Chemometric Determination of the Geographical Origin of Milk Samples in Malaysia

In this work, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Isotopic Ratio Mass Spectrometry (IRMS) and Ultrasound Milko Tester were used to study milk samples obtained from various geographical locations in Malaysia. ICP-MS was used to determine the concentration of trace elements in milk, water and soil samples obtained from seven dairy farms at different geographical locations in peninsular Malaysia. IRMS was used to analyze the milk samples for isotopic ratios of δ13C, 15N and 18O. Nutritional parameters in the milk samples were determined using an ultrasound milko tester. Data obtained from these measurements were evaluated by Principal Component Analysis (PCA) and Hierarchical Analysis (HA) as a preliminary step in determining geographical origin of these milk samples. It is observed that the isotopic ratios and a number of the nutritional parameters are responsible for the discrimination of the samples. It was also observed that it is possible to determine the geographical origin of these milk samples solely by the isotopic ratios of δ13C, 15N and 18O. The accuracy of the geographical discrimination is demonstrated when several milk samples from a milk factory taken from one of the regions under study were appropriately assigned to the correct PCA cluster

Chemometric Determination of the Geographical Origin of Milk Samples in Malaysia

In this work, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Isotopic Ratio Mass Spectrometry (IRMS) and Ultrasound Milko Tester were used to study milk samples obtained from various geographical locations in Malaysia. ICP-MS was used to determine the concentration of trace elements in milk, water and soil samples obtained from seven dairy farms at different geographical locations in peninsular Malaysia. IRMS was used to analyze the milk samples for isotopic ratios of δ13C, 15N and 18O. Nutritional parameters in the milk samples were determined using an ultrasound milko tester. Data obtained from these measurements were evaluated by Principal Component Analysis (PCA) and Hierarchical Analysis (HA) as a preliminary step in determining geographical origin of these milk samples. It is observed that the isotopic ratios and a number of the nutritional parameters are responsible for the discrimination of the samples. It was also observed that it is possible to determine the geographical origin of these milk samples solely by the isotopic ratios of δ13C, 15N and 18O. The accuracy of the geographical discrimination is demonstrated when several milk samples from a milk factory taken from one of the regions under study were appropriately assigned to the correct PCA cluster

Chemometric Determination of the Geographical Origin of Milk Samples in Malaysia

In this work, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Isotopic Ratio Mass Spectrometry (IRMS) and Ultrasound Milko Tester were used to study milk samples obtained from various geographical locations in Malaysia. ICP-MS was used to determine the concentration of trace elements in milk, water and soil samples obtained from seven dairy farms at different geographical locations in peninsular Malaysia. IRMS was used to analyze the milk samples for isotopic ratios of δ13C, 15N and 18O. Nutritional parameters in the milk samples were determined using an ultrasound milko tester. Data obtained from these measurements were evaluated by Principal Component Analysis (PCA) and Hierarchical Analysis (HA) as a preliminary step in determining geographical origin of these milk samples. It is observed that the isotopic ratios and a number of the nutritional parameters are responsible for the discrimination of the samples. It was also observed that it is possible to determine the geographical origin of these milk samples solely by the isotopic ratios of δ13C, 15N and 18O. The accuracy of the geographical discrimination is demonstrated when several milk samples from a milk factory taken from one of the regions under study were appropriately assigned to the correct PCA cluster

Chemometric approaches in the evaluation of trace metals in commercially raised tilapia and preliminary health risk assessment of its consumption / Low Kah Hin

The aims of this study are to evaluate the presence of trace metals in aquacultural samples using chemometric methods and to assess the safety of their consumption. In this work, chemometric techniques have been utilized to improve the analysis of metal content in commercially raised tilapia. In the method development phase, multivariate calibration techniques involving principal component regression and partial least squares were employed to establish a simple spectrophotometric method for the simultaneous determination of Cu2+, Ni2+ and Zn2+ in water samples in the presence of 1-(2-thiazolylazo)-2-naphthol as chromogenic reagent. In general, no significant difference in analytical performance was observed between the models as both exhibit high reliability. Unfortunately, the proposed alternative did not work well with other sample matrices. Consequently, the use of microwave accelerated reaction system with appropriate reagent mixture for quantitative matrix decomposition and its effective combination with certain determination techniques were then investigated by experimental design. In the preliminary study, fractional factorial design was utilized to evaluate the main effects of addition of HNO3, H2O2, HCl and H2O in microwave assisted digestion of fish muscle certified reference material. Significant losses of analytes via the vessel pressure regulating mechanism were observed, particularly for Hg under the designed condition. In this regard, digestion using a lesser amount sample and reagent was put forward for investigation with two-stage experimental designs. Initially, a Plackett-Burman design was carried out to estimate the main effects of the added reagents and the influence of microwave settings. The most significant microwave parameters were further evaluated by Box–Behnken design, while others were kept constant. The influence of different parameters vary according to the metal element, thus the working conditions for their simultaneous determination were established as a compromise within the optimum region found for each targeted element. Good agreement was observed between measured and certified values. In the assessment phase, the optimized microwave assisted digestion-inductively coupled plasma-mass spectrometry procedure was successfully applied for the determination of trace metal content in muscle, liver and gill tissues of red tilapia (Oreochromis spp) sampled from three different aquaculture sites in Jelebu, Negeri Sembilan. With the aid of pattern recognition techniques such as principal component analysis and its varimax rotation, it is not only possible to visualize the distribution pattern of metals in different organs as well as clustering tendencies of tilapia samples according to production sites but also to identify their corresponding relationships. For safety evaluation, the metal concentrations in the edible muscles were compared with the established legal limits and reasonable maximum exposures were simulated using the Monte Carlo algorithm

Differential-based biosensor array for fluorescence-chemometric discrimination and the quantification of subtle chloropropanols by cross-reactive serum albumin scaffolding

Food contamination is a serious concern because of a high level of chemicals in food causes severe health issues. Safeguarding the public from the risk of adulterated foods has become a challenging mission. Chloropropanols are of importance to food safety and food security because they are common chemical food contaminants and believed to be carcinogenic to humans. In chemical sensing, chloropropanols are challenging analytes owing to the lacking diversity of functional groups and difficulty in targeting the hydroxyl group in aqueous environments. Moreover, because of their small molecular size, the compositions of chloropropanols remain challenging for achieving chromatographic determination. Herein, to simulate human smell and taste sensations, serum albumins, which are protein-based receptors, were introduced as low-selective receptors for differential sensing. Utilizing serum albumins, a fluorophore (PRODAN), and an additive (ascorbic acid), a differential-based optical biosensor array was developed to detect and differentiate chloropropanols. By integrating the sensor array with linear discriminant analysis (LDA), four chloropropanols were effectively differentiated based on their isomerism properties and the number of the hydroxyl groups, even at ultra-low concentration (5 nM). This concentration is far below the maximum tolerable level of 0.18 μM for chloropropanols. The sensing array was then employed for chloropropanols differentiation and quantification in the complex mixtures (e.g., synthetic soy and dark soy sauces). Leave-one-out cross-validation (LOOCV) analysis demonstrated 100% accurate classification for all tests. These results signify our differential sensing array as a practical and powerful tool to speedily identify, differentiate, and even quantify chloropropanols in food matrices. © 2020 Elsevier B.V

Characterization of Sulfur-Compounds as Chemotaxonomic Markers in the Essential Oils of Allium Species by Solvent-Free Microwave Extraction and Gas Chromatography–Mass Spectrometry

Allium species were examined to authenticate the chemotaxonomic controversy about these plants by analyzing their extracted compound profiles. Essential oils of various species were isolated using conventional hydro-distillation and solvent-free microwave extraction (SFME). A comparison of the isolation procedures was performed. The presence of sulfur compounds in the Allium genus is a prominent characteristic for their medicinal uses. These components were characterized using two-way hierarchical cluster analysis (HCA) and principal component analysis (PCA). The variation of sulfur-compounds was performed by qualitative analysis of Allium species by gas chromatography–mass spectrometry (GC–MS). 2,4-Dimethyl-5,6-dithia-2,7-nonadienal, 4,6-diethyl-1,2,3,5-tetrathiolane, and 5,7-diethyl-1,2,3,4,6-pentathiepane were revealed as potential chemotaxonomic markers for all of the Alliums examined in this study. These markers may be used to provide improved systematics for other Allium species. © 2018, © 2018 Taylor & Francis

Consumption of water from ex-mining ponds in Klang Valley and Melaka, Malaysia: A health risk study

Evaluation of health risks due to heavy metals exposure via drinking water from ex-mining ponds in Klang Valley and Melaka has been conducted. Measurements of As, Cd, Pb, Mn, Fe, Na, Mg, Ca, and dissolved oxygen, pH, electrical conductivity, total dissolved solid, ammoniacal nitrogen, total suspended solid, biological oxygen demand were collected from 12 ex-mining ponds and 9 non-ex-mining lakes. Exploratory analysis identified As, Cd, and Pb as the most representative water quality parameters in the studied areas. The metal exposures were simulated using Monte Carlo methods and the associated health risks were estimated at 95th and 99th percentile. The results revealed that As was the major risk factor which might have originated from the previous mining activity. For Klang Valley, adults that ingested water from those ponds are at both non-carcinogenic and carcinogenic risks, while children are vulnerable to non-carcinogenic risk; for Melaka, only children are vulnerable to As complications. However, dermal exposure showed no potential health consequences on both adult and children groups

Determination of sofosbuvir and velpatasvir in solid pharmaceutical dosage form by hplc-pda and its application to in vitro dissolution studies

In the present study, a newly developed method based on high performance liquid chromatography (HPLC) was optimized for the simultaneous determination of sofosbuvir (SOFOS) and velpatasvir (VELPA) in commercial tablet formulations. Isocratic separation of SOFOS and VELPA was performed at 40 ºC with Purospher Star C18 column (5 μm, 4.6 × 250 mm) at a flow rate of 1.0 mL/min whereas the mobile phase consisted of aceto nitrile, phosphate buffer and methanol (60:30:10 v/v, pH 3.0). Both analytes were detected at a wavelength of 262 nm and the injection volume was 5.0 μL. The overall run time per sample was 7.0 min with retention time of 3.251 and 4.512 min for SOFOS and VELPA, respectively. The calibration curve was linear from 10.0-70 μg/mL for SOFOS and 5.0-35.0 μg/mL for VEL-PA with a coefficient of determination equal to 0.9999 while repeatability and reproducibility (expressed as relative standard deviation) were ≤ 1.32 and 1.61 %, respectively. The proposed HPLC method was rapid and simple for the determination of SOFOS and VELPA in commercially available tablet formulations providing recoveries ≥ 99.4 % and also for dissolution studies