Matrix‐induced peak enhancement of pesticides in gas chromatogrtaphy: Is there a solution?

Abstract

In this study, it is shown that calibration solutions prepared in control matrix extract can be used to compensate for matrix-induced chromatographic response enhancement observed for certain pesticides. This phenomenon is characterized by enhanced chromatographic response for certain pesticides in the presence of matrix due to reduced analyte loss during injection. Unacceptably high recoveries are seen for affected pesticides when matrix-free solutions are used for reference and calibration. The effects of matrix concentration on overall enhancement and linear response were determined. When used as reference standards for the determination of recovery, matrix-standard solutions were found to provide acceptable recoveries for pesticides subject to matrix-induced chromatographic response enhancement along with other pesticides. General guidelines are presented for using matrix-standard calibration solutions in pesticide residue analysis.

Influência dos constituintes químicos dos extratos de diferentes matrizes na resposta cromatográfica de agrotóxicos

“…[8][9][10] Também existem os procedimentos que promovem a compensação da ocorrência do efeito de matriz como a utilização de analitos protetores, [11][12][13] função de correção, 14,15 adição de padrão 16 e curva analítica preparada pela dissolução dos padrões em extratos da matriz. 17,18 Dentre os diversos métodos empregados para minimizar o efeito de matriz, a limpeza dos extratos (clean up) é o único que efetivamente elimina a causa do problema, ou seja, a remoção dos componentes da matriz. Após a extração dos analitos técnicas auxiliares são utilizadas para remoção de coextrativos (pigmentos, lipídios, carboidratos, etc.)…”

Analytical methods for water disinfection byproducts in foods and beverages

“…The brominated compounds also had low ECD responses (S:N%12:1 ) so the greater variability could be attributed, in part, to these low signals. Given that the recoveries were corrected for measured background concentrations in the food composites as well as individual foods, it is difficult to explain recoveries in excess of 130%, although matrix - induced peak enhancement, as reported for organophosphorus pesticides in milk extracts ( Erney et al, 1993( Erney et al, , 1997, could play a role. The recoveries of dichloroacetonitrile and 1,1 -dichloro -2-propanone were almost always within the 70 ±130% recovery range; chloral hydrate was well recovered from all foods tested.…”

Factors Affecting the Accurate Quantification of Pesticide Residues in Non-Fatty Matrices

“…Nowadays, the matrix effect is considered as one of the most persistent sources of uncertainty in pesticide residue analysis by increasing the level of random errors and/or introducing a systematic effect on the result . Available studies involving the analysis of various residues in different matrices (Erney et al, 1993;Erney et al, 1997;Johnson et al, 1997;Jimenez et al, 2001;Menkissoglu-Spiroudi & Fotopoulou, 2004) prove that its presence and extent depends on several parameters, most of which were previously reported. More specifically, many thermolabile compounds, containing polar structure/functional groups, quantified in low concentration (e.g., <0.1 mg/kg), are referred as "troublesome analytes" (e.g., methamidophos, acephate, captan, chlorothalonil, monocrotophos, folpet) since they are susceptible to matrix enhancement (Lee et al, 1991;Bernal et al, 1997;Hajšlová et al, 1998;Godula et al, 1999;Hajšlová & Zrostlíková, 2003;Poole, 2007).…”