scholarly journals Liquid Chromatographic Determination of Major Secondary Metabolites Produced by Aspergillus Species from Section Flavi

1998 ◽  
Vol 81 (1) ◽  
pp. 57-60 ◽  
Author(s):  
Victor S Sobolev ◽  
Bruce W Horn ◽  
Joe W Dorner ◽  
Richard J Cole
Keyword(s):  
Secondary Metabolites ◽  
Cyclopiazonic Acid ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Aspergillus Species ◽  
Uv Detector ◽  
Tetrabutylammonium Hydroxide ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed for simultaneous determination of major secondary metabolites—including cyclopiazonic acid (CPA), O-methylsterigmatocystin (OMST), and the versicolorins—produced by Aspergillus species from section Flavi (A. flavus, A. parasiticus, A. tamarii, and A. caelatus) on a liquid medium. Metabolites were extracted with chloroform and quantitated without prior cleanup by means of normal- phase ion-pair partition LC on silica gel with a mobile phase of n-heptane-2-propanol-n-butanolwater- tetrabutylammonium hydroxide (2560 + 900 + 230 + 32 + 8, v/v). Recoveries of CPA and OMST from fungal cultures spiked at 10 μg/mL were 98.90 + 3.27 and 95.92 + 5.27% (n = 5), respectively. At spike levels of 100 μg/mL, recoveries were 98.89 + 3.87 and 97.65 + 4.32% (n = 5), respectively. Limits of detection for pure standards were 0.25 μg/mL for CPA (at 280 nm) and 0.30 μg/mL for OMST (at 310 nm). UV detector responses to CPA and OMST were linear to about 0.5 and 3.5 μg/injection, respectively

Improved Liquid Chromatographic Determination of Riboflavin in Milk and Dairy Products

1985 ◽  
Vol 68 (4) ◽  
pp. 693-696 ◽  
Author(s):  
Samy H Ashoor ◽  
Michael J Knox ◽  
Jacquelyn R Olsen, ◽  
Dru Ann Deger
Keyword(s):  
Dairy Products ◽  
Chromatographic Determination ◽  
Simple Liquid ◽  
Uv Detector ◽  
Aoac Method ◽  
Total Analysis ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Milk And Dairy Products

Abstract Reported here is a simple liquid chromatographic (LC) method for the i determination of riboflavin in milk (liquid, evaporated, and dry), yogurt, ' and cheese. The method involves passing liquid samples or filtrates of semisolid and solid samples through a Clg cartridge. Retained riboflavin is then eluted with an aliquot of 50% methanol in 0.02M acetate buffer of pH 4. A volume of the eluate is injected into the LC system | consisting of a CJ8 column, a solvent of water-methanol-acetic acid (65 + 35 + 0.1, v/v) with a flow rate of 1 mL/min, and a UV detector set at 270 nm. The method is precise and accurate and compares i favorably with the present AOAC method. Moreover, it involves fewer sample preparation steps and has a total analysis time of less than 1 h.

Liquid Chromatographic Determination of Triadimefon in Technical and Formulated Products: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 586-589
Author(s):  
Stephen C Slahck
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Technical Products

Abstract A liquid chromatographic method for the determination of triadimefon (Bayleton™) in triadimefon technical and formulated products has been developed and subjected to a collaborative study with 7 participating collaborators. Formulations were extracted with mobile solvent and analyzed by normal phase chromatography, with 4-chlorophenyl sulfoxide as an internal standard. Collaborators were furnished with standards and samples of technical products, 50% wettable powders, and 25% wettable powders for analysis. Coefficients of variation of the values obtained on these samples were 1.42, 0.82, and 1.05%, respectively. The method has been adopted official first action.

High Pressure Liquid Chromatographic Determination of 5-(Hydroxymethyl)-2-Furaldehyde in Caramel Solution

1980 ◽  
Vol 63 (6) ◽  
pp. 1310-1313
Author(s):  
Felipe C Alfonso ◽  
Glenn E Martin ◽  
Randolph H Dyer
Keyword(s):  
Chromatographic Determination ◽  
Hplc Method ◽  
Uv Detector ◽  
High Pressure Liquid Chromatographic ◽  
Ethyl Vanillin ◽  
Caramel Color ◽  
Water Gradient ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract An HPLC method is described for the detection of caramel color by measuring the level of 5-(hydroxymethyl)-2-furaldehyde (5-HMF). For the several products of caramelization examined, 5-HMF was the most sensitive indicator of the presence of caramel. The method specifies a reverse phase C18 column, a UV detector set at 277 nm, and a methanol-water gradient to separate 5-HMF from interfering substances. Other flavor compounds resolved by the same gradient are vanillin, ethyl vanillin, coumarin, benzaldehyde, caffeine, anethole, theobromine, and cinnamaldehyde.

Liquid Chromatographic Determination of Furazolidone in Swine Serum and Avian Egg

1995 ◽  
Vol 78 (4) ◽  
pp. 1126-1130 ◽  
Author(s):  
Kenichi Yosheda ◽  
Fusao Kondo
Keyword(s):  
Chromatographic Determination ◽  
Accurate Method ◽  
Uv Detector ◽  
Drug Detection ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Swine Serum ◽  
Avian Egg

Abstract A rapid, simple, and accurate method for determination of furazolidone (FZ) in swine serum and avian egg using liquid chromatography (LC) with a 358 nm ultraviolet-visible spectrophotometric detector is described. After liquid–liquid extraction of sample with ethyl acetate using Extrelut-3, the extract is evaporated, redissolved in 40% acetonitrile, and injected directly into the chromatograph. The antibiotic can be analyzed within 30 min. Withinday recoveries for swine serum and avian egg spiked with FZ at 1 ppm were 90.0 and 88.1%, respectively, with coefficients of variation of 3.52 and 3.88%, respectively. Between days recoveries for the 1 ppm samples were 87.2 and 87.0%, with coefficients of variation of 3.10 and 4.29%, respectively. Determination of FZ also was performed by LC/mass spectrometry (MS) with an atmosphericpressure chemical-ionization interface (APCI) system. The LC/MS–APCI system is more applicable for qualitative analysis than quantitative analysis because the drug detection limit (about 0.1 μg/mL) is almost the same as that of the LC–UV detector.

Isolation, Purification, and Liquid Chromatographic Determination of Stilbene Phytoalexins in Peanuts

1995 ◽  
Vol 78 (5) ◽  
pp. 1177-1182 ◽  
Author(s):  
Victor S Sobolev ◽  
Richard J Cole ◽  
Joe W Dorner ◽  
Boris Yagen
Keyword(s):  
Acetic Acid ◽  
Silica Gel ◽  
Mobile Phase ◽  
High Speed ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Phase Partition ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method for determination of stilbene phytoalexins (SPs) in peanuts has been developed. SPs were extracted with acetonitrile–water (90 + 10, v/v) by high-speed blending. An aliquot of extract was applied to a minicolumn packed with AI2O3–ODS (C18) mixture and eluted with acetonitrile-water (90 + 10, v/v). Eluate was evaporated under nitrogen, and residue was dissolved in LC mobile phase. SPs in an aliquot of purified extract were quantitated by normal-phase partition LC on silica gel with n-heptane–2-propanol–water–acetonitrile–acetic acid (1050 + 270 + 17 + 5 + 1, v/v) as mobile phase. Recoveries of SPs [frans-4-(3-methyl-but-1-enyl)-3,5,4′-trihy-droxystilbene (trans-arachidin-3; t-Ar-3), trans-3-isopentadienyl-4,3′,5′-trihydroxystilbene (t-IPD), and trans-3,5,4′-trihydroxystilbene (trans-resveratrol; t-Res)] from peanuts spiked at 300 ppb were 96.05 ± 2.8%. Limits of quantitation for t-Ar-3 and t-IPD were about 100 ppb. t-Ar-3, t-IPD, and t-Res were found in all parts of the peanut plant as major SPs produced in response to fungal invasion.

Liquid Chromatographic Determination of Acifluorfen in Soil and Water

1990 ◽  
Vol 73 (4) ◽  
pp. 599-601
Author(s):  
Mara Gennari ◽  
Michèle Negre ◽  
Alessandro Cignetti
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Chromatographic Determination ◽  
Phase Extraction ◽  
Uv Detector ◽  
Liquid Chromatograph ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Soil And Water

Abstract An analytical method based on the use of a liquid chromatograph equipped with a UV detector was developed for the determination of acifluorfen In soil and water. Acifluorfen was extracted from soil In methanol-0.10N NaOH (80 + 20 v/ v) and from water by partition with dlchloromethane. Solvent partitioning and solid-phase extraction were used to separate acifluorfen from major Interfering sample components. Average recoveries from soil at 1, 0.1, and 0.01 ppm fortification levels were 95.1 ± 3.4,92.6 ± 2.9, and 73.9 ± 3.0%, respectively. Recoveries from water spiked at levels from 0.01 to 1 ppm averaged 96.5 ± 5.4%. Method limits of detection were 0.006 ppm in soil and 0.003 ppm In water.

scholarly journals Liquid Chromatographic Determination of Carotenoids and Vitamins A and E in Multivitamin Tablets

1999 ◽  
Vol 82 (1) ◽  
pp. 68-72 ◽  
Author(s):  
Jidong Sun
Keyword(s):  
Ammonium Acetate ◽  
Chromatographic Determination ◽  
Uv Detector ◽  
Retinyl Acetate ◽  
Coefficients Of Variation ◽  
Acid Succinate ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Β Carotene

Abstract Carotenoids and vitamins A and E in multivitamin tablets can be determined simultaneously by reversed-phased liquid chromatography (LC) with a programmable UV detector. Samples were dissolved in dimethyl sulfoxide and thenextracted with hexane. A portion was injected onto a SymmetryC18,150 × 4.6 mm id, 5 μm column and chroma tographed with a mobile phaseof acetonitrile–0.25% ammonium acetate in methanol and 0.05% triethylamine in dichloromethane. A step gradient was used. The system was operated at 25°C with a flow rate of 1.5 mL/min. UV detection was at 325 nm for retinols, 285 nm for tocopherols, and 450 nm for carotenoids. Detection limits were less than 0.3 ng for retinol and retinyl acetate; 2 ng for α-tocopherol acid succinate; 10 ng for α-tocopherol, γ-tocopherol, and α-tocopherol acetate; and 0.4 ng for α-carotene and β-carotene. Intraday and interday coefficients of variation ranged from 1.40 to 5.20%. The sample preparation method and LC assay are practical for quality control and routine analysis of multivitamin tablets.

High Pressure Liquid Chromatographic Determination of Vitamin D3 in Livestock Feed Supplements

1977 ◽  
Vol 60 (6) ◽  
pp. 1296-1301 ◽  
Author(s):  
Allen C Ray ◽  
J Nelson Dwyer ◽  
John C Reagor
Keyword(s):  
High Pressure ◽  
Vitamin D3 ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
High Pressure Liquid Chromatographic ◽  
Livestock Feed ◽  
Feed Supplements ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Vitamin D3 is determined in livestock feed supplements by high pressure liquid chromatography (HPLC). Extracts of the samples are quantitated using normal phase chromatography. If interfering co-extractives are present, an aliquot of the extract is injected on the normal phase column, and the fraction corresponding to vitamin D3 is collected. The vitamin fraction is then further cleaned up and separated from interferences by reverse phase chromatography, and quantitated by measuring the ultraviolet absorption at 254 and 280 nm. The method measures actual vitamin D3 content in the presence of pre-vitamin D, tachysterol, isotachysterol, and vitamin A.

Sign in / Sign up

Export Citation Format

Share Document