Test Method for Determination of Virucidal Efficacy of Liquid Surface Disinfectants

1976 ◽  
Vol 59 (5) ◽  
pp. 1150-1155
Author(s):  
Charles R McDuff ◽  
John W Gaustad
Keyword(s):  
Collaborative Study ◽  
Test Procedure ◽  
Test Method ◽  
Virus Concentration ◽  
Ammonium Compound ◽  
Concentration Technique ◽  
Modified Method ◽  
Culture Cells

Abstract A test method was developed incorporating AOAC use-dilution stainless steel Penicylinders and H.Ep.-2 tissue culture cells for the evaluation of disinfectants as virucides. The subsequent collaborative study using Herpes simplex and poliovirus type 1 in evaluation against a quaternary ammonium compound, phenolic, and iodiphor disinfectants indicated that the basic test procedure is sound. However, an improved virus concentration technique and a modified method for drying virus-contaminated cylinders are recommended. In addition, other types of disinfectants and test viruses should be included in order to demonstrate that the procedure is versatile as well as reproducible.

Collaborative Study of a Modified Method for the Determination of Aflatoxins in Copra, Copra Meal, and Coconut

1971 ◽  
Vol 54 (4) ◽  
pp. 874-878
Author(s):  
F J Baur ◽  
J C Armstrong
Keyword(s):  
Aflatoxin B1 ◽  
Quantitative Measurement ◽  
Collaborative Study ◽  
Copra Meal ◽  
Modified Method

Abstract A collaborative study, in which 19 laboratories participated, was conducted on a modified method for the determination of aflatoxins in 2 copra samples, one naturally contaminated, and 4 samples of naturally contaminated copra meal. The sensitivity and precision of the modified method for aflatoxin B1 and total aflatoxins were comparable to the official methods for peanuts and peanut products. Aflatoxins B2, G1, and G2 were reported by most of the laboratories, but background interferences made quantitative measurement less reliable than for B1. The method as it presently stands is also applicable to the analysis of coconut. The method has been adopted as official first action; further study will be directed toward improved precision for analysis of aflatoxins B2, G1, and G2.

scholarly journals Statistical determination of endotoxin content in influenza virus vaccine by the limulus amoebocyte lysate test

1977 ◽  
Vol 6 (2) ◽  
pp. 144-148
Author(s):  
S C Rastogi ◽  
H D Hochstein ◽  
E B Seligmann
Keyword(s):  
Influenza Virus ◽  
Virus Vaccine ◽  
Collaborative Study ◽  
Test Procedure ◽  
Influenza Virus Vaccine ◽  
Limulus Amoebocyte Lysate ◽  
Normal Test ◽  
Statistical Determination ◽  
Endotoxin Content

To determine laboratory-to-laboratory variability of the limulus amoebocyte lysate (LAL) test for evaluating endotoxin content in influenza virus vaccine, a collaborative study was designed. Participants were six influenza virus vaccine manufacturers and the Bureau of Biologics (BoB). Lysate lot 116, Reference Influenza Virus Vaccine for Endotoxin Assay E-1, and four test vaccines having different ratios of LAL activity relative to reference E-1 were supplied by the BoB. Each laboratory used its normal test procedure. All vaccines were coded. One pair (reference and test) of vaccines per day was tested for 4 days a week over a 4-week period. All data were analyzed at the BoB. The degree of variability experienced by testing laboratories was estimated by the study. This estimate did not conflict with experience gained from previous routine testing in any of the participating laboratories. A statistical approach to the evaluation of LAL data from testing influenza virus vaccine for endotoxin content was developed based upon the overall variation obtained from the collaborative study.

Determination of Amprolium in Feeds: Collaborative Study

1979 ◽  
Vol 62 (3) ◽  
pp. 621-623
Author(s):  
E Jack Davis
Keyword(s):  
Aluminum Oxide ◽  
Collaborative Study ◽  
Official Method ◽  
Modified Method

Abstract The official final action method, 42.028-42.032, for determining amprolium in feeds was modified by a change in the preparation of aluminum oxide for chromatography. A premix containing 0.5% amprolium was collaboratively studied by the modified and the official methods. Compared with the modified method, 87.7% of the drug was recovered from the premix by using the official method. The modification makes possible the assay of premixes as well as finished feeds. The official final action method has been modified to incorporate this change.

The modern methods of pin-type bearing test of metallic materials

2019 ◽  
Vol 85 (7) ◽  
pp. 41-49
Author(s):  
Yaroslava V. Sulimina ◽  
Nikolay O. Yakovlev ◽  
Vladimir S. Erasov ◽  
Aleksey Yu. Ampilogov ◽  
Andrey N. Polyakov ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Test Procedure ◽  
Test Methods ◽  
Test Method ◽  
Strength Characteristics ◽  
Metallic Materials ◽  
Bearing Strength ◽  
Bearing Stress ◽  
The Impact

The special features of various bearing deformation measurements for pin-type bearing tests of metallic materials are considered along with their impact on the magnitude of the «bearing elastic modulus» and bearing stress. These bearing test methods are present in ASTM and various institutional standards, though no state standard (GOST, GOST R) is currently available for bearing test method of metallic materials. Analysis of additional deformations which arise in determining the degree of hole bearing deformation is carried out. A set of sources of additional deformations is shown to be characteristic for each test procedure and is attributed to the design features of the device, the site and a way of mounting the extensometer. Additional deformations can be both tensile and compressive. It is shown that the impact of additional deformations on the «bearing elastic modulus» is limited to 14% for different procedures. No difference between the methods is revealed with regard to determination of the strength characteristics. At the same time the dispersion decreases with increase in plastic deformation and for bearing deformation about 4% the variation coefficient for all methods is no more than 1%. Advantages and shortcomings of the bearing test methods which affect the reproducibility of the results are considered. The effect of the specimen geometry on the bearing characteristics is considered. It is shown that increase both in the distance from the edge of the bearing specimen to the center of the hole for 1163T, VT6ch, 30KhGSA alloys and residual bearing deformation up to 6%, increase bearing strength characteristics.

Hot Pin Pull Method – New Test Procedure for the Adhesion Measurement for 3D-MID

2014 ◽  
Vol 1038 ◽  
pp. 115-120 ◽  
Author(s):  
Christian Goth ◽  
Thomas Kuhn ◽  
Gerald Gion ◽  
Jörg Franke
Keyword(s):  
Test Procedure ◽  
Test Methods ◽  
Test Method ◽  
Testing System ◽  
Adhesion Test ◽  
Metallic Structures ◽  
Adhesion Measurement ◽  
Molded Interconnect Devices ◽  
Unsolved Issue

The adhesion test of metallic structures on MID (Molded Interconnect Devices) parts is an unsolved issue. So far no method really works reliably. The test methods which are conventionally used are the pull-off test and the shear-test. Both show large standard deviation and the reproducibility is not assured. Nordson DAGE has introduced the new micro-material testing system 4000Plus. This device enables a new test method for the determination of the adhesion strength of MID structures using the hot pin pull (hot bump pull) method. Copper pins (tinned or untinned) are heated up with a user defined temperature profile, soldered to a metallized structure on the MID and then removed vertically upward, while the force is recorded. In this contribution investigations with this new test method are presented.

Charpy V notch tests – Risks associated with testing with 3 samples

2021 ◽  
Vol 109 (1) ◽  
pp. 105
Author(s):  
Michel Huther ◽  
Henri-Paul Lieurade
Keyword(s):  
Test Procedure ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Test Method ◽  
Transition Curve ◽  
Test Results ◽  
Working Groups ◽  
Temperature Work ◽  
Work Done

To estimate the risk of brittle fracture of a component in service, Charpy tests are generally carried out on 3 samples at the same temperature. Work done over many years on welded joint fatigue using probability and statistics has shown that to have a good assessment of minimum strength, it is clearly necessary to have a larger number of test results. In order to analyse the risks associated with this practice of 3 samples tested at the same temperature, a series of 17 Charpy impact test results of samples of the same steel plate was chosen. From this series, by translation, 2 series were generated, one with a test of 3 specimens showing acceptable steel and one with a test of 3 specimens showing unacceptable steel. The 3-test method was applied to these series leading to a possible simulation of 12 tests each. It was found that the 3-test practice leads to a risk of error of 30 to 40%. It is also found that the determination of the transition curve of a DH36 steel finally shows that its temperature for a CV of 27 J is of the order of −50 °C whereas the regulations require only −20 °C. In conclusion, a possible improvement of the test procedure is indicated, which is the subject of a study within the framework of the “CCRS rupture and fatigue” working groups of the Société des Ingénieurs Soudeurs (SIS).

Microbiological Assay of Streptomycin in Feeds: 1971 Collaborative Study

1972 ◽  
Vol 55 (4) ◽  
pp. 714-717
Author(s):  
John J Mayernik ◽  
Gloria Y Fiori ◽  
Shirley Hughes
Keyword(s):  
Sample Size ◽  
Reference Point ◽  
Collaborative Study ◽  
Microbiological Assay ◽  
Modified Method ◽  
Coefficients Of Variation ◽  
Aoac Official ◽  
Low Levels

Abstract The AOAC official first action method for the determination of streptomycin in feed in which the regular streptomycin assay agar is used was modified for application to the assay of low levels of streptomycin. The modifications consist of (1) increasing the sample size, (2) reducing the amount of agar in the assay plates, (3) lowering the concentration of the reference point on the assay plates, and (4) incubating the plates at 22–25°C instead of 37°C. Fifteen collaborators used the modified method to assay 6 feeds containing 5–30 g streptomycin/ ton. Mean recoveries ranged from 91.7 to 111.0% and coefficients of variation ranged from 5.8 to 8.7%. The method modified as described has been adopted as official first action for the assay of feeds containing 5–30 g streptomycin/ton.

Collaborative Study of the Determination of Ethoxyquin in Chick Tissue and Eggs by Fluorescence

1968 ◽  
Vol 51 (3) ◽  
pp. 537-539
Author(s):  
J M Van Deren ◽  
E G Jaworski
Keyword(s):  
Collaborative Study ◽  
Tissue Samples ◽  
Tolerance Level ◽  
Standard Curve ◽  
Modified Method ◽  
Fluorescent Spectrum ◽  
Egg Yolks ◽  
Chick Tissue ◽  
Control Samples

Abstract A collaborative study for the analysis of ethoxyquin was repeated with a modified procedure for the preparation of the standard curve, and all standard curves were satisfactory. Ethoxyquin recovery was good in all tissues analyzed: 76% from egg yolks (lowest recovery) and 88% from fat (highest recovery). The fluorescent spectrum for ethoxyquin shows that the secondary filter is quite critical; light scattering from the sample must be controlled to avoid interferences. Although variation in the control samples was caused by both the source of the tissue samples and the secondary filters, values did not exceed the 10% tolerance level established for ethoxyquin in tissue and eggs. It is recommended that this modified method be adopted as official, first action.

Collaborative Study of the Determination of Dithiocarbamate Residues by a Modified Carbon Disulfide Evolution Method

1971 ◽  
Vol 54 (3) ◽  
pp. 528-532 ◽  
Author(s):  
George E Keppel
Keyword(s):  
Hydrogen Sulfide ◽  
Stannous Chloride ◽  
Collaborative Study ◽  
The Other ◽  
Dilute Acid ◽  
Trap Hydrogen ◽  
Modified Method ◽  
Coefficients Of Variation ◽  
Naoh Solution

Abstract A modified method for determination of dithiocarbamate residue recoveries from grain was studied collaboratively. In this method dilute acid with stannous chloride is added to the crop, which is then heated to boiling for the dithiocarbamate decomposition step. A mixture of NaOH solution and benzene is used to trap hydrogen sulfide and other volatile interferences. Collaborative results were low and erratic, with large coefficients of variation. The results of the Associate Referee, on the other hand, were better. Further study on this method is recommended.

scholarly journals Performance of the AOAC Use-Dilution Method with Targeted Modifications: Collaborative Study

2012 ◽  
Vol 95 (6) ◽  
pp. 1618-1628 ◽  
Author(s):  
Stephen F Tomasino ◽  
Albert E Parker ◽  
Martin A Hamilton ◽  
Gordon C Hamilton
Keyword(s):  
Environmental Protection Agency ◽  
Horse Serum ◽  
Collaborative Study ◽  
Current Method ◽  
Hard Water ◽  
Test Method ◽  
Performance Standard ◽  
Dilution Method ◽  
Modified Method ◽  
Test Culture

Abstract The U.S. Environmental Protection Agency (EPA), in collaboration with an industry work group, spearheaded a collaborative study designed to further enhance the AOAC use-dilution method (UDM). Based on feedback from laboratories that routinely conduct the UDM, improvements to the test culture preparation steps were prioritized. A set of modifications, largely based on culturing the test microbes on agar as specified in the AOAC hard surface carrier test method, were evaluated in a five-laboratory trial. The modifications targeted the preparation of the Pseudomonas aeruginosa test culture due to the difficulty in separating the pellicle from the broth in the current UDM. The proposed modifications (i.e., the modified UDM) were compared to the current UDM methodology for P. aeruginosa and Staphylococcus aureus. Salmonella choleraesuis was not included in the study. The goal was to determine if the modifications reduced method variability. Three efficacy response variables were statistically analyzed: the number of positive carriers, the log reduction, and the pass/fail outcome. The scope of the collaborative study was limited to testing one liquid disinfectant (an EPA-registered quaternary ammonium product) at two levels of presumed product efficacies, high and low. Test conditions included use of 400 ppm hard water as the product diluent and a 5% organic soil load (horse serum) added to the inoculum. Unfortunately, the study failed to support the adoption of the major modification (use of an agar-based approach to grow the test cultures) based on an analysis of method's variability. The repeatability and reproducibility standard deviations for the modified method were equal to or greater than those for the current method across the various test variables. However, the authors propose retaining the frozen stock preparation step of the modified method, and based on the statistical equivalency of the control log densities, support its adoption as a procedural change to the current UDM. The current UDM displayed acceptable responsiveness to changes in product efficacy; acceptable repeatability across multiple tests in each laboratory for the control counts and log reductions; and acceptable reproducibility across multiple laboratories for the control log density values and log reductions. Although the data do not support the adoption of all modifications, the UDM collaborative study data are valuable for assessing sources of method variability and a reassessment of the performance standard for the UDM.

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