Liquid Chromatographic Determination of Benzoyl Peroxide in Acne Preparations

1984 ◽  
Vol 67 (5) ◽  
pp. 913-915
Author(s):  
Chih-Kuang Chou ◽  
David C Locke
Keyword(s):  
Benzoyl Peroxide ◽  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Detector Response ◽  
Electrochemical Detector ◽  
Reverse Phase ◽  
Order Of Magnitude ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A rapid, precise, and accurate liquid chromatographic (LC) method is described for the determination of benzoyl peroxide (BP) in acne preparations. BP is extracted from a water dispersion of the preparation with dichloromethane (DCM), and an aliquot is eluted from a C-18 reverse phase LC column with acetonitrile-O.lOM aqueous NaCI04. Selective and sensitive quantitation is accomplished with a reductive mode electrochemical detector. This detector is an order of magnitude more sensitive than a 240 nm UV absorption detector; the lower limit of detection is 2 ng for a 4 μL injection. The recovery of BP is 99.4% and the detector response is linear to at least 2 μg per 4 μL injection.

Liquid Chromatographic Determination of Norflurazon and Its Initial Metabolite in Soil

1994 ◽  
Vol 77 (3) ◽  
pp. 752-755 ◽  
Author(s):  
William T Willian ◽  
Thomas C Mueller
Keyword(s):  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Soil Samples ◽  
Detector Response ◽  
Liquid Chromatographic Separation ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Soluble Components

Abstract A rapid, sensitive method for the determination of norflurazon in 4 soils is described. Data on the initial soil metabolite is also obtained in soils with low organic matter. The method consists of extraction of soil samples with methanol, filtration, liquid chromatographic separation of methanol-soluble components by using a C18 column, and fluorescence detection with excitation at 294 nm and emission measured at 398 nm. Recoveries from fortified soils were >90% for norflurazon and >80% for desmethylnorflurazon from the Shipps, Lexington, and Harkey soils. Average percent relative standard deviations over the soils examined was 5.5% for norflurazon and 8.7% for desmethylnorflurazon. The limit of detection for norflurazon was 10 ng/g soil, whereas the limit of detection for desmethylnorflurazon was 100 ng/g soil because of its smaller relative detector response.

Liquid Chromatographic Determination of Propranolol Hydrochloride in Various Dosage Forms

1988 ◽  
Vol 71 (4) ◽  
pp. 761-763
Author(s):  
Carolyn S Olsen ◽  
Henry S Scroggins
Keyword(s):  
Pharmaceutical Preparations ◽  
Chromatographic Determination ◽  
Dosage Forms ◽  
Detector Response ◽  
Propranolol Hydrochloride ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple and rapid liquid chromatographic method is described for the determination of propranolol hydrochloride in pharmaceutical preparations. The separation was achieved on a reverse-phase octylsilane (C8) column by using a mobile phase composed of a mixture of 0.5 g dodecyl sodium sulfate in 18 mL (0.15 M) H3P04 plus 90 mL methanol, 90 mL acetonitrile, and 52 mL water. Detector response was linear for 0.03-3.1 mg/mL of propranolol. Recoveries from synthetic mixtures ranged from 99.6 to 101.7%. The results obtained by the proposed method were similar to those obtained by the USP XXI method.

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 Liquid Chromatographic Determination of Benzoic and Sorbic Acids in Fresh Cheese

1988 ◽  
Vol 71 (5) ◽  
pp. 1068-1071 ◽  
Author(s):  
Frans J. E. M Kuppers ◽  
Jan A Jans
Keyword(s):  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Acetate Buffer ◽  
Reverse Phase ◽  
Effluent Flow Rate ◽  
Fresh Cheese ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract The sorbate and benzoate contents of commercial fresh cheese (quarg) samples are determined by reverse-phase liquid chromatography following extraction with a methanol-acetate buffer pH 4.5 mixture (37 + 63). The mobile phase is acetonitrile-acetate buffer pH 4.5 (20 + 80), the effluent flow rate is maintained at 1.0 mL/min, and the detector is set at 232 nm. Recoveries from quarg spiked at the 5-50 mg/kg level ranged from 95 to 99%, which compares favorably with methods previously published. Precision averaged 2-5% RSD, whereas the limit of detection was 0.3 mg/kg (sorbic acid) and 1.0 mg/kg (benzoic acid).

Liquid Chromatographic Determination of Aflatoxins in Feedstuffs Containing Citrus Pulp

1988 ◽  
Vol 71 (5) ◽  
pp. 957-961 ◽  
Author(s):  
Walter E Paulsch ◽  
Eric A Sizoo ◽  
Hans P Van Egmond
Keyword(s):  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Citrus Pulp ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Postcolumn Derivatization

Abstract A liquid chromatographic (LC) method was developed for the determination of aflatoxins in feedstuffs containing citrus pulp. The feedstuff sample is extracted with chloroform, followed by Sep-Pak Florisil cartridge cleanup and Sep-Pak C18 cartridge cleanup. The final eluate (water-acetone, 85 + 15, v/v) is submitted to reverse-phase liquid chromatography with water-methanol-acetonitrile (130 + 70 + 40, v/v/v) as mobile phase and postcolumn derivatization with iodine. Citrus components are removed from the extract efficiently. The limit of detection for aflatoxin B1 is< 1 μg/kg. Other aflatoxins can also be detected and measured. Recoveries of aflatoxins B1 B2, G,1 and G2 for dairy rations spiked at 13, 5, 10, and 4 μg/kg were 87, 86, 81, and 82%, respectively. Corresponding coefficients of variation were 3.1, 3.6, 5.2, and 3.8%, respectively.

Liquid Chromatographic Determination of Zoalene in Medicated Feeds

1984 ◽  
Vol 67 (5) ◽  
pp. 861-862 ◽  
Author(s):  
John Morawski ◽  
Glenn Kyle
Keyword(s):  
Colorimetric Method ◽  
Chromatographic Determination ◽  
Activated Alumina ◽  
Reverse Phase ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Aoac Official ◽  
Liquid Chromatographic ◽  
Medicated Feeds

Abstract A rapid, reliable separation and quantitation of zoalene (3,5-dinitroo-toluamide) from feeds is accomplished by using reverse phase liquid chromatography (LC) and ultraviolet detection. An extraction technique which is similar to the present AOAC official colorimetric method is used before chromatographic analysis. This extraction is followed by an activated alumina cleanup and LC to separate zoalene from feed matrix. The methodology was applied to a variety of spiked feed matrices, and yielded good recoveries. Liquid chromatographic results were shown to correlate with colorimetric determinations.

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.

scholarly journals Liquid Chromatographic Method for the Analysis of Brimonidine in Ophthalmic Formulations

2012 ◽  
Vol 9 (3) ◽  
pp. 1327-1331 ◽  
Author(s):  
A. Narendra ◽  
D. Deepika ◽  
M. Mathrusri Annapurna
Keyword(s):  
Limit Of Detection ◽  
Detector Response ◽  
Eye Drops ◽  
Reverse Phase ◽  
Limit Of Quantification ◽  
Ich Guidelines ◽  
Acid Sodium Salt ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

A reverse phase LC method was developed for the determination of Brimonidine in eye drops. Chromatography was carried on an Inertsil ODS 3V column (C18) using a mixture of Octane 1- sulfonic acid sodium salt (0.02M) (pH 3.5 ± 0.05) and acetonitrile (64:36 v/v) as mobile phase at a flow rate of 1 mL/min with UV detection at 254 nm. The drug was eluted at 4.636 min. The detector response was linear in the concentration range of 0.4–72 μg/mL. The limit of detection and limit of quantification were found to be 0.0561 and 0.1848 μg/mL respectively. The proposed method was validated as per the ICH guidelines and can be applied for the routine analysis of Brimonidine in eye drops.

Reverse Phase Liquid Chromatographic Determination of Chlorophacinone and Diphacinone in Bait Formulations

1982 ◽  
Vol 65 (4) ◽  
pp. 927-929
Author(s):  
Brian R Bennett ◽  
Gregory S Grimes
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Target Concentration ◽  
External Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Chlorophacinone and diphacinone are extracted at the 0.005% level from grain or paraffinized baits with glacial acetic acid. The target concentration is 0.01 mg/mL. The filtered supernate is chromatographed on a Partisil PXS ODS10/25 liquid chromatography column with premixed and degassed glacial acetic acid-tetrahydrofuran-water (14 + 2 + 9) and detected at 288 nm. The concentration is calculated by using an external standard. The recovery from spiked samples averaged 96.6% for both analytes. The response is linear from 0.001 to 0.040 mg/mL. The coefficient of variation of within-day replicates ranged from 1.1 to 2.5%.

Liquid Chromatographic Determination of Diazepam in Tablets: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 545-546
Author(s):  
Michael Tsougros
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Photometric Detection ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
The Mean ◽  
Liquid Chromatographic

Abstract A stability indicating liquid chromatographic method for the determination of diazepam in tablets was collaboratively studied by 6 laboratories. The method uses a Cig reverse phase column, a methanolwater mobile phase, p-tolualdehyde as the internal standard, and photometric detection at 254 nm. The collaborators were supplied with a synthetic tablet powder and 3 commercial tablet samples. The mean recovery of diazepam from the synthetic tablet powder was 100.2%. For all samples analyzed, the coefficient of variation was < 1.5%. The method has been adopted official first action.

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