Optimization and Validation of HS-SPME-GCMS Method for Determination of Multifumigant Residues in Grain, Oilseeds, Nuts, and Dry Fruit

2019 ◽  
Vol 102 (6) ◽  
pp. 1877-1883 ◽  
Author(s):  
Xin Du ◽  
Wenjuan Zhang ◽  
Bo Liu ◽  
Tao Liu ◽  
Yu Xiao ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Propylene Oxide ◽  
Methyl Bromide ◽  
Ethyl Formate ◽  
Ethyl Bromide ◽  
Gas Chromatograph ◽  
Sulfuryl Fluoride ◽  
Dried Fruit ◽  
Food Matrices

Abstract Background: Fumigants are approved in many countries and used to treat food, feed, and seed. The amount of residue that remains in fumigated materials is measured and reported. Objective: The optimization and validation of a high-sensitivity headspace solid-phase microextraction gas chromatograph mass spectrometer (HS-SPME-GCMS) method for determination of eight fumigant residues—phosphine, methyl bromide, cyanogen, sulfuryl fluoride, ethylene oxide, propylene oxide, ethyl bromide and ethyl formate—in a range of food matrices were developed. The food matrices included grain, oilseed, dried fruit, and nut. Methods: The new method was used to determine residue levels from a fumigant complex in food matrices by monitoring the change of the absorption of spiked standards and desorption of fumigant from fumigated samples. Results: Based on the observation, the process of physical sorption and chemisorption was defined. The equilibrium time of the sample analysis was chosen at 5 hours. The LODs of the fumigants were in the range of 0.03 to 1.99 ng/g. Response to a range of diluted authentic standards gave significant linear regressions (r2 > 0.9983), and the RSDs were ≤8.7% at the 3 ng/g level of aged spiking standard, except for sulfuryl fluoride, for which the LOD was 1.99 ng/g and the RSD value was 39.7% (6.64 ng/g). Conclusions: The performance of the HS-SPME-GCMS method was more sensitive than the use of a gas syringe, except for sulfuryl fluoride. Highlights: An innovative multifumigant residue detection method based on HS-SPME sampling technology with gas chromatograph-mass selective detection (GC-MSD) analysis was established, including phosphine, methyl bromide, cyanogen, sulfuryl fluoride, ethylene oxide, propylene oxide, ethyl bromide, and ethyl formate; The first report of a sorption study of the process of physical sorption and chemisorption of residual fumigant in fruit and food matrices by an HS-SPME-GCMS method; Consider the effect of time on fumigant behavior in dried fruit, grain, and nut; The LODs of the fumigants were in the range of 0.03 to 1.99 ng/g.

Optimization and Validation of HS-SPME-GCMS Method for Determination of Multifumigant Residues in Grain, Oilseeds, Nuts, and Dry Fruit

2019 ◽  
Vol 102 (6) ◽  
pp. 1877-1883
Author(s):  
Xin Du ◽  
Wenjuan Zhang ◽  
Bo Liu ◽  
Tao Liu ◽  
Yu Xiao ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Propylene Oxide ◽  
Methyl Bromide ◽  
Ethyl Formate ◽  
Ethyl Bromide ◽  
Gas Chromatograph ◽  
Sulfuryl Fluoride ◽  
Dried Fruit ◽  
Food Matrices

Background: Fumigants are approved in many countries and used to treat food, feed, and seed. The amount of residue that remains in fumigated materials is measured and reported. Objective: The optimization and validation of a high-sensitivity headspace solid-phase microextraction gas chromatograph mass spectrometer (HS-SPME-GCMS) method for determination of eight fumigant residues—phosphine, methyl bromide, cyanogen, sulfuryl fluoride, ethylene oxide, propylene oxide, ethyl bromide and ethyl formate—in a range of food matrices were developed. The food matrices included grain, oilseed, dried fruit, and nut. Methods: The new method was used to determine residue levels from a fumigant complex in food matrices by monitoring the change of the absorption of spiked standards and desorption of fumigant from fumigated samples. Results: Based on the observation, the process of physical sorption and chemisorption was defined. The equilibrium time of the sample analysis was chosen at 5 hours. The LODs of the fumigants were in the range of 0.03 to 1.99 ng/g. Response to a range of diluted authentic standards gave significant linear regressions (r2 > 0.9983), and the RSDs were ≤8.7% at the 3 ng/g level of aged spiking standard, except for sulfuryl fluoride, for which the LOD was 1.99 ng/g and the RSD value was 39.7% (6.64 ng/g). Conclusions: The performance of the HS-SPME-GCMS method was more sensitive than the use of a gas syringe, except for sulfuryl fluoride. Highlights: An innovative multifumigant residue detection method based on HS-SPME sampling technology with gas chromatograph-mass selective detection (GC-MSD) analysis was established, including phosphine, methyl bromide, cyanogen, sulfuryl fluoride, ethylene oxide, propylene oxide, ethyl bromide, and ethyl formate; The first report of a sorption study of the process of physical sorption and chemisorption of residual fumigant in fruit and food matrices by an HS-SPME-GCMS method; Consider the effect of time on fumigant behavior in dried fruit, grain, and nut; The LODs of the fumigants were in the range of 0.03 to 1.99 ng/g.

Synthesis of Double Alkyl EO/PO Random Copolyethers with KOH Catalyst

2012 ◽  
Vol 472-475 ◽  
pp. 2681-2685
Author(s):  
Jian Guo Guo ◽  
Su Qin He ◽  
Jian Ming Jiang
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Propylene Oxide ◽  
Potassium Hydroxide ◽  
Random Copolymer ◽  
Alkyl Halides ◽  
Ethyl Bromide ◽  
Hydroxyl Group ◽  
Molar Ratio ◽  
End Capping

Ethylene oxide (EO) and propylene oxide (PO) random copolymer was synthesized with 1,2-propanediol as initiator, then the end-capping process was carried out by adding various alkyl halides and potassium hydroxide (KOH) to produce the double alkyl EO/PO random copolyethers. The factors effecting alkyl-capping rate were discussed. The results showed that when the molar ratio of hydroxyl group/KOH/1-bromobutane was 1/1.9/1.9, reacting time 6.5 hr and reacting temperature 50°C, the alkyl-capping rate could reach over 80%. The end-capping rate would also increase with the increasing content of ethylene oxide in the random polyether, and the end-capping rate of the EO/PO/EO block-polyether was high than that of the random polyether with same molecular weight. Instead of 1-bromobutane, ethyl bromide promised a higher whereas chloralkane gave a lower end-capping rate respectively.

Headspace Gas Chromatographic Method for Determination of Methyl Bromide in Food Ingredients

1985 ◽  
Vol 68 (6) ◽  
pp. 1112-1116
Author(s):  
Jonathan W DeVries ◽  
James M Broge ◽  
John P Schroeder ◽  
Raymond H Bowers ◽  
Paul A Larson ◽  
...  
Keyword(s):  
Detection Limit ◽  
Methyl Bromide ◽  
Chromatographic Method ◽  
Equilibration Time ◽  
Gas Chromatograph ◽  
Food Ingredients ◽  
Headspace Gas ◽  
The Matrix ◽  
Gas Chromatographic Method

Abstract A headspace gas chromatographic (GC) method, which can be automated, has been developed for determination of methyl bromide. This method has been applied to wheat, flour, cocoa, and peanuts. Samples to be analyzed are placed in headspace sample vials, water is added, and the vials are sealed with Teflon-lined septa. After an appropriate equilibration time at 32°C, the samples are analyzed within 10 h. A sample of the headspace is withdrawn and analyzed on a gas chromatograph equipped with an electron capture detector (ECD). Methyl bromide levels were quantitated by comparison of peak area with a standard. The standard was generated by adding a known amount of methyl bromide to a portion of the matrix being analyzed and which was known to be methyl bromide free. The detection limit of the method was 0.4 ppb. The coefficient of variation (CV) was 6.5% for wheat, 8.3% for flour, 3.3% for cocoa, and 11.6% for peanuts.

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