Simultaneous Liquid Chromatographic Determination of Thiabendazole, o-Phenylphenol, and Diphenyl Residues in Citrus Fruits, Without Prior Cleanup

1982 ◽  
Vol 65 (6) ◽  
pp. 1302-1304
Author(s):  
Yoshimi Kitada ◽  
Michiko Sasaki ◽  
Kaoru Tanigawa
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Citrus Fruits ◽  
Ultraviolet Detection ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple, rapid, efficient method has been developed for determining thiabendazole, o-phenylphenol, and diphenyl in citrus fruits by using high performance liquid chromatography, with fluorescence or ultraviolet detection. The compounds are extracted with ethyl acetate and separated from soluble fruit components on a LiChrosorb RP-8 column. Recovery of these compounds added to citrus fruits at 5 or 50 ppm levels was >93%; the limit of detection for the compounds is 1 ppm.

Liquid-chromatographic determination of 4-hydroxyproline in urine.

1986 ◽  
Vol 32 (6) ◽  
pp. 1002-1004 ◽  
Author(s):  
H Hughes ◽  
L Hagen ◽  
R A Sutton
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Present Method ◽  
High Performance ◽  
Protein Hydrolysate ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract In this method for 4-hydroxyproline in urine, hydroxyproline is derivatized with 4-chloro-7-nitrobenzofurazan, with subsequent estimation by reversed-phase "high-performance" liquid chromatography. The ranges for excretion of free and total hydroxyproline while the subjects were ingesting unrestricted diets were 2-29 and 122-374 mumol/24 h (n = 21), respectively, with no significant sex-related difference. A comparison with results by colorimetry indicated no significant differences: mean (n = 18) concentrations (mumol/L) of hydroxyproline in urine were 180 (SD 149) by the present method, 163 (SD 166) by colorimetry. For protein hydrolysate the respective values were 5.9 (SD 2.7) and 6.7 (SD 2.9).

Liquid-chromatographic determination of 5-S-L-cysteinyl-L-dopa with electrochemical detection in urine prepurified with a phenylboronate affinity gel.

1983 ◽  
Vol 29 (12) ◽  
pp. 2031-2034 ◽  
Author(s):  
B Kågedal ◽  
A Pettersson
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Electrochemical Determination ◽  
Chromatographic Separations ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A phenylboronate affinity gel has been investigated for use in the prepurification of urine before "high-performance" liquid chromatography and electrochemical determination of 5-S-L-cysteinyl-L-dopa. At pH 5.6 this naturally occurring 5-S-cysteinyldopa was adsorbed on a phenylboronate column and was quantitatively eluted with trichloroacetate, pH 3.0. This pretreatment of urine before "high-performance" liquid chromatography produced satisfactory chromatographic separations, and the results were further improved when the purification procedure also included treatment on a cation exchanger. By using 5-S-D-cysteinyl-L-dopa--a diastereomer to 5-S-L-cysteinyl-L-dopa--as an internal standard, we have developed a practical routine method for the quantitative determination of urinary 5-S-L-cysteinyl-L-dopa. The precision (CV = 2.4%) and analytical recovery (96.9%, SD 5.3%) were satisfactory and the results obtained correlated well with a previously described method.

High Performance Liquid Chromatographic Determination of Quinizarin, p-Toluidine, and D&C Violet No. 2 in D&C Green No. 6

1979 ◽  
Vol 62 (6) ◽  
pp. 1338-1341
Author(s):  
Elizabeth Cox
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract High performance liquid chromatography was used to determine quinizarin, p-toluidine, and D&C Violet No. 2 in D&C Green No. 6. Recoveries averaging 102, 105, and 104% were obtained for quinizarin, p-toluidine, and D&C Violet No. 2, respectively. Multiple runs on one sample of D&C Green No. 6 indicated variability in the amount of p-toluidine found.

Rapid Method for Extraction and Reverse Phase Liquid Chromatographic Determination of Paraquat Residues in Water

1983 ◽  
Vol 66 (3) ◽  
pp. 663-666
Author(s):  
Ijaz Ahmad
Keyword(s):  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reverse Phase ◽  
Ultraviolet Detection ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Low Levels ◽  
Liquid Chromatographic

Abstract A simple and fast analytical method is described for the quantitative determination of low levels of paraquat residues in water. The method involves extraction and concentration of paraquat in water by using a C18 Sep-Pak cartridge followed by reverse phase high performance liquid chromatographic determination with ultraviolet detection at 257 nm. Recoveries of paraquat from spiked samples were above 93% with a coefficient of variation of 6.1%. The method can be used for water samples with paraquat concentrations as low as 0.05 ppm.

Liquid-chromatographic determination of isoenzymes of alkaline phosphatase in serum and tissue homogenates.

1986 ◽  
Vol 32 (5) ◽  
pp. 816-818 ◽  
Author(s):  
E Schoenau ◽  
K H Herzog ◽  
H J Boehles
Keyword(s):  
Alkaline Phosphatase ◽  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Chromatographic Determination ◽  
Heat Inactivation ◽  
Tissue Homogenates ◽  
Stepwise Gradient ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We describe a new method for separating alkaline phosphatase (AP) isoenzymes by means of "high-performance" liquid chromatography. Isoenzymes are eluted from the column (Mono Q HR 5/5, a strong anion-exchanger) with a stepwise gradient of LiCl. The isoenzymes originating from small intestine, bone, liver, and bile were identified by use of tissue homogenates, pathological sera, and heat inactivation.

High Performance Liquid Chromatographic Determination of Phenothiazine Residues in Sheep Tissues

1980 ◽  
Vol 63 (5) ◽  
pp. 988-991
Author(s):  
Graeme L Blackman ◽  
Ah Chai Ho ◽  
Alex Jozsa ◽  
John D Kelly
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Tissue Samples ◽  
Silica Column ◽  
Liquid Chromatographic Determination ◽  
Residue Levels ◽  
Liquid Chromatographic

Abstract A high performance liquid chromatographic (HPLC) technique is described for the determination of residue levels of the anthelmintic drug phenothiazine in sheep tissues. Phenothiazine was administered to sheep which were slaughtered after withholding periods of 24, 48, and 72 h. Residues of phenothiazine were then extracted from tissue samples by homogenization in methanol. The HPLC analysis of the extracts involved separation on a 10 μm silica column using a mobile phase of 0.3% n-propanol in cyclohexane. The lower limit of detection by ultraviolet absorption at 254 nm was 0.05 ppm

Liquid Chromatographic Determination of Moxidectin Residues in Cattle Tissues and Confirmation in Cattle Fat by Liquid Chromatography/Mass Spectrometry

1993 ◽  
Vol 76 (6) ◽  
pp. 1230-1235 ◽  
Author(s):  
Alisa Khunachak ◽  
Adrian R Dacunha ◽  
Steven J Stout
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Limit Of Detection ◽  
Parent Compound ◽  
Chromatographic Determination ◽  
Liquid Chromatography Mass Spectrometry ◽  
Liver And Kidney ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Moxidectin, a potent new endo- and ectoparasitic agent, is determined in cattle tissues by liquid chromatography (LC) with fluorescence detection. Moxidectin residues in cattle fat are confirmed with thermospray LC/mass spectrometry (MS). Moxidectin is extracted from the tissue with acetonitrile; the extract is partitioned with hexane, concentrated, and reacted with acetic anhydride, 1-methylimidazole, and dimethylformamide to produce a fluorescent product. The validated sensitivity of the LC/fluorescence method was 10 ppb, with a limit of detection typically between 1 and 2 ppb. Average recoveries from cattle fat, muscle, liver, and kidney were 99,95,89, and 92%, respectively. LC/MS confirmatory method determined the underivatized parent compound following the acetonitrilehexane partitioning step, with an average recovery of 108% at the 250 ppb level in cattle fat.

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