Collaborative Study of a Semiautomated Fluorometric Method for the Determination of Reserpine in Tablets

1976 ◽  
Vol 59 (2) ◽  
pp. 289-292
Author(s):  
Mary A Kreienbaum
Keyword(s):  
Vanadium Pentoxide ◽  
Collaborative Study ◽  
Dosage Level ◽  
Fluorometric Method ◽  
Coefficients Of Variation ◽  
Semiautomated Method

Abstract A semiautomated fluorometric method for the determination of resperpine in tablets was collaboratively studied by 7 laboratories. The method is a modification of the semiautomated method of Urbányi and Stober, which involves formation of a fluorogen with vanadium pentoxide. Collaborators were supplied with 3 composites, each from a different dosage level of commercial tablets. The results obtained agreed well with the AOAC manual fluorometric method; coefficients of variation ranged from 0.45 to 2.70%. The method has been adopted as official first action.

Collaborative Study of a Semiautomated Method for the Analysis of Prednisolone and Prednisone Tablets

1977 ◽  
Vol 60 (1) ◽  
pp. 27-31
Author(s):  
James F Brower
Keyword(s):  
Collaborative Study ◽  
Colorimetric Method ◽  
Alcoholic Solution ◽  
Tetramethylammonium Hydroxide ◽  
Assay Method ◽  
Blue Tetrazolium ◽  
Coefficients Of Variation ◽  
The Individual ◽  
Semiautomated Method

Abstract A semiautomated colorimetric method for the determination of prednisolone and prednisone was collaboratively studied by 6 collaborators. In the method, an alcoholic solution of the drug is extracted with chloroform and the extract is reacted with tetramethylammonium hydroxide and blue tetrazolium; the absorbance of the resulting color is read at 525 nm. Collaborators were supplied with 4 composites of tablets of different dosage levels, 2 containing prednisolone and 2 containing prednisone. Results agreed with those obtained by the author using the CSP total steroid assay method. The coefficients of variation of the individual collaborator’s results for prednisolone and prednisone ranged from 0.54 to 2.38 and from 0.34 to 2.19%, respectively. This method has been adopted as official first action.

Liquid Chromatographic Determination and Identification Tests for Dexamethasone in Bulk Drugs and Elixirs: Collaborative Study

1987 ◽  
Vol 70 (6) ◽  
pp. 967-973
Author(s):  
Elaine A Bunch
Keyword(s):  
Methylene Chloride ◽  
Collaborative Study ◽  
Internal Standard ◽  
Dosage Level ◽  
Chromatographic Determination ◽  
Photometric Detection ◽  
Coefficients Of Variation ◽  
Bulk Drug ◽  
Liquid Chromatographic

Abstract A normal phase liquid chromatographic method for the determination of dexamethasone in bulk drugs and elixirs was collaboratively studied by 6 laboratories. The method uses a silica column, water-modified acetic acid-methanol-methylene chloride mobile phase, cortisone internal standard, and photometric detection at 254 nm. Collaborators were supplied blind duplicate samples of 3 bulk drugs, 2 commercial elixirs, and 1 authentic elixir. Dexamethasone elixir dosage level is 0.5 mg/5 tnL. Mean recovery of dexamethasone from the authentic elixir formulated to contain 0.471 mg/5 mL was 94.5%. (Authentic elixirs were found to stabilize about 6% below the theoretical concentration.) Mean recovery for the bulk drugs was between 97.1 and 100.1%. Mean coefficients of variation for bulk drug and elixir samples were less than 0.8% and 3.6%, respectively. Identification tests for dexamethasone by thin-layer chromatography, infrared spectroscopy, and relative LC retention times, as well as the gas chromatographic determination of alcohol in the elixirs were also collaboratively studied. Mean recovery of alcohol from the synthetic elixir was 98.6%. The mean coefficient of variation for alcohol for all samples analyzed was less than 1.4%. The LC method for dexamethasone in drug substance and elixirs, the identification tests, and the GC method for alcohol in dexamethasone elixirs have been adopted official first action.

Semiautomated Fluorometric Method for Determination of Vitamin C in Foods: Collaborative Study

1983 ◽  
Vol 66 (6) ◽  
pp. 1371-1377
Author(s):  
Jonathan W DeVries ◽  
◽  
P W Defibaugh ◽  
D Dunmire ◽  
F Ebert ◽  
...  
Keyword(s):  
Vitamin C ◽  
Continuous Flow ◽  
Collaborative Study ◽  
Fluorometric Method ◽  
Manual Method ◽  
Relative Standard ◽  
Sensitivity Specificity ◽  
The Cost ◽  
Semiautomated Method

Abstract Continuous flow automation of the microfluorometric procedure compares favorably with the manual method in sensitivity, specificity, and generality, and reduces the cost of routine vitamin C assay. Fifteen samples of 12 different products of ready-to-eat cereals, fruit juices, and infant formula were sent to 6 collaborators; one sample in each category was sent as blind duplicates. The within-laboratory standard deviations for 5 collaborators on the 3 sets of blind duplicates were 1.23, 0.87, and 3.64 mg/100 g, respectively. Overall, the average relative standard deviation between laboratories was 11.1% (range 4.5-16.6%) for the manual method and 4.99% (range 1.5-12.6%) for the semiautomated method. The method has been adopted official first action.

Fluorometric Determination of Estradiol Valerate in Sesame Oil or Ethyl Oleate Injectables. II. Collaborative Study

1973 ◽  
Vol 56 (1) ◽  
pp. 86-87
Author(s):  
Theron James
Keyword(s):  
Collaborative Study ◽  
Ethyl Oleate ◽  
Sesame Oil ◽  
Estradiol Valerate ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Coefficients Of Variation

Abstract A fluorometric method for determining estradiol valerate in sesame oil or ethyl oleate was subjected to collaborative study. The method utilizes a nitromethane-Celite column to isolate and purify the steroid, which is then measured fluorometrically. Four commercial samples and 3 synthetic samples, varying in concentration from 4 to 20 mg/ml, were used in the study. The collaborative results were acceptable: Coefficients of variation ranged from 2.48 to 3.55%; average recoveries for the synthetics ranged from 98.6 to 102%. The method has been adopted as official first action.

Collaborative Study of a Fluorometric Method for Determining Selenium in Foods

1974 ◽  
Vol 57 (2) ◽  
pp. 373-378 ◽  
Author(s):  
Milan Ihnat
Keyword(s):  
Standard Deviation ◽  
Systematic Error ◽  
Collaborative Study ◽  
Bovine Liver ◽  
Standard Reference Materials ◽  
Fluorometric Method ◽  
Naturally Occurring ◽  
Coefficients Of Variation ◽  
Error Standard Deviation

Abstract A fluorometric method for the determination of selenium in foods reported previously was studied collaboratively. Nineteen laboratories reported analytical results on 10 samples representative of vegetables, cereal, dairy products, meat, and fish, and containing naturally occurring selenium. For the 5 pairs of samples, the coefficients of variation based on precision standard deviation were 2 5 . 9% at 16 ng selenium, 15.8% at 98 ng, 8.5% at 233 ng, 6.1% at 379 ng, and 4.1 % at 427 ng. The corresponding coefficients of variation computed from overall standard deviations were 65.3, 17.5, 8.9, 8.1, and 5.6%. Systematic error was significant for 2 pairs (F-test, p = 0.01), but not for the remaining 3 (p = 0.05). The ratio of the systematic error standard deviation to the precision standard deviation varied from 0.21 to 1.64. Analyses of 2 NBS standard reference materials, orchard leaves (75 ng selenium) and bovine liver (208 ng selenium), yielded results higher by 16 and 10%, respectively. The precision and accuracy of the collaborative procedure were deemed acceptable and the method has been adopted as official first action.

Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Poultry Fat: Collaborative Study

1984 ◽  
Vol 67 (2) ◽  
pp. 284-289 ◽  
Author(s):  
James A Ault ◽  
Tim E Spurgeon ◽  
◽  
M M Anderson ◽  
R Bowers ◽  
...  
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Gel Permeation Chromatography ◽  
Accuracy And Precision ◽  
Coefficients Of Variation ◽  
Poultry Fat ◽  
Gel Permeation ◽  
Detector Method ◽  
Gas Chromatographic Method

Abstract A gas chromatographic electron capture detector method is described for the quantitative determination of organochlorine pesticide residues in poultry fat. The samples are rendered and cleaned up using automated gel permeation chromatography. The collaborative samples consisted of 10 fortified samples and one incurred residue sample, all in duplicate. Fortification levels ranged from 0.15 to 1.0 ppm for a-BHC, lindane, cis- and frans-chlordane, octachlor epoxide, o,p' and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 91.9% with a range of 81-102%. The ranges of coefficients of variation were: CVo = 3.39-14.79%; CVL = 0-16.6%; and CVx = 5.82-19.0%. The results indicate accuracy and precision comparable to other official methodology. The method has been adopted official first action.

Automated Method for the Determination of Niacin and Niacinamide in Cereal Products: Collaborative Study

1975 ◽  
Vol 58 (4) ◽  
pp. 799-803
Author(s):  
Anthony F Gross
Keyword(s):  
Chemical Method ◽  
Collaborative Study ◽  
Pet Food ◽  
Microbiological Method ◽  
Chemical Methods ◽  
Cereal Products ◽  
Automated Method ◽  
Coefficients Of Variation ◽  
Baked Products

Abstract In a collaborative study, an automated method for the determination of niacin and niacinamide in cereal products was compared with the official final action microbiological (43.121–43.125) and chemical (43.044–43.046) methods. Ten samples of cereal products, including enriched flour, yeast-leavened baked products, fortified breakfast cereals, and baked pet food products, were submitted to 14 laboratories. Nine laboratories reported values by the automated method, 6 reported values by the microbiological method, and 7 reported values by the chemical method. The results from the microbiological method were not subjected to analysis of variance because of the unusually large between-laboratory variation. The between-laboratory coefficients of variation for the automated and chemical methods were 10.90 and 10.18%, on the basis of results from 7 and 4 laboratories, respectively. There was no significant (p>0.05) difference between methods when results from the 4 laboratories who used both methods were compared. The automated chemical method has been adopted as official first action.

Gas-Liquid Chromatographic Determination of Tetradif on Technical and Formulations: Collaborative Study

1981 ◽  
Vol 64 (4) ◽  
pp. 829-832
Author(s):  
Bram Van Rossum ◽  
Albertus Martijn ◽  
James E Launer ◽  
◽  
E C Calamita ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Flame Ionization ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The gas-liquid chromatographic determination of tetradifon technical and formulations was collaboratively studied in duplicate with 12 laboratories. Six samples were dissolved in dichloroethane with n-hexacosane as the internal standard, chromatographed on a column of 3% SE-52, and detected by flame ionization. The average coefficients of variation were 1.2% for the 2 technical samples, 1.6% for the 2 wettable powders, and 1.5% for the 2 emulsifiable concentrates. The method has been adopted official first action.

Liquid Chromatographic Determination of Triadimefon in Technical and Formulated Products: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 586-589
Author(s):  
Stephen C Slahck
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Technical Products

Abstract A liquid chromatographic method for the determination of triadimefon (Bayleton™) in triadimefon technical and formulated products has been developed and subjected to a collaborative study with 7 participating collaborators. Formulations were extracted with mobile solvent and analyzed by normal phase chromatography, with 4-chlorophenyl sulfoxide as an internal standard. Collaborators were furnished with standards and samples of technical products, 50% wettable powders, and 25% wettable powders for analysis. Coefficients of variation of the values obtained on these samples were 1.42, 0.82, and 1.05%, respectively. The method has been adopted official first action.

Spectrophotometric Determination of Phosphorus in Certifiable Straight Color Additives: Collaborative Study

1981 ◽  
Vol 64 (4) ◽  
pp. 808-813
Author(s):  
Wallace S Brammell ◽  
◽  
C Arozarena ◽  
J Hunter ◽  
H G Kiernan ◽  
...  
Keyword(s):  
Total Phosphorus ◽  
Phosphorus Content ◽  
Collaborative Study ◽  
Mean Values ◽  
Total Phosphorus Content ◽  
Standard Curve ◽  
Coefficients Of Variation ◽  
Molybdovanadophosphoric Acid ◽  
Acid Reagent

Abstract A simple and rapid spectrophotometric method was developed for determining the total phosphorus content of certifiable straight color additives. The dye sample is mixed with a cellulose powder and MgO mixture, and ashed at 500°C in a small Pyrex beaker in a muffle furnace. The ash is dissolved in vanadomolybdic acid reagent and filtered through glass wool, and the absorbance of the resulting yellow molybdovanadophosphoric acid solution is measured at 400 nm. The total phosphorus content of the sample, expressed as percent Na3PO4, is determined from a standard curve. Recovery of phosphorus added as KH2PO4 to 39 different dyes in amounts equivalent to 0.300% Na3PO4 ranged from 95.3 to 106.8%, averaging 100.6%. In the collaborative study, 7 laboratories successfully performed duplicate analyses of 6 different dyes (D&C Orange No. 5, D&C Yellow No. 8, FD&C Blue No. 2, FD&C Red No. 3, FD&C Red No. 40, and FD&C Green No. 3). The mean values found ranged from 0.325 to 6.86% Na3PO4. In general, the accuracy and reproducibility of the method were satisfactory, with single determination coefficients of variation ranging from 3.76 to 9.60%. The method was adopted official first action.

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