Collaborative Study of Spectrophotometric Determination of Hexachlorocyclopentadiene in Technical Chlordane

1966 ◽  
Vol 49 (2) ◽  
pp. 254-257
Author(s):  
Marshall Malina
Keyword(s):  
Spectrophotometric Determination ◽  
Collaborative Study ◽  
Quantitative Measure ◽  
Ultraviolet Absorption ◽  
The Other ◽  
Positive Bias ◽  
Alternative Procedures ◽  
Small Absorption

Abstract Hexachlorocyclopentadiene exhibits strong ultraviolet absorption at 324 mμ, while technical chlordane exhibits only small absorption at this wavelength. The intensity of this absorption is a quantitative measure of the hexachlorocyclopentadiene content. Eight laboratories cooperated in a collaborative study of two alternative procedures on six samples. Results show that one procedure exhibits a positive bias and that the other procedure does not. The precision of both procedures is excellent. The methods are recommended for adoption as official, first action.

Determination of Procaine and Related Local Anesthetics. II. Collaborative Study

1975 ◽  
Vol 58 (1) ◽  
pp. 93-94
Author(s):  
Joseph B Proctor ◽  
Thomas D Doyle
Keyword(s):  
Spectrophotometric Determination ◽  
Local Anesthetics ◽  
Active Component ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Ion Pairing ◽  
The Other ◽  
Three Solutions ◽  
Average Recovery

Abstract The ion-pairing chromatographic method reported previously for the isolation and spectrophotometric determination of the local anesthetics, alone and in combination, was studied collaboratively. Three solutions were assayed. One containing procaine as the single active component gave an average recovery of 99.8± 1.7%. A mixture of procaine and tetracaine gave results of 99.3±1.6 and 98.9±8.82%, respectively. A third solution containing procaine and propoxycaine assayed 100.0±1.5 and 99.1±1.9%, respectively. It was shown that low results for tetracaine were due to loss during the final evaporative step. The method for samples containing tetracaine should be studied further. The other methods have been adopted as official first action.

Procedures for the Quantitative Determination of Autoprothrombin C

1962 ◽  
Vol 08 (03) ◽  
pp. 434-441 ◽  
Author(s):  
Edmond R Cole ◽  
Ewa Marciniak ◽  
Walter H Seegers
Keyword(s):  
Quantitative Determination ◽  
Plasma Sample ◽  
Quantitative Measure ◽  
The Other ◽  
Clotting Time ◽  
Bovine Plasma ◽  
Autoprothrombin C

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.

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.

Comparison of Methods for Determining Biuret in Urea

1979 ◽  
Vol 62 (1) ◽  
pp. 153-159
Author(s):  
Luis F Corominas ◽  
Victor M Boy ◽  
Manuel Guijosa
Keyword(s):  
Atomic Absorption ◽  
Spectrophotometric Determination ◽  
Atomic Absorption Spectrophotometry ◽  
International Organization ◽  
Comparison Of Methods ◽  
Definite Advantage ◽  
Absorption Spectrophotometry ◽  
Alternative Procedures ◽  
Aoac Method

Abstract The official first action AOAC method for the spectrophotometric determination of biuret in urea, 2.072—2.074, was compared with official first action AOAC method 2.C01-2.C03 (atomic absorption spectrophotometry), 2 simplified versions of 2.072-2.074, and modified versions of 2 alternative procedures of the International Organization for Standardization. Three synthetic urea samples (0.3, 1.4, and 3.0% biuret) and 1 commercial urea sample (1.0% biuret) were analyzed. The methods proved to be equivalent and none showed a definite advantage over 2.072-2.074. The purification of biuret and the interference by ammonia are also discussed.

Spectrophotometric Determination of Phosphine Residues in Rice

1985 ◽  
Vol 68 (2) ◽  
pp. 205-208 ◽  
Author(s):  
Jois R Rangaswamy ◽  
Mysore Muthu
Keyword(s):  
Spectrophotometric Determination ◽  
Closed System ◽  
The Other ◽  
Parboiled Rice ◽  
Polished Rice ◽  
Rice Samples ◽  
Phosphine Residues

Abstract Phosphine residues were determined in 2 types of rice samples, raw polished and parboiled. The yellow chromophore due to phosphine from raw polished rice had 2 absorption maxima, a strong one at 370- 380 nm and a weaker one at 400-410 nm. The chromophore from parboiled rice also had 2, one at 390-400 nm and the other at 410-420 nm. A closed system containing rice and a phosphine tablet or powder yielded 93-99% recovery of fortified phosphine. At any given dose of phosphine, parboiled rice retained a higher amount of residue after aeration than did raw polished rice.

Collaborative Study of the Determination of Molybdenum in Fertilizers

1972 ◽  
Vol 55 (5) ◽  
pp. 989-990
Author(s):  
S R Koirtyohann
Keyword(s):  
Atomic Absorption ◽  
Collaborative Study ◽  
Positive Bias ◽  
Absorption Method ◽  
Atomic Absorption Method ◽  
Additional Work

Abstract An atomic absorption method for the determination of molybdenum in fertilizers was tested collaboratively. The results indicate that additional work is needed to improve precision at low molybdenum levels and to test for a possible positive bias in the method.

scholarly journals Determination of Cholecalciferol (Vitamin D3) in Selected Foods by Liquid Chromatography: NMKL Collaborative Study

2003 ◽  
Vol 86 (2) ◽  
pp. 400-406 ◽  
Author(s):  
Anders Staffas ◽  
Arne Nyman ◽  
K Ask ◽  
E Hermansson ◽  
J S Jacobsen ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Fish Oil ◽  
Vitamin D3 ◽  
Collaborative Study ◽  
The Other ◽  
Vitamin D2 ◽  
Cooking Oil ◽  
Relative Standard

Abstract Results are presented from an NMKL (Nordic Committee on Food Analysis) collaborative study of a method for the determination of cholecalciferol (vitamin D3) in foods. The method is based on the addition of an internal standard (vitamin D2), followed by saponification and extraction with n-heptane. The fraction that contains vitamin D2/D3 is separated by preparative normal-phase liquid chromatography (LC), and the analytes are determined by reversed-phase LC with UV detection at 265 nm. The method was tested by 8 participating laboratories. In this study 6 different matrixes were analyzed for cholecalciferol content: milk, liquid infant formula (gruel), cooking oil, margarine, infant formula, and fish oil. The contents varied from 0.4 to 12 μg/100 g. Three matrixes (milk, gruel, and margarine) were fortified with vitamin D3. In the other matrixes, vitamin D3 was added at 3 different levels at the Swedish National Food Administration. The milk was analyzed as a blind duplicate, whereas the other matrixes were analyzed as split-level pairs. The recoveries from the samples with vitamin D3 added varied from 93 to 102%. The repeatability relative standard deviation (RSDr) values for accepted results varied between 2.2% (fish oil) and 7.4% (cooking oil), whereas the reproducibility relative standard deviation (RSDR) values varied between 6.8% (margarine) and 24% (cooking oil).

Evaluation of Agreement Among Routine Methods for Determination of Fluoride in Vegetation: Interlaboratory Collaborative Study

1982 ◽  
Vol 65 (5) ◽  
pp. 1150-1154
Author(s):  
Jay S Jacobson ◽  
John J Troiano ◽  
Christina C Cosentini ◽  
John Evans
Keyword(s):  
Significant Interaction ◽  
Collaborative Study ◽  
Considerable Improvement ◽  
The Other ◽  
Mean Values ◽  
Potentiometric Analysis ◽  
Aoac Official ◽  
Vegetation Samples ◽  
Action Methods

Abstract An interlaboratory collaborative study was conducted to evaluate the performance of methods and laboratories for the measurement of fluoride in vegetation. Samples of 8 plant species containing about 5-200 ppm fluoride were distributed to 40 participants who were instructed to use their routine methods of analysis. Methods which had sufficient participants to allow the inclusion of results in statistical analyses were classified into 3 categories: (1) Willard-Winter method (similar to the AOAC official final action method); (2) semiautomated and potentiometric methods (similar to the 2 AOAC official first action methods); and (3) potentiometric analysis with prior ashing, fusion, and/or distillation (not an approved method). There was a significant interaction of methods with samples caused by 3 of the 8 samples. In the other 5 samples, the Willard-Winter and semiautomated methods gave higher mean values for fluoride content than did the 2 potentiometric methods. Despite considerable improvement in speed and simplicity of fluoride analyses during the last decade, agreement between laboratories has not improved because of the variety of methods and techniques in use, the inherent differences between methods, and, apparently, poor laboratory quality control.

Gas Chromatographic Methods for Determination of γ-BHC in Technical Emulsifiable Concentrates and Water-Dispersible Powder Formulations and in Lindane Shampoo and Lotion: Collaborative Study

1984 ◽  
Vol 67 (4) ◽  
pp. 834-837
Author(s):  
James W Miles ◽  
Dwight L Mount ◽  
◽  
T J Beckmann ◽  
S K Carrigan ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Internal Standard ◽  
The Other ◽  
Water Dispersible ◽  
Coefficients Of Variation ◽  
Aoac Method ◽  
Liquid Chromatographic ◽  
Gas Chromatographic Separation

Abstract Although the gas chromatographic separation of the isomers of BHC was demonstrated two decades ago, the present AOAC method of analysis of BHC for gamma-isomer (lindane) content is based on a separation carried out on a liquid chromatographic partition column. A method of analysis has been developed that uses an OV-210 column for separation of the gamma-isomer from the other isomers and impurities in technical BHC. Di-n-propyl phthalate was chosen as an internal standard. The same system allows quantitation of lindane in lotion and shampoo after these products are extracted with ethyl acetate-isooctane (1 + 4). The analytical methods were subjected to a collaborative trial with 10 laboratories. The coefficient of variation for technical BHC was 2.83%. For the water-dispersible powder and emulsifiable concentrate, the coefficients of variation were 2.89% and 4.62%, respectively. Coefficients of variation for 1% lindane lotion and shampoo were 4.36% and 11.92%, respectively. The method has been adopted official first action.

Collaborative Study of the Separation and Spectrophotometric Determination of Acetylcarbronial and Bromisovalum

1968 ◽  
Vol 51 (3) ◽  
pp. 621-623
Author(s):  
James M Look
Keyword(s):  
Spectrophotometric Determination ◽  
Collaborative Study ◽  
Column Separation

Abstract The method for Celite column separation and infrared spectrophotometric determination of acetylcarbronial and bromisovalum, reported to the AOAC last year, was studied collaboratively. Nine collaborators made duplicate determinations for each ingredient on a powder from a commercial tablet and a powder prepared by the Associate Referee. Recovery on the authentic powder was 104.7 ± 3.1% for acetylcarbronial and 95.8 ± 2.5% for bromisovalum. The tablet powder assayed 101.1 ± 3 . 1 % of declared acetylcarbronial and 91 ± 3.6% of declared bromisovalum. The Associate Referee recommends that the method be adopted as official, first action

Sign in / Sign up

Export Citation Format

Share Document