Collaborative Study of the Official AOAC Flame Photometric Method for the Determination of Sodium in Fertilizers

1972 ◽  
Vol 55 (5) ◽  
pp. 986-988
Author(s):  
Luis F Corominas
Keyword(s):  
Ion Exchange ◽  
Systematic Error ◽  
Collaborative Study ◽  
Flame Photometry ◽  
Photometric Method ◽  
Standard Deviations

Abstract The present official final action method, 2.132–2.135 (11 th Ed.), has been compared with the 10th Edition method, 2.117–2.120; the need for ion exchange cleanup before flame photometry was also studied for samples containing 0.1-0.7% sodium. In general, the 11th Edition method produced more precise results; elimination of ion exchange treatment improved values obtained for the standard deviations of the systematic error. These findings are based on 600 individual results reported by 9 laboratories for 4 samples.

Collaborative Study of the GLC Determination of Glycerine and Propylene Glycol in Tobacco

1969 ◽  
Vol 52 (4) ◽  
pp. 753-756
Author(s):  
J A Giles ◽  
R H Cundiff
Keyword(s):  
Gas Chromatography ◽  
Systematic Error ◽  
Propylene Glycol ◽  
Standard Method ◽  
Collaborative Study ◽  
Standard Deviations

Abstract A method for the methanolic extraction of glycerine and propylene glycol from tobacco and their determination by gas chromatography was collaboratively studied by 11 laboratories. Results show unacceptably high systematic error standard deviations. Additional study and refinement of the procedure will be required before it is suitable as a standard method.

Spectrophotometric Determination of Nitrate in Baby Foods: Collaborative Study

1994 ◽  
Vol 77 (2) ◽  
pp. 425-430 ◽  
Author(s):  
Anna-Maua K Sjöberg ◽  
Timo A Alanko
Keyword(s):  
Collaborative Study ◽  
Photometric Method ◽  
Chromatographic Technique ◽  
Baby Foods ◽  
Relative Standard ◽  
Food Matrices ◽  
Standard Deviations ◽  
Liquid Chromatographic ◽  
Concentration Levels

Abstract A collaborative study was conducted of a spectro-photometric method for determination of nitrate after cadmium reduction to nitrite in baby foods containing meat. Thirty-one municipal and 2 industrial food laboratories participated in the study. The study design involved 2 baby food matrices. Samples of both matrices were prepared at 3 concentration levels between 52 and 309 mg NaNO3/kg as blind duplicates. A blank without added nitrate was also included. The outlier percentage of the results was very low (4.3%). It was typical for the method that recoveries were slightly >100%. Recoveries for baby foods varied between 113.3 and 116.9%, and were acceptable for control purposes. The relative standard deviations for repeatability were 5.0–18.1%. The relative standard deviations for reproducibility were 8.3–21.6%. Three collaborators also evaluated liquid chromatographic technique for nitrate determinations. These preliminary results are presented but are not analyzed statistically. The spectrophotometric method was adopted first action by AOAC INTERNATIONAL.

Collaborative Study of the Spectrophotometric Determination of Procainamide Hydrochloride

1976 ◽  
Vol 59 (4) ◽  
pp. 807-810
Author(s):  
Jeffrey C Hamm
Keyword(s):  
Sodium Hydroxide ◽  
Acid Medium ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Dosage Forms ◽  
Standard Deviations

Abstract The USP analysis for procainamide HCl is titrimetric and relatively nonspecific, capsule and tablet dyes may interfere, and the method is not applicable to coated tablets. In the spectrophotofluorometric method the sample deteriorates when exposed to a xenon source. In the ultraviolet spectrophotometric method reported here, the sample is dispersed in acid medium, possible interferences are extracted in chloroform, base is added, procainamide is extracted in chloroform, the residue is dissolved in sodium hydroxide, and the compound is measured by absorption at 272 nm and comparison with a standard. Recoveries of standards added to capsule, tablet, and injection composites ranged from 99.3 to 102%. Twelve collaborators reported duplicate assay results for all 3 dosage forms with per cent standard deviations for 5 samples ranging from 1.01 to 1.27%. The method has been adopted as official first action.

Quantitative Ultraviolet Determination of Amiben in Dry Granular and Liquid Formulations: Collaborative Study

1970 ◽  
Vol 53 (6) ◽  
pp. 1155-1159
Author(s):  
Joax W Brunstad
Keyword(s):  
Sodium Salt ◽  
Collaborative Study ◽  
Standard Deviations

Abstract Amiben is determined as the sodium salt in 1% NaOH at 297 nm. Prepared materials and technical formulations containing 0-60 μg amiben/ml were analyzed in a collaborative study. Standard deviations for technical samples ranged from 0.05 to 0.45 and for prepared samples from 0.02 to 0.35. The method is recommended for adoption as official first action.

Colorimetric Determination of the Progestational Steroids in Contraceptive Tablets

1970 ◽  
Vol 53 (4) ◽  
pp. 831-833
Author(s):  
John Y P Wu
Keyword(s):  
Oral Contraceptive ◽  
Medroxyprogesterone Acetate ◽  
Collaborative Study ◽  
Chloroform Extract ◽  
Colorimetric Determination ◽  
Standard Deviations ◽  
Isonicotinyl Hydrazide ◽  
Norethindrone Acetate

Abstract Norethindrone, norethindrone acetate, dimethisterone, medroxyprogesterone acetate, and norethynodrel are determined in oral contraceptive tablets. For the first 4 compounds, a chloroform extract of the tablets is treated directly with isonicotinyl hydrazide reagent to produce a stable color which is measured at 380 nm. The chloroform extract of norethynodrel tablets is isomerized before the reagent is added. An intralaboratory study gave good results, with standard deviations of 0.74 to 1.21%. A collaborative study is recommended.

Collaborative Study of the Gas-Liquid Chromatographic Method for Determination of Stereochemical Composition of Amphetamine

1972 ◽  
Vol 55 (1) ◽  
pp. 146-148
Author(s):  
Clyde E Wells
Keyword(s):  
Column Chromatography ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Good Precision ◽  
Liquid Chromatographic Method ◽  
Precision And Accuracy ◽  
Standard Deviations ◽  
Liquid Chromatographic ◽  
Amphetamine Sulfate

Abstract Eight laboratories collaboratively studied a method for the quantitative GLC determination of d- and l-amphetamine in tablets. The drugs are separated from tablet excipients by column chromatography and reacted with Ntrifluoroacetyl-( 0-prolyl chloride, and the resulting derivatives are analyzed by GLC. The samples consisted of commercial d-amphetamine sulfate tablets (with and without butabarbital), dl-amphetamine sulfate tablets, and a mixed d- and l-amphetamine sulfate standard. Recoveries were acceptable, and the standard deviations never exceeded 0.64%. The results demonstrate that the method gives good precision and accuracy, and the method is recommended for adoption as official first action.

scholarly journals Determination of Ochratoxin A in Wine and Beer by Immunoaffinity Column Cleanup and Liquid Chromatographic Analysis with Fluorometric Detection: Collaborative Study

2001 ◽  
Vol 84 (6) ◽  
pp. 1818-1827 ◽  
Author(s):  
Angelo Visconti ◽  
Michelangelo Pascale ◽  
Gianluca Centonze ◽  
E Anklam ◽  
A M Betbeder ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Red Wine ◽  
Collaborative Study ◽  
White Wine ◽  
Fluorometric Detection ◽  
Immunoaffinity Column ◽  
Relative Standard ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract The accuracy, repeatability, and reproducibility characteristics of a liquid chromatographic method for the determination of ochratoxin A (OTA) in white wine, red wine, and beer were established in a collaborative study involving 18 laboratories in 10 countries. Blind duplicates of blank, spiked, and naturally contaminated materials at levels ranging from ≤0.01 to 3.00 ng/mL were analyzed. Wine and beer samples were diluted with a solution containing polyethylene glycol and sodium hydrogen carbonate, and the diluted samples were filtered and cleaned up on an immunoaffinity column. OTA was eluted with methanol and quantified by reversed-phase liquid chromatography with fluorometric detection. Average recoveries from white wine, red wine, and beer ranged from 88.2 to 105.4% (at spiking levels ranging from 0.1 to 2.0 ng/mL), from 84.3 to 93.1% (at spiking levels ranging from 0.2 to 3.0 ng/mL), and from 87.0 to 95.0% (at spiking levels ranging from 0.2 to 1.5 ng/mL), respectively. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 6.6 to 10.8% for white wine, from 6.5 to 10.8% for red wine, and from 4.7 to 16.5% for beer. Relative standard deviations for between-laboratories reproducibility (RSDR) ranged from 13.1 to 15.9% for white wine, from 11.9 to 13.6% for red wine, and from 15.2 to 26.1% for beer. HORRAT values were ≤0.4 for the 3 matrixes.

Sulfuric Acid/Hydrogen Peroxide Digestion and Colorimetric Determination of Phosphorus in Meat and Meat Products: Collaborative Study

1991 ◽  
Vol 74 (1) ◽  
pp. 22-26 ◽  
Author(s):  
David K Christians ◽  
Thomas G Aspelund ◽  
Scott V Brayton ◽  
Larry L Roberts
Keyword(s):  
Hydrogen Peroxide ◽  
Sulfuric Acid ◽  
Collaborative Study ◽  
Meat Products ◽  
Colorimetric Determination ◽  
Pork Sausage ◽  
Relative Standard ◽  
Significant Difference ◽  
Standard Deviations

Abstract Seven laboratories participated In a collaborative study of a method for determination of phosphorus in meat and meat products. Samples are digested In sulfuric acid and hydrogen peroxide; digestion Is complete In approximately 10 mln. Phosphorus Is determined by colorimetric analysis of a dilute aliquot of the sample digest. The collaborators analyzed 3 sets of blind duplicate samples from each of 6 classes of meat (U.S. Department of Agriculture classifications): smoked ham, water-added ham, canned ham, pork sausage, cooked sausage, and hamburger. The calibration curve was linear over the range of standard solutions prepared (phosphorus levels from 0.05 to 1.00%); levels in the collaborative study samples ranged from 0.10 to 0.30%. Standard deviations for repeatability (sr) and reproducibility (sR) ranged from 0.004 to 0.012 and 0.007 to 0.014, respectively. Corresponding relative standard deviations (RSDr and RSDR, respectively) ranged from 1.70 to 7.28% and 3.50 to 9.87%. Six laboratories analyzed samples by both the proposed method and AOAC method 24.016 (14th Ed.). One laboratory reported results by the proposed method only. Statistical evaluations Indicated no significant difference between the 2 methods. The method has been adopted official first action by AOAC.

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.

Atomic Absorption Spectrophotometric Method for Determination of Water-Soluble Copper in Water-Insoluble Copper Fungicides: CIPAC Collaborative Study. Comparison with Bathocuproine Method

1981 ◽  
Vol 64 (1) ◽  
pp. 75-78
Author(s):  
F Sánchez Rasero ◽  
◽  
P G Balayannis ◽  
H P Beyers ◽  
E Celma ◽  
...  
Keyword(s):  
Atomic Absorption ◽  
Collaborative Study ◽  
The United States ◽  
Atomic Absorption Spectrophotometry ◽  
Water Soluble ◽  
Absorption Spectrophotometry ◽  
Aas Method ◽  
Standard Deviations ◽  
The Difference

Abstract An atomic absorption spectrophotometric (AAS) method was collaboratively studied by 8 laboratories from Africa, the United States, Australia, and Europe. The samples were dispersed in deionized water. After centrifuging and filtering, the water-soluble copper in the filtrate was acidified and measured by atomic absorption spectrophotometry, in an airacetylene flame, at 324.7 nm. The results from 7 laboratories were satisfactory and no unfavorable comments were received. Repeatability standard deviations ranged from 0.005 to 0.023, and reproducibility standard deviations ranged from 0.012 to 0.062. When compared with the bathocuproine method, the difference in bias between both methods is not significant. They were both adopted as full CIPAC methods, with the bathocuproine method as the referee method. Both methods have been adopted official first action.

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