Is SPE Necessary for Environmental Analysis? A Quantitative Comparison of Matrix Effects from Large-Volume Injection and Solid-Phase Extraction Based Methods

Abstract

Environmental analysis by large-volume injection (LVI) was compared to solid-phase extraction (SPE) based methods using matrix effects as a quantitative indicator of analytical signal quality. LVI was performed by the direct injection of 900 μL of wastewater onto a high-performance liquid chromatography (HPLC) column while SPE-based methods utilized octadecyl silane (C18) and hydrophobic-lypophilic balance (HLB) solid phases to preconcentrate wastewater prior to analysis. Model analytes from three classes of environmental contaminants were selected for study including four estrogens (estrone, estradiol, estriol, and ethinylestradiol), eight perfluoroalkyl carboxylates (C4-C11), and five perfluoroalkyl sulfonates (C4, C6-C8, and C10). The matrix effects on analytes were assessed by two approaches (quantitatively by calculating percent matrix effects and qualitatively with postcolumn infusions) and compared across LVI- and SPE-based methods at constant (high and low) analyte-to-matrix mass ratios. The results from this study demonstrated that the LVI-based method produced analytical signals of quality similar to the two SPE-based methods. Furthermore, LVI presented a clear advantage over SPE because it was performed at lower cost, required fewer materials, involved less labor and eliminated the analyte loss associated with SPE.

Natural and synthetic estrogens in wastewater treatment plant effluent and the coastal ocean

“…The matrix effects observed in this study (see Table 1) are consistent with ion suppression reported in other studies of estrogens in wastewater matrices (Kang, Hick et al 2007;Backe and Field 2012). Notably, glucuronide conjugates exhibit severe ion suppression, which is likely the result of high concentrations of co-eluting polar interferences near the solvent front.…”

Recent development in analysis of persistent organic pollutants under the Stockholm Convention

“…Lots of determinations of perfluorinated compounds previously done by GC have shifted to LC-MS/MS because of its simplicity without the need for time-consuming GC derivatization [49][50][51][52][53][54][55][56][58][59][60][61][62][63][64][65]. C18 columns of various dimensions were previously normally employed in analyte separation.…”

“…The use of LVI in LC was further demonstrated by injecting 900 lL of untreated water sample onto a HPLC column for analyzing three classes of environmental contaminants, including PFOS [63]. The analytical signals were on a par with two off-line SPEbased methods.…”

Measuring Free, Conjugated, and Halogenated Estrogens in Secondary Treated Wastewater Effluent

“…45 The matrix effects observed in this study [2−123% (see Table 1)] are consistent with other studies of estrogen matrix effects (20−125%) in wastewater matrices. 45,51 Notably, glucuronide conjugates exhibit severe ion suppression (matrix effect of <10%), which is likely the result of high concentrations of coeluting polar interferences near the solvent front.…”