Liquid Chromatographic Methodology for the Characterization of Orange Juice

1988 ◽  
Vol 71 (3) ◽  
pp. 469-473
Author(s):  
Gracia A Perfetti ◽  
Frank L Joe ◽  
Thomas Fazio ◽  
Samuel W Page
Keyword(s):  
Pattern Recognition ◽  
Orange Juice ◽  
Mobile Phase ◽  
Grapefruit Juice ◽  
Methylene Chloride ◽  
Coefficients Of Variation ◽  
Pattern Recognition Analysis ◽  
Methoxylated Flavones ◽  
Liquid Chromatographic

Abstract Liquid chromatographic (LC) methodology potentially useful for the characterization of orange juice, with particular regard to detecting adulteration of orange juice by computer pattern recognition analysis, has been developed. After dilution with methanol the juice is extracted with hexane to remove the carotenoids, which are chromatographed on a C18 column with an acetonitrile-methanol-methylene chloride mobile phase and detection at 450 nm. Further extraction of the juice with methylene chloride isolates the methoxylated flavones, which are chromatographed by reverse phase LC with an acetonitrile-methanol-water mobile phase and detection at 280 nm. The flavanone glycosides remaining in solution are chromatographed on a C18 column with an acetonitrile-water mobile phase and detection at 280 nm. The precisions of the heights of the 32 LC peaks selected for pattern recognition analysis were determined from 5 replicate analyses of a single juice. Coefficients of variation of the replicates ranged from 0.3 to 4.5%, with an average of 2.1%. Adulteration of products with sodium benzoate-fortified pulpwash or grapefruit juice can be detected by this method. Pattern recognition analysis of the data obtained for 80 authentic and 19 adulterated orange juices showed that the method is potentially useful for distinguishing between authentic and adulterated products.

High Performance Liquid Chromatographic Determination of Carbaryl Insecticide in Formulations

1980 ◽  
Vol 63 (3) ◽  
pp. 650-652
Author(s):  
William H Mcdermott
Keyword(s):  
High Performance ◽  
Methylene Chloride ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Modified Silica Gel ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A high performance liquid chromatographic method for carbaryl in formulations has been developed and used to assay 3 formulations in a 10-day repeatability study. The method uses a cyano modified silica gel column packing and a mobile phase of heptane-methylene chloride-isopropanol-methanol (60+35+4.8+0.2). The coefficients of variation for 2 wettable powders and one aqueous flowable formulation were 0.61, 0.62, and 0.75%, respectively. It is recommended that a collaborative study be conducted on this method.

Determination of iV-Methylcarbamate Pesticides in Liver by Liquid Chromatography

1989 ◽  
Vol 72 (4) ◽  
pp. 586-592 ◽  
Author(s):  
Sher M Ali
Keyword(s):  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Fluorescence Detection ◽  
Methylene Chloride ◽  
Gel Permeation Chromatography ◽  
Purification Technique ◽  
Coefficients Of Variation ◽  
Gel Permeation ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method using a 2-step purification technique for the simultaneous determination of 10 carbamates in bovine, swine, and duck livers has been developed. Carbamates are extracted from liver samples with methylene chloride. After evaporation, the residues from the extract are dissolved in methylene chloride- cyclohexane (1 + 1) and cleaned up by gel permeation chromatography. The eluate containing carbamate residues is evaporated to dryness, reconstituted in methylene chloride, further purified by passing it through an aminopropyl Bond Elut extraction cartridge, and analyzed by liquid chromatography using post-column derivatization with orthophthalaldehyde and fluorescence detection. Excitation and emission are set at 340 and 418 nm, respectively. Liver samples for beef, pork, and duck were fortified with 5, 10, and 20 ppb of mixed carbamate standards. The average of 10 recoveries of 10 carbamates at all 3 levels of fortification was greater than 80% with coefficients of variation less than 17%.

scholarly journals Liquid Chromatographic Determination of Mebendazole and its Metabolites, Aminomebendazole and Hydroxymebendazole, in Eel Muscle Tissue

1996 ◽  
Vol 79 (3) ◽  
pp. 645-651 ◽  
Author(s):  
Christiaan A J Hajee ◽  
Nel Haagsma
Keyword(s):  
Muscle Tissue ◽  
Mobile Phase ◽  
Solid Phase ◽  
Chromatographic Determination ◽  
Extraction Column ◽  
Phase Extraction ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract An analytical method is presented for liquid chromatographic (LC) determination of mebendazole (MBZ), hydroxymebendazole (MBZ-OH), and aminomebendazole (MBZ-NH2) in eel muscle tissue. Muscle tissue is extracted with ethyl acetate at pH 7.5. After addition of n-hexane, the extract is cleaned up and concentrated on an aminopropyl solid-phase extraction column. The test solutions are analyzed isocratically on a ChromSpher B LC column with acetonitrile–phosphate buffer, pH 6.2, as mobile phase. Limits of detection and quantitation were 0.7 and 1.1 ¼g/kg, respectively, for MBZOH; 1.4 and 2.3 ¼g/kg, respectively, for MBZ; and 1.5 and 2.1 ¼g/kg, respectively, for MBZ-NH2. Interand intraday coefficients of variation were 3.5 and 3.4%, respectively, for MBZ-OH; 2.5 and 3.1%, respectively, for MBZ; and 5.8 and 4.8%, respectively, for MBZ-NH2. Mean recoveries were 90% for MBZ, 74% for MBZ-NH2, and 92% for MBZ-OH. A linear range of applicability of at least 10–1000 ¼g/kg was found for each analyte. Incurred MBZ-NH2 (181.3 ¼g/kg) was identified in eel muscle tissue apart from MBZ (23.7 ¼g/kg) after 48 h exposure ina treatment bath containing MBZ at 1 mg/L.

Liquid chromatographic analysis of disopyramide and its mono-N-dealkylated metabolite.

1979 ◽  
Vol 25 (3) ◽  
pp. 405-408 ◽  
Author(s):  
J J Lima
Keyword(s):  
Chromatographic Analysis ◽  
Mobile Phase ◽  
High Performance ◽  
Antiarrhythmic Drugs ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic ◽  
Lower Limits

Abstract We describe a rapid, sensitive, and specific "high performance" liquid chromatographic analysis for disopyramide and its mono-N-dealkylated metabolite in serum, urine, and saliva. We used a mu-Bondapak CN column and an acetate buffer mobile phase containing methanol. Retention times for the two compounds and the internal standard, p-chlorodisopyramide, were 3.4, 4.1, and 6.3 min, respectively. The lower limits of sensitivity for drug and metabolite were 50 and 80 micrograms/L, respectively, with maximum coefficients of variation of 4.6 and 12%, respectively. Currently used antiarrhythmic drugs did not interfere with the analysis of disopyramide, and the pharmacokinetics of the drug, obtained from studies of one subject, agree well with reported values.

Normal Phase Liquid Chromatographic Determination of Sulfamethoxazole in Tablets: Collaborative Study

1985 ◽  
Vol 68 (1) ◽  
pp. 88-91
Author(s):  
John W Robinson
Keyword(s):  
Mobile Phase ◽  
Methylene Chloride ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Synthetic Sample ◽  
Photometric Detection ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Powdered Composite ◽  
Liquid Chromatographic

Abstract A stability-indicating liquid chromatographic method is presented for determining sulfamethoxazole in tablets. The method uses a 10 p.m silica column, an isooctane-methylene chloride-2-propanol-acetonitrile- glacial acetic acid (70 + 25 + 5 + 5 + 0.5) mobile phase, and photometric detection at 254 nm. Seven laboratories collaboratively studied this method on powdered composite samples prepared from commercial 500 and 1000 mg tablets and on an authentic tablet mixture containing 83.32% added sulfamethoxazole. Mean assay results for the 500 and 1000 mg tablets w ere 102.2 and 97.9% of declared, respectively (n = 4). The mean recovery value for the synthetic sample was 99.4% (n = 4). The pooled reproducibility standard deviation (SD) (coefficient of variation (CV) ) and pooled repeatability SD (CV) were ± 1.01 (1.01%) and ± 0.96 (0.96%), respectively. These results were in good agreement with those obtained by the Associate Referee for the titration method of USP XX. The proposed method can also be used for monitoring the presence of sulfanilamide in sulfamethoxazole by increasing the proportions of both acetonitrile and 2-propanol in the mobile phase. The method has been adopted official first action.

Liquid Chromatographic Determination of Simazine, Atrazine, and Propazine Residues in Catfish

1995 ◽  
Vol 78 (4) ◽  
pp. 1067-1071 ◽  
Author(s):  
David C Holland ◽  
Robert K Munns ◽  
José E Roybal ◽  
Jeffrey A Hurlbut ◽  
Austin R Long
Keyword(s):  
Ethyl Acetate ◽  
Petroleum Ether ◽  
Simultaneous Determination ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Triazine Herbicides ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the simultaneous determination of the triazine herbicides, simazine (SIM), atrazine (ATZ), and propazine (PRO) in the 12.5–100 ppb range in catfish. The herbicides are extracted from catfish homogenates with ethyl acetate, followed by solvent partitioning between acetonitrile and petroleum ether and additional cleanup on a C18 cartridge. A Supelcosil LC-18-DB column is used for LC separation, and UV determination is at 220 nm. The isocratic mobile phase is a mixture of methanol, acetonitrile, and water. Mean recoveries from catfish were 88.7, 96.9, and 91.7%; standard deviations were 6.84,7.78, and 6.26%; and coefficients of variation were 7.72,8.03, and 6.82% for SIM, ATZ, and PRO, respectively.

Determination of N-Methylcarbamate Insecticides in Vegetables, Fruits, and Feeds Using Solid-Phase Extraction Cleanup in the Normal Phase

1992 ◽  
Vol 75 (6) ◽  
pp. 1073-1083 ◽  
Author(s):  
Michael J Page ◽  
Mark French
Keyword(s):  
Solid Phase Extraction ◽  
Methylene Chloride ◽  
Solid Phase ◽  
Extraction Column ◽  
Phase Extraction ◽  
Coefficients Of Variation ◽  
Recovery Study ◽  
Initial Recovery ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the simultaneous determination of 8 carbamate pesticides in vegetable, fruit, and feed crops. Carbamates are extracted and then partitioned from vegetable, fruit, and feed crop samples using procedures previously developed. An aliquot is taken from the sample partitioning, evaporated by a nitrogen stream, and reconstituted in 5 mL 5% methylene chloride-hexane. Sample cleanup is accomplished by aspirating through an aminopropyl Bond Elut (NH2) solid-phase extraction column. Following aspiration, the sample is eluted with 10 mL 2% methanol-methylene chloride. The eluate is evaporated, again under nitrogen, and reconstituted in methanol for fluorometric LC analysis. The method provides an excellent cleanup for all matrixes studied. Initial recoveries of 98,90, and 91% were obtained for fortifications of 0.05,0.5, and 5.0 ppm, respectively. Linear range recovery studies demonstrated results that agreed with the initial recovery study. An intralaboratory study of the method was conducted in quadruplicate, using 10 assorted vegetable, fruit, and feed crops. With no exceptions, the overall average pesticide recovery for this study was 92%, with a standard deviation of 7.1 (n = 253). Carbamate recoveries varied from 80 to 105%, with coefficients of variation (CVs) that compared favorably to the intralaboratory Horwitz CV. Detection limits of less than 0.01 ppm are obtainable with the described method

A high-performance liquid-chromatographic method for routine simultaneous determination of nicotine and cotinine in plasma.

1988 ◽  
Vol 34 (4) ◽  
pp. 724-729 ◽  
Author(s):  
M Hariharan ◽  
T VanNoord ◽  
J F Greden
Keyword(s):  
Simultaneous Determination ◽  
Mobile Phase ◽  
High Performance ◽  
Methylene Chloride ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Standard Curve ◽  
Liquid Chromatographic

Abstract We describe a rapid, sensitive method for the routine simultaneous determination of nicotine and cotinine in 1 mL of plasma. Extraction in 10-mL screw-capped Teflon tubes with methylene chloride after deproteinization with trichloroacetic acid eliminated emulsion formation. The extract, after evaporation and reconstitution in 30 microL of mobile phase, is injected into a reversed-phase C-18 ion-pair column of an isocratic high-performance liquid-chromatographic unit. Absorbance is monitored at 256 nm. The mobile phase is a citrate-phosphate (30 mmol each per liter) buffer mixture containing 50 mL of acetonitrile and 1 mmol of sodium heptanesulfonate per liter. 2-Phenylimidazole is the internal standard. The detection limit is 1 microgram/L for nicotine and 3 micrograms/L for cotinine. The standard curve is linear from 0 to 700 micrograms/L for both compounds. The average CV for nicotine in the concentration range 0-100 micrograms/L is 6.5%, and that for cotinine in the concentration range 50-700 micrograms/L is 4%.

scholarly journals An Updated Liquid Chromatographic Assay for the Determination of Glyphosate in Technical Material and Formulations

2008 ◽  
Vol 91 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Walter K Gavlick ◽  
David F Tomkins
Keyword(s):  
Refractive Index ◽  
Phosphate Buffer ◽  
Mobile Phase ◽  
Matched Pair ◽  
Matched Pairs ◽  
Coefficients Of Variation ◽  
Technical Material ◽  
Liquid Chromatographic ◽  
Glyphosate Formulations

Abstract An updated liquid chromatographic (LC) method for the determination of glyphosate in technical material and formulations was tested by 7 laboratories. Samples were dissolved in water and injected into an LC system with a C18 guard column, an anion exchange analytical column, and a phosphate buffer mobile phase with 12 to 15 methanol. Detection was by UV absorption at 195 nm or refractive index. Automated injections were made. Calculations were based on peak area comparisons with external standards. The interlaboratory study analyzed 6 matched pairs of 3 glyphosate technical materials and 3 glyphosate formulations. The matched pair results were analyzed by using the AOAC spreadsheet and Youden's matched pair calculations. Coefficients of variation for the 6 samples ranged from 0.46 to 0.85.

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