Design and Conduct of Collaborative Studies: CIPAC Collaborative Experience in Pesticide Formulations

1986 ◽  
Vol 69 (3) ◽  
pp. 408-409
Author(s):  
J Henriet ◽  
A Martijn
Keyword(s):  
Collaborative Study ◽  
Final Decision ◽  
Collaborative Trial ◽  
Collaborative Studies ◽  
Interlaboratory Studies ◽  
Pesticide Formulations ◽  
Study Evaluation ◽  
Set Up

Abstract CIPAC has set up procedures for carrying out interlaboratory studies on analysis of technical pesticide materials and formulations. CIPAC studies comprise several steps: allocation of leadership; method survey and selection; pre-collaborative trial; full collaborative study; evaluation of results and final decision on acceptance.

Colorimetric Determination of Hydroxyproline as Measure of Collagen Content in Meat and Meat Products: NMKL Collaborative Study

1990 ◽  
Vol 73 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Kurt Kolar
Keyword(s):  
Collaborative Study ◽  
Colorimetric Method ◽  
Meat Products ◽  
Acid Oxidation ◽  
Colorimetric Determination ◽  
Mean Values ◽  
Collaborative Studies ◽  
Freeze Dried ◽  
Analytical Result

Abstract A colorimetric method for the determination of hydroxyproline as a measure of collagen in meat and meat products has been collaboratively studied in 18 laboratories. The method includes hydrolysis with sulfuric acid, oxidation with chloramine- T, and formation of a reddish purple complex with 4- dimethylaminobenzaldehyde. Five frozen and 3 freeze-dried samples were tested, ranging in content from 0.11 to 0.88% and from 0.39 to 4.0% hydroxyproline, respectively. The mean values of 2 identical samples were 0.245 and 0.251 %. The average recovery from a spiked sample was 96.1 %. The hydroxyproline content of a known sample (a mixture of 2 samples in the ratio 5:2) was calculated to 1.42%, which agrees well with the analytical result, 1.40%. In comparison with other collaborative studies, based on the ISO analytical method, the repeatability and reproducibility of this method agree well with the other results. This method was accepted as an official NMKL method by all national Committees, and has been adopted official first action by AOAC as an NMKLAOAC method.

Collaborative Studies of Methods for Butterfat in omogenized and Chocolate Milk

1964 ◽  
Vol 47 (3) ◽  
pp. 573-576
Author(s):  
D J Mitchell
Keyword(s):  
Collaborative Study ◽  
Chocolate Milk ◽  
Collaborative Studies

Abstract The AOAC Roese-Gottlieb and Rapid Detergent (TeSa) methods for the determination of butterfat in pasteurized, homogenized milk and in chocolate milk were compared in a collaborative study. The results by the detergent method on both products were comparable to those by the Roese-Gottlieb method. The Babcock method gave low results on the homogenized milk.

Determination of mono- and diacylglycerols in edible oils and fats by high performance liquid chromatography and evaporative light scattering detector: Results of collaborative studies and the standardised method

1999 ◽  
Vol 71 (10) ◽  
pp. 1983-1991 ◽  
Author(s):  
D. Berner ◽  
A. Dieffenbacher
Keyword(s):  
Liquid Chromatography ◽  
Light Scattering ◽  
High Performance ◽  
Edible Oils ◽  
Collaborative Study ◽  
Evaporative Light Scattering Detector ◽  
Light Scattering Detection ◽  
Collaborative Studies ◽  
Evaporative Light Scattering

The development, by collaborative study, of standardised method for the determination of mono- and diacylglycerols in vegetable oils and fats is described. The method involves separation of mono- and diacylglycerols by normal phase high-performance liquid-liquid chromatography (HPLC) and evaporative light scattering detection of a solution of oil, fat or a commercial mono- and diacylglycerol preparation in a organic solvent.

Analytical Strategy for the Regulatory Control of Residues of Chloramphenicol in Meat: Preliminary Studies in Milk

1992 ◽  
Vol 75 (2) ◽  
pp. 245-256 ◽  
Author(s):  
H J Keukens ◽  
M M L Aerts ◽  
W A Traag ◽  
J F M Nouws ◽  
W G De Ruig ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Collaborative Study ◽  
Regulatory Control ◽  
Veterinary Drug ◽  
Uv Spectrum ◽  
Analytical Strategy ◽  
Column Liquid Chromatographic ◽  
Set Up ◽  
Diagnostic Ions ◽  
Liquid Chromatographic

Abstract An analytical strategy Is described for the regulatory control of residues of the veterinary drug chloramphenicol (CAP) In meat. Screening is performed directly in meat by a simple immunochemical card test with a limit of detection of about 2 μg/kg. Statistical evaluation of a collaborative study involving 13 laboratories showed that at CAP concentrations exceeding 8 μg/kg, no false negatives are found (N = 554). In positive samples, CAP Is quantltated with a routinely applicable, collaboratively tested column liquid chromatographic method with a limit of detection of about 1 μg/kg. At concentrations exceeding 10 μg/kg, the Identity of CAP Is established by Its UV spectrum obtained by using diode-array UV/VIS detection. A further confirmation can be obtained by the combination of gas chromatography/ mass selective detection In the electron Impact mode. Using 2 diagnostic Ions (m/z 225 and 208), the limit of identification Is about 5 μg/kg. The combination of the different analytical principles ensures reliable quantitation and Identification of CAP in positive samples, as established experimentally in Incurred samples and spiked samples (n > 100), and theoretically by the estimation of the uncertainty factor. The proposed set-up makes a regulatory program possible in which screening can be performed In a simple laboratory environment, followed by quantitation and Identification under more sophisticated conditions. Preliminary experiments Indicate that the analytical strategy Is also applicable to the control of CAP in milk. Application of mass spectrometry with negative chemical ionization permits the confirmation of CAP concentrations as low as 0.2 μg/L.

scholarly journals Chloride in Milk, Milk Powder, Whey Powder, Infant Formula, and Adult Nutritionals Potentiometric Titration: Collaborative Study, Final Action 2016.03

2019 ◽  
Vol 102 (2) ◽  
pp. 564-569
Author(s):  
Greg Jaudzems ◽  
Fengxia Zhang ◽  
Wu Bolong ◽  
Lei Bao ◽  
Jing Xiao
Keyword(s):  
Infant Formula ◽  
Collaborative Study ◽  
Milk Powder ◽  
Method Performance ◽  
Expert Review ◽  
Performance Requirements ◽  
Expert Review Panel ◽  
Repeatability And Reproducibility ◽  
Set Up ◽  
Single Laboratory

Abstract Background: In September 2015, both AOAC Official Methods 2015.07and 2015.08 single-laboratory validations (SLVs) were reviewed against Standard Method Performance Requirements® (SMPR) 2014.015by the AOAC Stakeholder Panel for Infant Formula andAdult Nutritional (SPIFAN) Expert Review Panel (ERP). Looking at the similarity and uniqueness of the two methods, the authors agreed, as advised by the ERP, to work together to merge the two methods intoone. This combined method was assigned Method 2016.03. Objective: In order to determine the repeatability and reproducibility of the AOAC First Action 2016.03 method, a collaborative study was organized. The study was divided in two parts: (Part 1) method set up and qualification of participants and (Part 2) collaborative study participation. During Part 1, each laboratory was asked to analyze two practice samples. The laboratories that provided results within a range of expected levels were qualified for Part 2, during which they analyzed 25 samples in blind duplicates. Results: The results were compared with SMPR 2014.015 established for chloride. The precision results (repeatability and reproducibility) were within therequirements stated in the SMPR. In general, the precision results (repeatability and reproducibility)were well within the limits stated in the SMPR. Repeatability ranged from 0.4 to 1.9%, in accordance with data obtained during SLV, with reported RSD of repeatability from 0.03 to 1.6%. Meanwhile, reproducibility ranged from 0.6 to 4.0%. Finally, the Horwitz ratio values were all below 1, from 0.2 to 0.9%. Conclusions: The ERP determined that the data presented met the SMPR and accordingly recommended the method to be granted Final Actionstatus. In January 2018, the Official Methods Boardapproved the method as Final Action.

Microchemical Oxygen Flask Sulfur Determination: General Review and Collaborative Study of an Alternative Method Using Thorin-Methylene Blue Indicator

1976 ◽  
Vol 59 (5) ◽  
pp. 1135-1139
Author(s):  
Laverne H Scroggins
Keyword(s):  
Methylene Blue ◽  
Collaborative Study ◽  
Critical Factor ◽  
Potassium Sulfate ◽  
Masking Effect ◽  
Average Deviation ◽  
Collaborative Studies ◽  
Sulfur Determination ◽  
The Mean ◽  
Barium Perchlorate

Abstract Recent collaborative studies of microchemical oxygen flask sulfur determinations are summarized and compared statistically, and the 1975 collaborative study is presented. This volumetric technique, using a peroxide solution as absorbent, barium perchlorate as titrant, and a combination of thorin and methylene blue as indicator, was tested by 8 collaborators. Data from 72 determinations were reported. The samples studied were sulfanilamide, benzylisothiourea hydrochloride, cystine, potassium sulfate, and potassium sulfate with a phosphate additive. Overall statistical results for the 3 pure organic compounds gave satisfactory values: average standard deviation 0.10, overall average deviation of the mean from the theoretical value 0.13, and average bias −0.04. The overall average deviation of the mean from the theoretical value for the potassium sulfate compound was high (1.94) in this study, and that of the phosphated potassium sulfate compound was even higher (6.46). Thorin-methylene blue does not require a titration assembly (required by tetrahydroxyquinone) and has greater stability than dimethylsulfonazo III whose indicator lag-time causes troublesome pseudo end points. However, a critical factor, when using thorin-methylene blue, is the masking effect of foreign ions. All reagents must be as pure as possible, since concentrations of chloride, fluoride, nitrate, phosphate, potassium, and sodium interfere. The thorin-methylene blue method for sulfur determination has been adopted as official first action as an alternative oxygen flask microchemical method of analysis.

Collaborative Study of the Gas-Liquid Chromatographic Assay for Vitamin E

1972 ◽  
Vol 55 (6) ◽  
pp. 1211-1218
Author(s):  
B C Rudy ◽  
F P Mahn ◽  
B Z Senkowski ◽  
A J Sheppard ◽  
W D Hubbard
Keyword(s):  
Vitamin E ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Tocopheryl Acetate ◽  
Pharmaceutical Manufacturers ◽  
Collaborative Studies ◽  
Soft Gelatin Capsules ◽  
Acid Succinate ◽  
The Mean ◽  
Liquid Chromatographic

Abstract A collaborative study for the analysis of vitamin E in multivitamin tablets was conducted and the method was subsequently approved as official first action by the AOAC. Additional data were obtained by an extensive collaborative study sponsored by the Pharmaceutical Manufacturers Association, which verified the usefulness of GLC for the assay of α-tocopherol, α-tocopheryl acetate, and α-tocopheryI acid succinate. The mean coefficient of variation obtained from the 8 participating laboratories for duplicate samples, duplicate injections, was ±2.04, 1.75, and 2.71%, respectively. Further collaborative studies were conducted on samples of mixed tocopherol concentrate, multivitamin tablets, and multivitamin soft gelatin capsules. The mean coefficient of variation obtained from 13 collaborators was in the range of ±5%. The accumulated data demonstrate the utility of this technique for improved specificity and reliability of the analysis of vitamin E.

Collaborative Studies on the Salmonella/Microsome Mutagenicity Assay

1979 ◽  
Vol 62 (4) ◽  
pp. 874-882
Author(s):  
Virginia C Dunkel
Keyword(s):  
Collaborative Study ◽  
Metabolic Activation ◽  
Plate Test ◽  
The Third ◽  
Collaborative Studies ◽  
Mutagenicity Assay ◽  
B6c3f1 Mice ◽  
Fischer Rats ◽  
Interlaboratory Reproducibility ◽  
Positive Results

Abstract Although the Salmonella/plate test has been used extensively, a collaborative study was undertaken to determine the interlaboratory reproducibility of this microbial mutagenicity assay. Four laboratories participating in the study have completed testing, under code, of 61 carcinogens and noncarcinogens. All chemicals were tested both with and without metabolic activation in Salmonella typhimurium strains TA1535, 1537, 1538, 98, and 100. The metabolic activation systems used were derived from the livers of both uninduced and Aroclor 1254-induced Fischer rats, B6C3F1 mice, and Syrian hamsters. Analysis of the results on 23 of the chemicals tested in 3 of the participating laboratories showed that 8 were negative when tested in all laboratories and 13 were positive. Two chemicals gave positive results in 2 laboratories; the same 2 chemicals were negative when tested in the third laboratory.

Diagnostic Data Evaluation. Part II. Collaborative Study Evaluation: Coefficient of Variation Considered To Be A Constant

1990 ◽  
Vol 73 (2) ◽  
pp. 235-241
Author(s):  
Anthony J Malanoski
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Performance Standards ◽  
Data Evaluation ◽  
Diagnostic Data ◽  
Study Evaluation

Abstract The principles described in Part I were used to determine standards of performance for the method and for analysts from a collaborative study of the determination of nitrosopyrrolidine (NPYR). Performance standards for the method were 10.4% RSDa, 9.2% for RSDo, and 14.2% for RSDx.

Collaborative Studies of Methods for Butterfat in Homogenized and Chocolate Milk

1967 ◽  
Vol 50 (3) ◽  
pp. 537-541
Author(s):  
D J Mitchell
Keyword(s):  
Collaborative Study ◽  
Chocolate Milk ◽  
Collaborative Studies ◽  
Significant Difference

Abstract The modified rapid detergent (TeSa), AOAC Roese-Gottlieb, and Babcock methods for determining butterfat were compared in a collaborative study on 8 samples of homogenized milk by 6 laboratories. The modified rapid detergent and Roese- Gottlieb methods were also compared on 4 samples of chocolate milk by the same collaborators. There was a statistically significant difference between the Roese-Gottlieb and detergent methods in 5 laboratories for homogenized milk and in 4 laboratories for chocolate milk. Additional developmental work is necessary before the detergent method can be applied to homogenized and chocolate milk

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