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.

Sampling dried figs for aflatoxin – Part 1: variability associated with sampling, sample preparation, and analysis

2017 ◽  
Vol 10 (1) ◽  
pp. 31-40 ◽  
Author(s):  
H. Ozer ◽  
H.I. Oktay Basegmez ◽  
T.B. Whitaker ◽  
A.B. Slate ◽  
F.G. Giesbrecht
Keyword(s):  
Sample Preparation ◽  
Test Procedure ◽  
Portion Size ◽  
Total Variance ◽  
Sampling Variance ◽  
Regression Equations ◽  
Sampling Step ◽  
Test Portion ◽  
Analytical Variance ◽  
Aflatoxin Concentration

The variability associated with the aflatoxin test procedure used to estimate aflatoxins in bulk shipments of dried figs was investigated. Sixteen 10 kg laboratory samples were taken from each of twenty commercial bulk lots of dried figs suspected of aflatoxin contamination. Two 55 g test portions were taken from each comminuted laboratory sample using water-slurry comminution methods. Finally, two aliquots from the test portion/solvent blend were analysed for both aflatoxin B1 and total aflatoxins. The total variance associated with testing dried figs for aflatoxins was measured and partitioned into sampling, sample preparation and analytical variance components (total variance is equal to the sum of the sampling variance, sample preparation variance, and analytical variance). Each variance component increased as aflatoxin concentration increased. Using regression analysis, mathematical expressions were developed to model the relationship between aflatoxin concentration and the total, sampling, sample preparation and analytical variances when testing dried figs for aflatoxins. The regression equations were modified to estimate the variances for any sample size, test portion size, and number of analyses for a specific lot aflatoxin concentration. When using the above aflatoxin test procedure to sample a fig lot at 10 μg/kg total aflatoxins, the sampling, sample preparation, analytical, and total variances were 47.20, 0.29, 0.13, and 47.62, respectively. The sampling, sample preparation, and analytical steps accounted for 99.1, 0.6, and 0.3% of the total variance, respectively. For the aflatoxin test procedure used in this study, the sampling step is the largest source of variability.

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 The Application of NMR Spectroscopy and Chemometrics in Authentication of Spices

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 382
Author(s):  
Barbara Pacholczyk-Sienicka ◽  
Grzegorz Ciepielowski ◽  
Łukasz Albrecht
Keyword(s):  
Quality Assurance ◽  
Nmr Spectroscopy ◽  
Sample Preparation ◽  
Bioactive Compounds ◽  
Analytical Methods ◽  
Structural Information ◽  
Chemometric Analysis ◽  
Spectroscopic Methods ◽  
Regular Consumption ◽  
No Sample Preparation

Spices and herbs are among the most commonly adulterated food types. This is because spices are widely used to process food. Spices not only enhance the flavor and taste of food, but they are also sources of numerous bioactive compounds that are significantly beneficial for health. The healing effects of spices are connected with their antimicrobial, anti-inflammatory and carminative properties. However, regular consumption of adulterated spices may cause fatal damage to our system because adulterants in most cases are unhealthy. For that reason, the appropriate analytical methods are necessary for quality assurance and to ensure the authenticity of spices. Spectroscopic methods are gaining interest as they are fast, require little or no sample preparation, and provide rich structural information. This review provides an overview of the application of NMR spectroscopy combined with chemometric analysis to determine the quality and adulteration of spices.

Analysis of Synthetic Fibers by Diamond Cell and Sapphire Cell Infrared Spectrophotometry

1978 ◽  
Vol 61 (3) ◽  
pp. 526-532
Author(s):  
Leonard K Read ◽  
Robert J Kopec
Keyword(s):  
Sample Preparation ◽  
Analytical Methods ◽  
Nondestructive Method ◽  
Spectrophotometric Analysis ◽  
Infrared Spectrophotometry ◽  
Generic Type ◽  
Synthetic Fibers ◽  
Fiber Sample

Abstract A rapid, simple, and nondestructive method of sample preparation and analysis is described for the infrared spectrophotometric analysis of synthetic fibers. This method uses a combined diamond cell and sapphire cell technique that yields highly resolved spectra with microgramsize fiber samples. From these highly resolved spectra, the generic type of fiber can be readily determined. Although the fiber sample has been physically crushed, it is not destroyed during the analysis and can be further examined by other analytical methods.

Considerations in the preparation of laboratory samples for the analysis of ochratoxin A in wheat

2012 ◽  
Vol 5 (2) ◽  
pp. 107-116 ◽  
Author(s):  
S.A. Tittlemier ◽  
M. Roscoe ◽  
C. Kobialka ◽  
R. Blagden
Keyword(s):  
Ochratoxin A ◽  
Whole Grain ◽  
Laboratory Sample ◽  
Test Portion ◽  
Homogeneous Sample ◽  
Ambient Temperatures ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
The Mean ◽  
Ground Wheat

A process used to prepare the test portion of ground wheat from the whole grain laboratory sample for ochratoxin A (OTA) analysis using dry comminution with homogenisation and sub-sampling via a rotary sample divider was developed and evaluated. With respect to OTA content, the developed process produced a homogeneous sample of ground wheat from 10 kg of whole grain. Relative standard deviations of the mean OTA concentration for five naturally contaminated wheat samples processed using the developed method ranged from 9% to 19% over a relevant concentration range of 1.7 to 7.6 mg/kg. Additional studies demonstrated that OTA was stable in ground wheat with moisture content between 12 to 13% for at least a year when stored at ambient temperatures. Further examination of the developed comminution and dividing procedure demonstrated that higher concentrations were measured in smaller sized particles, indicating that the accuracy and precision of OTA analyses could be affected by the particle size of ground wheat.

Synthetic cannabinoids in biological specimens: a review of current analytical methods and sample preparation techniques

Bioanalysis ◽  
2018 ◽  
Vol 10 (19) ◽  
pp. 1609-1623 ◽  
Author(s):  
Tiago Rosado ◽  
Joana Gonçalves ◽  
Ângelo Luís ◽  
Sara Malaca ◽  
Sofia Soares ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Analytical Methods ◽  
Synthetic Cannabinoids ◽  
Preparation Techniques

scholarly journals Implementing Green Analytical Methodologies Using Solid-Phase Microextraction: A Review

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5297
Author(s):  
Kayla M. Billiard ◽  
Amanda R. Dershem ◽  
Emanuela Gionfriddo
Keyword(s):  
Analytical Chemistry ◽  
Sample Preparation ◽  
Analytical Method ◽  
Analytical Methods ◽  
Solid Phase Microextraction ◽  
Method Development ◽  
Assessment Tool ◽  
Solid Phase ◽  
Assessment Tools ◽  
Green Analytical Chemistry

Implementing green analytical methodologies has been one of the main objectives of the analytical chemistry community for the past two decades. Sample preparation and extraction procedures are two parts of analytical method development that can be best adapted to meet the principles of green analytical chemistry. The goal of transitioning to green analytical chemistry is to establish new methods that perform comparably—or superiorly—to traditional methods. The use of assessment tools to provide an objective and concise evaluation of the analytical methods’ adherence to the principles of green analytical chemistry is critical to achieving this goal. In this review, we describe various sample preparation and extraction methods that can be used to increase the greenness of a given analytical method. We gave special emphasis to modern microextraction technologies and their important contributions to the development of new green analytical methods. Several manuscripts in which the greenness of a solid-phase microextraction (SPME) technique was compared to other sample preparation strategies using the Green Analytical Procedure Index (GAPI), a green assessment tool, were reviewed.

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