Silver-modified mobile phase for normal-phase liquid chromatographic determination of prostaglandins and their 5,6-trans isomers in prostaglandin bulk drugs and triacetin solutions

1985 ◽  
Vol 321 ◽  
pp. 353-362 ◽  
Author(s):  
L.D. Kissinger ◽  
R.H. Robins
Keyword(s):  
Mobile Phase ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Trans Isomers ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

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 Hydrocortisone in Bulk Drug Substance and Tablets: Collaborative Study

1984 ◽  
Vol 67 (2) ◽  
pp. 218-221 ◽  
Author(s):  
Milda J Walters ◽  
◽  
N Falcone ◽  
K G Hanel ◽  
E H Jefferson ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Drug Substance ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Bulk Drug ◽  
Liquid Chromatographic

Abstract A normal phase liquid chromatographic (LC) method for determining the hydrocortisone content of bulk drug substance, tablet composites, and individual tablets was subjected to a collaborative study by 6 laboratories. The results showed a mean recovery of 98.5% for an authentic tablet formulation and reproducibility coefficients of variation of 0.97, 1.6, and 2.7% for bulk drug substance, tablet composites, and individual tablets, respectively. Infrared (IR) and thin layer chromatographic (TLC) identification tests, also included in the collaborative study, were satisfactory. The LC method for determining hydrocortisone in bulk drug substance, tablet composites, and individual tablets, with IR and TLC identification, has been adopted official first action.

Liquid Chromatographic Determination of Major Alkaloids in Gum Opium

1985 ◽  
Vol 68 (4) ◽  
pp. 801-803
Author(s):  
Vinod K Srivastava ◽  
Mohan L Maheshwari
Keyword(s):  
Mobile Phase ◽  
Sodium Acetate ◽  
Chromatographic Determination ◽  
Aqueous Acetic Acid ◽  
Reverse Phase ◽  
Qualitative And Quantitative ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract An isocratic reverse phase liquid chromatographic (LC) system has been developed for qualitative and quantitative assay of morphine, codeine, thebaine, papaverine, and narcotine in gum opium. Five extractions with 2.5% aqueous acetic acid quantitatively extracted the major alkaloids. A mixture of 1% aqueous sodium acetate (pH 6.78), acetonitrile, and 1,4-dioxane (75 + 20 + 5) is used as LC mobile phase | for better resolution of alkaloid peaks, especially those of morphine and codeine. The method is suitable for routine analysis of gum opium I samples.

Normal-Phase Liquid Chromatographic Determination of Menadione in Animal Feeds

1988 ◽  
Vol 71 (4) ◽  
pp. 826-828 ◽  
Author(s):  
Roberto Laffi ◽  
Silvia Marchetti ◽  
Mario Marchetti
Keyword(s):  
Liquid Chromatography ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Vitamin K3 ◽  
Simple Method ◽  
Working Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A simple method is presented for determination of menadione in vitamin premixes and feedstuffs by normal-phase liquid chromatography (LC). Vitamin K3 is extracted and converted to free menadione, which can be determined directly by LC analysis. Peak area or height is measured at 251 nm, and menadione is quantitated by comparison with the working standard. Menadione can be estimated with a detection limit of 2.5 ppm. Recoveries for premixes ranged from 97.3 to 98.3% and for feedstuffs from 93.7 to 96.8%. The method allows the assay of all commercial K3 compounds in pure or stabilized form and is applicable to a wide variety of feeds and premixes.

Simultaneous Liquid Chromatographic Determination of Some Tetracyclines in Serum

1986 ◽  
Vol 69 (5) ◽  
pp. 760-762
Author(s):  
Krystyna Tyczkowska ◽  
Arthur L Aronson
Keyword(s):  
Molecular Weight ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Molecular Weight Cutoff ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A sensitive liquid chromatographic method has been developed for the simultaneous determination of oxytetracycline, minocycline, tetracycline, and doxycycline in serum. A serum sample is vortex-mixed with a solution of mobile phase for tetracyclines and 2% (v/v) phosphoric acid. The mixture is filtered using a 30 000 molecular weight cutoff microseparation tube which separates high-molecular-weight solutes following low-speed centrifugation. Tetracyclines are separated from other serum components by reverse phase liquid chromatography (LC) with buffered methanol mobile phase. Ultraviolet absorbance of the column effluent is monitored at 267 nm. Concentrations as low as 0.2 μg/mL of tetracyclines in serum are quantitatable, with recoveries from 76.2 to 102.6% and coefficients of variation from 2.69 to 5.36%. The method has been tested in bovine, porcine, equine, caprine, ovine, canine, feline, and avian (turkey) serum.

Reverse Phase Liquid Chromatographic Determination of Aspartame in Beverages and Beverage Mixes

1984 ◽  
Vol 67 (3) ◽  
pp. 510-513 ◽  
Author(s):  
Norma G Webb ◽  
Darrell D Beckman
Keyword(s):  
Mobile Phase ◽  
Isopropyl Alcohol ◽  
Chromatographic Determination ◽  
Artificial Sweetener ◽  
Reverse Phase ◽  
Acetic Acid Water ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A method is described for determining the artificial sweetener aspartame in beverages and beverage mixes by liquid chromatography. Aspartame is separated on a μC18 column, using a mobile phase of acetic acid, water, and isopropyl alcohol at pH 3.0 and UV detection at 254 nm. Beverages are filtered through 0.45 μm filters and injected directly into the chromatograph. Aspartame is eluted in approximately 7 min. Detection of aspartame is confirmed by a UV scan of the trapped peak. Aspartame is quantitated in the presence of other beverage additives such as saccharin, caffeine, sodium benzoate, artificial colors, and artificial flavors. Results are presented for spiked soda beverages, beverages from fruit-flavored mixes, instant tea, reconstituted presweetened drink mixes, and a powdered tabletop sweetener.

Effects of Injection Solvent and Mobile Phase on Efficiency in Reverse-Phase Liquid Chromatographic Determination of Aflatoxin M1

1990 ◽  
Vol 73 (1) ◽  
pp. 69-70 ◽  
Author(s):  
Rodney W Beaver
Keyword(s):  
Mobile Phase ◽  
Chromatographic Determination ◽  
Aflatoxin M1 ◽  
Mobile Phase Composition ◽  
Reverse Phase ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Theoretical Plates

Abstract The effects of Injection solvent and mobile phase composition on the reverse-phase liquid chromatographic determination of aflatoxin M1 (M1) were examined. M1 was converted to the more highly fluorescent derivative aflatoxin M2a (M2a)- Using a C-18 column and a mobile phase of H20-MeCNMeOH (60 + 20 + 20) (MP-A), M2a was dissolved in various ratios of MeCN-H20 prior to Injection. Chromatographic efficiency for the M2a peak varied from ca 2000 theoretical plates when injected in 30% aqueous MeCN to ca 9000 plates when injected in water alone. However, using the same C-18 column but with a mobile phase of H20-IPAMeCN (80 + 12 + 8) (MP-B), the M2a peak exhibited 25000 plates when injected in 30% aqueous MeCN and 10000 plates when injected in water alone.

Liquid Chromatographic Determination of Residual Styrene in Polystyrene Food Packaging

1981 ◽  
Vol 64 (3) ◽  
pp. 647-652
Author(s):  
Sandra L Varner ◽  
Charles V Breder
Keyword(s):  
Mobile Phase ◽  
Food Packaging ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Plastic Containers

Abstract The determination of residual styrene in polystyrene food packaging polymers by a reverse phase liquid chromatographic method is described. The polymer is dissolved in tetrahydrofuran and then reprecipitated with methanol. The filtered solution is chromatographed by using an aqueous tetrahydrofuran mobile phase, and the styrene is detected and quantitated by ultraviolet at 254 nm. The detection limit for the method is about 0.5 ppm styrene on a solution basis and 20 ppm in the polymer. The average recovery of styrene from spiked polymer (about 50–3700 ppm) is 88%. Apparent residual styrene was determined in several commercial products, including rigid polystyrene cups, flexible plastic containers, and several foam products. The monomer levels ranged from about 60 to 2250 ppm.

Ion-Pairing Liquid Chromatographic Determination of Benzimidazole Fungicides in Foods

1990 ◽  
Vol 73 (5) ◽  
pp. 753-761 ◽  
Author(s):  
Dalia M Gilvydis ◽  
Stephen M Walters
Keyword(s):  
Mobile Phase ◽  
Ion Pairing ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Benzimidazole Fungicides ◽  
Reverse Phase Liquid Chromatography ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A method Is described for determining residues in foods of thiabendazole, thlophanate methyl, the dl-oxygen analogue metabolite [dimethyl 4,4'-0-phenylene bis (allophanate)] that Is the metabolite name of the latter, and methyl-2- benzlmldazole carbamate, which Is the major metabolite and fungltoxlc principle common to both thlophanate methyl and benomyl. The residues are extracted from the product using methanol and are partitioned Into dlchloromethane after initial acidification and again after subsequent alkalinization of the extract. Residues are separated and quantified by reverse- phase liquid chromatography using an ion-pairing mobile phase with UV and fluorescence detectors In tandem. Recoveries from 7 different food crops fortified at 0.2-35 ppm levels ranged from 64 to 105%.

Sign in / Sign up

Export Citation Format

Share Document