Solid recovered fuels. Methods for laboratory sample preparation

2015 ◽  
Keyword(s):  
Sample Preparation ◽  
Laboratory Sample

scholarly journals Status Report on Sample Preparation Protocols Developed at the LMC14 Laboratory, Saclay, France: From Sample Collection to 14C AMS Measurement

Radiocarbon ◽  
2017 ◽  
Vol 59 (3) ◽  
pp. 713-726 ◽  
Author(s):  
J-P Dumoulin ◽  
C Comby-Zerbino ◽  
E Delqué-Količ ◽  
C Moreau ◽  
I Caffy ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Accelerator Mass Spectrometry ◽  
Storage Time ◽  
Status Report ◽  
Sample Collection ◽  
Laboratory Sample ◽  
Different Types ◽  
Chemical Pretreatments ◽  
Sampling Procedures

AbstractThe main objective of this report is to present the dating process routinely applied to different types of samples at the Laboratoire de Mesure du Carbone 14 (LMC14). All the results and protocols refer to our procedures over the last 5 years. A description of the sorting and chemical pretreatments of the samples as well as the extraction and graphitization of CO2 are reported. Our last study concerning the degradation of the blank level according to the storage time of the targets between graphitization and accelerator mass spectrometry (AMS) measurement is also presented. This article also provides information on how to submit a valid laboratory sample. We give details relating to sampling procedures on site as well as contamination issues relative to the 14C dating methodology.

Assessment of laboratory sample preparation for fibre reinforced sands

2012 ◽  
Vol 34 ◽  
pp. 69-79 ◽  
Author(s):  
E. Ibraim ◽  
A. Diambra ◽  
A.R. Russell ◽  
D. Muir Wood
Keyword(s):  
Sample Preparation ◽  
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.

scholarly journals Maize meal slurry mixing: an economical recipe for precise aflatoxin quantitation

2019 ◽  
Vol 12 (3) ◽  
pp. 203-212 ◽  
Author(s):  
J. Kumphanda ◽  
L. Matumba ◽  
T.B. Whitaker ◽  
W. Kasapila ◽  
J. Sandahl
Keyword(s):  
Sample Preparation ◽  
Analytical Methods ◽  
Laboratory Sample ◽  
Test Portion ◽  
Sampling Plans ◽  
Dry Grind ◽  
Water Matrix ◽  
Analytical Variance ◽  
Aflatoxin Concentration ◽  
Maize Meal

The laboratory sample preparation for mycotoxin determination in cereals, often overlooked among sampling plans and analytical methods, was further studied. The precision of aflatoxin analysis in comminuted maize samples using 25 g slurry (prepared from 250 g test portion of comminuted maize, water/matrix (1+1, v/w)) and 12.5 g dry grind test portion were compared against the conventional 50 g dry grind test portion through replicated (10) Aflatest® immunoaffinity fluorometric tests of naturally contaminated samples with aflatoxin concentration ranging from 4.9 to 81.7 μg/kg. The overall mean aflatoxin concentration obtained from the 10 different samples tested using 12.5 g and 50.0 g dry grind procedures was 12% significantly (P<0.05) lower (poorer) compared to 25 g slurry. The sample preparation plus analytical variance associated with testing 25.0 g slurry, 50.0 g dry grind and 12.5 g dry grind test portions were in the ratio of 1:5:15, respectively.

Variability and distribution among sample test results when sampling unprocessed wheat lots for ochratoxin A

2016 ◽  
Vol 9 (2) ◽  
pp. 163-178 ◽  
Author(s):  
T.B. Whitaker ◽  
A.B. Slate ◽  
T.W. Nowicki ◽  
F.G. Giesbrecht
Keyword(s):  
Liquid Chromatography ◽  
Sample Preparation ◽  
Ochratoxin A ◽  
Test Procedure ◽  
Test Results ◽  
Laboratory Sample ◽  
Sampling Step ◽  
Test Portion ◽  
Sample Test ◽  
Sampling Statistics

In 2008, Health Canada announced it was considering the establishment of maximum levels for ochratoxin A (OTA) in unprocessed wheat, oats, and their products. The Canada Grains Council and Canadian National Millers Association initiated two studies to measure the variability and distribution among sample test results for unprocessed wheat and oats so that scientifically based OTA sampling plans could be designed to meet regulatory and industry requirements. Sampling statistics related to detecting OTA in oats has been published. 54 OTA contaminated wheat lots representing three wheat classes were identified for the sampling study. Each lot was sampled according to a nested experimental protocol where sixteen 2-kg laboratory samples were taken from each lot, multiple 5-g test portions were taken from each comminuted 2-kg laboratory sample, and multiple OTA measurements were made on each test portion using liquid chromatography. The sampling, sample preparation, and analytical variances associated with each step of the OTA test procedure were found to be a function of OTA concentration and regression equations were developed to predict the functional relationships between variance and OTA concentration. When sampling a wheat lot containing 5 µg/kg OTA with an OTA test procedure consisting of a sampling step employing a single 2-kg laboratory sample, sample preparation step employing a single 100-g test portion, and an analytical step that used liquid chromatography to quantify OTA, the sampling step accounted for 95.3% of the total variability. The observed OTA distribution among the 16 OTA sample results was found to be positively skewed and the negative binomial distribution was selected to model the OTA distribution among sample test results. The sampling statistics were incorporated into the FAO Mycotoxin Sampling Tool and the chances of rejecting good lots and accepting bad lots were calculated for various sampling plan designs.

scholarly journals Woods Hole Oceanographic Institution Radiocarbon Laboratory: Sample Treatment and Gas Preparation

Radiocarbon ◽  
1985 ◽  
Vol 27 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Sheila Griffin ◽  
Ellen R M Druffel
Keyword(s):  
Sample Preparation ◽  
National Science Foundation ◽  
Sample Treatment ◽  
Woods Hole Oceanographic Institution ◽  
Laboratory Sample ◽  
National Science ◽  
Oceanographic Research

The purpose of this paper is to present the methodology used for sample preparation at the Woods Hole Oceanographic Institution Radiocarbon Laboratory. The WHOI lab is dedicated to oceanographic research supported by the National Science Foundation (OCE81-11954). We began operation in March 1982. The methods used for the production of samples are based on those developed previously (Barker, 1953; Suess, 1954; Noakes, Kim, & Stipp, 1969; Linick, 1975). Subsequent changes and refinements to these methods are described. This paper will present detailed descriptions of how various samples are collected and sectioned, then converted to CO2 and to C2H2, the primary counting gas for most of our samples.

Comparison of Slurry Mixing and Dry Milling in Laboratory Sample Preparation for Determination of Ochratoxin A and Deoxynivalenol in Wheat

2012 ◽  
Vol 95 (2) ◽  
pp. 452-458 ◽  
Author(s):  
Vincenzo Lippolis ◽  
Michelangelo Pascale ◽  
Stefania Valenzano ◽  
Angelo Visconti
Keyword(s):  
Sample Preparation ◽  
Ochratoxin A ◽  
Ad Hoc ◽  
High Variability ◽  
Dry Milling ◽  
Laboratory Sample ◽  
Water Slurry ◽  
Official Control ◽  
Accuracy And Precision

Abstract The significance of laboratory sample preparation for the determination of two important mycotoxins, ochratoxin A (OTA) and deoxynivalenol (DON), in wheat was investigated by comparing water-slurry mixing and dry-milling procedures. The distribution of OTA and DON in 10 kg samples of naturally contaminated wheat was established by analyzing one hundred 100 g subsamples of each sample. A normal distribution and a good repeatability of DON measurements was observed for both water-slurry mixing (mean 2290 μg/kg, CV 4.6%, median 2290 μg/kg) and dry milling (mean 2310 μg/kg, CV 6.4%, median 2290 μg/kg) procedures. For OTA determinations, reliable results could be obtained only by slurry mixing sample preparation (mean 2.62 μg/kg, CV 4.0%, median 2.62 μg/kg), whereas dry-milling comminution resulted in an inhomogeneous distribution with a high variability (mean 0.83 μg/kg, CV 75.2%, median 0.60 μg/kg) and a positive skewness (2.12). Ad hoc experiments were performed on different size portions of the same sample (10 kg) to assess accuracy and precision of the comminution/homogenization procedures (slurry mixing and dry milling). Very good results were obtained for DON determination with both procedures in terms of accuracy (&gt;98.7% of the “weighted value”) and precision (CV &lt;3%). For OTA determination good results were only obtained by slurry mixing (99.4% of the “weighted value,” CV 10%), whereas dry milling provided results with low accuracy (43.2% of the “weighted value”) and high variability (CV 110%). This study clearly demonstrated that sample preparation by slurry mixing is strictly necessary to obtain reliable laboratory samples for OTA determination in wheat to minimize misclassification of acceptable/rejectable lots, mainly within official control.

Pollutant Identification by Selected Area Electron Diffraction

1974 ◽  
Vol 32 ◽  
pp. 532-533
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson ◽  
C. W. Walker
Keyword(s):  
Thermal Treatment ◽  
Electron Diffraction ◽  
Sample Preparation ◽  
Crystal Structures ◽  
Water Samples ◽  
Environmental Samples ◽  
Short Review ◽  
Selected Area Electron Diffraction ◽  
Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

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