scholarly journals Analytical Method Development and Chemometric Approach for Evidencing Presence of Plasticizer Residues in Nectar Honey Samples

2020 ◽  
Vol 17 (5) ◽  
pp. 1692 ◽  
Author(s):  
Ivan Notardonato ◽  
Sergio Passarella ◽  
Giuseppe Ianiri ◽  
Cristina Di Fiore ◽  
Mario Vincenzo Russo ◽  
...  
Keyword(s):  
Analytical Method ◽  
Method Development ◽  
Correlation Coefficients ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Anthropogenic Sources ◽  
Mass Spectrometry Analysis ◽  
Chemical Contamination ◽  
Spectrometry Analysis ◽  
Chemometric Approach

Over the years, anthropogenic sources have increasingly affected food quality. One of the most sensitive and nutritional matrices affected by chemical contamination is honey, due to the use of acaricides. Recently, the attention has moved to the presence of phthalates (PAEs) and bisphenol A (BP-A), molecules present in plastic materials used both in the production phase and in the conservation of honey. In this study, an analytical method for the simultaneous determination of PAEs (dimethyl phthalate DMP, diethyl phthalate DEP, diisobutyl phthalate DiBP, dibutyl phthalate DBP, bis(2-ethylhexyl) phthalate DEHP, and di-n-octyl-phthalate DnOP) and BP-A was developed. The extraction technique is the ultrasound-vortex-assisted dispersive liquid–liquid microextraction (UVA-DLLME), using 150 µL of toluene as an extraction solvent, followed by the gas chromatography coupled with ion trap mass spectrometry analysis (GC–IT/MS). The developed method is sensitive, reliable, and reproducible: it shows high correlation coefficients (R > 0.999); limits of detection (LODs) less than 11 ng·g−1; limits of quantification (LOQs) less than 16 ng·g−1; repeatability below 3.6%, except BP-A (11.6%); and accuracy below 4.8%, except BP-A (17.6%). The method was applied to 47 nectar honey samples for evidencing similarities among them. The chemometric approach based on Hierarchical Cluster Analysis and Principal Component Analysis evidenced some similitudes about sample origin as well as marked differences between PAE and BP-A sources.

scholarly journals Chemometric analysis of volatiles of propolis from different regions using static headspace GC-MS

2014 ◽  
Vol 12 (6) ◽  
pp. 736-746 ◽  
Author(s):  
Vilma Kaškonienė ◽  
Paulius Kaškonas ◽  
Audrius Maruška ◽  
Loreta Kubilienė
Keyword(s):  
Principal Component ◽  
Hierarchical Cluster ◽  
Statistical Investigation ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Static Headspace ◽  
Spectrometry Analysis ◽  
Three Samples ◽  
Brazilian Propolis ◽  
Processing Techniques

AbstractSix samples of propolis were analyzed in the paper: a sample from Brazil, Estonia, China and three samples from different locations of Uruguay. Static headspace technique coupled with gas chromatography-mass spectrometry analysis has been applied for the determination of the characteristic volatile profile with the aim to differentiate the propolis from different regions. Monoterpenes (α- and β-pinenes) were predominant in all samples, except the sample from China. This sample separated itself by the alcohols 3-methyl-3-buten-1-ol and 3-methyl-2-buten-1-ol, (40.33% and 11.57%, respectively) and ester 4-penten-1-yl acetate (9.04%). α-Pinene and β-pinene composed 64.59–77.56% of volatiles in Brazilian and Uruguayan propolis, and 29.43% in Estonian propolis. Brazilian propolis was distinguished by a high amount of β-methyl crotonaldehyde (10.11%), one of Uruguayan samples 3- by limonene (15.58%), and the Estonian sample — by eucalyptol (25.95%). Statistical investigation of the samples was made applying principal component, hierarchical cluster and K-Means cluster analyses. Various data pre-processing techniques were proposed and used to study and obtain the important volatile compounds contributed to the differentiation of the propolis samples from different regions to separate clusters.

scholarly journals A Chemometric Approach to Establish Underlying Connections between Lipid and Protein Oxidation and Instrumental Color and Texture Characteristics in Brazilian Dry-cured Loin

Foods ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 536 ◽  
Author(s):  
Denes K. A. Rosario ◽  
Maraysa R. Furtado ◽  
Yhan S. Mutz ◽  
Bruna L. Rodrigues ◽  
Yago A. A. Bernardo ◽  
...  
Keyword(s):  
Protein Oxidation ◽  
Principal Component ◽  
High Hardness ◽  
Hierarchical Cluster ◽  
Instrumental Color ◽  
Color Quality ◽  
Texture Characteristics ◽  
Lipid And Protein Oxidation ◽  
Chemometric Approach ◽  
Nondestructive Measurements

This study aimed to use chemometrics to evaluate the influence of lipid and protein oxidation on the color and texture characteristics of Brazilian dry-cured loin (Socol, BDL). Upon exploration using hierarchical cluster analysis (HCA), two clusters were formed, indicating that higher water activity (aw) was associated with higher lipid and protein oxidation. However, this fact was associated with softening and low color quality (a*, chroma, and cured color). In a more in-depth exploration, using principal component analysis (PCA) for each cluster separately, connections between protein and lipid oxidation were found in high aw, as demonstrated by their statistical association. In the same way, relationships between high hardness and carbonyl contents were obtained only in high aw. In addition, an overall relationship (p < 0.05) between nondestructive measurements, such as hardness, and destructive methods (malonaldehyde and carbonyl contents) demonstrate that nondestructive techniques can be promising for further studies in the method replacement field. In this study, reasonable explanations of the connections between oxidative damage and quality traits in Socol are provided.

scholarly journals Metabolic Signature Profiling as a Diagnostic and Prognostic Tool in Pediatric Plasmodium falciparum Malaria

2015 ◽  
Vol 2 (2) ◽  
Author(s):  
Izabella Surowiec ◽  
Judy Orikiiriza ◽  
Elisabeth Karlsson ◽  
Maria Nelson ◽  
Mari Bonde ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Principal Component ◽  
Malaria Diagnosis ◽  
Plasmodium Falciparum Malaria ◽  
Metabolite Profile ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
In Vivo Model ◽  
Spectrometry Analysis

Abstract Background.  Accuracy in malaria diagnosis and staging is vital to reduce mortality and post infectious sequelae. In this study, we present a metabolomics approach to diagnostic staging of malaria infection, specifically Plasmodium falciparum infection in children. Methods.  A group of 421 patients between 6 months and 6 years of age with mild and severe states of malaria with age-matched controls were included in the study, 107, 192, and 122, individuals, respectively. A multivariate design was used as basis for representative selection of 20 patients in each category. Patient plasma was subjected to gas chromatography-mass spectrometry analysis, and a full metabolite profile was produced from each patient. In addition, a proof-of-concept model was tested in a Plasmodium berghei in vivo model where metabolic profiles were discernible over time of infection. Results.  A 2-component principal component analysis revealed that the patients could be separated into disease categories according to metabolite profiles, independently of any clinical information. Furthermore, 2 subgroups could be ide.jpegied in the mild malaria cohort who we believe represent patients with divergent prognoses. Conclusions.  Metabolite signature profiling could be used both for decision support in disease staging and prognostication.

scholarly journals A validated method for the analysis and profiling of ‘nyaope’ using gas chromatography – mass spectrometry

2021 ◽  
Vol 117 (11/12) ◽  
Author(s):  
Pabalala M. Mthembi ◽  
Ellen M. Mwenesongole ◽  
Michael D. Cole
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Principal Component ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Drug Cocktail ◽  
Spectrometry Analysis ◽  
Chromatography Mass Spectrometry ◽  
First Time ◽  
Problem Drug

Nyaope, a Tswana word for a mixture or ‘mish-mash’, describes a drug cocktail consisting of heroin, cannabis, and on occasion other controlled substances and warfarin. It is highly addictive with extremely unpleasant side effects caused by withdrawal from the drug. It is a problem drug especially in townships in South Africa. However, its prevalence in neighbouring southern African states and further afield is not yet known. There is currently no validated method for the analysis and comparison of nyaope. We describe a validated method for the gas chromatography – mass spectrometry analysis of nyaope so that within-batch and between-batch comparisons of nyaope can successfully be made for the first time. The validated method managed an accuracy within the range 80–120%, the precision was less than 20% for all analytes and managed linearity with R2≥0.99. The detection limits for diamorphine, efavirenz, nevirapine and Δ9-tetrahydrocannabinol were 14.2, 18.6, 18.7 and 9.94 pg on column, respectively, and the limits of quantitation were 43.1, 56.3, 56.6 and 30.1 pg on column, respectively. The simulated and casework samples were successfully discriminated into original batches using the identified nyaope components, the unsupervised chemometric methods principal component analysis and hierarchical clustering, as well as chromatographic profiles.

scholarly journals Development and validation of modified QuEChERS methods for the analysis of fipronil and its metabolites in chicken meat

2021 ◽  
Vol 854 (1) ◽  
pp. 012096
Author(s):  
Aleksandra Tasic ◽  
Ksenija Nesic ◽  
Marija Pavlovic ◽  
Djordje Radojicic
Keyword(s):  
Magnesium Sulphate ◽  
Correlation Coefficients ◽  
Chicken Meat ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Meat Sample ◽  
Second Phase ◽  
Spectrometry Analysis ◽  
Modified Quechers ◽  
Analytical Response

Abstract A sensitive method for the precisely and accurate determining the presents of fipronil and its metabolites in chicken meat was developed and validated using a modified quick, easy, cheap, effective, rugged and safe approach coupled with gas chromatography-mass spectrometry analysis. The solvent acetonitrile was used for the extraction of the samples with the salt phases composed of sodium chloride and magnesium sulphate, and then in the second phase used C18 and anhydrous magnesium sulphate. The linearity of the analytical response across the studied range of concentrations (0.005-0.050 mg kg-1) was excellent, obtaining correlation coefficients higher than 0.99. The average recoveries of the pesticide ranged from 75 to 106% for fortification levels of 0.005, 0.01 and 0.05 mg kg-1. The precision values associated with the analytical method, expressed as RSD values, were less than 11.15%. Matrix-matched solutions were also prepared by serially diluting the intermediate solution with blank chicken meat sample extracts containing none of the tested analytes to perform matrix-matched calibration with the same concentrations as in the solvent. The validated method was used to analyse the target compounds in 30 real samples imported from European countries. The present of fipronil-desulfinyl metabolite was confirmed in four samples.

Identifying pathfinder elements for gold in bulk-rock geochemical data from the Cripple Creek Au–Te deposit: a statistical approach

2020 ◽  
Vol 21 (1) ◽  
pp. geochem2020-048
Author(s):  
Irene M. Kadel-Harder ◽  
Paul G. Spry ◽  
Audrey L. McCombs ◽  
Haozhe Zhang
Keyword(s):  
Gold Mineralization ◽  
Correlation Coefficients ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Geochemical Data ◽  
Northwestern Part ◽  
Low Grade ◽  
Gold Telluride ◽  
Cripple Creek ◽  
Host Rocks

The Cripple Creek alkaline igneous rock-related, low-sulfidation epithermal gold telluride deposit, Colorado, is hosted in the 10 km wide Oligocene alkaline volcanic Cripple Creek diatreme in Proterozoic rocks. Gold occurs as native gold, Au-tellurides, and in the structure of arsenian pyrite, in potassically altered high-grade veins, and as disseminations in the host rocks.Correlation coefficients, principal component analysis, hierarchical cluster analysis and random forests were used to analyse major and trace element compositions of 995 rock samples primarily from low-grade gold mineralization in drill core from three currently operating pits (Wild Horse Extension, Globe Hill and Schist Island) in the northwestern part of the Cripple Creek diatreme. These methods suggest that Ag, As, Bi, Te and W are the best pathfinders to gold mineralization in low-grade disseminated ore. Although Mo correlates with gold in other studies and is spatially related to gold veins, molybdenite post-dated the formation of gold and is likely related to a late-stage porphyry overprint. These elements, in conjunction with mineralogical studies, indicate that tellurides, fluorite, quartz, carbonates, roscoelite, tennantite-tetrahedrite, pyrite, sphalerite, muscovite, monazite, bastnäsite and hübnerite serve as exploration guides to ore.

scholarly journals Major Sensory Attributes and Volatile Compounds of Korean Rice Liquor (yakju) Affecting Overall Acceptance by Young Consumers

Foods ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 722
Author(s):  
JeongAe Heo ◽  
Han Sub Kwak ◽  
Miran Kim ◽  
Jae-Ho Kim ◽  
Hyung Hee Baek ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Descriptive Analysis ◽  
Principal Component ◽  
Sweet Taste ◽  
Sensory Attributes ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Multiple Factor Analysis ◽  
Spectrometry Analysis ◽  
Young Consumers

The sensory characteristics and volatile compounds that affect consumers’ acceptance of rice liquors were investigated. A total of 80 consumers evaluated 12 yakju samples and descriptive analysis by 11 trained panelists was conducted. Solvent-assisted flavor evaporation-gas chromatography-mass spectrometry analysis also was conducted revealing 120 volatile compounds in the yakju samples. Sensory attributes (n = 31) except appearance attributes were used for principal component analysis (PCA). As results, fruit odor (apple, hawthorn, omija, and pineapple odor) and flower odor (chrysanthemum, pine, and peppermint odor) were placed on the positive side of PC1 whereas persimmon vinegar odor, bitter taste, alcohol flavor, stinging and coating mouthfeel were located on the negative side of PC1. The yakju samples were mainly characterized by their alcohol content and supplementary ingredients. Sensory descriptors (n = 31; except appearance attributes and p > 0.05) and volatile compounds (n = 30; p > 0.5 correlation coefficient with overall acceptance) were chosen for multiple factor analysis (MFA). The MFA correlation map showed that ethyl propanoate, ethyl-2-hydroxy-2-methylbutanoate, methyl 2-furoate, γ-butyrolactone, 4-ethoxycarbonyl-γ-butyrolactone, hawthorn odor, apple flavor, grape flavor, and sweet taste were positively correlated with young consumers’ overall acceptance. Additionally, negative correlation with overall acceptance was found in 1,3-butanediol, 2,3-butanediol, and 1,1-diethoxy-3-methylbutane.

scholarly journals Secondary organic aerosol formation from the photooxidation of isoprene, 1,3-butadiene, and 2,3-dimethyl-1,3-butadiene under high NO<sub>x</sub> conditions

2011 ◽  
Vol 11 (14) ◽  
pp. 7301-7317 ◽  
Author(s):  
K. Sato ◽  
S. Nakao ◽  
C. H. Clark ◽  
L. Qi ◽  
D. R. Cocker III
Keyword(s):  
Volatile Compounds ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Anthropogenic Sources ◽  
Mass Spectrometry Analysis ◽  
Unsaturated Aldehyde ◽  
Reaction Products ◽  
Aerosol Formation ◽  
Spectrometry Analysis ◽  
The Subject

Abstract. Secondary organic aerosol (SOA) formation from atmospheric oxidation of isoprene has been the subject of multiple studies in recent years; however, reactions of other conjugated dienes emitted from anthropogenic sources remain poorly understood. SOA formation from the photooxidation of isoprene, isoprene-1-13C, 1,3-butadiene, and 2,3-dimethyl-1,3-butadiene is investigated for high NOx conditions. The SOA yield measured in the 1,3-butadiene/NOx/H2O2 irradiation system (0.089–0.178) was close to or slightly higher than that measured with isoprene under similar NOx conditions (0.077–0.103), suggesting that the photooxidation of 1,3-butadiene is a possible source of SOA in urban air. In contrast, a very small amount of SOA particles was produced in experiments with 2,3-dimethyl-1,3-butadiene. Off-line liquid chromatography – mass spectrometry analysis revealed that the signals of oligoesters comprise a major fraction (0.10–0.33) of the signals of the SOA products observed from all dienes investigated. The oligoesters originate from the unsaturated aldehyde gas phase diene reaction products; namely, semi-volatile compounds produced by the oxidation of the unsaturated aldehyde undergo particle-phase oligoester formation. Oligoesters produced by the dehydration reaction between nitrooxypolyol and 2-methylglyceric acid monomer or its oligomer were also characterized in these experiments with isoprene as the starting diene. These oligomers are possible sources of the 2-methyltetrols found in ambient aerosol samples collected under high NOx conditions. Furthermore, in low-temperature experiments also conducted in this study, the SOA yield measured with isoprene at 278 K was 2–3 times as high as that measured at 300 K under similar concentration conditions. Although oligomerization plays an important role in SOA formation from isoprene photooxidation, the observed temperature dependence of SOA yield is largely explained by gas/particle partitioning of semi-volatile compounds.

scholarly journals Chemical derivatization of pharmaceutical samples prior to Gas-Chromatography and Mass-Spectrometry analysis

2016 ◽  
Vol 11 (4) ◽  
pp. 852 ◽  
Author(s):  
Vivek K. Bajpai ◽  
Na-Hyung Kim ◽  
Kangmin Kim
Keyword(s):  
Mass Spectrometry ◽  
Thermal Stability ◽  
Gas Chromatography ◽  
Analytical Method ◽  
Mass Spectrometry Analysis ◽  
Chemical Derivatization ◽  
Pharmaceutical Samples ◽  
Spectrometry Analysis ◽  
Peak Areas ◽  
Visual Demonstration

<p>Derivatization is the process by which a compound is chemically changed, that has properties more amenable to a particular analytical method. Some samples analyzed by Gas-chromatography and Mass-spectrometry (GC-MS) require derivatization in order to make them suitable for analysis. Especially the compounds that have poor volatility, poor thermal stability, or that can be adsorbed in the injector will exhibit non-reproducible peak areas, heights, and shapes. Hence, this study focused on step-by-step visual demonstration of chemical derivatization of pharmaceutical samples prior to GC-MS analysis for their better elution and detection.</p>

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