bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and Evaluation of Thin-Layer Chromatography-Digital Image-Based Analysis for the Quantitation of the Botanical Pesticide Azadirachtin in Agricultural Matrixes and Commercial Formulations: Comparison with ELISA
Authors: Tanuja Penmatsa , Venugopal Namburi , Sashidhar Rao Beedu 
Published: February 2020

Abstract
A simple thin-layer chromatography-digital image-based analytical method has been developed for the quantitation of the botanical pesticide, azadirachtin. The method was validated by analyzing azadirachtin in the spiked food matrixes and processed commercial pesticide formulations, using acidified vanillin reagent as a postchromatographic derivatizing agent. The separated azadirachtin was clearly identified as a green spot. The Rf value was found to be 0.55, which was similar to that of a reference standard. A standard calibration plot was established using a reference standard, based on the linear regression analysis [r2 = 0.996; y = 371.43 + (634.82)x]. The sensitivity of the method was found to be 0.875 g azadirachtin. Spiking studies conducted at the 1 ppm (g/g) level in various agricultural matrixes, such as brinjal, tomato, coffee, and cotton seeds, revealed the recoveries of azadirachtin in the range of 6792%. Azadirachtin content of commercial neem formulations analyzed by the method was in the range of 1901825 ppm (g/mL). Further, the present method was compared with an immunoanalytical method enzyme-linked immonosorbent assay developed earlier in our laboratory. Statistical comparison of the 2 methods, using Fischer's F-test, indicated no significant difference in variance, suggesting that both methods are comparable.
Determination of Domoic Acid Toxins in Shellfish by Biosense ASP ELISAA Direct Competitive Enzyme-Linked Immunosorbent Assay: Collaborative Study
Authors: Kleivdal Hans , Kristiansen Sven-Inge , Nilsen Mona V , Goksyr Anders , Briggs Lyn , Holland Patrick , McNabb Paul ,   Collaborators:, Aasheim A , Aune T , Bates S , Bavington C , Caron D , Doucette G , Gago-Martinez A , Gallacer S , Grieve M , Haley S , Hess P , Hughes P , Léger C , Macaillou-Le Baut C , Myrland C , Neil T , Nguyen L , Ross K , Samdal I , Schaffner R , Smith E , Sosa S , Towers N , Tubaro A , Vaquero E , Wells M , Werner M , White P 
Published: February 2020

Abstract
A collaborative study was conducted on the Biosense amnesic shellfish poisoning (ASP) enzyme-linked immunosorbent assay (ELISA) for the determination of domoic acid (DA) toxins in shellfish in order to obtain interlaboratory validation data for the method. In addition, a method comparison study was performed to evaluate the ASP ELISA as an alternative to the current liquid chromatography (LC) reference method for DA determination. The study material comprised 16 shellfish samples, including blue mussels, Pacific oysters, and king scallops, spiked with contaminated mussel homogenates to contain 0.120 mg DA/kg shellfish flesh. The shellfish samples were extracted with 50% aqueous methanol, and the supernatants were directly analyzed. Sixteen participating laboratories in 10 countries reported data from the ASP ELISA, and 4 of these laboratories also reported data from instrumental LC analysis. The participating laboratories achieved interlaboratory precision estimates for the 8 Youden paired shellfish samples in the range of 1020% for RSDr (mean 14.8 4%), and 1329% for RSDR (mean 22.7 6%). The precision estimates for the ELISA data did not show a strong dependence on the DA concentration in the study samples, and the overall precision achieved was within the acceptable range of the Horwitz guideline with HorRat values ranging from 1.1 to 2.4 (mean HorRat 1.7 0.5). The analysis of shellfish samples spiked with certified reference material (CRM)-ASP-MUS-b gave recoveries in the range of 88122%, with an average recovery of 104 10%. The estimate on method accuracy was supported by a correlation slope of 1.015 (R2 = 0.992) for the determined versus the expected DA values. Furthermore, the correlation of the ASP ELISA results with those for the instrumental LC analyses of the same sample extracts gave a correlation slope of 1.29 (R2 = 0.984). This indicates some overestimation of DA levels in shellfish by the ELISA, but it is also a result of apparent low recoveries for the LC methods. This interlaboratory study demonstrates that the ASP ELISA is suitable for the routine determination and monitoring of DA toxins in shellfish, and that it offers a rapid and cost-effective methodology with high sample throughput.
Use of Multitoxin Immunoaffinity Columns for Determination of Aflatoxins and Ochratoxin A in Ginseng and Ginger
Authors: Trucksess Mary W , Weaver Carol M , Oles Carolyn J , Rump Lydia V , White Kevin D , Betz Joseph M , Rader Jeanne I 
Published: February 2020

Abstract
Conditions were optimized for the simultaneous, alkaline, aqueous methanol extraction of aflatoxins (AFL), i.e., B1 (AFB1), B2 (AFB2), G1 (AFG1), and G2 (AFG2), and ochratoxin A (OTA) with subsequent purification, isolation, and determination of the toxins in ginseng and ginger. Powdered roots were extracted with methanol0.5% NaHCO3 solution (7 + 3). After shaking and centrifugation, the supernatant was diluted with 100 mM phosphate buffer containing 1% Tween 20 and filtered through glass microfiber filter paper. The filtrate was then passed through an immunoaffinity column, and the toxins were eluted with methanol. The AFL were separated and determined by reversed-phase liquid chromatography (RPLC) with fluorescence detection after postcolumn UV photochemical derivatization. OTA was separated and determined by RPLC with fluorescence detection. Recoveries of AFL added at 216 ng/g and OTA added at 18 ng/g to ginseng were 7280 and 8695%, respectively. Recoveries of AFL and OTA added to ginger were similar to those for ginseng. A total of 39 commercially available ginger products from 6 manufacturers were analyzed. Twenty-six samples were found to be contaminated with AFL at 131 ng/g and 29 samples, with OTA at 110 ng/g. Ten samples contained no AFL or OTA. Ten ginseng finished products were also analyzed; 3 contained AFL at 0.1 ng/g and 4 contained OTA at levels ranging from 0.4 to 1.8 ng/g. LC/tandem mass spectrometry with multiple-reaction monitoring of 3 collisionally induced product ions from the protonated molecular ions of OTA, AFB1, and AFG1 was used to confirm the identities of the toxins in extracts of the finished products.
Identification of Lactic Acid Bacteria within the Consortium of a Kefir Grain by Sequencing 16S rDNA Variable Regions
Authors: Ninane Véronique , Mukandayambaje Radegonde , Berben Gilbert 
Published: February 2020

Abstract
The microflora of a kefir grain was identified using a polymerase chain reaction-based strategy combined with 16S rRNA gene sequencing. DNA was extracted from the kefir grain and amplified in its 16S rDNA V1 and V2 regions. To guarantee a good representation of the overall lactic acid bacteria populations, DNA amplification was performed separately with primers specific either to the dominant or to the less abundant bacterial groups. The amplified fragments were cloned in Escherichia coli and then sequenced. Sequences of the V1 region were gathered into 5 groups of similarity and identified by aligning with the sequences of a public library. The V1 region allowed the identification of Lactobacillus kefiranofaciens, L. kefir, L. parakefir, and Lactococcus lactis but was inappropriate for the identification of leuconostocs at species level. Among 16S rDNA variable regions, the V2 region showed the highest variability between Leuconostoc species. Nevertheless, even in the V2 region, differences were too tenuous for effective identification of L. mesenteroides. The methodology described here allowed detection of the dominant species within each targeted microbial group.
Interlaboratory Comparison for the Determination of Five Residual Organochlorine Pesticides in Ginseng Root Samples by Gas Chromatography
Authors: Kong Mei-Fung , Chan Serena , Wong Yiu-Chung , Wong Siu-Kay , Sin Della Wai-Mei 
Published: February 2020

Abstract
An interlaboratory comparison study for the determination of 5 residual organochlorine pesticides (hexachlorobenzene and 4 hexachlorocyclohexane isomers) in ginseng root was performed. This program [Asia Pacific Laboratory Accreditation Cooperation (APLAC) T049] was the first of its kind for an herbal matrix and involved the participation of 70 laboratories from 26 countries worldwide. Consensus mean values were computed statistically from the reported results, which were eventually used to assess the performance of individual laboratories in terms of the z-scores. The distribution of analytical data was found to be widespread, with standard deviation ranging from 43.9 to 55.9%, and the result patterns obtained were similar to those residue pesticide programs using other matrixes. Although the estimation of measurement uncertainty is a crucial requirement for all quantitative tests for laboratories that meet the requirements of International Organization for Standardization/International Electrotechnical Commisssion (ISO/IEC) 17025, some laboratories in this program had difficulties and showed unfamiliarity with respect to that quality criterion. It was recommended that laboratories review and rectify the situation promptly so that they would have a better understanding of measurement uncertainty or the test service provided.
Simultaneous Analysis of 260 Pesticide Residues in Agricultural Products by Gas Chromatography/Triple Quadrupole Mass Spectrometry
Authors: Okihashi Masahiro , Takatori Satoshi , Kitagawa Yoko , Tanaka Yukio 
Published: February 2020

Abstract
A method for simultaneous analysis of about 260 pesticides by gas chromatography coupled to tandem mass spectrometry (GC/MS/MS) with a triple quadrupole analyzer (QqQ) has been studied. The pesticides were extracted with acetonitrile and cleaned up by a bilayer cartridge. A single injection method was developed for the monitoring of all of the targeted pesticides. Two MS/MS transitions were selected for each analyte using the intensity ratio obtained from them as a confirmatory parameter. By using matrix-matched standards, 260 pesticides could be determined in most matrixes with recoveries of 70120% and a standard deviation of 20 at 2 different fortification levels of 0.02 and 0.1 g/g. The developed method was applied to the monitoring of 173 agricultural product samples from the local market. The sensitivities of this method were lower than with most of the selective GC detectors, such as flame photometric or single MS. The selectivity of QqQ gives a very clean chromatogram, making compound identification and confirmation easy. The quick and reliable monitoring was achieved by combination with rapid extraction and cleanup.
Evaluation of Thin-Layer Chromatography Methods for Quality Control of Commercial Products Containing Aesculus hippocastanum, Turnera diffusa, Matricaria recutita, Passiflora incarnata, and Tilia occidentalis
Authors: RAMÍREZ-DURÓN Rosalba , Ceniceros-Almaguer LucÍa , Salazar-Aranda Ricardo , Salazar-Cavazos Ma De La Luz , De Torres Noemi Waksman 
Published: February 2020

Abstract
In Mexico, plant-derived products with health claims are sold as herbal dietary supplements, and there are no rules for their legal quality control. Aesculus hippocastanum, Turnera diffusa, Matricaria recutita, Passiflora incarnata, and Tilia occidentalis are some of the major commercial products obtained from plants used in this region. In this paper, we describe the effectiveness of thin-layer chromatography methods to provide for the quality control of several commercial products containing these plants. Standardized extracts were used. Of the 49 commercial products analyzed, only 32.65% matched the chromatographic characteristic of standardized extracts. A significant number of commercial products did not match their label, indicating a problem resulting from the lack of regulation for these products. The proposed methods are simple, sensitive, and specific and can be used for routine quality control of raw herbals and formulations of the tested plants. The results obtained show the need to develop simple and reliable analytical methods that can be performed in any laboratory for the purpose of quality control of dietary supplements or commercial herbal products sold in Mexico.
Membrane Electrodes for Determination of Some -Blocker Drugs
Authors: Ramadan Nesrin K , Zaazaa Hala E 
Published: February 2020

Abstract
Five poly(vinyl chloride) (PVC) matrix membrane electrodes responsive to the -blockers atenolol (AT), bisoprolol fumarate (BI), timolol maleate (TI), and levobunolol HCl (LV) were developed and characterized. A precipitation-based technique with ammonium reineckate anion as an electroactive material in PVC matrix with AT, BI, TI, and LV cations was used for fabrication of Electrodes 14, respectively. Electrode 5 fabrication was based on precipitation of LV cation with tungstophosphate anion as an electroactive material. Fast and stable Nernstian responses at 1 1021 107 M for different -blockers over the pH range of 28 were found for these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The method was successively applied for the determination of -blockers in their pharmaceutical formulations. Validation of the method according to quality assurance standards showed the suitability of the proposed electrodes for use in the quality control assessment of these drugs. The recoveries for the determination of the -blocker drugs by the 5 proposed selective electrodes were 100.1 0.7, 99.9 0.8, 100.0 1.1, 100.5 1.1, and 100.6 0.7% for Sensors 15, respectively. Statistical comparison between the results obtained by this method and the official method of the drugs was performed and no significant difference was found.
Liquid Chromatographic Determination of 6-, 8-, 10-Gingerol, and 6-Shogaol in Ginger (Zingiber officinale) as the Raw Herb and Dried Aqueous Extract
Authors: Lee Samiuela , Khoo Cheang , Halstead Clynton Wade , Huynh Thuy , Bensoussan Alan 
Published: February 2020

Abstract
The determination of 6-, 8-, 10-gingerol, and 6-shogaol in dried ginger (Zingiber officinale) and in the dried aqueous extract of ginger is reported. This is the first study to report a validated method for the determination of these 4 analytes. Several extraction solvents and methods were examined, and the optimum combination was determined. The samples were extracted at room temperature by sonication with methanol, and the extract was analyzed by liquid chromatography with photodiode array detection. A C18 column was used with a wateracetonitrile gradient mobile phase. Quantification was at 200 nm. The levels of 6-, 8-, 10-gingerol, and 6-shogaol in the raw herb were 9.3, 1.6, 2.3, and 2.3 mg/g, respectively. The levels of gingerols found in the dried aqueous extract were between 5 and 16 times lower than those in the raw herb, but the level of 6-shogaol was higher. Analyte identity was confirmed by negative-ion electrospray ionization tandem mass spectrometry, in which 2 daughter ions were obtained for each analyte. The average recovery was 97 with a relative standard deviation of &lt;8. The limits of detection for 6-, 8-, 10-gingerol, and 6-shogaol in the raw herb were 0.22, 0.04, 0.09, and 0.07 mg/g, respectively, and in the dried aqueous extract, 0.11, 0.02, 0.02, and 0.14 mg/g, respectively.
Determination of Ubidecarenone (Coenzyme Q10, Ubiquinol-10) in Raw Materials and Dietary Supplements by High-Performance Liquid Chromatography with Ultraviolet Detection: Single-Laboratory Validation
Authors: Orozco Debra , Skamarack Jules , Reins Kelly , Titlow Barry , Lunetta Steve , Li Fang , Roman Mark 
Published: February 2020

Abstract
A method based on high-performance liquid chromatography with ultraviolet detection has been developed to quantify ubidecarenone [coenzyme Q10 (CoQ10)] in raw materials and dietary supplements. Single-laboratory validation has been performed on the method to determine repeatability, accuracy, selectivity, limits of detection and quantification (LOQ), ruggedness, and linearity for CoQ10. As CoQ10 can exist as the biologically active reduced form, the application of an oxidizing agent, ferric chloride, drives the equilibrium mechanics to the fully oxidized state and allows for exact quantification of total CoQ10 in the sample. This method was found to be fit and linear for the testing of materials containing CoQ10 in the range of 501000 mg/g. Repeatability precision for CoQ10 was between 2.15 and 5.00 relative standard deviation. Observed recovery of CoQ10 was found to be between 93.8 and 100.9. LOQ was found to be 9 g/mL. Further, limited studies showed that some adulterants and degraded material could be satisfactorily separated from CoQ10 and identified.
Validation of a Method Based on Triglycerides for the Detection of Low Percentages of Hazelnut Oil in Olive Oil by Column Liquid Chromatography
Authors: García-González Diego L , Viera-Macías María , Aparicio-Ruiz Ramón , Morales Maria T , Aparicio Ramón 
Published: February 2020

Abstract
The difference between theoretical and empirical triglyceride content is a powerful tool to detect the presence of any vegetable oil in olive oil. The current drawback of the method is the separation between equivalent carbon number ECN42 compounds, which affects the reliability of the method and, hence, its cutoff limit. The determination of the triglyceride profile by liquid chromatography using propionitrile as the mobile phase has recently been proposed to improve their quantification, together with a mathematical algorithm whose binary response determines the presence or absence of hazelnut oil. Twenty-one laboratories from 9 countries participated in an interlaboratory study to evaluate the performance characteristics of the whole analytical method. Participants analyzed 12 samples in duplicate, split into 3 intercomparison studies. Statistically significant differences due to the experimental conditions were found in some laboratories, which were detected as outliers by use of Cochran's and Grubbs' tests. The relative standard deviations (RSD) for repeatability and reproducibility were determined following the AOAC Guidelines for Collaborative Studies. The analytical properties of the method were determined by means of the sensitivity (0.86), selectivity (0.94), and reliability (72) for a cutoff limit of 8 (probability 94).
Simplified Pesticide Multiresidue Analysis of Soybean Oil by Low-Temperature Cleanup and Dispersive Solid-Phase Extraction Coupled with Gas Chromatography/Mass Spectrometry
Authors: Li Li , Xu Yanjun , Pan Canping , Zhou Zhiqiang , Jiang Shuren , Liu Fengmao 
Published: February 2020

Abstract
A simple, fast, and economical method has been developed for the simultaneous determination of 28 various types of pesticides in soybean oil. Pesticides of low molecular mass were separated from the fat of the oil, which has a high molecular mass, by using low-temperature fat precipitation, followed by a cleanup process based on dispersive solid-phase extraction with primary secondary amine and C18 as sorbents and magnesium sulfate for the removal of residual water. The results for all pesticides determined by gas chromatography with mass spectrometry in the selected-ion monitoring mode were linear, and the matrix effect of the method was evaluated. Recoveries of most pesticides were acceptable at fortification levels of 0.02, 0.05, 0.2, and 1 mg/kg. The relative standard deviation was &lt;20 even for determinations without internal standards. Limits of quantitation ranged from 20 to 250 g/kg.
Determination of Benzoylurea Insecticide Residues in Tomatoes by High-Performance Liquid Chromatography with Ultraviolet-Diode Array and Atmospheric Pressure Chemical Ionization-Mass Spectrometry Detection
Authors: Markoglou Anastasios N , Bempelou Eleftheria D , Liapis Konstantinos S , Ziogas Basil N 
Published: February 2020

Abstract
A simple and sensitive method using high-performance liquid chromatography/mass spectrometry (LC/MS) was developed and validated for simultaneous determination of 5 benzoylurea insecticidesdiflubenzuron, triflumuron, teflubenzuron, lufenuron, and flufenoxuronin tomatoes. Residues were successfully separated on a C18 column by methanolwater isocratic elution. Detection was carried out by an ultraviolet diode array detector (UV-DAD) coupled with a quadrupole mass spectrometer, using atmospheric pressure chemical ionization (APCI) in negative-ion mode. The main ions were the deprotonated molecules [MH]&lt;sup/&gt; for triflumuron, and the anions formed by elimination of hydrofluoric acid [MHHF]&lt;sup/&gt; for diflubenzuron and flufenoxuron, and [M2HHF] for lufenuron and teflubenzuron. The calibration plots were linear for both detectors over the range 0.05 to 10 g/mL, and the method presented good quality parameters. The limits of detection for standard solutions were 0.0080.01 mg/L (equivalent to 0.080.1 ng injected) for both detectors, and the limits of quantification (LOQs) were approximately 10 times lower than national maximum residue levels (MRLs). Depending on the compound and the detector, the LOQ values ranged from 0.2 to 0.4 ng injected. The optimum LC-UV-DAD/APCI-MS conditions were applied to the analysis of benzoylureas in tomatoes. The obtained recoveries from fortified tomato samples (50 g), extracted with ethyl acetate and purified by solid-phase extraction on silica sorbent, were 88100 and 92.9105 for the UV-DAD and MS detectors, respectively, with precision values (relative standard deviations) of 2.911 and 3.714, respectively. The method was applied to 12 tomato samples from local markets, and diflubenzuron and lufenuron were detected in only one sample at concentrations lower than the MRLs. The results indicate that the developed LC/MS method is accurate, precise, and sensitive for quantitative and qualitative analysis at low levels of benzoylureas required by legislation.
Determination of Alkylphenol Ethoxylates in Textiles by Normal-Phase Liquid Chromatography and Reversed-Phase Liquid Chromatography/Electrospray Mass Spectrometry
Authors: Wang Chao , Ma Qiang , Wang Xing 
Published: February 2020

Abstract
Comprehensive analytical methods based on pressurized liquid extraction followed by normal-phase liquid chromatography (NPLC) with ultraviolet detection and reversed-phase liquid chromatography (RPLC)/electrospray mass spectrometry (MS) have been developed for determination of alkylphenol ethoxylates (APEOs) in textile samples. NPLC with an aminosilica column allowed for the chromatographic separation of APEOs according to the increasing number of ethylene units and revealed the exact distribution of individual oligomers. RPLC coupled with electrospray MS was highly sensitive and enabled the complete qualitative and quantitative determination of individual APEOs in textile samples. The 2 analytical methods based on different chromatographic separation mechanisms, i.e., NPLC and RPLC, may provide complementary information of APEOs in textile materials. The 2 detection methods were successfully applied to the investigation of various textile samples, and the data of our research suggested actual pollution in real textile products.