Elimination of sulfate interferences in the Chromatographic determination of o-phosphate using liquid-liquid extraction

1996 ◽  
Vol 356 (5) ◽  
pp. 335-338 ◽  
Author(s):  
Jürgen Mattusch ◽  
Rainer Wennrich
Keyword(s):  
Chromatographic Determination ◽  
Liquid Extraction ◽  
Liquid Liquid Extraction

scholarly journals Comparison of two sample preparation procedures for HPLC determination of ochratoxin A

2009 ◽  
Vol 61 (4) ◽  
pp. 639-644 ◽  
Author(s):  
Gorica Vukovic ◽  
Snezana Pavlovic ◽  
M.S. Ristic
Keyword(s):  
Sample Preparation ◽  
Phosphoric Acid ◽  
Ochratoxin A ◽  
Chromatographic Determination ◽  
Liquid Extraction ◽  
Immunoaffinity Column ◽  
Maize Flour ◽  
Liquid Liquid Extraction ◽  
Immunoaffinity Columns

In preparation of samples for chromatographic determination of ochratoxin A, two types of columns were used for sample cleanup (SPE and immunoaffinity columns). The first method consisted of liquid-liquid extraction with a mixture of chloroform and phosphoric acid, followed by ion-exchange cleanup on Waters Oasis MAX columns. The sec?ond method consisted of extraction with a mixture of water and methanol, followed by LCTech OtaCLEAN immunoaf?finity column cleanup. Recoveries of the methods were determined at three levels in three repetitions for maize flour, and they were 84% (%RSD = 19.2) for the first method of sample preparation and 101% (%RSD = 2.2) for the second method. Values of LOQ for OTA were 0.25 and 1.00 ?g/kg for the IAC and SPE clean-up procedures, respectively. Both methods comply with present regulations, but the MAX sample clean-up procedure should be used as an alternative, since the immunoaffinity column clean-up procedure is characterized by better reproducibility, accuracy, and efficiency.

scholarly journals High performance thin layer chromatographic determination of nifedipine in human serum after liquid-liquid extraction

Química Nova ◽  
2012 ◽  
Vol 35 (2) ◽  
pp. 411-415 ◽  
Author(s):  
Sigrid Mennickent ◽  
Jonathan Contreras ◽  
Berta Schulz ◽  
Marta de Diego ◽  
Mario Vega
Keyword(s):  
Thin Layer ◽  
Human Serum ◽  
High Performance ◽  
Chromatographic Determination ◽  
Liquid Extraction ◽  
Liquid Liquid Extraction

Gas Chromatographic Determination of Diethylstilbestrol and Its Glucuronide in Cattle Tissues

1973 ◽  
Vol 56 (4) ◽  
pp. 785-792 ◽  
Author(s):  
Alvin L Donoho ◽  
William S Johnson ◽  
Robert F Sieck ◽  
William L Sullivan
Keyword(s):  
Electron Affinity ◽  
Chromatographic Determination ◽  
Liquid Extraction ◽  
Liquid Liquid Extraction ◽  
Assay Procedure ◽  
Routine Basis ◽  
Liver And Kidney ◽  
Liquid Chromatographic ◽  
Dichloroacetyl Chloride

Abstract A gas-liquid chromatographic (GLC) method is described for the determination of diethylstilbestrol (DES) and its glucuronide (DES-G) in cattle tissues. Muscle, liver, and kidney samples are extracted with methanol and centrifuged. An aliquot of extract equivalent to 50 g tissue is evaporated to remove methanol and hydrolyzed overnight, using β-glucuronidase. In the resulting sample, free DES is purified by alkaline liquid-liquid extraction and is reacted in base with dichloroacetyl chloride to form the DES diester. The diester is measured by GLC, using a 5% UC W-98 column and electron affinity detection. Fat samples are assayed for free DES by extracting with chloroform and processing as other tissues, beginning with the alkaline purification. Residues from tissues of steers fed DES, assayed by both GLC and bioassay procedures, showed excellent agreement. In these studies the GLC procedure had a sensitivity of about 0.001 ppm. Lean and fat contained no DES residue when animals were slaughtered at 0 time off medicated feed. Liver and kidney contained residues on the order of 0.02 ppm at 0 time. The DES declined to nondetectable levels in liver and kidney by 96 hr after withdrawal. The assay procedure has been used successfully on a routine basis for several months.

Electron Capture Gas Chromatographic Determination of Thiabendazole in Yams

1986 ◽  
Vol 69 (1) ◽  
pp. 114-116 ◽  
Author(s):  
Promode C Bardalaye ◽  
Willis B Wheeler
Keyword(s):  
Ethyl Acetate ◽  
Electron Capture ◽  
Dilute Hydrochloric Acid ◽  
Chromatographic Determination ◽  
Liquid Extraction ◽  
Electron Capture Detection ◽  
Distilled Water ◽  
Liquid Liquid Extraction ◽  
Acidic Fraction

Abstract A method for the determination of thiabendazole in yams is reported. The method consists of extracting the chopped crops with ethyl acetate followed by distilled water wash and liquid liquid extraction of the chemicals into dilute hydrochloric acid. The sample is further cleaned up by making the aqueous acidic fraction alkaline and repartitioning into ethyl acetate. The determination step includes evaporation of the cleaned up extract to dryness, derivatization with pentamiorobenzoyl chloride, and determination of the derivatized thiabendazole in acetone by gas chromatography with electron capture detection.

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