High Performance Liquid Chromatographic Determination of Caffeine in Decaffeinated Coffee, Tea, and Beverage Products

1983 ◽  
Vol 66 (3) ◽  
pp. 606-609 ◽  
Author(s):  
Samy H Ashoor ◽  
George J Seperich ◽  
Woodrow C Monte ◽  
Jim Welty
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Uv Detector ◽  
Coefficients Of Variation ◽  
Decaffeinated Coffee ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method was developed for determining caffeine in decaffeinated coffee, tea, and beverage products by high performance liquid chromatography (HPLC). The HPLC system consisted of a Bio-Sil ODS-5S C18 column, methanol-water (25 + 75) mobile phase at 1 mL/min, and a UV detector. The method is simple and specific. Caffeine recoveries were 93.8-98.3% and coefficients of variation were 0.90-2.25%.

High Performance Liquid Chromatographic Determination of Methapyrilene Hydrochloride in Feed and Sleep Aid Tablets

1981 ◽  
Vol 64 (4) ◽  
pp. 889-892
Author(s):  
Badaruddin Shaikh ◽  
Margarette R Hallmark
Keyword(s):  
High Performance ◽  
Ammonium Carbonate ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reverse Phase ◽  
Phase Partition ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Methapyrilene hydrochloride (MP·HCl) was extracted from feed with methanol and determined by reverse phase partition chromatography in less than 15 min, using isocratic elution with acetonitrile-1.1% ammonium carbonate (1 + 1) as the mobile phase. This procedure was tested on feed treated with MP·HCl at levels of 125,500, and 2000 ppm. Recoveries were 104,95, and 96% with coefficients of variation of 2.4,1.6, and 0.6%, respectively. MP·HCl in feed was stable for 14 days. This method was also successfully used to determine MP·HCl in 3 sleep aid tablets.

High Performance Liquid Chromatographic Determination of Primidone in Tablets

1982 ◽  
Vol 65 (5) ◽  
pp. 1063-1065
Author(s):  
Stanley E Roberts
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Hplc Method ◽  
Average Recovery ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A high performance liquid chromatographic (HPLC) method is described for the quantitative determination of primidone in tablets. A ground tablet sample is diluted directly in the mobile phase, at a concentration of about 1 mg/mL of primidone, mixed and deaerated, and filtered. The resulting solution is then quantitated by HPLC. The average spike recoveries for the 50 mg and 250 mg tablets were 101.2% and 99.0%, respectively. The average recovery for an authentic mixture formulated at the 250 mg level was 100.1% with a relative standard deviation of 0.45%.

Liquid-chromatographic determination of alpha- and gamma-tocopherols in erythrocytes, with fluorescence detection.

1983 ◽  
Vol 29 (10) ◽  
pp. 1840-1842 ◽  
Author(s):  
J Lehmann ◽  
H L Martin
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We have adapted to erythrocytes a method for the determination of alpha- and gamma-tocopherols in plasma and platelets. Erythrocytes (50 microL) were extracted with methanol containing tocol (internal standard) and pyrogallol. Tocopherols were partitioned into chloroform, washed, and injected in methanol onto a reversed-phase (C18) "high-performance" liquid-chromatographic column. The mobile phase was methanol/water (99/1 by vol) at a flow rate of 2 mL/min and detection was with a "high-performance" spectrophotofluorometer. The limit of detection for either tocopherol is 0.10 microgram/mL of packed cells. Analytical recoveries ranged from 93 to 104%. Some values for tocopherols in human erythrocytes are presented.

High Performance Liquid Chromatographic Determination of Aflatoxicol in Milk, Blood, and Liver

1981 ◽  
Vol 64 (5) ◽  
pp. 1083-1087 ◽  
Author(s):  
Mary W Trucksess ◽  
Leonard Stoloff
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Raw Milk ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Fluorescence Detector ◽  
Beef Liver ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Samples of milk were extracted with chloroform, the extract was transferred to methanol, and residual interferences were removed by liquid-liquid partition against hexane and by silica gel column chromatography. Aflatoxicol (AFL) in the purified extract was resolved on a μBondapak C18 column, using water - methanol - acetonitrile - tetrahydrofuran (70 + 15 + 20 + 3) as the mobile phase, and measured with a fluorescence detector (excitation 325-385 nm, emission >408 nm). Recoveries of AFL added to samples of whole pasteurized milk at levels ranging from 0.025 to 0.10 ng/mL averaged 92% (range 78- 100%). The method for AFL has also been applied to the analysis of raw milk, whole beef blood, and beef liver, with recoveries of 70-88%.

Liquid Chromatographic Determination of Acetic Acid in Foods

1984 ◽  
Vol 67 (5) ◽  
pp. 885-887
Author(s):  
Samy H Ashoor ◽  
Jim Welty
Keyword(s):  
Acetic Acid ◽  
Flow Rate ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Uv Detector ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method has been developed for the determination of acetic acid in vinegar and other foods. The LC system includes an Aminex HPX-87H column and a UV detector set at 210 nm. The mobile phase is 0.009N H2S04 at a flow rate of 0.7 mL/min. The method is simple and specific for acetic acid. Recoveries of acetic acid from a variety of products ranged from 93.3 to 102% with coefficients of variation from 2.4 to 4.6%.

High Performance Liquid Chromatographic Determination of Lactose in Milk

1981 ◽  
Vol 64 (4) ◽  
pp. 805-807
Author(s):  
Leslie G West ◽  
Marie A Llorente
Keyword(s):  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Chocolate Milk ◽  
Silica Column ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A rapid and simple high performance liquid chromatographic method for the determination of lactose in milk was developed. Samples were diluted with 0.5% perchloric acid and centrifuged, and an aliquot of the supernate was mixed with acetonitrile. Lactose was separated on a 10 μm particle-size silica column with aqueous acetonitrile as the mobile phase. The recovery of lactose from whole, skim, and chocolate milk averaged 99.2, 101.1, and 100.4%, respectively. Coefficients of variation for routinely performed duplicate determinations are between 1.0 and 1.5%.

High Performance Liquid Chromatographic Determination of Vitamin D in Fortified Milks, Margarine, and Infant Formulas

1982 ◽  
Vol 65 (3) ◽  
pp. 624-631 ◽  
Author(s):  
James N Thompson ◽  
George Hatina ◽  
William B Maxwell ◽  
Suzanne Duval
Keyword(s):  
Vitamin D ◽  
High Performance ◽  
Room Temperature ◽  
Chromatographic Determination ◽  
Solvent System ◽  
High Performance Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Fortified milks were saponified overnight at room temperature with 1% ethanolic pyrogallol and KOH. The digest was extracted with hexane after adding water and ethanol, and the extract was washed consecutively with 5% KOH, water, and 55% aqueous ethanol to remove polar lipids. After evaporation, the residue was first chromatographed on a column of 5 μm silica. A fraction containing vitamin D was collected, evaporated, and rechromatographed on a reverse phase column for the separation and quantitation of vitamins D2 and D3. Recovery was 96-99% and the coefficient of variation was 3% (8 replicates). Infant formula was diluted and then saponified and extracted as in the analysis of milk. Margarine was saponified by shaking overnight with 1% ethanolic pyrogallol and 80% KOH. Water and ethanol were added to the digest before extraction. Extracts from formula and margarine were chromatographed as milk except, before HPLC, the extract was dissolved in isopropanol-hexane (1 + 99) and passed through 5 cm alumina in a Pasteur pipet, and the concentration of isopropanol in the first high performance liquid chromatographic (HPLC) solvent system was halved to improve the separation of vitamin D from other absorbing lipids. Usually several peaks were obtained during the final HPLC analysis, and the identification of vitamins D2 and D3 was less certain than in the analysis of milk. The coefficients of variation for formula and margarine were 6% (5 replicates) and 9% (6 replicates), respectively.

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