Oilseeds. Reduction of laboratory sample to test sample

2008 ◽  
Keyword(s):  
Test Sample ◽  
Laboratory Sample

An alternative to slurry mixing to minimise sample preparation variance for determination of ochratoxin A in wheat

2010 ◽  
Vol 3 (2) ◽  
pp. 147-156 ◽  
Author(s):  
T. Nowicki ◽  
M. Roscoe
Keyword(s):  
Sample Preparation ◽  
Ochratoxin A ◽  
Mixing Time ◽  
Test Sample ◽  
Laboratory Sample ◽  
Analytical Process ◽  
Accuracy And Precision ◽  
Primary Sample ◽  
Surveillance Programs ◽  
Ground Wheat

Many countries have established maximum limits for ochratoxin A (OTA) in cereal grains and implemented surveillance programs for OTA in wheat shipments. For shipment to some countries, certification for OTA content is mandatory. These control activities require the capability to measure OTA in bulk grain shipments with accuracy and precision. It is known that the nugget effect caused by the heterogeneous nature of mycotoxin contamination in agricultural commodities creates major challenges for generating representative test results due to the potential for high variances in the sampling / sample preparation phases of the analytical process. The water-slurry mixing approach to sample preparation has greatly minimises variances associated with this phase of the analytical process, but this is not a practical technique for all laboratories. The potential magnitude of variances for subsampling raw and ground grain for the dry-milling approach to sample preparation and the means for reducing variances to acceptable levels is not fully understood. We investigated the repeatability of OTA measurements in 2 kg laboratory samples subsampled from 20 kg samples of raw wheat and in 100 g test portions subsampled from 2 kg of ground wheat. In addition, the effect of mixing time on the repeatability of OTA results was investigated prior to subsampling to obtain test portions for analysis. Results show that for subsampling of a primary sample of raw wheat using a conventional sample divider the variability of OTA results decreases with increasing weight of the laboratory sample relative to the weight of the primary sample. In order to improve repeatability, the proportion of primary sample separated out to produce a laboratory sample should be as large as operationally feasible and ideally about 50% of the weight of the primary sample. Four factors are identified for separating out a test sample from a raw wheat laboratory sample.

Sampling and Preparation of Sample for Chemical Examination

1988 ◽  
Vol 71 (2) ◽  
pp. 241-245
Author(s):  
William Horwitz
Keyword(s):  
Total Error ◽  
Test Sample ◽  
Laboratory Sample ◽  
Chemical Examination ◽  
Large Samples

Abstract Sampling and methods for reducing a laboratory sample to a test sample are discussed, with particular emphasis on sampling peanuts for aflatoxin analysis as a practical example. The only way to control the total error in the analysis of this heterogeneous product is to take and to analyze many and large samples.

A Novel Functional Assay of Protein C in Human Plasma and fts Comparison with Amidolytic and Anticoagulant Assays

1992 ◽  
Vol 67 (01) ◽  
pp. 046-049 ◽  
Author(s):  
H A Guglielmone ◽  
M A Vides
Keyword(s):  
Oral Anticoagulant ◽  
Protein C ◽  
Activated Protein C ◽  
Protein S ◽  
Normal Subjects ◽  
Test Sample ◽  
Functional Assay ◽  
Fast Method ◽  
Factor Va ◽  
Protein C Activity

SummaryA simple and fast method for the quantitative determination of protein C activity in plasma is here described. The first step consists in the conversion of protein C in the test sample into activated protein C by means of an activator isolated from Southern Copperhead venom. Subsequently, the degradation of factor Va, in presence of protein C-deficient plasma, is measured by the prolongation of the prothrombin time which is proportional to the amount of protein C in the sample. The dose-response curve showed a linear relationship from 6 to 150% protein C activity and the inter- and intra-assay reproducibility was 3.5% and 5.6% respectively. In normal subjects, a mean of protein C level of 98 ± 15% of normal pooled plasma was found. Comparison with the anticoagulant assay in samples of patients with oral anticoagulant, liver cirrhosis, disseminated intravascular coagulation and severe preeclampsia revealed an excellent correlation (r = 0.94, p <0.001). Also, a similar correlation (r = 0.93, p <0.001) existed between amidolytic assay and the method here proposed for all the samples studied without including the oral anticoagulant group. These results allowed us to infer that this method evaluates the ability of protein C to interact with protein S, phospholipids, calcium ions and factor Va.

An evaluation of ECT sample height for small flute board grades and Box Manufacturer’s Certification compliance

TAPPI Journal ◽  
2009 ◽  
Vol 8 (6) ◽  
pp. 24-28
Author(s):  
CORY JAY WILSON ◽  
BENJAMIN FRANK
Keyword(s):  
Compressive Strength ◽  
Compressive Load ◽  
Test Sample ◽  
Test Methods ◽  
Test Method ◽  
Initial Development ◽  
Sample Height ◽  
Relationship Of ◽  
The Relationship ◽  
Corrugated Fiberboard

TAPPI test T811 is the specified method to ascertain ECT relative to box manufacturer’s certification compliance of corrugated fiberboard under Rule 41/ Alternate Item 222. T811 test sample heights were derived from typical board constructions at the time of the test method’s initial development. New, smaller flute sizes have since been developed, and the use of lighter weight boards has become more common. The T811 test method includes sample specifications for typical A-flute, B-flute, and C-flute singlewall (and doublewall and triplewall) structures, but not for newer thinner E-flute or F-flute structures. This research explores the relationship of ECT sample height to measured compressive load, in an effort to determine valid E-flute and F-flute ECT sample heights for use with the T811 method. Through this process, it identifies challenges present in our use of current ECT test methods as a measure of intrinsic compressive strength for smaller flute structures. The data does not support the use of TAPPI T 811 for ECT measurement for E and F flute structures, and demonstrates inconsistencies with current height specifi-cations for some lightweight B flute.

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