High Pressure Liquid Chromatographic Analysis of Chlorpyrifos Containing Insecticidal Formulations: Collaborative Study

1981 ◽  
Vol 64 (3) ◽  
pp. 628-634 ◽  
Author(s):  
Norman E Skelly ◽  
David J Jackson ◽  
Phyllis K Anderson ◽  
◽  
J B Audino ◽  
...  
Keyword(s):  
High Pressure ◽  
Chromatographic Analysis ◽  
Collaborative Study ◽  
Internal Standard ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Analysis ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic method for determining chlorpyrifos was collaboratively studied. Three liquid and 2 solid formulations were analyzed by 12 collaborators. Samples were weighed and diluted with acetonitrile containing the internal standard, 1,4-dibromonaphthalene. Chlorpyriphos is separated on a Zorbax ODS column with acetonitrile- water-acetic acid (82 ± 17.5 ± 0.5) at 2 mL/min and monitored at 300 nm. Clay samples are extracted with the internal standard solution by agitation for 5 min. Coefficients of variation ranged from 1.28 to 2.40%. Results of all 12 collaborators fell within the 5% two-tail limits. The method has been adopted official first action.

Isomer Specific Assay of Ester and Salt Formulations of 2,4-Dichlorophenoxyacetic Acid by High Pressure Liquid Chromatography: Collaborative Study

1978 ◽  
Vol 61 (5) ◽  
pp. 1163-1165 ◽  
Author(s):  
Timothy S Stevens ◽  
Norman E Skelly ◽  
Robert B Grorud
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Internal Standard ◽  
Dichlorophenoxyacetic Acid ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Standard Solution ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic (HPLC) assay of ester and salt formulations of 2,4-D has been collaboratively studied. The method is specific for 2,4-D isomer and resolves all known impurities from 2,4-D and the internal standard p-bromophenol. In situ saponification, at room temperature, is performed by adding a combined saponification-internal standard solution to ester products. The same saponification- internal standard solution is added to amine salts and the analytical standard. The injected aqueous potassium salt solution of 2,4-D is then converted to the acid form by an acidic buffered mobile solvent of 20% acetonitrile in water. Optimum chromatography is attained by a mobile solvent pH of 2.95 in a reverse phase microparticulate column, by ion suppression. Each of the 9 collaborators received 3 different ester and 2 different amine formulations of 2,4-D. The coefficients of variation of 2,4-D acid equivalent ranged from 1.22 to 1.59%. The method has been adopted as official first action.

Collaborative Study of Gas-Liquid Chromatographic Method for Determining Methyl Parathion

1977 ◽  
Vol 60 (3) ◽  
pp. 720-723 ◽  
Author(s):  
Edwin R Jackson
Keyword(s):  
Methyl Parathion ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Flame Ionization ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Technical Material ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract Methyl parathion in technical material, 4 lb/gal. emulsifiable concentrate, and 25% wettable powder was chromatographed on a 1.5% SE-30 + 1.5% OV-210 column with p,p′-DDE as internal standard and flame ionization detection. Three matched sample pairs were analyzed by 15 collaborators using peak height measurements. Liquids were diluted to volume with p,p′-DDE internal standard solution; wettable powders were extracted with chloroform-acetone (9+1), solvent was removed, and extracts were dissolved in internal standard solution. The mean of the coefficients of variation for the 6 samples was 1.65%. 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.

Collaborative Study of the High-Pressure Liquid Chromatographic Analysis of Picloram-2,4-D Formulations

1976 ◽  
Vol 59 (4) ◽  
pp. 748-752
Author(s):  
Norman E Skelly ◽  
Robert J Russell ◽  
Deborah F Porter
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Sodium Perchlorate ◽  
Internal Standard ◽  
Dichlorophenoxyacetic Acid ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Strong Anion Exchange ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Liquid Chromatographic

Abstract A high-pressure liquid chromatographic method for the analysis of picloram-2,4-D formulations has been studied by 11 collaborators. The method requires no sample preparation other than weighing and dilution. Salicylic acid is used as the internal standard. The compounds are separated on DuPont Zipax SAX (strong anion exchange resin) with 0.01M sodium tetraborate and 0.002M sodium perchlorate as the mobile phase, and measured by ultraviolet spectroscopy at 280 nm. Coefficients of variation for the 6 samples studied ranged from 1.35 to 3.54% for picloram (4-amino-3,5,6-trichloropicolinic acid) and 0.83 to 2.30% for 2,4-D (2,4-dichlorophenoxyacetic acid). Comments from the collaborators were generally favorable. The method has been adopted as official first action for the determination of both picloram and 2,4-D in picloram-2,4-D formulations.

High Performance Liquid Chromatographic Analysis of Diflubenzuron and Its Formulations: Collaborative Study

1983 ◽  
Vol 66 (2) ◽  
pp. 312-316 ◽  
Author(s):  
Bram Van Rossum ◽  
Albertus Martijn ◽  
Albert A De Reijke ◽  
Jakob Zeeman ◽  
◽  
...  
Keyword(s):  
Chromatographic Analysis ◽  
High Performance ◽  
Collaborative Study ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Water Dispersible ◽  
Liquid Chromatographic Method ◽  
Powder Samples ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic

Abstract Diflubenzuron 90% pre-concentrate and its 25% water-dispersible powder were analyzed by a high performance liquid chromatographic method. Six samples were extracted with 1,4-dioxane, linuron was added as internal standard, and diflubenzuron was separated on a 25 cm × 4.6 mm column packed with Zorbax BP-C8 with acetonitrile-water-l,4-dioxane (450 + 450 + 100) at 1.3 mL/min and monitored at 254 nm. Results were obtained from 17 laboratories. Within-laboratory repeatability was 0.6% for both the pre-concentrate and the water-dispersible powder samples and the reproducibility was 1.2%. The method has been adopted as a full CIPAC method and was adopted official first action by AOAC.

High Pressure Liquid Chromatographic Method for Indole in Shrimp: Development of Method and Collaborative Study

1981 ◽  
Vol 64 (3) ◽  
pp. 592-602 ◽  
Author(s):  
Theodore L Chambers ◽  
Walter F Staruszkiewicz ◽  
◽  
G Bohm ◽  
J F Bond ◽  
...  
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Hplc Method ◽  
Fluorescence Detector ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Spectrofluorometric Method ◽  
Liquid Chromatographic

Abstract A collaborative study on the determination of indole in shrimp was conducted in which a high pressure liquid chromatographic (HPLC) method and a spectrofluorometric method were compared with the AOAC gas-liquid chromatographic (GLC) method (18.075–18.078,13th ed.). In the HPLC method, 10 g shrimp was blended with methanol, an internal standard was added, and the extract was filtered. Indole was separated on an octadecylsilane reverse phase column, using 60% MeOH-H2O, and quantitated with a fluorescence detector (excitation 280 nm, emission 330 nm) by comparing the indole peak height with that of an internal standard, 2-methylindole. Recoveries at a 25 μg/100 g level averaged 104% with a range of 90–127%, and at a level of 35 μg/100 g averaged 102% with a range of 93–112%. In the spectrofluorometric method, 25 g shrimp was extracted with 2% EtOAc-hexane. After several washes, indole was partitioned into a saturated NaCl-MeOH solution and its fluorescence was measured (excitation 280 nm, emission 332 nm). Recoveries at a 25 μg/100 g level averaged 93% with a range of 0–255% and at a level of 35 μg/100 g averaged 64% with a range of 0–107%. Recoveries obtained by the AOAC-GLC method at a level of 25 μg/100 g averaged 96% with a range of 81–116% and at a level of 35 μg/100 g averaged 101% with a range of 81–119%. The coefficients of variation were 20,10, and 64% at a 25 μg/100 g level for the GLC method, the HPLC method, and the spectrofluorometric method, respectively. The HPLC method was adopted as official first action for indole levels in shrimp exceeding 1 μg/100 g.

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 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.

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