Discrimination of Sri Lankan black teas using fluorescence spectroscopy and linear discriminant analysis

Seetohul, L. Nitin; Scott, Simon M.; O’Hare, W. T.; Ali, Zulfiqur; Islam, Meez

doi:10.1002/jsfa.6044

Cited by 33 publications

(11 citation statements)

References 33 publications

(66 reference statements)

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“…PCA is an unsupervised multivariate procedure which is a well-known linear data compression and feature extraction technique [28]. It derives new, uncorrelated variables that are linear combinations of the original variable set ordered by reducing variability.…”

Section: Statistical Analysis Of Resultsmentioning

confidence: 99%

Postmortem redistribution of the heroin metabolites morphine and morphine-3-glucuronide in rabbits over 24 h

Maskell

Albeishy²,

Paoli

et al. 2015

Int J Legal Med

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The interpretation of postmortem drug levels is complicated by changes in drug blood levels in the postmortem period, a phenomena known as postmortem drug redistribution. We investigated the postmortem redistribution of the heroin metabolites morphine and morphine-3-glucuronide in a rabbit model. Heroin (1mg/kg) was injected into anesthetised rabbit, after 1 hour an auricular vein blood sample was taken and the rabbit was euthanised. Following death rabbits were placed in a supine position at room temperature and divided into 3 groups namely 1) immediate autopsy, 2) autopsy after 30 minutes and 3) autopsy 24 h after death. Various samples which included femoral

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Section: Statistical Analysis Of Resultsmentioning

confidence: 99%

Postmortem redistribution of the heroin metabolites morphine and morphine-3-glucuronide in rabbits over 24 h

Maskell

Albeishy²,

Paoli

et al. 2015

Int J Legal Med

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show abstract

“…The data was also analyzed using principal component analysis (PCA). PCA is an unsupervised multivariate procedure and is a well‐known linear data compression and feature extraction technique . It derives new, uncorrelated variables that are linear combinations of the original variable set ordered by reducing variability.…”

Section: Methodsmentioning

confidence: 99%

Postmortem tissue distribution of morphine and its metabolites in a series of heroin‐related deaths

Maskell

Wilson

Seetohul

et al. 2018

Drug Testing and Analysis

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The abuse of heroin (diamorphine) and heroin-related deaths are increasing around the world. The interpretation of the toxicological results from suspected heroin-related deaths is notoriously difficult, especially in cases where there may be limited samples. To help forensic practitioners with heroin interpretation, we determined the concentration of morphine (M), morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) in blood (femoral and cardiac), brain (thalamus), liver (deep right lobe), bone marrow (sternum), skeletal muscle (psoas), and vitreous humor in 44 heroin-related deaths. The presence of 6-monoacetylmorphine (6-MAM) in any of the postmortem samples was used as confirmation of heroin use. Quantitation was carried out using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with solid-phase extraction. We also determined the presence of papaverine, noscapine and codeine in the samples, substances often found in illicit heroin and that may help determine illicit heroin use. The results of this study show that vitreous is the best sample to detect 6-MAM (100% of cases), and thus heroin use. The results of the M, M3G, and M6G quantitation in this study allow a degree of interpretation when samples are limited. However in some cases it may not be possible to determine heroin/morphine use as in four cases in muscle (three cases in bone marrow) no morphine, M3G, or M6G were detected, even though they were detected in other case samples. As always, postmortem cases of suspected morphine/heroin intoxication should be interpreted with care and with as much case knowledge as possible.

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“…By combining appropriate analytical methods, it cannot only detect the main components of tea (Zhao, Wang, Ouyang, & Chen, 2011), but also effectively classify tea varieties (Puneet et al, 2018;Sun et al, 2018). Fluorescence spectroscopy, which is a mature, simple, fast, accurate and nondestructive technique, has been found to be highly effective in tea classification and quality assessment due to its high sensitivity (Dong et al, 2014;Seetohul, Scott, O'Hare, Ali, & Islam, 2013).…”

Section: Introductionmentioning

confidence: 99%

Grade Identification of Tieguanyin Tea Using Fluorescence Hyperspectra and Different Statistical Algorithms

Sun

et al. 2019

Journal of Food Science

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In order to rapidly and nondestructively identify tea grades, fluorescence hyperspectral imaging (FHSI) technology was proposed in this paper. A total of 309 Tieguanyin tea samples with three different grades were collected and the fluorescence hyperspectral data was acquired by hyperspectrometer (400 to 1000 nm). The characteristic wavelengths were respectively selected by Bootstrapping Soft Shrinkage (BOSS), Variable Iterative Space Shrinkage Approach (VISSA) and Model Adaptive Space Shrinkage (MASS) algorithms. Then, Support Vector Machine (SVM) was applied to establishing the relationship between the characteristic peaks, the full spectra, three characteristic spectra and the labels of tea grades. The results showed that VISSA‐SVM model had the best classification performance, but the model precision can still be improved. Thus, Artificial Bee Colony (ABC) algorithm was introduced to optimize the parameters of SVM model. The accuracy and Kappa coefficient of test set of VISSA‐ABC‐SVM model were improved to 97.436% and 0.962, respectively. Therefore, the combination of fluorescence hyperspectra with VISSA‐ABC‐SVM model can accurately identify the grade of Tieguanyin tea. Practical Application The rapid and accurate nondestructive tea grade identification method contributes to the construction of the tea online grade detection system. FHSI technology can solve the shortcomings of the reported methods and improved the identification accuracy of tea grades. It can be applied to the rapid detection of tea quality by tea companies, tea market, tea farmers and other demanders.

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Discrimination of Sri Lankan black teas using fluorescence spectroscopy and linear discriminant analysis

Abstract: Further development of this work could lead to a simple device that could be used by tea manufacturers instead of or alongside trained tea tasters to grade teas.

Cited by 33 publications

References 33 publications

Postmortem redistribution of the heroin metabolites morphine and morphine-3-glucuronide in rabbits over 24 h

Postmortem redistribution of the heroin metabolites morphine and morphine-3-glucuronide in rabbits over 24 h

Postmortem tissue distribution of morphine and its metabolites in a series of heroin‐related deaths

Grade Identification of Tieguanyin Tea Using Fluorescence Hyperspectra and Different Statistical Algorithms

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