Analysis of multi-component pesticide residues in herbal medicines by GC-MS with electron impact ionization and with positive- and negative-ion chemical ionization

1999 ◽  
Vol 49 (9-10) ◽  
pp. 525-534 ◽  
Author(s):  
H. R. Yoon ◽  
S. Y. Cho ◽  
J. M. Kim ◽  
I. B. Yoon ◽  
M. K. Park ◽  
...  
Keyword(s):  
Electron Impact ◽  
Pesticide Residues ◽  
Chemical Ionization ◽  
Impact Ionization ◽  
Herbal Medicines ◽  
Electron Impact Ionization ◽  
Negative Ion ◽  
Negative Ion Chemical Ionization

Gas-Liquid Chromatographic/Mass Spectrometric Screening Method for T-2 Toxin in Milk

1979 ◽  
Vol 62 (6) ◽  
pp. 1274-1280
Author(s):  
George J Collins ◽  
Joseph D Rosen
Keyword(s):  
Mass Spectrometry ◽  
Electron Impact ◽  
Chemical Ionization ◽  
Impact Ionization ◽  
Trimethylsilyl Ether ◽  
Screening Method ◽  
Internal Standard ◽  
Electron Impact Ionization ◽  
Gas Liquid Chromatography ◽  
Ionization Mass

Abstract A method for the analysis of T-2 toxin in milk is presented. Ethyl acetate extracts of milk samples which had been spiked with T-2 toxin were purified by thin layer chromatography and derivatized with N,O-bis(trimethylsilyl)acetamide to produce the T-2 toxin trimethylsilyl ether (T-2 toxin-TMS). N,O-bis(trimethylsilyl-d9)acetamide was used to make T-2 toxin d9-trimethylsilyl ether (T-2 toxin-d9TMS) which was added to the derivatized milk extract as an internal standard. Samples were analyzed by combined gas-liquid chromatography/mass spectrometry using either electron impact ionization or chemical ionization mass spectrometry. In electron impact ionization analyses, simultaneous monitoring of the T-2 toxin-TMS fragment ion at m/z 436 and the T-2 toxin-d9TMS fragment ion at m/z 445 gave a T-2 toxin-TMS detectability estimated at 6 μg/kg. In chemical ionization analyses, the T-2 toxin-TMS fragment ion at m/z 377 and the T-2 toxin-d9TMS fragment ion at m/z 386 were simultaneously monitored to give a T-2 toxin-TMS detectability estimated at 3 μg/kg. Average recovery was 85% at 200 μg/kg and 65% at 20 μg/kg.

Determination of 3,3'-Dichlorobenzidine in Industrial Wastewaters

2004 ◽  
Vol 39 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Hing-Biu Lee ◽  
Thomas E. Peart ◽  
Ken Terry ◽  
James Maguire
Keyword(s):  
Electron Impact ◽  
Chemical Ionization ◽  
Solid Phase ◽  
Negative Ion ◽  
Gas Chromatography Mass Spectrometry ◽  
Ms Detection ◽  
Negative Ion Chemical Ionization ◽  
Ionization Mode ◽  
Wastewater Samples

Abstract A solid-phase extraction, chemical derivatization, and gas chromatography/mass spectrometry (GC/MS) method has been developed for the determination of trace 3,3'-dichlorobenzidine (DCB) in industrial wastewater samples. Instead of an octadecylsilane (ODS) cartridge, a Porapak RDX cartridge was used since the latter could be optimized for the extraction of DCB. After the pre-concentration, interfering coextractives in the sample were selectively removed from the cartridge by elution with a 1:1 mixture of acetonitrile and water. DCB was then eluted with acetonitrile and derivatized with pentafluoropropionic acid anhydride. The product was subsequently analyzed by GC/MS in either the electron impact or negative ion chemical ionization mode. Recoveries of DCB and the surrogate, DCB-d6, were better than 90% at spiking levels of 10, 1, and 0.1 µg/L. Based on a concentration factor of 100, the detection limits for DCB in wastewater samples were determined to be 0.1 µg/L by electron impact GC/MS detection, and 0.01 µg/L by negative ion chemical ionization GC/MS detection, respectively. This method has been successfully applied to wastewater samples collected in the Toronto area.

Sign in / Sign up

Export Citation Format

Share Document