Collaborative Study of a Titrimetric Method for the Assay of Amitrole Formulations

1967 ◽  
Vol 50 (3) ◽  
pp. 568-572
Author(s):  
J Russell Bishop
Keyword(s):  
Collaborative Study ◽  
Statistical Analyses ◽  
Standard Samples ◽  
Titrimetric Method ◽  
Inflection Points ◽  
Good Agreement

Abstract titrimetric method for the assay of dry and liquid amitrole formulations was studied by 10 collaborators. In the method, acid is added to the prepared amitrole sample, the solution is titrated potentiometrically with standard alkali, and the amitrole content is measured as the amount of alkali consumed between the first and second inflection points. Collaborative results on standard samples of a dry 90% formulation, a dry 50% formulation, and a liquid 2 lb/gallon formulation showed good agreement between samples and laboratories. Statistical analyses of the results were satisfactory, and the method for the assay of amitrole formulations is recommended for adoption as official, first action

Collaborative Study of the Ultraviolet Spectrophotometric Determination of Sulfoxide in Formulations

1968 ◽  
Vol 51 (3) ◽  
pp. 562-564
Author(s):  
Joseph B Haus ◽  
Lazar Manolev
Keyword(s):  
Spectrophotometric Determination ◽  
Silicic Acid ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Poor Correlation ◽  
Complex Nature ◽  
Uv Spectrophotometry ◽  
Standard Samples ◽  
Good Agreement

Abstract A spectrophotometric method for the analysis of sulfoxide formulation was studied by six collaborators. The method consists of separating the sulfoxide from other components by column chromatography on silicic acid with three successive eluting solutions: chloroform, 2% acetone in chloroform, and 1 0% acetone in chloroform. Sulfoxide is removed in the last eluate and is determined by UV spectrophotometry. Solvents, emulsifiers, pyrethrins, compounds related to sulfoxide, and other insecticides are separated by the column. Results on standard samples of four formulations showed good agreement between samples and laboratories with the exception of one sample which, because of its complex nature and low sulfoxide content, resulted in poor correlation within and between the laboratories. It is recommended that the method for the assay of sulfoxide formulations be adopted as official, first action.

Moisture in Cheese: Collaborative Study of a Distillation Method and Discussion of a Karl Fischer Procedure

1969 ◽  
Vol 52 (1) ◽  
pp. 117-125
Author(s):  
Theron E Strange
Keyword(s):  
Collaborative Study ◽  
Cheddar Cheese ◽  
Amyl Alcohol ◽  
Distillation Method ◽  
Karl Fischer ◽  
Blue Cheese ◽  
Good Agreement

Abstract Eleven laboratories studied a proposed method of determining moisture in cheese by distillation with a mixture of n-amyl alcohol and xylene and compared it with method 15.157. Samples from two Cheddar cheeses and two Blue cheeses were analyzed. There was reasonably good agreement between the two methods for moisture in Cheddar cheese. The distillation method gave lower and more consistent results for moisture in Blue cheese, and a proposed adaptation of the Karl Fischer tilration procedure gave still lower results.

A multi-centre collaborative study on the potency estimation of ReFacto

2003 ◽  
Vol 90 (12) ◽  
pp. 1088-1093 ◽  
Author(s):  
Dawn Sands ◽  
Eva Sandberg ◽  
Rainer Seitz ◽  
Trevor Barrowcliffe ◽  
Anthony Hubbard
Keyword(s):  
Factor Viii ◽  
Collaborative Study ◽  
Full Length ◽  
European Pharmacopoeia ◽  
International Standard ◽  
Assigned Value ◽  
Coagulant Activity ◽  
The Mean ◽  
Good Agreement

SummarySeven laboratories estimated factor VIII coagulant activity in recombinant B-domain-deleted (ReFacto) and plasma-derived FVIII concentrates (Octonativ-M) using chromogenic methods relative to the WHO 6th International Standard FVIII Concentrate (WHO 6th IS), European Pharmacopoeia BRP#2 (EP#2) and the ReFacto Laboratory Standard (RLS). Significantly higher estimates were obtained for all batches of product when calculated relative to the RLS in comparison with estimates vs WHO 6th IS and EP#2. Mean estimates for two batches of ReFacto product vs the RLS were within 10% of the labelled potency whereas estimates vs WHO 6th IS and EP#2 ranged from 21 to 31% lower than the label. Conversely, mean estimates for Octonativ-M relative to WHO 6th IS and EP#2 were within 10% of the label whereas the mean estimate vs RLS was 117% of label. Mean estimates for the ReFacto product, vs the WHO 6th IS and EP#2, varied considerably between the different chromogenic kits whereas estimates vs the RLS showed good agreement between kits. Mean estimates for the RLS vs the WHO 6th IS (8.10 IU/vial) and the EP#2 (7.66 IU/vial) were lower than the assigned value of 9.4 IU/vial. The results are consistent with ReFacto and full-length FVIII responding differently to variations in assay methodology and also indicate that the assigned value on the RLS may be too high. Since this study the unitage on the RLS has been adjusted to effectively increase the amount of ReFacto in the product by 20%.

Collaborative Study of the Determination of Phosphorus in Gelatin, Dessert Preparations, and Mixes

1972 ◽  
Vol 55 (3) ◽  
pp. 581-582
Author(s):  
Roger G Burkepile
Keyword(s):  
Collaborative Study ◽  
Official Method ◽  
Standard Samples ◽  
Preliminary Work ◽  
Aoac Method ◽  
Standard Deviations

Abstract A collaborative study of the proposed method for phosphorus in gelatin, dessert preparations, and mixes has been conducted. The present AOAC method for phosphorus in fertilizers, 2.023–2.025(a), was modified for this study. Preliminary work by the Associate Referee involving 4 phosphorus standard samples compared the proposed method with the official final action AOAC method for gelatin, 23.004. Additionally, phosphorus standard spikes in gelatin at the 1 and 10 mg P2O5, levels were determined by the proposed method. The proposed method is faster and more sensitive than the official method and is as accurate. Five collaborators and the Associate Referee analyzed 4 prepared samples containing various levels of phosphorus by the proposed method. The standard deviations varied from 0.005 for a 225 Bloom gelatin containing an average of 0.273% P2O5 to 0.016 for a strawberry-flavored commercial gelatin with added lecithin containing an average of 0.110% P2O5. The proposed method has been adopted as official first action to replace 23.004, which was repealed, official first action.

Determination of Sevin Insecticide Residues in Fruits and Vegetables

1964 ◽  
Vol 47 (2) ◽  
pp. 283-286
Author(s):  
D P Johnson
Keyword(s):  
Fruits And Vegetables ◽  
Collaborative Study ◽  
Colorimetric Determination ◽  
Average Recovery ◽  
Insecticide Residues ◽  
Chromogenic Agent ◽  
Hydrolysis Of ◽  
Concentration Levels ◽  
Good Agreement

Abstract Collaborative study of a method for Sevin insecticide residues was repeated with apples and lettuce as test crops. The method is based on alkaline hydrolysis of Sevin and colorimetric determination of the resulting 1-naphthol with p-nitrobenzenediazonium fluoborate as chromogenic agent. Data from 5 collaborators were in good agreement with an average recovery of 87.8% at 2 concentration levels. It is recommended that the method be adopted as official, first action.

Report of Ad Hoc Committee on Vitamin D Methodology, AOAC

1975 ◽  
Vol 58 (2) ◽  
pp. 330-332
Author(s):  
Forrest W Quackenbush ◽  
Daniel Banes ◽  
Philip H Derse
Keyword(s):  
Maleic Anhydride ◽  
Chemical Method ◽  
Ad Hoc ◽  
Collaborative Study ◽  
Mean Values ◽  
Biological Tests ◽  
Aoac Official ◽  
The Mean ◽  
Biological Methods ◽  
Good Agreement

Abstract In a collaborative study 6 samples of vitamin D3 resins were analyzed chemically by 9 laboratories and tested biologically by 3 laboratories to determine whether there exists a discrepancy between chemical and biological methods of measuring potency of these materials. The chemical methods employed saponification with and without subsequent maleic anhydride treatment. The biological method was the AOAC official final action rat assay, 39.149–39.162. The results showed good agreement between laboratories in the chemical analysis and relatively poor agreement in the biological tests. However, based upon the mean values as reported by the different laboratories, the chemical method employing saponification alone consistently overestimated biopotency, whereas the chemical method including maleic anhydride treatment gave results which averaged much closer to the mean biopotency values. There was no evidence that maleic anhydride treatment reduced values significantly below biopotency values.

Collaborative Study of Two New Methods for the Determination of Phosphorus in Fruits and Fruit Products

1970 ◽  
Vol 53 (3) ◽  
pp. 575-578
Author(s):  
Ben Estrin ◽  
Frederick E Boland
Keyword(s):  
Aqueous Solution ◽  
Satisfactory Agreement ◽  
Collaborative Study ◽  
Volumetric Method ◽  
Acid Solutions ◽  
Dilute Acid ◽  
New Methods ◽  
Molybdate Method ◽  
Good Agreement

Abstract A collaborative study was conducted to compare a spectrophotometric molybdovanadate method and the official gravimetric quinoline molybdate fertilizer method 2.025(b), slightly modified, with the official volumetric method 20.032. Six collaborating laboratories analyzed dilute acid solutions of the ash of 5 different kinds of fruit products and an aqueous solution containing only KH2PO4 by each of the 3 methods. Satisfactory agreement between laboratories and good agreement between methods were obtained. From the results of this collaborative study it appears that the quinoline molybdate and the molybdovanadate methods are more accurate and precise than the official volumetric method. It is recommended that both the spectrophotometric molybdovanadate method and the gravimetric quinoline molybdate method for the determination of phosphorus in fruits and fruit products be adopted as official first action.

Collaborative Study of Modified Elmore Method for Mercury in Formulations

1971 ◽  
Vol 54 (3) ◽  
pp. 685-687
Author(s):  
James E Launer
Keyword(s):  
Standard Deviation ◽  
Systematic Error ◽  
Random Error ◽  
Collaborative Study ◽  
Test Pair ◽  
Titrimetric Method ◽  
Mercuric Nitrate ◽  
Thiocyanate Solution ◽  
Diluted Solution ◽  
Bearing Materials

Abstract The titrimetric method for mercury described by Elmore in 1946 was modified and collaboratively studied with formulations containing 6.7% phenylmercury urea in one test pair and 1% mercuric nitrate in another test pair. Mercury is determined in diluted solution, following reflux at 30 drops/min with fuming H2SO4-red fuming HNO3, by titration with standard thiocyanate solution, using ferric alum as indicator. The method is not applicable in presence of large quantities of chlorine-bearing materials. Single determinations on 4 samples by 14 collaborators showed that the standard deviation estimation of random error was 0.058 for phenylmercury urea and 0.004 for mercuric nitrate. Standard deviation estimates of systematic error were 0.048 and 0.009, respectively. The method has been adopted as official first action.

Assay of Rauwolfia serpentina

1968 ◽  
Vol 51 (1) ◽  
pp. 157-159
Author(s):  
Frieda M Kunze ◽  
Susan Barkan ◽  
Daniel Banes
Keyword(s):  
Collaborative Study ◽  
Official Method ◽  
Extraction Procedures ◽  
Rauwolfia Serpentina ◽  
Good Agreement

Abstract The lengthy NF XII assay for Rauwolfia serpentina products can be considerably shortened by faster extraction procedures. In the proposed method, Rauwolfia root is homogenized for 10 min with alcoholsulfuric acid, and the evaporation of solvents in the chromogenic step has been eliminated. This modification requires only 3 hr and results are in good agreement with the official method. A collaborative study is planned.

Collaborative Study of a Method for the Determination of Trimethylamine Nitrogen in Fish

1971 ◽  
Vol 54 (3) ◽  
pp. 725-727 ◽  
Author(s):  
Frederick E Boland ◽  
Dorothy D Paige
Keyword(s):  
Statistical Analysis ◽  
Collaborative Study ◽  
Standard Solution ◽  
Good Agreement

Abstract Dyer’s method for the determination of trimethylamine was collaboratively studied. Six samples of fish extract and one standard solution were sent to each of 9 collaborators. The results from one laboratory differed significantly from the remainder and were not included in the statistical analysis. The results from the remainder of the collaborators were generally in good agreement. Results clearly differentiate between the acceptable and decomposed samples which were used in this study. The method for determining trimethylamine nitrogen in fish has been adopted as official first action.

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