High Pressure Liquid Chromatographic Determination of Theobromine and Caffeine in Cocoa and Chocolate Products: Collaborative Study

1980 ◽  
Vol 63 (3) ◽  
pp. 591-594
Author(s):  
Wesley R kreiser ◽  
Robert A Martin ◽  
◽  
R Bigornia ◽  
R Bond ◽  
...  
Keyword(s):  
High Pressure ◽  
Petroleum Ether ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Peak Height ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Determination ◽  
The Mean ◽  
Liquid Chromatographic

Abstract Four duplicate samples of cocoa-containing materials, a practice sample, and standards were submitted to the collaborators for theobromine and caffeine analysis by HPLC. In the method the samples are defatted with petroleum ether, and dried. The fat-free residue is then extracted with water and an aliquot is injected into the chromatograph. Compounds are quantitated by comparison with internal or external standards, either by peak height or peak area. Results for all the analyses showed that few of the values were more than 2 standard deviations from the mean. The method has been adopted as official first action.

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.

High Pressure Liquid Chromatographic Determination of Major Organic Acids in Cranberry Juice

1978 ◽  
Vol 61 (6) ◽  
pp. 1490-1492 ◽  
Author(s):  
Elia D Coppola ◽  
Edward C Conrad ◽  
Richard Cotter
Keyword(s):  
High Pressure ◽  
Organic Acids ◽  
Chromatographic Determination ◽  
Cranberry Juice ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
The Mean ◽  
Liquid Chromatographic

Abstract A reverse phase high pressure liquid chromatographic method is presented for the simultaneous separation and determination of quinic, malic, and citric acids in single strength, undiluted cranberry juice. After a 1:10 dilution and cleanup through a disposable column, major organic acids in cranberry juice are separated on a Bondapak/C18 column and quantitated by using a differential refractometer. Twenty-seven samples of different single strength cranberry juice were analyzed using this method; the mean content of quinic, malic, and citric acids were 1.32 (std dev. 0.150), 0.92 (std dev. 0.079), and 1.08% (std dev. 0.111), respectively. Mean percent recoveries of each acid were quinic 95.4 (std dev. 6.8), malic 96.6 (std dev. 5.8), and citric 94.0% (std dev. 4.8).

Reverse Phase High Pressure Liquid Chromatographic Determination of Arprinocid in Animal Feeds

1982 ◽  
Vol 65 (1) ◽  
pp. 43-47
Author(s):  
Virginia A Thorpe
Keyword(s):  
High Pressure ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Simple Method ◽  
Working Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple method is presented for determination of arprinocid in finished feeds by reverse phase high pressure liquid chromatography. The sample is extracted with 95% DMF, the major feed interferences are removed by alumina chromatography, and arprinocid is separated from the remaining interferences on the HPLC column. The peak height detected at 254 nm can be quantitated by direct comparison with the working standard.

High Pressure Liquid Chromatographic Determination of Phenol in Honey

1981 ◽  
Vol 64 (2) ◽  
pp. 337-339
Author(s):  
Peter Sporns
Keyword(s):  
High Pressure ◽  
Mobile Phase ◽  
Silicic Acid Column ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method is described for determining phenol in honey by using high pressure liquid chromatography (HPLC). An internal standard, 2-phenylethanol, was added to honey which was steam-distilled and chromatographed on a 25 cm × 3.2 mm id Spherisorb 5 µm silicic acid column using water as the mobile phase. Absorbance was monitored at 195 nm. Using a mixed standard of known concentration and peak height measurements, the amount of phenol in the honey could be quantitated. Recovery of added phenol was checked at levels from 0.1 to 33 ppm.

High Pressure Liquid Chromatographic Determination of Antihistamine-Adrenergic Combination Products: Collaborative Study

1981 ◽  
Vol 64 (3) ◽  
pp. 564-569 ◽  
Author(s):  
William J Bachman ◽  
◽  
M Y Alpert ◽  
E Bargo ◽  
R E Draper ◽  
...  
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Chlorpheniramine Maleate ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A reverse phase high pressure liquid chromatographic method in which ion-pairing is used for the determination of combinations of pseudoephedrine hydrochloride with triprolidine hydrochloride or chlorpheniramine maleate in syrups and tablets was collaboratively studied by 8 laboratories. Collaborators were supplied with 12 samples including synthetic and commercial syrup formulations and commercial tablet composites. Mean recoveries of pseudoephedrine hydrochloride and triprolidine hydrochloride from synthetic syrup formulations were 100.5 and 99.6%, respectively. Mean recoveries of pseudoephedrine hydrochloride and chlorpheniramine maleate from synthetic syrups were 98.8 and 100.5%, respectively. Mean coefficients of variation for syrups and tablets ranged from 1.68 to 3.07% for pseudoephedrine hydrochloride, from 2.92 to 3.85% for triprolidine hydrochloride, and from 1.34 to 2.15% for chlorpheniramine maleate. The method has been adopted official first action.

High Pressure Liquid Chromatographic Determination of Patulin in Apple Juice

1978 ◽  
Vol 61 (6) ◽  
pp. 1359-1362 ◽  
Author(s):  
Helge Stray
Keyword(s):  
High Pressure ◽  
Ethyl Acetate ◽  
Apple Juice ◽  
Chromatographic Determination ◽  
High Pressure Liquid Chromatographic ◽  
Lower Detection ◽  
Liquid Chromatographic Determination ◽  
The Mean ◽  
Liquid Chromatographic

Abstract Patulin was extracted from apple juice with ethyl acetate and the extract was purified by elution from a silica gel column with ethyl acetate-toluene. The eluate was concentrated, and patulin was determined by reverse phase high pressure liquid chromatography using a 25 cm PartisiI-10 ODS column. The lower detection limit was 1 μg/L and the mean recovery of patulin added to apple juice was 82.6± 2.8%. The patulin content ranged from <1 to 220 μg/L for the 140 samples analyzed.

High Pressure Liquid Chromatographic Determination of Ethion in Formulations: Collaborative Study

1979 ◽  
Vol 62 (1) ◽  
pp. 11-14
Author(s):  
James E Launer
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Hplc Method ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple and rapid high pressure liquid chromatographic (HPLC) method is described for determining ethion (O,O,O',0'-tetraethyl-S,S'-methylene bisphosphorodithioate) in formulations, using reverse phase columns of either μBondapak C18/Porasil or ODS Permaphase. The sample is dissolved in either methanol for μBondapak C18 or acetonitrile for ODS Permaphase; pentachloronitrobenzene is used as an internal standard. After inert materials are removed, the supernate is injected onto the HPLC column and the compound is quantitated by peak height ratios at 254 nm. Six collaborators made single determinations of 8 samples. The average coefficients of variation were 0.76% for the 2 technical samples, 0.63% for the two 50% formulations, 0.95% for the two 25% wettable powders, and 0.76% for the two 2% oil formulations. The method was adopted as official first action.

High Pressure Liquid Chromatographic Determination of Monoand Disaccharides in Presweetened Cereals: Collaborative Study

1982 ◽  
Vol 65 (2) ◽  
pp. 256-264 ◽  
Author(s):  
Lucian C Zygmunt ◽  
◽  
E Anderson ◽  
B Behrens ◽  
R Bowers ◽  
...  
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Hplc Method ◽  
High Pressure Liquid Chromatographic ◽  
Aoac Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Water Alcohol

Abstract A collaborative study was conducted using a modified AOAC method (sugars in chocolate) for the determination of fructose, glucose, sucrose, and maltose in presweetened cereals by high pressure liquid chromatography (HPLC). Eight samples consisting of 6 products were analyzed in duplicate by the HPLC method and the AOAC Lane-Eynon method. The AOAC method was modified to use water-alcohol (1 + 1) and Sep-Pak C18 cartridges for sample cleanup. The HPLC results indicate precision comparable to the Lane-Eynon method and the chocolate method. The modified HPLC method has been adopted official first action.

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