Application of Gel Permeation Chromatography and Nonaqueous Reverse Phase Chromatography to High Pressure Liquid Chromatographic Determination of Retinyl Palmitate in Fortified Breakfast Cereals

1980 ◽  
Vol 63 (1) ◽  
pp. 131-136 ◽  
Author(s):  
William O Landen
Keyword(s):  
High Pressure ◽  
Vitamin A ◽  
Methylene Chloride ◽  
Colorimetric Method ◽  
Gel Permeation Chromatography ◽  
Retinyl Palmitate ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Gel Permeation ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic (HPLC) method was developed for determining retinyl palmitate in cereals. Retinyl palmitate is fractionated from other methylene chloride-soluble components by using high pressure gel permeation chromatography (HP-GPC) followed by quantitation with nonaqueous reverse phase HPLC (RPHPLC). HP-GPC fractionation was accomplished using 2 µStyragel (100Å) columns connected in series on sample extracts in methylene chloride with methylene chloride as the mobile phase. A valve designed to facilitate the collection of the vitamin A fraction was installed in-line between the refractive index and absorbance detectors. RPHPLC quantitation was achieved on µBondapak C18 (10 µm) using methylene chloride–acetonitrile (30+70). Based on 23 repetitive analyses, recovery of vitamin A as retinyl palmitate in cereal products was 95.4±4.2% with spiking levels between 21.4 and 140 µg/g. Vitamin A in 15 cereals, representing bran, corn, oats, rice, and wheat, ranged from 34 to 194% of the declared level. The HPLC procedure was compared with the AOAC official colorimetric method and with an ultraviolet spectrophotometric method.

Application of Gel Permeation Chromatography and Nonaqueous Reverse Phase Chromatography to High Pressure Liquid Chromatographic Determination of Retinyl Palmitate and β-Carotene in Oil and Margarine

1979 ◽  
Vol 62 (2) ◽  
pp. 283-289 ◽  
Author(s):  
William O Landen ◽  
Ronald R Eitenmiller
Keyword(s):  
High Pressure ◽  
Vitamin A ◽  
Methylene Chloride ◽  
Gel Permeation Chromatography ◽  
Retinyl Palmitate ◽  
High Pressure Liquid Chromatographic ◽  
Rp Hplc ◽  
Liquid Chromatographic ◽  
Β Carotene

Abstract A high pressure liquid chromatographic method was developed using high pressure gel permeation chromatography (HP-GPC) and high pressure reverse phase chromatography (RP-HPLC) for quantitation of retinyl palmitate and β-carotene. HP-GPC was used for fractionation of vitamin A active compounds from oil preliminary to quantitation on nonaqueous RP-HPLC. HP-GPC fractionation was completed on oil and margarine dissolved in methylene chloride by 2 elution passes through 2 μStyragel (100Å) columns connected in series with methylene chloride as the mobile phase. RPHPLC separation of retinyl palmitate and β-carotene was achieved on μBondapak C18 (10 μm), using methylene chloride-acetonitrile ( 3 0 + 7 0 ) . Based on 10 repetitive analyses, recoveries of added β-carotene and retinyl palmitate from vegetable oils were 98.6±2.9 and 95.2±2.6%, respectively. The coefficients of variation were 2.9% for β-carotene and 2.7% for retinyl palmitate. The determination of vitamin A activity in 7 margarine brands with label claims of 10% U.S.RDA/serving revealed that all but one of the margarines contained at least 94% of the label claim. Vitamin A activity in the margarines ranged from 90.6 to 110.8% of the label declaration.

Differential Pulse Polarographic Determination of N-Nitrosodiethanolamine in Cosmetic Products

1982 ◽  
Vol 65 (4) ◽  
pp. 850-854 ◽  
Author(s):  
Hardy J Chou ◽  
Ronald L Yates ◽  
Raymond J Gajan ◽  
Henry M Davis
Keyword(s):  
Gel Permeation Chromatography ◽  
Differential Pulse ◽  
Preparative Hplc ◽  
Cosmetic Products ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Gel Permeation ◽  
Standard Additions ◽  
Liquid Chromatographic

Abstract A differential pulse polarographic (DPP) method is described for the detection and determination of JV-nitrosodiethanolamine (NDELA) in cosmetic products. The cosmetic sample is partitioned between IN HC1 and chloroform. The aqueous extract is isolated and further purified by passing it through a cartridge containing reverse phase high pressure liquid chromatographic (HPLC) packing (C18 Sep- Pak). Samples containing proteins are cleaned up by gel permeation chromatography. Direct polarographic interferences are removed by preparative HPLC. The prepared samples are then analyzed by polarography using the method of standard additions for quantitation. The DPP method can be used to determine NDELA in cosmetic products at levels as low as 100 ppb. Analyses of a commercial lotion and a commercial cream spiked at 3 levels in the ppm range gave recoveries ranging from 73 to 91%. The average of all recoveries was 80%.

High Pressure Liquid Chromatographic Determination of Melengestrol Acetate in Dry Feed Supplements

1981 ◽  
Vol 64 (3) ◽  
pp. 661-664
Author(s):  
Jose E Roybal
Keyword(s):  
High Pressure ◽  
Standard Deviation ◽  
Methylene Chloride ◽  
Animal Feed ◽  
Confirmatory Test ◽  
High Pressure Liquid Chromatographic ◽  
Melengestrol Acetate ◽  
Feed Supplements ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic (HPLC) method is described for the quantitative determination of melengestrol acetate (MGA) in dry animal feed supplements containing 0.000027-0.000220% MGA (0.125-1.00 mg/lb). Ground feed is Soxhletextracted with hexane, and the extract is partitioned from hexane into aqueous methanol and then into methylene chloride, followed by mixed column chromatography. MGA is then quantitated by HPLC. Average recovery of standard MGA through the method at 1.00 ppm (0.454 mg/lb).was 94.8% with a 3.58% standard deviation. Average spike recovery of MGA in fortified feed at 0.100 ppm (0.0454 mg/lb) to 2.00 ppm (0.907 mg/lb) level was 97.8% with a standard deviation of 5.39%. In addition, the method includes a 2-dimensional thin layer chromatographic confirmatory test for MGA.

High Pressure Liquid Chromatographic Determination of Vitamins A and E in Cereal Products

1979 ◽  
Vol 62 (3) ◽  
pp. 637-641
Author(s):  
Warren A Widicus ◽  
James R Kirk
Keyword(s):  
High Pressure ◽  
Direct Injection ◽  
Chromatographic Determination ◽  
Retinyl Palmitate ◽  
Tocopheryl Acetate ◽  
High Pressure Liquid Chromatographic ◽  
Cereal Products ◽  
Average Recovery ◽  
Liquid Chromatographic

Abstract A rapid method for the simultaneous determination of vitamins A and E in fortified cereal products has been developed. Saponification of retinyl or tocopheryl esters is not required, permitting direct injection of the extracted lipids onto the high pressure liquid chromatographic column without sample cleanup. Elution times of 2.46 and 3.40 min were determined for retinyl palmitate and tocopheryl acetate, respectively, using a μPorasil column and an isocratic mobile phase of hexane-chloroform (85+15) with a flow rate of 1.5 mL/min. The average recovery of retinyl palmitate was 99.2% (std dev. 4.28), and the average recovery of tocopheryl acetate was 94.9% (std dev. 4.10) in 2 cereals containing corn, oat, rice, and wheat. No significant amounts of naturally occurring tocopherols were found in the cereals.

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%.

High Pressure Liquid Chromatographic Determination of Sulfanitran and Dinsed in Medicated Feeds and Premixes

1977 ◽  
Vol 60 (5) ◽  
pp. 1064-1066
Author(s):  
Kathleen L Eaves ◽  
Billy M Colvin ◽  
Alan R Hanks ◽  
Rodney J Bushway
Keyword(s):  
High Pressure ◽  
Colorimetric Method ◽  
Chromatographic Determination ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Method ◽  
Medium Porosity ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple reverse phase high pressure liquid chromatographic method is described for determining sulfanitran (acetyl-p-nitrophenylsulfanilamide) and Dinsed (dinitrodiphenylsulfonylethylenediamine) in a variety of feed premixes and formulations. Feed premixes are extracted with dimethylformamide, and formulated feeds are extracted with hot methanol. The extract is filtered through medium porosity paper and injected into a liquid chromatograph equipped with a 254 nm ultraviolet detector and a 30 cm column packed with μBondapak C18. The mobile phase is acetonitrile-water (45+55) at a flow rate of 1.0 ml/min. Chromatography was complete in 10 min and peak heights were used for quantitation. Comparison of analyses of commercial samples by this method and by the AOAC colorimetric method, 42.176–42.179, showed close agreement. Recovery of spiked feed samples ranged from 98 to 105%. Butynorate and roxarsone, 2 other drugs which are normally found in combination with sulfanitran and Dinsed, do not interfere.

Switching Valve Designed For High Pressure Liquid Chromatographic Fraction Collection

1979 ◽  
Vol 62 (6) ◽  
pp. 1355-1357
Author(s):  
William O Landen
Keyword(s):  
High Pressure ◽  
Oil Removal ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
Switching Valve ◽  
Gel Permeation ◽  
In Series ◽  
High Pressure Liquid Chromatograph ◽  
Pass Through ◽  
Liquid Chromatographic

Abstract The use of a collection valve specifically designed for high pressure liquid chromatography is described. Application of the valve to high pressure gel permeation chromatographic (GPC) separation of oil from the vitamin A active fraction of margarine resulted in efficient oil removal after one pass through 2 μStyragel (100A) columns connected in series. Using the normal collection mode of the high pressure liquid chromatograph, 2 passes through the GPC columns were required to adequately resolve the fractions.

High Pressure Liquid Chromatographic Determination of Oxazepam Dosage Forms: Collaborative Study

1983 ◽  
Vol 66 (4) ◽  
pp. 864-866
Author(s):  
Eileen S Bargo ◽  
◽  
E Aranda ◽  
C Bonnin ◽  
S Hauser ◽  
...  
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A reverse phase high pressure liquid chromatographic method for the determination of oxazepam in tablets and capsules was collaboratively studied by 9 laboratories. Collaborators were supplied with 6 samples that included synthetic and commercial formulations. Tablet and capsule composites are diluted with methanol and filtered. Oxazepam is determined at 254 nm by using a C18 column. Mean recoveries of oxazepam from synthetic tablet and capsule formulations were 97.2 and 99.0%, respectively. Mean coefficients of variation for tablets and capsules ranged from 1.85 to 2.86%. The method has been adopted official first action.

High Pressure Liquid Chromatographic Determination of Physostigmine Salicylate and Physostigmine Sulfate in Liquids and Ointments: Collaborative Study

1982 ◽  
Vol 65 (1) ◽  
pp. 132-137
Author(s):  
Norlin W Tymes ◽  
◽  
G Briguglio ◽  
C Corcoran ◽  
R Everett ◽  
...  
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Internal Standard ◽  
Pharmaceutical Formulations ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Results of 11 laboratories are presented for the collaborative study of a proposed method for the quantitative reverse phase high pressure liquid chromatographic (HPLC) determination of physostigmine salicylate and physostigmine sulfate in pharmaceutical formulations. The samples consisted of commercial solution, injection, and ointment preparations, each containing one of the physostigmine salts. The physostigmine salt is extracted from ointments with acetonitrile after the ointment is dissolved in hexane. Liquid preparations are diluted directly. Physostigmine is determined at 254 nm on a C18 column by comparison with a physostigmine standard. Flurazepam hydrochloride is the internal standard. The method has been adopted official first action for the solution dosage form.

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