scholarly journals Liquid Chromatographic Determination of S-Adenosyl-L-Methionine in Dietary Supplement Tablets

2002 ◽  
Vol 85 (4) ◽  
pp. 901-905 ◽  
Author(s):  
Joseph Ziqi Zhou ◽  
Ted Waszkuc ◽  
Spiro Garbis ◽  
Felicia Mohammed
Keyword(s):  
Dietary Supplement ◽  
Phosphate Buffer ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Ion Pair ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple and reliable liquid chromatographic method was developed for the determination of S-adenosyl-L-methionine (SAM) in dietary supplement tablets. SAM in products was extracted with a phosphate buffer and separated from the mixture on a reversed-phase C8 column by ion-pair chromatography. A gradient mobile phase containing phosphate buffer, sodium octanesulfonate as the ion-pair reagent, and acetonitrile at a flow rate of 1.2 mL/min was used in the analysis. The UV detection wavelength was set at 257 nm. The calibration curve was linear over a range of 75–375 μg/mL for the SAM active ion with R2 = 0.9999. Replicate tests indicated good reproducibility of the method with a relative standard deviation of 0.9% (n = 8). The multiple extractions and recoveries from fortified products showed the high accuracy of the analysis. The use of the acidic buffer for SAM extraction and elution and the use of a fresh standard for each calibration to counteract the instability of the SAM compound significantly improved the accuracy of the method.

scholarly journals Liquid Chromatographic Determination of the Glycoalkaloids α-Solanine and α-Chaconine in Potato Tubers: NMKL Interlaboratory Study

1997 ◽  
Vol 80 (3) ◽  
pp. 549-554 ◽  
Author(s):  
Karl-Erik Hellenás ◽  
Carina Branzell ◽  
H Poutanen ◽  
T Suortti ◽  
R Kaario ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Potato Tubers ◽  
Photometric Detection ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Twelve laboratories participated in a collaborative study to evaluate precision parameters of a liquid chromatographic method for analysis of the glycoalkaloids α-solanine and α-chaconine in potato tubers. Samples consisted of frozen potato tuber homogenates distributed as 3 blind duplicates and 3 split-level pairs. The analytical method included aqueous extraction, workup on disposable solidphase extraction cartridges, and reversed-phase chromatography with photometric detection at 202 nm. Results for α-solanine and α-chaconine were received from 10 and 9 laboratories, respectively. Relative standard deviations for reproducibilo ity for α-solanine and α-chaconine were similar, ranging from 8 to 13% in the applied concentration range of 12 to 260 mg/kg fresh weight.

scholarly journals Liquid Chromatographic Determination of Scopolamine, Hyoscyamine, and Phenobarbital in Tablets

1997 ◽  
Vol 80 (2) ◽  
pp. 331-334 ◽  
Author(s):  
Susan Ting
Keyword(s):  
Mobile Phase ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Scopolamine Hydrobromide ◽  
Acid Sodium Salt ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method using a reversed- phase C18 column and octanesulfonic acid sodium salt-methanol as the mobile phase was developed for the simultaneous determination of phenobarbi- tal, scopolamine, and hyoscyamine in tablets. The mixture of the 3 drugs was resolved in <8 min. Detector responses were linear for 10 μL injections of the following: scopolamine hydrobromide, 8.25-206.3 μg/mL; hyoscyamine sulfate, 15.01-750.76 μg/mL; and phenobarbital, 250-751 μg/mL. Recoveries from tablets were 100.8% for scopolamine hydrobromide, 100.1% for hyoscyamine sulfate, and 100.3% for phenobarbital. Replicate injections of scopolamine hydrobromide, hyoscyamine sulfate, and phenobarbital gave an overall relative standard deviation of <1.0% (n = 10). The method detected as little as 3.3 ng scopolamine hydrobromide.

Optimized liquid-chromatographic determination of metronidazole and its metabolites in plasma.

1984 ◽  
Vol 30 (5) ◽  
pp. 784-787 ◽  
Author(s):  
R A Gibson ◽  
L Lattanzio ◽  
H McGee
Keyword(s):  
Rapid Determination ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Detector Response ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Method ◽  
Wide Range ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Metronidazole and its known metabolites in plasma can be rapidly separated by a "high-pressure" liquid-chromatographic method that can also be adapted for rapid determination of tinidazole. Samples deproteinized with trichloroacetic acid (50 g/L final concentration) undergo isocratic separation on a reversed-phase C18 column eluted with an 8/92 (by vol) mixture of acetonitrile/KH2PO4 (5 mmol/L, pH 3.0). The method is sensitive, reliably detecting as little as 25 micrograms of metronidazole and (or) its metabolites per milliliter of plasma. The detector response varied linearly with concentration for all compounds tested over a wide range (25-500 micrograms/L). Within-day and between-day variation was generally less than 2.5% for all concentrations of all compounds tested. Various other antibiotics tested did not interfere.

Liquid Chromatographic Determination of Carminic Acid in Yogurt

1989 ◽  
Vol 72 (2) ◽  
pp. 231-234 ◽  
Author(s):  
Mercedes Jalón ◽  
Majesús Peńa ◽  
Julián C Rivas
Keyword(s):  
Chromatographic Determination ◽  
Carminic Acid ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Array Detection ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A reverse-phase liquid chromatographic method is described for the determination of carminic acid in yogurt. A C18 column is used with acetonitrile-1.19M formic acid (19 + 81) as mobile phase and diode array detection. Sample preparation includes deproteinization with papain and purification in a polyamide column. The relative standard deviation for repeated determinations of carminic acid in a commercial strawberry-flavored yogurt was 3.0%. Recoveries of carminic acid added to a natural-flavored yogurt ranged from 87.2 to 95.3% with a mean of 90.2%. The method permits measurement of amounts as low as 0.10 mg/kg.

Liquid Chromatographic Determination of Thiamine in Rodent Feed by Postcolumn Derivatization and Fluorescence Detection

1995 ◽  
Vol 78 (2) ◽  
pp. 307-309 ◽  
Author(s):  
Theresa A Gehring ◽  
Willie M Cooper ◽  
Claude L Holder ◽  
Harold C Thompson
Keyword(s):  
Chromatographic Determination ◽  
Reversed Phase ◽  
Detector Response ◽  
Fluorescence Excitation ◽  
Liquid Chromatographic Method ◽  
Essential Nutrient ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed for determination of the essential nutrient thiamine (vitamin Bi) in rodent feed. Thiamine was extracted with hydrochloric acid, separated by reversed-phase liquid chromatography, derivatized postcolumn to thiochrome with potassium hydroxide and potassium ferricyanide, and detected by fluorescence. Excitation and emission wavelengths were 370 and 430 nm, respectively. Detector response was linear in the range of 2.58 to 15.5 ng of thiamine injected. Instrument detection limit was 5 pg of thiamine injected.

scholarly journals Reversed-Phase Ion-Pair Liquid Chromatographic Determination of Chlorophacinone and Diphacinone in Steam- Rolled Oat Baits and Steam-Rolled Oat/Wax Baits

1998 ◽  
Vol 81 (2) ◽  
pp. 349-358 ◽  
Author(s):  
Thomas M Primus ◽  
Doreen L Griffin ◽  
Stephanite A Volz ◽  
John J Johnston
Keyword(s):  
Petroleum Ether ◽  
Ion Pairing ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Extraction ◽  
Ion Pair ◽  
Limits Of Detection ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

abstract A reversed-phase ion-pair liquid chromatographic (LC) method was developed for analysis of steam-rolled oat (SRO) baits fortified with either chlorophacinone or diphacinone. Baits were prepared with and without paraffin wax. Chlorophacinone or diphacinone was extracted from wax-free SRO baits with 5 mM tetrabutylammonium phosphate methanolic ion-pairing solution. Wax baits were initially extracted with petroleum ether and then cleaned up by liquid extraction into methanolic ion-pairing solution containing 20% water. SRO extracts were analyzed with reversed-phase ion-pair LC. Chlorophacinone and diphacinone were quantified by UV absorption at 325 nm. Recoveries from SRO fortified with chlorophacinone at 25 and 150 μg/g were 90.7 and 90.8%, respectively, whereas for diphacinone at the same levels, recoveries were 93.5 and 92.3%, respectively. Recoveries from wax baits fortified at 25 and 75 μg/g chlorophacinone were 98.5 and 100%, respectively, whereas for diphacinone at the same levels, recoveries were 93.6 and 98.0%, respectively. Method limits of detection for chlorophacinone and diphacinone in SRO baits were estimated to be 1.0 and 0.76 μg/g, respectively. Method limits of detection for chlorophacinone and diphacinone in wax baits were estimated to be 4.2 and 2.8 μg/g, respectively.

Liquid Chromatographic Determination of Morphine Sulfate and Some Contaminants in Injections and Bulk Drug Material: Collaborative Study

1988 ◽  
Vol 71 (5) ◽  
pp. 1046-1048
Author(s):  
Ada C Bello ◽  
Rita K Jhangiani
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Morphine Sulfate ◽  
System Suitability ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Bulk Drug ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for the assay of morphine sulfate and some preservatives and impurities in the bulk drug and in injections has been developed and collaboratively studied in 8 laboratories. Each collaborator analyzed 5 samples: 1 bulk drug, 3 different concentrations of injectable dosages, and 1 prepared mixture containing, in addition to morphine sulfate, phenol, 2-mercaptobenzothiazole, and pseudomorphine. The proposed method quantitates morphine sulfate and resolves the other components for identification using a Clg reverse-phase column with a mobile solvent containing 240 mL methanol, 720 mL 0.005M 1-heptanesulfonic acid Na salt, and 10 mL acetic acid. Samples are prepared by direct dilution with mobile solvent minus 1-heptanesulfonic acid. All collaborators met system suitability requirements and performed the analysis without difficulty. No outliers were found when data were analyzed by the Dixon, Grubbs, double Grubbs, and Cochran tests. Relative standard deviations between laboratories (RSDR) for duplicate determinations of morphine sulfate ranged from 1.4 to 2.1%. Mean morphine sulfate recoveries for the bulk drug and the prepared mixture were 100.8 and 100.4%, respectively. The method has been approved interim official first action.

Liquid-chromatographic determination of 5-fluorocytosine.

1980 ◽  
Vol 26 (1) ◽  
pp. 117-119
Author(s):  
J O Miners ◽  
T Foenander ◽  
D J Birkett
Keyword(s):  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Therapeutic Monitoring ◽  
Pharmacokinetic Studies ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We report a "high-performance" liquid-chromatographic method for measuring 5-fluorocytosine in plasma and cerebrospinal fluid. After deproteinization with trichloroacetic acid, the supernates are chromatographed on a reversed-phase (C18) column. Response to concentration is linear in the range of 5 to 200 mg/L, with ultraviolet detection at 276 nm. The assay requires only 0.1 mL of plasma, is reproducible, and may be performed in less than 12 min. 5-Fluorocytosine concentrations determined by this procedure correlated well with those obtained by spectrofluorometry, although the present method is more specific with no observable interference from co-administered amphotericin B and most other commonly encountered drugs, including salicylat:. This method is applicable to the routine therapeutic monitoring of pediatric and adult patients as well as to pharmacokinetic studies.

Liquid-chromatographic determination of 5-fluorocytosine.

1980 ◽  
Vol 26 (1) ◽  
pp. 117-119 ◽  
Author(s):  
J O Miners ◽  
T Foenander ◽  
D J Birkett
Keyword(s):  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Therapeutic Monitoring ◽  
Pharmacokinetic Studies ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We report a "high-performance" liquid-chromatographic method for measuring 5-fluorocytosine in plasma and cerebrospinal fluid. After deproteinization with trichloroacetic acid, the supernates are chromatographed on a reversed-phase (C18) column. Response to concentration is linear in the range of 5 to 200 mg/L, with ultraviolet detection at 276 nm. The assay requires only 0.1 mL of plasma, is reproducible, and may be performed in less than 12 min. 5-Fluorocytosine concentrations determined by this procedure correlated well with those obtained by spectrofluorometry, although the present method is more specific with no observable interference from co-administered amphotericin B and most other commonly encountered drugs, including salicylat:. This method is applicable to the routine therapeutic monitoring of pediatric and adult patients as well as to pharmacokinetic studies.

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