Determination of Coumaphos and Its Oxygen Analog in Eggs and Milk by Using a Multiresidue Method with Liquid Chromatographic Quantitation and Capillary Gas Chromatographic/Mass Spectrometric Confirmation

1983 ◽  
Vol 66 (6) ◽  
pp. 1353-1357
Author(s):  
Richard T Krause ◽  
Zhao Min ◽  
Sharona H Shotkin
Keyword(s):  
High Performance ◽  
Mass Spectrometric ◽  
Fluorescence Detector ◽  
High Performance Liquid Chromatograph ◽  
Liquid Chromatograph ◽  
Multiresidue Method ◽  
Oxygen Analog ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract A multiresidue method for carbamate insecticides was adapted for the determination of coumaphos and its oxygen analog in eggs and milk. Eggs were extracted with acetonitrile and milk was extracted with acetone. Co-extractives were removed using liquid partitioning and charcoal column procedures described in the carbamate method. Coumaphos and its oxygen analog were determined by using a high performance liquid chromatograph equipped with a fluorescence detector. Recovery studies were performed for the 2 compounds at levels of 0.01 and 0.10 ppm in eggs and 0.01 and 0.02 ppm in milk. Overall average recovery was 100% (range 95-109%). In a trial of the method by another laboratory, the recovery of coumaphos and its oxygen analog from milk averaged 87 and 96%, respectively. Data are presented on the capillary gas chromatographic/mass spectrometric confirmation of coumaphos residues.

Applicability of a Carbamate Insecticide Multiresidue Method for Determining Additional Types of Pesticides in Fruits and Vegetables

1983 ◽  
Vol 66 (2) ◽  
pp. 234-240 ◽  
Author(s):  
Richard T Krause ◽  
E Michael August
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Fruits And Vegetables ◽  
Naphthalene Acetic Acid ◽  
Gas Liquid Chromatography ◽  
Fluorescence Detector ◽  
Liquid Chromatograph ◽  
Multiresidue Method ◽  
Oxygen Analog ◽  
Azinphos Methyl

Abstract Several fruits and vegetables were fortified at a low (0.02-0.5 ppm) and at a high (0.1-5 ppm) level with pesticides and with a synergist, and recoveries were determined. Analyses were performed by using 3 steps of a multiresidue method for determining N-methylcarbamates in crops: methanol extraction followed by removal of plant co-extractives by solvent partitioning and chromatography with a charcoal-silanized Celite column. Eleven compounds were determined by using a high performance liquid chromatograph equipped with a reverse phase column and a fluorescence detector. Twelve additional compounds were determined by using a gas-liquid chromatograph equipped with a nonpolar packed column and an electron capture or flame photometric detector. Recoveries of 10 pesticides (azinphos ethyl, azinphos methyl, azinphos methyl oxygen analog, carbaryl, carbof uran, naphthalene acetamide, naphthalene acetic acid methyl ester, napropamide, phosalone, and phosalone oxygen analog) and the synergist piperonyl butoxide, which were determined by high performance liquid chromatography, averaged 100% (range 86-117) at the low fortification level and 102% (range 93-115) at the high fortification level. Quantitative recovery of naphthalene acetamide through the method required that an additional portion of eluting solution be passed through the charcoal column. Recoveries of 7 additional pesticides (dimethoate, malathion, methyl parathion, mevinphos, parathion, phorate oxygen analog, and pronamide), which were determined by gas-liquid chromatography (GLC), averaged 108% (range 100-120) at the low fortification level and 107% (range 99-122) at the high fortification level. DDT, diazinon, dieldrin, phorate, and pirimiphos ethyl, which were determined by GLC, were not quantitatively recovered.

Determination of thiamin and thiamin phosphate esters in blood by liquid chromatography with post-column derivatization.

1983 ◽  
Vol 29 (12) ◽  
pp. 2073-2075 ◽  
Author(s):  
M Kimura ◽  
Y Itokawa
Keyword(s):  
High Performance ◽  
Sodium Hydroxide Solution ◽  
Potassium Ferricyanide ◽  
Phosphate Esters ◽  
High Performance Liquid Chromatograph ◽  
Liquid Chromatograph ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic ◽  
Thiamin Pyrophosphate

Abstract We demonstrate a liquid-chromatographic method involving post-column derivatization for determining the concentration of thiamin and its phosphate esters in human blood. Blood, erythrocytes, or plasma is deproteinized and centrifuged. Aliquots of the samples are applied to a mu Bondapak C18 column attached to a "high-performance" liquid chromatograph. Addition of potassium ferricyanide/sodium hydroxide solution to the column effluent with a proportioning pump converts thiamin phosphates into fluorophores, the intensities of which are measured with a spectrofluorophotometer. Thiamin, thiamin monophosphate, thiamin pyrophosphate, and thiamin triphosphate eluted as single peaks; no coeluting substances were detected. Thiamin pyrophosphate was the ester present in greatest concentration, followed by thiamin triphosphate; thiamin monophosphate and thiamin were present in slight amounts. This method allows easy determination of thiamin and its phosphate esters in 0.1 mL of blood.

Simple liquid-chromatographic determination of urinary coproporphyrin in workers exposed to lead.

1986 ◽  
Vol 32 (5) ◽  
pp. 872-873 ◽  
Author(s):  
K Tomokuni ◽  
Y Hirai
Keyword(s):  
High Performance ◽  
Chromatographic Determination ◽  
Hplc Method ◽  
Simple Liquid ◽  
Fluorescence Detector ◽  
Liquid Chromatograph ◽  
Simple Method ◽  
Liquid Chromatographic ◽  
Urinary Coproporphyrin

Abstract We developed a simple method for the determination of urinary coproporphyrin (CP) in lead workers, using a "high-performance" liquid chromatograph (HPLC) equipped with a fluorescence detector. The detection limit of urinary CP in this method was 5 micrograms per liter of urine. The working linear range of urinary CP concentration was 5 to 1500 micrograms/L. In 41 lead-exposed workers, the urinary CP values obtained by the present HPLC method were well correlated with those obtained by a conventional spectrophotometric method (r = 0.94). The present method is useful for screening workers exposed to lead.

Liquid-chromatographic determination of the total thiamin content of blood.

1982 ◽  
Vol 28 (1) ◽  
pp. 29-31 ◽  
Author(s):  
M Kimura ◽  
T Fujita ◽  
Y Itokawa
Keyword(s):  
High Performance ◽  
Chromatographic Determination ◽  
Potassium Ferricyanide ◽  
Phosphate Esters ◽  
High Performance Liquid Chromatograph ◽  
Liquid Chromatograph ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid-chromatographic method for determining the total thiamin content of blood is presented. Blood is deproteinized and incubated with Aspergillus oryzae carboxyl proteinase (EC 3.4.23.6; Takadiastase) to convert thiamin phosphate esters to free thiamin. An aliquot of the sample is applied to the column (Shodex OH-Pak M-414) of a high-performance liquid chromatograph. A 100 mg/L solution of potassium ferricyanide in 150 g/L sodium hydroxide is added to the column effluent with a proportioning pump, to convert thiamin into a fluorophore. The intensity of the fluorophore is measured with a spectrofluorophotometer and recorded graphically. The total thiamin in each blood sample appears as a single peak, and no co-eluting substance was detected. This method is simple, highly reproducible, and rapid, and its sensitivity is sufficient for determination of the thiamin content of 0.1-mL blood samples.

Sign in / Sign up

Export Citation Format

Share Document