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.

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.

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 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.

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.

High Pressure Liquid Chromatography of Ester and Salt Formulations of 2-Methyl-4-Chlorophenoxyacetic Acid

1979 ◽  
Vol 62 (4) ◽  
pp. 738-741
Author(s):  
Timothy Stevens ◽  
Robert B Grorud
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Collaborative Study ◽  
Internal Standard ◽  
Hplc Method ◽  
Hplc Assay ◽  
High Pressure Liquid Chromatographic ◽  
Chlorophenoxyacetic Acid ◽  
Liquid Chromatographic ◽  
Selection Of

Abstract A high pressure liquid chromatographic (HPLC) assay of amine salt and ester formulations of MCPA has been collaboratively studied. The AOAC 2,4-D HPLC method has been modified for application to MCPA products. The MCPA methodology is identical to that of 2,4-D except in strength of mobile solvent, pH of mobile solvent, heating of ester formulations to 50°C to ensure complete saponification, and the use of glass microfiber filters. The method is specific and separates all known impurities. Examination of chromatograms and percentage results from 8 collaborators indicate that selection of a practical internal standard would improve precision in the procedure and a second collaborative study is recommended.

High Pressure Liquid Chromatographic Analysis of Food for Folates

1977 ◽  
Vol 60 (6) ◽  
pp. 1248-1251 ◽  
Author(s):  
Carolyn K Clifford ◽  
Andrew J Clifford
Keyword(s):  
High Pressure ◽  
Folic Acid ◽  
High Pressure Liquid Chromatographic ◽  
Relative Contribution ◽  
Coefficients Of Variation ◽  
Strong Anion Exchange ◽  
Liquid Chromatographic Analysis ◽  
Tetrahydrofolic Acid ◽  
Liquid Chromatographic ◽  
Area Response

Abstract The multiplicity of naturally occurring chemical forms of folates and the lack of technology to measure these forms individually stimulated the application of high pressure liquid chromatographic procedures to the separation and quantitation of these compounds. Optimum conditions for separating a mixture of tetrahydrofolic acid (THF), N5-methyltetrahydrafolic acid (N5-CH3-THF), dihydrofolic acid (DHF), and folic acid (FA) were established for a pellicular strong anion exchange resin (0.01 × 300 cm) and a potassium chloride gradient in phosphate buffer at pH 7.5, 40°C, flowing at 15.2 ml/hr. The order of elution was THF, N5-CH3-THF, DHF, and FA. The coefficients of variation for standard peak area responses ranged from 5 to 8%, and for retention times from 1.3 to 1.8%. Separations were dependent on the substitution on the pteridine portion of the molecule and were independent of the number of glutamic acid residues. Compounds were completely separated in less than 75 min. The smallest amount of folic acid which could be measured reliably was 0.035 nmole/10 μl placed on the column. Peak area response to each folate increased linearly to at least 0.21 nmole/10 μl. The relative contribution of each of the 4 folates to the total folate content of a number of fruit juices and foods differed markedly and may be related to the relative availability of folate from these sources.

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.

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.

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

1977 ◽  
Vol 60 (4) ◽  
pp. 868-872
Author(s):  
Norman E Skelly ◽  
Timothy S Stevens ◽  
David A Mapes
Keyword(s):  
High Pressure ◽  
Internal Standard ◽  
Dichlorophenoxyacetic Acid ◽  
Precision Data ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Liquid Chromatographic ◽  
Better Than

Abstract An automated high pressure liquid chromatographic method is described for the assay of 2,4-dichlorophenoxyacetic acid (2,4-D) in either salt or ester herbicide formulations. The method is specific for the 2,4-D isomer, and resolves all known impurities from 2,4-D and the internal standard. Ester products are assayed similarly to salt formulations, following room temperature in situ saponification. Results are thus obtained for all products as a per cent 2,4-D acid equivalent. Compounds are separated on a reverse phase microparticulate column with acetonitrile-water (20+80), buffered at pH 3. Precision data indicate a relative standard deviation of better than 1%. The method was developed to replace the nonspecific total chlorine, titration, and saponification assay procedures.

High Pressure Liquid Chromatography of Captan in Formulations: Collaborative Study

1980 ◽  
Vol 63 (6) ◽  
pp. 1231-1237
Author(s):  
A Aner Carlstrom ◽  
◽  
M Akerblom Bryant ◽  
G C Allochuku ◽  
J B Audino ◽  
...  
Keyword(s):  
High Pressure ◽  
Methylene Chloride ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Diethyl Phthalate ◽  
Response Factors ◽  
Simple Method ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic

Abstract A simple method for measuring captan was tested by 18 collaborators. Formulations are extracted with methylene chloride which contains diethyl phthalate as an internal standard, and detected at 254 nm after high pressure liquid chromatographic separation in a 25 cm × 4 mm column packed with 10 µm silica gel. After inert materials are removed, the supernate is added directly to the column with methylene chloride as the mobile phase; peak height ratios are used for quantitation. Most pesticides commonly formulated with captan do not interfere. Retention times and UV response factors relative to captan are listed for 34 pesticides formulated with captan. The collaborators made single determinations on 6 samples (3 pairs of duplicates). The coefficients of variation were 0.67% for the technical, 1.16% for the 50% wettable powder, and 1.71% for the 5% dust. Several collaborators were unable to separate carbaryl and diethyl phthalate on a combination dust containing captan, dicofol and carbaryl; therefore, the method has been adopted as official first action only for captan formulations containing no other active ingredients.

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