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

1978 ◽  
Vol 61 (6) ◽  
pp. 1424-1427 ◽  
Author(s):  
Wesley R Kreiser ◽  
Robert A Martin
Keyword(s):  
High Pressure ◽  
Chromatographic Determination ◽  
Hot Water ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Hot Water Extraction ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method was developed for determining theobromine and caffeine in cocoa and chocolate products by high pressure liquid chromatography. After a simple hot water extraction, both theobromine and caffeine were separated by using a reverse phase Cl s column and a mobile phase of methanol-water-acetic acid (20+ 79+1). Theobromine and caffeine were quantitated at 280 nm; average recoveries were 98.7 and 95.0%; and coefficients of variation were 2.31 and 3.91%, respectively.

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.

Ion Pairing High Pressure Liquid Chromatographic Determination of Amaranth in Licorice Products

1981 ◽  
Vol 64 (6) ◽  
pp. 1411-1413
Author(s):  
William J Hurst ◽  
James M Mckim ◽  
Robert A Martin
Keyword(s):  
High Pressure ◽  
Ion Pairing ◽  
Chromatographic Determination ◽  
Buffer Solution ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic method is described for the determination of amaranth (FD&C Red No. 2; Red No. 2) in licorice products. The Red No. 2 is extracted with a basic buffer solution, cleaned up on a Sep-Pak column, chromatographed on a reverse phase column in the ion pairing mode, and detected at 254 nm. The procedure is time-conservative with accurate and precise results. Recovery data ranged from 93 to 104%, and coefficients of variation were less than 4% for standards and samples.

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 Antihistamine-Adrenergic Combination Products

1980 ◽  
Vol 63 (1) ◽  
pp. 91-94 ◽  
Author(s):  
William J Bachman
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Chromatographic Determination ◽  
Step Response ◽  
Chlorpheniramine Maleate ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Reverse phase high pressure liquid chromatography (HPLC) with ion-pairing is used for the determination of pseudoephedrine hydrochloride in combination with triprolidine hydrochloride or chlorpheniramine maleate in sirups and tablets. Sirups require a preliminary column chromatography cleanup step. Response is linear for pseudoephedrine hydrochloride (range of 0–20 μg), chlorpheniramine maleate (range of 0–1.3 μg), and triprolidine hydrochloride (range of 0–1.0 μg). Recoveries from synthetic formulations were 98.8–101.3% for pseudoephedrine hydrochloride, 100.0–101.2% for chlorpheniramine maleate, and 97.7–99.8% for triprolidine hydrochloride. The coefficient of variation for the method is less than 1%.

High Pressure Liquid Chromatographic Determination of Allantoin in Cosmetic Creams and Lotions

1982 ◽  
Vol 65 (6) ◽  
pp. 1362-1365
Author(s):  
Kazuo Nakao ◽  
Keiichi Honda ◽  
Tohru Yoneya
Keyword(s):  
High Pressure ◽  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Silica Column ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A sensitive high pressure liquid chromatographic method was developed for the determination of allantoin in cosmetic preparations. The procedure consists of simple cleanup of samples, derivatization with p-nitrobenzaldehyde in N,N-dimethylformamide to an ultraviolet labeled derivative, and reverse phase chromatography on an octadecylsilylated silica column. Ultraviolet absorbance was measured at 270 nm. Recovery was greater than 97% for cosmetic samples, and the minimum limit of detection was 10 ng.

Reverse Phase High Pressure Liquid Chromatographic Determination of Vitamin K1 in Infant Formulas

1983 ◽  
Vol 66 (5) ◽  
pp. 1063-1066
Author(s):  
Martin P Bueno ◽  
Melina C Villalobos
Keyword(s):  
High Pressure ◽  
Chromatographic Determination ◽  
Hplc Method ◽  
Vitamin K1 ◽  
Infant Formulas ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A reverse phase high pressure liquid chromatographic (HPLC) method for quantitating vitamin K1 in enzymatic hydrolysates of infant formula is described. The vitamin is extracted with n-pentane before determination by isocratic and isothermal reverse phase HPLC. Recovery of vitamin Ki added io 5 infant formulas ranged from 84 to 103%

High Pressure Liquid Chromatographic Determination of Carbadox and Pyrantel Tartrate in Swine Feed and Supplements

1983 ◽  
Vol 66 (3) ◽  
pp. 602-605
Author(s):  
Dwight M Lowie ◽  
Robert T Teague ◽  
Floyd E Quick ◽  
Clarence L Foster
Keyword(s):  
High Pressure ◽  
Chromatographic Determination ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Wide Range ◽  
Liquid Chromatographic Determination ◽  
Reliable Procedure ◽  
Liquid Chromatographic ◽  
Pyrantel Tartrate

Abstract A rapid yet reliable procedure for the simultaneous extraction and assay of carbadox and pyrantel tartrate is described. The feed is extracted with water-acetonitrile-methanol and cleaned up on a short alumina column. The eluant is separated by high pressure liquid chromatography and the compounds are detected at different wavelengths. The drugs of interest are well resolved in all feeds studied. The procedure has also been applied to a wide range of feeds which contained either one of the drugs or both in combination. No significant interferences were observed. Spiked sample recoveries were 97% for carbadox and 101% for pyrantel tartrate. Ruggedness test coefficients of variation were 2.0% for carbadox and 2.1% for pyrantel tartrate.

Reverse Phase High Pressure Liquid Chromatographic Determination of Some Iodoamino Acid Contaminants in Sodium Liothyronine or Sodium Levothyronine

1979 ◽  
Vol 62 (4) ◽  
pp. 818-821
Author(s):  
Donald J Smith ◽  
Joseph H Graham
Keyword(s):  
High Pressure ◽  
Orthophosphoric Acid ◽  
Potassium Phosphate ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Some iodoamino acids have been separated and determined by high pressure liquid chromatography on octadecylsilane reverse phase packing with a mobile phase consisting of methanol, potassium phosphate monobasic, and orthophosphoric acid at 44°C. The method separates and quantitates mixtures of 3,5-diiodothyronine, liothyronine, isoliothyronine, and levothyroxine. The procedure provides an accurate, sensitive, and rapid estimation of decomposition and/or impurities in standards in approximately 30 min, at the <75 pmole level, using an ultraviolet detector at 254 nm.

Sign in / Sign up

Export Citation Format

Share Document