Chemometric Study and Optimization of Headspace Solid-Phase Microextraction Parameters for the Determination of Multiclass Pesticide Residues in Processed Cocoa from Nigeria Using Gas Chromatography/Mass Spectrometry

2014 ◽  
Vol 97 (4) ◽  
pp. 1007-1011 ◽  
Author(s):  
Lukman Bola Abdulra'uf ◽  
Guan Huat Tan
Keyword(s):  
Sample Preparation ◽  
Pesticide Residues ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Internal Standard ◽  
Calibration Method ◽  
Gas Chromatography Mass Spectrometry ◽  
Design Matrix ◽  
Analytical Methodology ◽  
Cocoa Powder

Abstract Solid-phase microextraction (SPME) is a solventless sample preparation method that combines sample preparation, isolation, concentration, and enrichment into one step. A simple and effective method coupling headspace-SPME to GC/MS was developed for the analysis of chlorpyrifos, fenitrothion, endosulfan I, and endosulfan II pesticide residues in cocoa powder. In this study, multivariate strategy was used to determine the significance of the factors affecting the SPME of the pesticides using a Plackett-Burman design, and the significant factors were optimized using central composite design. The analytes were extracted with 100 μm polydimethylsiloxane fibers according to the factorial design matrix and desorbed into a GC/MS instrument. The developed method was applied for the analysis of a cocoa powder sample, and it exhibited good figures of merit for the analytical methodology. Using the optimized conditions, the linearity ranged from 2.5 to 500 μg/kg (R2 > 0.99) using an internal standard calibration method, and the average recoveries were between 75 and 95%, with RSD values between 3.8 and 9.7%.

Recent achievements and applications of solid – phase microextraction in pesticide residues analysis in food

2015 ◽  
Vol 8 (2) ◽  
pp. 178-190
Author(s):  
Mária Andraščíková ◽  
Svetlana Hrouzková
Keyword(s):  
Sample Preparation ◽  
Pesticide Residues ◽  
Solid Phase Microextraction ◽  
Method Development ◽  
Solid Phase ◽  
Current Trend ◽  
Preparation Methods ◽  
Pesticides Residues ◽  
Fiber Coating ◽  
Food Matrices

Abstract The current trend in sample preparation methods is devoted to minimizing or eliminating the volume of extractive solvent. In this review, the focus on solid phase microextraction (SPME) as a solvent free sample preparation method for the isolation of pesticides residues in different food matrices is given. To achieve satisfactory extraction efficiency, selection of the fiber coating is an important step in the method development. Here, recent trends in new supporting materials and new fiber coatings development are discussed. Finally, applicability of SPME for the pesticide residues analysis in various food matrices using mainly chromatographic methods is also reviewed.

scholarly journals Application of Multivariate Data Analysis to the Determination of Multiclass Pesticide Residues in Fruits and Vegetables using Headspace Solid-Phase Microextraction Gas Chromatography-Mass Spectrometry

2020 ◽  
Vol 45 (6) ◽  
Author(s):  
L. B. Abdulra’uf ◽  
A. Lawal
Keyword(s):  
Mass Spectrometry ◽  
Central Composite Design ◽  
Pesticide Residues ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Statistical Software ◽  
Central Composite ◽  
Significant Factors

Design of experiment (DOE) was employed to develop a headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS) method for multiresidue analysis. The significance of SPME parameters was determined using Placket-Burman (P-B) design. The main effect and the interaction effect of the significant factors were also determined followed by the optimization of the significant factors using central composite design (CCD). A Minitab® statistical software was used to generate both the 27-4 Placket-Burman and the central composite design matrix. The same statistical software was also employed in the determination of the optimum level of the significant parameters using surface response optimizer and desirability surface plot. The most significant factors are: extraction temperature (90%), extraction time (80%), the pH and stirring rate (50% and 60% respectively). The optimum parameters are: Temperature, 62 °C; time, 34 min; NaCl, 10%; stirring, 350rpm; pH, 6. The figures of merit of analytical methodologies was determined using an internal standard calibration method. The linearity of the developed method ranges from 1- 500 µg/kg and correlation coefficient (R2) greater than 0.99. The average recovery was found between 74 – 115% and relative standard deviation ranges from 1.1 – 14%. The developed method was used to analyze 14 multiclass pesticide residues in two fruit (pear and grape) and two vegetable (lettuce and broccoli) samples, and the method was found to be satisfactory with LOD between 0.17 – 7.34 µg/kg and LOQ ranges from 0.55 – 24.50 µg/kg. Keyword: Design of experiment (DOE), solid phase microextraction, response surface optimizer, pesticide residues, Central composite Design

scholarly journals A multi internal standard calibration approach for the automated and robust analysis of wine volatiles by headspace Solid Phase Microextraction and further Gas Chromatography-Mass Spectrometry

1970 ◽  
pp. 34
Author(s):  
P. Herrero ◽  
J. Zapata ◽  
J. Cacho ◽  
Vicente Ferreira
Keyword(s):  
Volatile Compounds ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Relative Weight ◽  
Experimental Parameter ◽  
Internal Standard ◽  
Partial Least Square ◽  
Least Square ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Constituents

Head space solid phase microextraction (HS-SPME) is a solvent-free technique that allows an almost complete automatization and getting amazing sensitivities. The hidden risk of SPME lies in the fact that as the amount of analyte extracted is very low; it is extremely sensitive to any experimental parameter that may affect the liquid-gas and gas-solid distribution coefficients. Our aims are to measure the relative weight of these factors on the lack of accuracy, and to design a robust calibration system able to avoid or limit their effects.For the first goal, synthetic but real-like wines containing a fixed amount of selected analytes (70) and variable amounts of ethanol, non-volatile constituents and major volatile constituents were prepared following a 3-Factor complete Factorial design. The study of the relevance of the Factors carried out by analysis of variance (ANOVA) and by Principal Component Analysis revealed that the levels of major volatile constituents affected the extraction of most analytes, while ethanol and matrix affected particularly low volatile compounds. Lipophilic esters are most influenced by major volatile compounds, while acids, phenols and lactones are affected by the non-volatile matrix.13 different internal standard compounds belonging to different chemical classes were used in the calibration experiment. This was similar to the aforementioned experiment, but including as well 5 different concentration levels. In 29 out of 65 cases, a single internal standard provided a robust calibration guaranteeing an accuracy better than 10%, while in others a Partial Least Square Regression analysis was run in order to find a model able to provide maxima accuracy. Satisfactory models in terms of precision, linearity and recovery could be built for 30 other compounds, so that the method can quantify up to 59 relevant wine volatile compounds.

scholarly journals Determination of atrazine, acetochlor, clomazone, pendimethalin and oxyfluorfen in soil by a solid phase microextraction method

2008 ◽  
Vol 23 (4) ◽  
pp. 265-271 ◽  
Author(s):  
Rada Djurovic ◽  
Jelena Gajic-Umiljendic ◽  
Tijana Djordjevic
Keyword(s):  
Sample Preparation ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Soil Samples ◽  
Extraction Time ◽  
Gas Chromatography Mass Spectrometry ◽  
Optimum Number ◽  
Extraction Solvent ◽  
Relative Standard

A solid phase microextraction (SPME) method for simultaneous determination of atrazine, acetochlor, clomazone, pendimethalin and oxyfluorfen in soil samples was developed. The method is based on a combination of conventional liquid-solid procedure and a following SPME determination of the selected pesticides. Initially, various microextraction conditions, such as the fibre type, desorption temperature and time, extraction time and NaCl content, were investigated and optimized. Then, extraction efficiencies of several solvents (water, hexane, acetonitrile, acetone and methanol) and the optimum number of extraction steps within the sample preparation step were optimized. According to the results obtained in these two sets of experiments, two successive extractions with methanol as the extraction solvent were the optimal sample preparation procedure, while the following conditions were found to be most efficient for SPME measurements: 100 ?m PDMS fibre, desorption for 7 min at 2700C, 30 min extraction time and 5% NaCl content (w/v). Detection and quantification were done by gas chromatography-mass spectrometry (GC/MS). Relative standard deviation (RSD) values for multiple analysis of soil samples fortified at 30 ?g/kg of each pesticide were below 19%. Limits of detection (LOD) for all the compounds studied were less than 2 ?g/kg.

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