-Phase Extraction Method Using Centrifugation for the Determination of 16 Polycyclic Aromatic Hydrocarbons in Water

Abstract

A fast and reliable method for the determination of polycyclic aromatic hydrocarbons (PAHs) in water samples by solid-phase extraction (SPE) using centrifugation has been developed and optimized. A silica-based C18 cartridge was used; parameters affecting the extraction procedure such as type and volume of the elution solvent, breakthrough volume of the percolated water sample, drying of the sorbent, and evaporation of the elute have been studied. The innovation of this work was the examination of the use of a centrifugation technique in both the drying and elution steps. When combined with centrifugation, the volume of the elution solvent was reduced to 1 mL and the time for sorbent drying decreased also to 10 min under vacuum. Under optimal conditions, recoveries for the 16 U.S. EPA PAHs were between 70 and 85% and the relative standard deviation varied between 1 and 14%. Surrogate standard recoveries were similarly between 61 and 94% with a relative standard deviation between 2 and 15%. The simplicity of the described method, use of less of organic solvent, short procedure time, and good recoveries demonstrate the advantages of this environmentally friendly approach for routine analysis of numerous samples.

Multiresidue Method for Determination of 67 Pesticides in Water Samples Using Solid-Phase Extraction with Centrifugation and Gas Chromatography-Mass Spectrometry

“…In our work, the centrifugation technique was applied as an alternate to traditional elution, in order to reduce the volume of the elution phase required. The efficiency of this technique was proved in our previous paper [10], where recoveries obtained using a small volume of elution phase with centrifugation were comparable to those obtained with large volume of elution phase in the traditional elution. The rapid rotation of the centrifuge ensures that the adsorbent is well impregnated with the elution solvent, enabling a complete desorption of the analytes, even the strongly adsorbed, into the solvent.…”

“…The outlines of the SPE procedure used for the extraction of pesticides in water samples were described in our previous paper [10]. The Chromabond C 18 and Oasis HLB cartridges were preconditioned and activated at the beginning with 3 mL of methanol and then 3 mL of water.…”

“…The influence of the drying time (from 10 to 60 min) was investigated Chromabond C 18 and Oasis HLB cartridges, after the percolation of 500 mL of blank water fortified with the suite of pesticide compounds (50 ng each). In our previous paper [10], we have shown that the use of the centrifugation technique before vacuum drying ensures the complete remove of residual water from SPE cartridge and reduce the necessary drying time. Therefore, removing water from SPE cartridge using centrifugation technique (2500 rpm for 2 min) followed by a short time vacuum (10 min) was evaluated as well.…”

“…In our previous paper [10], we have reported a rapid and reliable method based on SPE with centrifugation for the extraction and followed by GC/MS detection for the determination of the 16 PAH identified by the US environmental protection agency (US-EPA) as priority pollutants in water samples. The focus of the present research is the development of a similar rapid multi-residue method for the analysis and ultra-trace quantification of 67 pesticides from different classes in waters.…”

Analytical Methods for Polycyclic Aromatic Hydrocarbons and their Global Trend of Distribution in Water and Sediment: A Review

“…PAHs are usually present in water samples in trace quantity, owing to their low solubility [61]. Therefore, the analytical method to use should be of high enrichment factors for the target compounds and should allow concentrating and increasing the low levels to values that can be detected using analytical instrument [20,62].…”