Evaluation of a new column backflushing set-up in the gas chromatographic–tandem mass spectrometric analysis of pesticide residues in dietary supplements

Inlet backflushing device for the improvement of comprehensive two dimensional gas chromatographic separations

“…This experiment utilised the pulsed splitless mode which has been previously recognised as reducing matrix effects by minimising analyte interactions with active sites within the inlet [52,57,58]. With optimal conditions established, 1 l of the lemon extract underwent a pulsed splitless injection with a pulse of 50 psi hydrogen carrier gas for 1.1 min.…”

“…The GC inlet has been recognised for some time as producing non-ideal injection bands, especially when highly concentrated samples or those with complicated matrices are evaluated [52][53][54]. It is possible that polar and/or non-volatile analytes linger within the inlet volatilising slowly and entering the column over extended time in the form of elongated bands.…”

Comparison of QuEChERS official methodologies for the analysis of pesticide residues on Colombian fruit by GC-MS

“…An Aux He line with EPC allows the pressure to be kept at the top of the column, while the flow is reversed in the first section (retention gap) thus obtaining a venting flow towards the inlet. The implementation of this last set-up was inspired by the advances of Mastovska & Wylie (2012) and calls for the determination of the minimum time that must elapse after the injection, so that the inlet pressure can turn off for the start of flow reversal in order to avoid nonvolatile matrix interferences entering the column without incurring any losses of analytes. However, the evaluation of the time in which the compounds of interest are transferred to the analytical column demands the use of a different configuration since solvent residues after venting would get into the ionisation chamber (approximately 10 −6 torr) causing permanent damage to the filament of the MS.…”

Multi-class determination of pesticides and mycotoxins in isoflavones supplements obtained from soy by liquid chromatography coupled to Orbitrap high resolution mass spectrometry

“…It is important to mention that none of these articles report the detection of toxic substances in nutraceutical products but only in the raw material. However, there are some articles that determine pesticides in dietary supplements obtained from Scutellaria baicalensis and Acacia catechu (Lee, Zahn, Trinh, Brooke, & Ma, 2008), or in ginseng and dandelion (Kowalski, Misselwitz, Thomas, & Cochran, 2011;Mastovska & Wylie, 2012), while mycotoxins have been detected in soy isoflavones (Di Mavungu et al, 2009) and in supplements from green coffee beans (Vaclavik, Vaclavikova, Begley, Krynitsky, & Rader, 2013), ginger (Whitaker, Trucksess, Weaver, & Slate, 2009), herbs (Vaclavik, Krynitsky, & Rader, 2014), wheat and oat (Vidal, Marín, Ramos, Cano, & Sanchis, 2013). These two types of toxic substances can be found in this kind of products; therefore methodologies that allow a multi-class analysis are necessary in order to ensure food safety in nutraceutical products.…”