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001 mg/kg. For diaminotriazine, the LOQ was 0.005 mg/kg. The method accuracy and precision complied with the SANTE/12682/2019 guidelines of analytical quality control.
The potentiality of the method lies in a high throughput analysis of IND and its metabolites in a single chromatographic run with high selectivity and sensitivity. Considering its fit-for-purpose performance, the method can be implemented in regulatory testing of IND residues in a wide range of palm oil matrices that are consumed and traded worldwide.
This work has provided a validated method for simultaneous residue analysis of indaziflam and its metabolites in crude palm oil and its derived matrices with high sensitivity, selectivity, and throughput.
This work has provided a validated method for simultaneous residue analysis of indaziflam and its metabolites in crude palm oil and its derived matrices with high sensitivity, selectivity, and throughput.
The quality discrimination of dairy products is an important basis on which to achieve quality assurance.
Taking the discriminant analysis of brand yogurt products as an example, a new rapid discriminant method can be constructed.
The first three principal components were selected as the pattern vectors of the samples. Entinostat molecular weight Then, at random, 75% of the samples were collected as a training set, and their mean values and covariance matrices were calculated to construct a Gauss Bayesian discriminant model. The remaining 25% of samples were employed as a test set, and the pattern vectors of each sample were input into the above model. Next, the posterior probability of each sample in relation to each category could be obtained. Results The category corresponding to the maximum posterior probability as the brand classification of each sample was defined.
We constructed a Gauss Bayesian discriminant model to discriminate these different yogurt products after the principal component feature extraction of Raman properties. The results indicate the rationality and wide application prospects of this approach.
A fast dairy product discriminant method based on Gauss Bayesian model and Raman spectroscopy was established.
A fast dairy product discriminant method based on Gauss Bayesian model and Raman spectroscopy was established.Medicinal herbs are the ancient, traditional way of treating many diseases and are now considered the first natural source of pharmaceutical active ingredients. Therefore, it is very important to focus on the hygiene of these plants so as to make sure they are safe for consumption. This work aimed to monitor the common heavy and radioactive elements in some commonly used herbs anise, chamomile, clover, cumin, coriander, fennel, roselle, rosemary, sage, and thyme. A total of 12 elements were measured including 2 radionuclides, Al, As, Cd, Hg, Co, Cr, Ni, Pb, Sr, Th, U, and V. Heavy metals are ecologically and biologically important, and may be involved in some health disorder symptoms within the human body. Samples were digested with a microwave digester and measurements were completed with ICP-MS/MS in Helium mode to increase sensitivity, lower the background, and avoid interferences. Method validation and verification were performed through the spiking process at 2.0 µg/kg level, and then RSD, LOD, and LOQ were calculated. Recoveries ranged from 93-103% for all elements and RSD% from 2.8-9.6%. Hg and Th were not detected in all samples, while U was detected in some sample of anise, rosemary, sage, and thyme, and ranged from 0.018-0.048 mg/kg. As was detected in anise, fennel, roselle, and rosemary, and ranged from 0.0.031-5.88 mg/kg. Al, Cd, Co, Cr, Ni, Pb, Sr, and V were detected in most samples of all herbs, and ranged from 3.88-17.80, 0.122-0.654, 0.019-0.851, 0.344-2.91, 1.872-5.82, 0.120-12.56, 0.128-0.844, and 0.083-0.912 mg/kg, respectively.
There exists several statistical methods for detecting a difference of detection rates between alternative and reference qualitative microbiological assays in a single laboratory validation study with an unpaired design.
We compared performance of eight methods including Fisher's exact test, unequal variance two-sample t-test, Wilcoxon rank-sum test, z-test, and methods based on Wilson confidence intervals, complementary log-log regression, Firth's logistic regression, and ordinary logistic regression.
We first compared the minimum detectable difference in the proportion of detections between the alternative and reference methods among these statistical methods for a varied number of test portions. We then compared power and size of test of these methods using simulated data.
Firth's logistic regression and the unequal variance two-sample t-test had the lowest minimum detectable difference and highest power. None of these statistical methods had an estimated size of test always within a 95% confidence interval of the nominal value 0.05 with small numbers of test portions (n = 12, 20, 30). Fisher's exact test, the Wilcoxon rank-sum test, and the z-test were conservative even with a moderately large number of test portions (n = 40), while Firth's logistic regression and the unequal variance two-sample t-test had a size of test closer to 0.05 than other methods.
Firth's logistic regression and the unequal variance two-sample t-test are better choices than other competing methods.
We recommend the unequal variance two-sample t-test over Firth's logistic regression because the unequal variance two-sample t-test is better known and easier to use. We provide an example using real data.
We recommend the unequal variance two-sample t-test over Firth's logistic regression because the unequal variance two-sample t-test is better known and easier to use. We provide an example using real data.
Propolis is a resinous substance produced by bees. Propolis extracts have been used for anti-inflammatory and antimicrobial activities. The use of propolis dietary supplements has been increasing in the United States and the rest of the world.
A simple, economic, and valid analytical method is needed for quality assessment of dietary supplements and extracts claiming to contain propolis.
A ultra-high performance liquid chromatography (UHPLC) quadropole time-of-flight-MS method was used to characterize the chemical composition of northern Indian propolis. Fourteen major phenolic compounds were quantified using a UHPLC-DAD method. An HPTLC method was used to develop chemical fingerprinting profiles for propolis extracts and dietary supplements. The seven propolis extracts and 14 dietary supplements purchased in the U.S. were analyzed using the UHPLC-DAD-QToF method.
Fifty-seven compounds belonging to phenolic, coumarin, fatty acid, and terpene classes were identified in propolis extracts. Based on quantification results, the content of 14 phenolic compounds in propolis extracts varied from 19-32% in dietary supplements, a significant variation to the recommended daily intake (0.