High Pressure Liquid Chromatographic Determination of Xanthomegnin in Corn

1978 ◽  
Vol 61 (3) ◽  
pp. 590-592
Author(s):  
Michael E Stack ◽  
Nathan L Brown ◽  
Robert M Eppley

Abstract A method is described for the detection and quantitative analysis of xanthomegnin in corn samples. Initial extraction with CHCI3 in the presence of 0.5M H3PO4 is followed by additional purification using silica gel column chromatography. A high pressure liquid chromatograph equipped with a microparticle silica gel column and a 405 nm absorbance detector is used for detection and quantitation of the xanthomegnin. The identity of xanthomegnin is confirmed by thin layer chromatography on silica gel plates developed with benzenemethanol- acetic acid (90-(-5+5). The recovery of xanthomegnin added to corn samples at levels of 0.75–9.6 mg/kg averaged 41% with a coefficient of variation of 25%.

1979 ◽  
Vol 62 (5) ◽  
pp. 1001-1003
Author(s):  
Ralph G Grant ◽  
Richard K Pike

Abstract A simple and rapid method is described determining for 2- ((p-chlorophenyl) phenylacetyl-1,3- indandione (chlorophacinone) in rodenticides formulated as tracking powders and whole grain and crushed grain baits. The bait is extracted with methanol containing an internal standard, and the extract is injected into a high pressure liquid chromatograph. The sample is analyzed by reverse phase chromatography on octadecyl (C18) bonded to glass beads with a mobile phase of methanolwater (35+65) plus 0.75% NH4OH. A 5 μL injection containing 240 ng benzophenone internal standard and 77 ng chlorophacinone produces half scale peaks at 280 nm with a full scale absorbance of 0.01 absorbance unit. Two formulations and a spiked sample were analyzed by the method. Recovery as determined by peak area was >97%.


1979 ◽  
Vol 62 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Arnost B Vilim ◽  
Agnes I Macintosh

Abstract A rapid high pressure liquid chromatographic (HPLC) screening method for the quantitative determination of nitrofurazone in milk has been developed. The drug is extracted with ethyl acetate from a 2.0 ml milk serum sample, the organic layer is evaporated to dryness, and the residue is dissolved in the mobile phase and injected into the liquid chromatograph. A reverse phase μBondapak C18 column is used with monitoring at 365 nm. The detection limit is 5 ppb and recoveries are 57—67%. Mass spectroscopic confirmation of the HPLC nitrofuran peak is described.


1980 ◽  
Vol 63 (6) ◽  
pp. 1278-1281 ◽  
Author(s):  
Michael E Stack ◽  
Robert M Eppley

Abstract A high pressure liquid chromatographic (HPLC) method is described for the detection and quantitative determination of satratoxins G and H in cereal grains. The toxins are extracted from the sample by blending with methanol-water (55+45) in the presence of hexane, followed by partitioning into chloroform. The chloroform extract is further purified on a 10 g silica gel column. A high pressure liquid chromatograph, equipped with a microparticle silica gel column and a 254 nm absorbance detector, is used for the determination. Additional confirmation of identity is obtained by mass spectrometry or by a brine shrimp bioassay of the HPLC eluates corresponding to the retention times of satratoxins G and H. The recoveries of added satratoxins G and H from wheat samples averaged 65% for G and 71% for H (200–1000 mg/kg). The coefficients of variation (CV) were 15% for G and 14% for H. The lower limit of detection was 200 μg/kg for wheat. Analysis of corn, oats, and barley samples (400 μg/kg of each toxin added) gave comparable recoveries. Only the corn extract exhibited HPLC interferences at the retention time for satratoxin H. The method was also used to analyze samples of corn, oats, wheat, barley, and rice on which Stachybotrys atra had been cultured.


1977 ◽  
Vol 60 (6) ◽  
pp. 1375-1378
Author(s):  
Carl W Sims ◽  
Richard K Gard

Abstract A simple and rapid method is described for determining N′-3-pyridylmethyl-N′-p-nitrophenylurea (RH-787) in Vacor Ratkiller rodenticide. The bait is extracted with acetone, the extract is evaporated to dryness, an internal standard is added, and the solution is injected into a high pressure liquid chromatograph. The sample is analyzed by normal phase chromatography on a Partisil 10 column with a mobile phase of methanol-methylene chloride (10+90). An 8 μl injection containing 4 μg pyridine internal standard and 8 μg RH-787 produces half-scale peaks at 254 nm with a full scale absorbance of 0.5 absorbance unit. In an alternative procedure, the active ingredient is extracted from the bait with acetone and titrated to a methyl red end point with 0.1N perchloric acid dissolved in acetic acid. Two samples of Vacor Ratkiller and a spiked blank were analyzed by both procedures.


1983 ◽  
Vol 66 (2) ◽  
pp. 284-286
Author(s):  
Thomas D Macy ◽  
Andrew Loh

Abstract A high pressure liquid chromatographic (HPLC) method has been developed to determine monensin in feed premixes. The method is simple and rapid. Monensin is extracted with methanol-water and determined in the extracting solution by HPLC. Average recovery for monensin from a 13.2% premix sample was 103% (coefficient of variation (CV), 2.6%) by HPLC and compares with the value of 100% (CV, 3.4%) obtained by the turbidimetric bioassay method.


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