Determination of volatile profile of citrus fruit by HS-SPME/GC-MS with oxidized NiTi fibers using two temperatures in the same extraction procedure

2013 ◽  
Vol 109 ◽  
pp. 128-133 ◽  
Author(s):  
Giuliana S. Nardini ◽  
Josias O. Merib ◽  
Adriana N. Dias ◽  
Joyce N.B. Dutra ◽  
Cristine D.S. Silveira ◽  
...  
1992 ◽  
Vol 57 (8) ◽  
pp. 1632-1638 ◽  
Author(s):  
Věra Tatarkovičová ◽  
Zdeněk Stránský

The procedure for the determination of carbamate pesticides in soil was optimized. The following factors affecting the final results were investigated: extracting solvent, extraction procedure, extract purification procedure, and soil type. Triple extraction with acetone and purification of the extract on a two-stage purification column containing an activated carbon-silica gel 1+1 mixture were found optimal. The extracts after treatment were analyzed by RP-HPLC with UV detection. The method developed allows carbamate pesticides in soil to be determined at concentrations in excess of 30 μg kg-1.


2020 ◽  
Vol 11 (1) ◽  
pp. 985-992
Author(s):  
Hymavati Muppalla ◽  
Kiranmayi Peddi

The presence of pesticide residues in primary and derived agricultural products raises serious health concerns for consumers across the globe. The aim of the present study was to assess the level of pesticide residues in Okra in India. A multi-residue method for the quantification of fifty-four pesticides in okra is described in this work. The present study employed a modified quick, easy cheap, effective rugged and safe (QuEChERS) extraction procedure followed by UHPLC-MS/MS (Ultra-High-Performance Liquid Chromatography coupled to Tandem Mass Spectrometry) analysis. Validation of the method was according to the guidelines given by European Union SANCO/12571/2013. The levels of validation were 10.0, 50.0 and 100 µg kg-1. The following parameters such as linearity, the limit of detection (LOD) (nearer to 0.005 mg kg-1) and limit of quantification (LOQ) (nearer to 0.01 mg kg-1) were set to be acceptable. The trueness of the method for 54 pesticides in all Okra commodities was between 80-110% with satisfactory repeatability and within-run reproducibility except for the pesticide residues such as Thiamethoxam and Fenamidone. The measurement of uncertainty for each of the pesticide was below 50% and was estimated to be in the range of 5.37% - 10.71%, which meets the criteria established in the SANCO/12571/2013 document (European Union, 2013). This method is concluded to be applicable for the determination of pesticide residues in Okra.


2016 ◽  
Vol 51 (4) ◽  
pp. 344-356 ◽  
Author(s):  
Hing-Biu Lee ◽  
M. Lewina Svoboda ◽  
Thomas E. Peart ◽  
Shirley Anne Smyth

A microwave-assisted extraction method for the determination of 15 alkyl, aryl, and halogenated phenols in sewage sludge and biosolids samples was developed and optimized. The effects of solvent, temperature, time, moisture content, acid, and number of extractions on the recovery of phenols were evaluated. Results indicated that extraction solvent had the greatest impact on the recovery of all phenols while pH had the largest effect on recovery of hexachlorophene and pentachlorophenol. Wet sludge samples were extracted with acetone-hexane mixture in the presence of glacial acetic acid. The extract was evaporated, acetylated by acetic anhydride and cleaned up by silica gel. For dry sludge samples, an optional procedure for the simultaneous extraction and acetylation of phenols was also proposed. Triclosan (TCS) and the alkyl and aryl phenols in sludge extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) in electron-impact mode while polyhalogenated phenols were analyzed by GC-MS in negative ion chemical ionization mode. Method detection limits were ca. 200 ng/g for nonylphenol, <25 ng/g for TCS and other alkyl and aryl phenols, and <5 ng/g for other halogenated phenols. This method has been applied to the determination of phenolic compounds in over 150 sludge and biosolids samples since 2009.


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