Development, validation and application of a methodology based on solid-phase micro extraction followed by gas chromatography coupled to mass spectrometry (SPME/GC–MS) for the determination of pesticide residues in mangoes

Abstract

A method was developed for the simultaneous analysis of 14 pesticide residues (clofentezine, carbofuran, diazinon, methyl parathion, malathion, fenthion, thiabendazole, imazalil, bifenthrin, permethrin, prochloraz, pyraclostrobin, difenoconazole and azoxystrobin) in mango fruit, based on solid-phase micro extraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS). Different parameters of the method were evaluated, such as fiber type, extraction mode (direct immersion and headspace), temperature, extraction and desorption times, stirring velocities and ionic strength. The best results were obtained using polyacrylate fiber and direct immersion mode at 50 degrees C for 30 min, along with stirring at 250 rpm and desorption for 5 min at 280 degrees C. The method was validated using mango samples spiked with pesticides at concentration levels ranging from 33.3 to 333.3 microg kg(-1). The average recoveries (n=3) for the lowest concentration level ranged from 71.6 to 117.5%, with relative standard deviations between 3.1 and 12.3%, respectively. Detection and quantification limits ranged from 1.0 to 3.3 microg kg(-1) and from 3.33 to 33.33 microg kg(-1), respectively. The optimized method was then applied to 16 locally purchased mango samples, all of them containing the pesticides bifenthrin and azoxystrobin in concentrations of 18.3-57.4 and 12.7-55.8 microg kg(-1), respectively, although these values were below the MRL established by Brazilian legislation. The method proved to be selective, sensitive, and with good precision and recovery rates, presenting LOQ below the MRL admitted by Brazilian legislation.

Use of SPME and Chemometrics in Method Development for Food and Environmental Analysis of Pesticide Residues

“…Derivitization can be applied before, during or after extraction, post derivitization only aids chromatographic separation and detection [37] e.g., dilution, centrifugation, use of organic solvent, pre-concentration [38][39][40][41][42][43]. This is done to prevent irreversible absorption of large molecules from the sample matrix, Current trends in SPME coatings [15].…”

In-house method validation and occurrence of alpha-, beta-endosulfan, endosulfan sulphate, lambda-cyhalothrin, procymidone and trifluralin residues in strawberry

“…Although there are several detection systems available, the electron capture detector (ECD) is suitable for their quantitative analysis due to the presence of one or more halogens in the organohalogen molecules (CHEN;WANG, 1996;COLUMÉ et al, 2001;LENTZA-RIZOS;AVRAMIDES;VISI, 2001;VIEIRA;NEVES;QUEIROZ, 2007;ZAWIYAH et al, 2007;PINHO et al, 2009;MENEZES;SANTOS;PEREIRA, 2010).…”

“…Adopting the same criterion, Cardoso et al (2010) established LD for tomato samples: 0.006 mg/kg for chlorothalonil and procymidone; 0.005 mg/kg for HCH and fenitrothion; and 0.004 mg/kg for chlorpyrifos. Menezes, Santos and Pereira (2010) determined LD for pesticide residues in sleeve samples in the range from 0.001 mg/kg to 0.033 mg/kg, but they did not describe how the limits were calculated.…”

Desenvolvimento e aplicação de uma nova fase para extração por sorção em barra de agitação (SBSE)

“…Polidimetilsiloxano ( Atualmente, a SPME em conjunto com a cromatografia gasosa e líquida tem sido aplicada com êxito em diversas áreas, como a forense [18,19], alimentícia [20][21][22][23][24][25][26][27], farmacêutica [28,29] e ambiental [30][31][32][33][34]. Entretanto, a principal limitação da técnica SPME é a pequena quantidade de fase polimérica presente no revestimento da fibra.…”

“…O desenvolvimento de barras SBSE de PDMS modificado com carvão ativado teve como base o sucesso do emprego da fibra mista PDMS/Carboxen de SPME comercializada pela Supelco em diversos trabalhos [23,[91][92][93]. Adicionalmente, somente barra SBSE de PDMS são disponíveis comercialmentes.…”