Wide-Bore Capillary Gas Chromatographic Determination of Organophosphorus Pesticide Residues in Foods: Interlaboratory Trial

1994 ◽  
Vol 77 (1) ◽  
pp. 92-101
Author(s):  
Charles H Parfitt
Keyword(s):  
Pesticide Residues ◽  
Stationary Phases ◽  
Packed Column ◽  
Capillary Columns ◽  
Packed Columns ◽  
Detector Response ◽  
Official Method ◽  
Methyl Silicone ◽  
Interlaboratory Trial

Abstract Wide-Bore capillary columns are often used as alternatives to traditionally packed columns for gas chromatographic (GC) determination of pesticide residues in foods. Fused silica columns with cross-linked, bonded stationary phases are reproducible, rugged, and easy to use and are substantially more inert than their packed column equivalents. An interlaboratory trial was conducted in 5 U.S. Food and Drug Administration laboratories to determine the practicability of using isothermal wide-bore capillary GC as an alternative to the packed column GC systems used in AOAC Official Methods for determining pesticide residues in foods. Two wide-bore capillary columns with flame photometric detection were evaluated with respect to the following: linearity of detector response; repeatability of response for equal and unequal injection volumes of standard solutions; accuracy of quantitating pesticides in food extracts when the injection volumes or analyte concentrations of the standard solution and the food extract are different; recoveries of 23 pesticides from 5 fortified food extracts, calculated from both duplicate and single injections; and relative retention times. Before shipment, food extracts supplied to participants were fortified with pesticides after preparation and extraction of the foods by Official Method 985.22. The performance of wide-bore capillary columns with cross-linked bonded methyl silicone and methyl phenyl silicone stationary phases was equal or superior to that of the packed columns specified in the Official Method.

scholarly journals Statistical Analysis for Comparison of the Results Obtained by Capillary Columns and Packed Columns in the Determination of Water Yield in Smoke Condensates Analyzed in Cigarettes for the 24th Asia Collaborative Study

2020 ◽  
Vol 29 (2) ◽  
pp. 97-118
Author(s):  
Hisayuki Takahashi ◽  
Masayasu Tanaka
Keyword(s):  
Statistical Analysis ◽  
Capillary Column ◽  
Collaborative Study ◽  
Capillary Columns ◽  
Packed Columns ◽  
Water Yield ◽  
Yield Data ◽  
Repeatability And Reproducibility ◽  
Comparison Of The Results

SummaryRecently, capillary columns have been widely used in the methodology for the determination of water yields in smoke condensate, even though ISO 10362-1:1999, “Cigarettes - Determination of water in smoke condensates – Part 1: Gas chromatographic method” specifies a packed gas chromatographic column. As a result of a systematic review in 2015, ISO/TC126 decided to revise the standard to include the use of capillary columns.The goal of this study was to confirm the comparability of water yields obtained from capillary column methodology to those yields from packed columns by the statistical analysis of yield data from the 24th Asia Collaborative Study which included 86 datasets submitted by 64 laboratories. After the exclusion of outliers by Cochran’s and Grubbs’ tests, the datasets were classified by GC column type and then mean water yields, and their repeatability and reproducibility were calculated for each type of column. No significant differences were observed in water yields between capillary and packed columns. Repeatability and reproducibility of water yields using capillary column were comparable to those using packed columns as described in ISO 10362-1:1999. From these results, it was confirmed that the capillary columns are an appropriate alternative to packed columns for the gas chromatographic procedure described in ISO 10362-1:1999.

scholarly journals Optimalization of multiresidue method for the determination of pesticide residues in fruits

2021 ◽  
Vol 61 (3) ◽  
pp. 221-238
Keyword(s):  
Water Content ◽  
Pesticide Residues ◽  
High Water ◽  
High Water Content ◽  
Detector Response ◽  
Wide Range ◽  
Comprehensive Determination ◽  
Selective Detectors ◽  
Active Substances

The main aim of this study was to optimize the QuEChERS methodology for the comprehensive determination of pesticide residues using a simple and inexpensive gas chromatography equipped with selective detectors working simultaneously (GC-ECD/NPD). The method was validated in accordance with the SANTE/11945/2015 guidelines. Representative fruit matrices were chosen from the commodities group with high water content (apples), and with high acidity and high water content (strawberry) for a 160 compounds in the range of 0.005−0.02 mg/kg. The accuracy of the method was as required (recovery: 70–120%, precision: below 20%) for 135 active substances in apples samples and 137 in strawberries samples. The main advantages of the methodology include: good detector response linearity (R2 above 0.995), low limits of detection (0.005 mg/kg for more than 20 compounds, 0.01 mg/kg for about 120 compounds), possibility of simultaneous determination of a wide range of compounds (including some “difficult” ones) without use of a single residue methods. The simultaneous use of two selective detectors allows to obtain more data during a single dose of the sample and confirmation of the result for most compounds, which allows to prevent false positives ones.

Comparative Study of Methods for the Extraction of Eleven Organophosphorus Pesticide Residues in Rice

1975 ◽  
Vol 58 (6) ◽  
pp. 1286-1293
Author(s):  
Yoichi Aoki ◽  
Mitsuharu Takeda ◽  
Mitsuru Uchiyama
Keyword(s):  
Analytical Method ◽  
Pesticide Residues ◽  
Organophosphorus Pesticides ◽  
Stationary Phases ◽  
Organophosphorus Pesticide ◽  
Extraction Methods ◽  
Rice Samples ◽  
Liquid Chromatographic ◽  
Unpolished Rice

Abstract Several extraction methods are compared for the simultaneous analysis of organophosphorus pesticides in unpolished rice. Four stationary phases were used for the subsequent gas-liquid chromatographic (GLC) determination of the selected pesticides. Using 3 different GLC columns, 11 pesticides were completely separated and identified. The efficiency of the cleanup and the sensitivity of the analytical method were evaluated by using powdered unpolished rice samples fortified with the pesticides and also wheat and dried bean samples. Average recoveries ranged from 74.7% for disulfoton to 97.4% for malathion in unpolished rice and from 68.1% for disulfoton to 108.3% for malathion in other crops. The method described is applicable to the analysis of selected organophosphorus pesticide residues in unpolished rice, wheat, buckwheat, and dried beans.

Pillar Density Modulation in a Semi-packed MEMS Column

2017 ◽  
Vol 2017 (DPC) ◽  
pp. 1-22
Author(s):  
Ryan Chan ◽  
Bishnu Regmi ◽  
Ana Lopez Marcano ◽  
Sarah El-Helw ◽  
Masoud Agah
Keyword(s):  
Pressure Drop ◽  
High Speed ◽  
Stationary Phases ◽  
Current Trend ◽  
Packed Column ◽  
Packed Columns ◽  
Maximum Density ◽  
Plate Height ◽  
Minimum Density ◽  
Pillar Density

Gas chromatography is a technology that is constantly moving forward. The current trend for this field is moving towards miniaturizing the columns towards achieving high-speed separations. Groups are constantly researching different geometries, topographies, and stationary phases in order to make these separations more efficient. In order to achieve this goal of increased efficiency, we have taken two ideas from previous works, namely being width modulated channels as well as semi-packed columns, and tried to use the redeeming qualities that exist in both and combine them to achieve something that shares their positive points. Semi-packed columns have been shown to increase the plate height for a column. However, the pressure drop that occurs in these types is a significant drawback that makes high-speed separations very difficult to achieve with lower inlet pressures. Width modulation of the column channel can be used to change the overall velocity of the gas as it travels throughout the column resulting in a lower overall pressure drop. The method that was used to combine these two ideas was to change the density of the pillars in the semi-packed column along the length of the channel to achieve the same effect of the width modulation. This was achieved by changing the number of pillars across in the channel as well as the pitch distance between sets of pillars. Controls were also fabricated so the results could be compared to the two extreme designs. After extensive testing, the results indicated that between the minimum and maximum density, the maximum density allowed only ~50% of the total flow that the minimum density design showed at the same inlet pressure. In comparison, the design that changed pillar density throughout the channel allowed ~89% of the flow the minimum density design. This is a significant increase in flow and allows for much more to pass through the chip in a given time span increasing the efficiency of high-speed separations. The other factor that was tested for was the number of theoretical plates for each of the designs. It was shown through testing with a constant sample that the minimum density column behaves very similarly to an open column without pillars whereas the density modulated column has plate numbers between those of the minimum density and the maximum density. This is even further data that supports the use of a pillar density modulated chip for high-speed separations.

Determination of Chlorinated Pesticide Residues in Fat by Electron Capture Gas Chromatography

1964 ◽  
Vol 47 (4) ◽  
pp. 652-659
Author(s):  
K A Mccully ◽  
W P Mckinley
Keyword(s):  
Gas Chromatography ◽  
Stationary Phase ◽  
Electron Capture ◽  
Pesticide Residues ◽  
Screening Method ◽  
Fats And Oils ◽  
Methyl Silicone ◽  
Chlorinated Pesticides ◽  
Pesticide Mixture

Abstract A general screening method has been developed for the cleanup and estimation of chlorinated pesticide residues in fats and oils. The fats were dissolved in benzene-acetone (1 + 19) and then precipitated at — 70 °C. The precipitated fat was removed by filtration through a column of Darco G-60 and Solka Floe in a jacketed filtering funnel. The filtrate was concentrated to a standard volume and an aliquot was analyzed by electron capture gas chromatography. With the exception of a few pesticides in butterfat and aldrin in beef fat, recoveries were 81 to 112% after a mixture of 12 chlorinated pesticides had been added to the fats prior to precipitation. A Pyrex gas chromatographic column containing a 10% stationary phase of mixed silicones (4% SE-30 methyl silicone + 6% QF-1 fluoro silicone) was used to resolve this pesticide mixture. The compounds eluted from the column in the following order: lindane, heptachlor, aldrin, Telodrin, heptachlor epoxide, p,p’-DDE, dieldrin, o,p’-DDT, Rhothane, p,p’-DDT, endrin, and methoxychlor.

Sign in / Sign up

Export Citation Format

Share Document