Determination of trihalomethanes in soil matrices by simplified quick, easy, cheap, effective, rugged and safe extraction and fast gas chromatography with electron capture detection

An LC-MS/MS Method for the Simultaneous Analysis of 380 Pesticides in Soybeans, Kidney Beans, Black Soybeans, and Mung Beans: The Effect of Bean Grinding on Incurred Residues and Partitioning

The significance of sample grinding is frequently disregarded during the development of analytical methods, which are often validated with spiked samples that may not accurately reflect incurred residues. This study investigated the particle size of ground beans as a key factor in optimizing extraction efficiency in order to develop a simple quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based modified method for identifying 380 pesticides in beans using liquid chromatography-tandem mass spectrometry. The efficacy of pesticide extraction was found to be significantly affected by particle size. With small particle sizes (>40 mesh), no supernatant was recovered after QuEChERS partitioning. Therefore, a simple modification was performed before partitioning. The modified method was validated for selective extraction of pesticides, limits of quantification, linearity, accuracy, and precision. This method is simple to implement and, therefore, useful for the analysis of pesticide residues in beans.

Trihalomethanes in water samples: Recent update on pretreatment and detection methods

Trihalomethanes (THMs) are classified as volatile organic compounds, considered to be a disinfection by-product during water disinfection process. THMs have been shown to be cytotoxic, genotoxic and mutagenic, with a risk of cancer when they contact with people directly. To protect public health and monitor water quality, it is important to monitor and measure THMs in drinking water. Therefore, it is crucial to develop fast, accurate, highly sensitivity and green analysis methods of THMs in various complicated matrices. Here, this review presents an overall summary of the current state of the pretreatment and detection methods for THMs in various sample matrices since 2005. In addition to the traditionally used pretreatment methods for THMs (such as headspace extraction, microwave-assisted extraction, liquid-liquid extraction), the new-developed methods, including solid-phase extraction, QuEChERS and different microextraction methods, have been summarized. The detection methods include gas chromatography-based methods, sensors and several other approaches. Additionally, benefits and limitations of different techniques were also discussed and compared. This study is anticipated to offer fruitful insights into the further advancement and widespread applications of pretreatment and detection technologies for THMs as well as for related substances.

Evaluation of QuEChERS sample preparation and liquid chromatography-triple-quadrupole mass spectrometry method for the determination of 109 pesticide residues in tomatoes

A multiresidue method based on modified QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of 109 selected multiclass pesticides in tomatoes. The recovery yields ranged from 77.1% to 113.2%, with repeatabilities of 4.4-19.2% and within-laboratory reproducibilities of 7.1-18.4%. The limit of detections (LODs) for target analytes in tomato extract were between 0.5 and 10.8μgkg(-1), and the limit of quantifications (LOQs) were between 1.3 and 30.4μgkg(-1). The expanded measurement uncertainty was not higher than 30% for all target analytes. The method has been successfully applied to the analysis of 345 tomato samples obtained from local markets and tomato traders. Residues of acetamiprid, azoxystrobin and triadimefon were identified and measured in 9.6% of tomato samples, ranging from 0.015 to 0.37mgkg(-1).

Ionic liquids as stationary phases in gas chromatography: determination of chlorobenzenes in soils

The present research focuses on the evaluation of different ionic liquid (IL) stationary phases in gas chromatography. The different IL columns were evaluated in terms of peak resolution (Rs) and peak symmetry for the separation of the chlorobenzenes. The determination of chlorobenzenes in soil samples by means of the optimal IL stationary phase (SLB-IL82) is proposed as an application. Soil pretreatment was based on a simplified quick, easy, cheap, effective, rugged, and safe extraction procedure and a large injection volume via a programed temperature vaporizer working in solvent vent mode. The retention time of the chlorobenzenes increased as the polarity of the IL column decreased. SLB-IL82 is the stationary phase that provides the best values as regards Rs and asymmetry factor. Soil sample blanks were spiked with the analytes before subjecting the sample to the extraction process. The existence of a matrix effect was checked and the analytical characteristics of the method were determined in a fortified garden soil sample. The method provided good linearity, good repeatability and reproducibility values, and the LODs were in the 0.1-4.7 μg/kg range. Two fortified soil samples were applied to validate the proposed methodology.

Rapid analysis of multi-pesticide residues in lotus seeds by a modified QuEChERS-based extraction and GC-ECD

A modified quick, easy, cheap, efficient, rugged and safe method (QuEChERS) coupled to gas chromatography with electron capture detector (GC-ECD) was developed for rapid extraction and simultaneous determination of 36 pesticides in lotus seeds. The extraction solvent (acetone, ethyl acetate, acetonitrile, n-hexane and n-hexane in combination with ethyl acetate) and purifying agent (neutral alumina, primary secondary amine, graphite carbon block and florisil) for QuEChERS extraction were optimized. The GC-ECD method was in-house validated in terms of linearity, selectivity, reproducibility, stability and recovery. The limits of detection (LODs) of the developed GC-ECD method for all investigated pesticides ranged from 0.01 to 3.0μgL(-1) and limits of quantification (LOQs) from 0.05 to 10.0μgL(-1). The satisfactory data demonstrated the good reproducibility and stability of the method with relative standard deviations (RSDs) lower than 15%. Recoveries for spiked lotus seed samples were from 60.84% to 119.91% with RSDs lower than 13.06%. Two out of 24 batches of lotus seeds collected in China were found to be contaminated with trans-chlordane, which were below LOQ. This is the first attempt in China using QuEChERS to GC-ECD to determine 36 major pesticides with differences in physio-chemical properties in lotus seeds. The method described here was found to be practicable in the routine residue analysis of pesticides in lotus seeds.

Evaluation of a modified QuEChERS extraction of multiple classes of pesticides from a rice paddy soil by LC-APCI-MS/MS

A new method for the determination of clomazone, fipronil, tebuconazole, propiconazole, and azoxystrobin in samples of rice paddy soil is presented. The extraction of the pesticides from soil samples was performed by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. Some extraction conditions such as salt addition, sample acidification, use of buffer, and cleanup step were evaluated. The optimized method dealt with a single extraction of the compounds under study with acidified acetonitrile, followed by the addition of MgSO(4) and NaCl prior to the final determination by liquid chromatography-atmospheric chemical pressure ionization-tandem mass spectrometry. Validation studies were carried out in soil samples. Recoveries of the spiked samples ranged between 70.3 and 120% with relative standard deviation lower than 18.2%. The limits of quantification were between 10 and 50 μg kg(-1). The method was applied to the analysis of real samples of soils where rice is cultivated.

Simultaneous multiresidue analysis of 41 pesticide residues in cooked foodstuff using QuEChERS: Comparison with classical method

The principal objective of this study was to develop a simple multiresidue method involving a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method for the identification and quantification of 41 pesticide residues in cooked foodstuffs including cooked potatoes, radishes, and rice using GC-μECD. The analytes were subsequently confirmed via GC-MS. The results were then compared using the classical method established by the KFDA. The quantitation of individual pesticides was based on matrix-matched calibration curves with a correlation coefficient in excess of 0.993 for the 41 pesticides selected herein. Using QuEChERS, the mean recoveries ranged between 68.6 and 130.0% for the majority of the tested pesticides; however, the classical method exhibited low recoveries for dichlofluanid, tetraconazole, oxadixyl, fenbuconazloe, and paclobutrazol. After QuEChERS, the LODs and LOQs ranged between 0.004 and 0.3μg/kg and 0.0125 and 1.0μg/kg, respectively. The proposed method was applied successfully to determine the residue levels in cooked foodstuffs, and none of the samples contained detectable amounts of pesticide residues.