Optimization of the liquid–liquid extraction method and low temperature purification (LLE–LTP) for pesticide residue analysis in honey samples by gas chromatography

Determination of carbamates in beverages by liquid-liquid extraction with low temperature partitioning and liquid chromatography

“…It can be observed in Figures 2a and 3a that the volume increase of acetonitrile from 2 to 4 mL caused an increase of approximately 21% in efficiency of pesticide extraction for the three carbamates in the two beverages studied. In the LLE-LTP technique, it was observed in this study, as well as in similar studies, 64,71,73,74 that a sample to solvent extractor volume of 1:2 (v/v) facilitated the migration of the solutes to the organic phase, independent of the matrix and class of pesticides studied. …”

“…Recently, SE-LTP (liquid-liquid extraction or solid-liquid extraction with low temperature partitioning) has emerged as an alternative for pesticide extraction in water, 64,71 milk, 72,73 honey, 74 tomato, 75 fish, 76 meat and fatty matrices, 77 virgin olive oil 78,79 and butter. 80 One modification for this technique was proposed for quantification of 15 sulfonamides in porcine liver 61 and four benzodiazepines in human urine.…”

“…81 The method consists of the addition of small portions of acetonitrile to a given sample, which is then placed in a freezer at −20 °C for a period of time. The aqueous phase is iced [73][74][75] or more recently, just refrigerated 64 to separate the phases. The analytes preferentially migrate into the organic phase, which is isolated and subsequently analyzed.…”

“…Therefore, the solvent extraction with low temperature partitioning [74][75][76][77][78][79][80][81] (SE-LTP) is promising for the field of analytical chemistry since this technique presents some advantages in relation to other extraction techniques, such as practicability, reduced number of steps and low consumption of organic solvents, as well as being reliable and selective. …”

Organophosphorus Pesticides Analysis

“…Other methods aimed to ensure a high sensitivity of the determination, in concert with the reliable sample preparation technique, apart of the mentioned above, are: gas chromatography with nitrogen-phosphorus detection (Fenoll et al, 2007;Georgakopoulos et al, 2009;Pagliuca et al, 2005;Ravelo-Pérez et al, 2008), gas chromatography with flame thermionic detection (Tsoutsi et al, 2006), gas chromatography with electron capture detection (Chai & Tan, 2009;Guardia-Rubio et al, 2007;Ibrahim et al, 2010;Pinho et al, www.intechopen.com 2010; Ramos et al, 2009), gas chromatography with flame photometric detection (Ahmadi et al, 2006;Wang & Du, 2010;Xiao et al, 2006;Zhao et al, 2011), gas chromatography with flame ionization detection (Pinheiro, & Andrade, 2009), liquid chromatography with electrochemical flow detection (Trojanowicz, 2010), liquid chromatography with UV detection (Buonasera et al, 2009), high performance liquid chromatography with UV detection (Zhu et al, 2007), high performance liquid chromatography with fluorimetric detection (Pérez-Ruiz et al, 2005), and high performance liquid chromatography with diode array detection (Wu et al, 2010). Relevant data collected for the period 2010-2011, revealing the analytical performances of some selected chromatographic methods are summarized in Table 3.…”