bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous Screening and Target Analytical Approach by Gas Chromatography-Quadrupole-Mass Spectrometry for Pesticide Residues in Fruits and Vegetables
Authors: Mezcua Milagros , Martínez-uroz Maria A , Wylie Philip L , fernández-alba Amadeo R
Published: February 2020

A full-scan GC/quadrupole/MS method has been developed to perform large-scale screenings of pesticides and simultaneous quantification of 95 target compounds in a single run of 21 min. The screening method was performed by using a deconvolution of the spectrum of the full-scan data files acquired under a retention time locked method. The identification performance of the screening method was evaluated in eight different food matrixes at three different concentrations. The system was equipped with a programmable temperature vaporizing inlet, allowing 10 L injections. The LOQ in the full-scan mode and linearity were studied for four different matrixes. Correlation coefficients >0.99 were achieved in all cases, and the LOD was <20 g/kg for 80 of the studied pesticides. Maintenance of the system was reduced by the use of a QuickSwap device that provided backflush capabilities by reversing column flow immediately after elution of the last compound of interest. The combined screening and target method was used in the analysis of more than 100 food samples, including a carrot sample from the European Proficiency Test FV 10, with good results.
Stability-Indicating RP-HPLC Method Development and Validation for Duloxetine Hydrochloride in Tablets
Authors: Patel Sejal K , Patel Natavarlal J , Prajapati Arun M , Patel Dipti B , Patel Satish A
Published: February 2020

This paper describes the development of a stability-indicating RP-HPLC method for duloxetine hydrochloride (DLX) in the presence of its degradation products generated from forced decomposition studies. The drug substance was found to be susceptible to stress conditions of acid, base, oxidation, wet heat, dry heat, and photodegradation. The drug was found to be stable to the dry heat condition attempted. Successful separation of the drug from the degradation products formed under stress conditions was achieved on a Phenomenex C18 column (250 4.6 mm id, 5 µm particle size) using acetonitrilemethanol0.032 M ammonium acetate buffer (55 + 05 + 40, v/v/v) as the mobile phase at a flow rate of 1.0 mL/min at 40°C temperature. Quantification was achieved with photodiode array detection at 290 nm over the concentration range 0.25 µg/mL with mean recovery of 101.048 ± 0.53 for DLX by the RP-HPLC method. Statistical analysis proved the method is repeatable, specific, and accurate for estimation of DLX. Because the method could effectively separate the drug from its degradation products, it can be used as a stability-indicating method.
Membrane Sensors for the Selective Determination of Donepezil Hydrochloride
Authors: Mostafa Gamal Abdel Hafiz , Hefnawy Mohamed , Al-Majed Abdulrahman
Published: February 2020

The construction and electrochemical response characteristics of polyvinylchloride (PVC) membrane sensors for donepezil HCl (DP) are described. The sensing membranes incorporated ion-association complexes of DP cation and sodium tetraphenyl borate (sensor 1), phosphomolybdic acid (sensor 2), or phosphotungstic acid (sensor 3) as electroactive materials. The sensors displayed a fast, stable, and near-Nernstian response over a relatively wide DP concentration range (1 102 to 1 106 M), with cationic slopes of 53.0, 54.0, and 51.0 mV/ concentration decade over a pH range of 4.0 to 8.0. The sensors showed good discrimination of DP from several inorganic and organic compounds. The direct determination of 2.54000.0 g/mL DP showed average recoveries of 99.0, 99.5, and 98.5, and mean RSDs of 1.6, 1.5, and 1.7 at 100.0 g/mL for sensors 1, 2, and 3, respectively. The proposed sensors have been applied for direct determination of DP in two pharmaceutical preparations. The results obtained for determination of DP in tablets using the proposed sensors compared favorably with those obtained using an HPLC method. The sensors have been used as indicator electrodes for potentiometric titration of DP.
Detection of Methamphetamine, Methylenedioxymethamphetamine, and 3,4-Methylenedioxy-N-ethylamphetamine in Spiked Plasma by HPLC and TLC
Authors: Öztunç Aysel , Önal Armağan , Toker Sidika Ertürk
Published: February 2020

HPLC and TLC methods were developed for separation and detection of some amphetamine analogs: methamphetamine (MA); 3,4-methylenedioxymethamphetamine (MDMA, ecstasy); and 3,4-methylenedioxy-N-ethylamphetamine (MDEA) in spiked plasma samples. The methods are based on purple chromogens formed by displacement reaction of these secondary aliphatic amine-bearing drugs with 7,7,8,8-tetracyanoquinodimethane at 80C for 25 min. For HPLC, both normal phase (silica gel) and RP (C18) columns were used. With the former, good detection limits in plasma were obtained with a 6 min run: 70, 100, and 500 ng/mL for MDMA, MA, and MDEA, respectively. For TLC, hexanechloroform (1 + 9) and benzene-diethyl ether-petroleum ether (4060)acetonitrileethyl methyl ketone (2 + 3.5 + 3.5 + 0.5 + 0.5) were used as mobile phases for silica gel 60 TLC and cyano-bonded silica gel HPTLC plates, respectively. The former offered more sensitive results than the latter. Influence of evaporation steps on recovery and interferences for the HPLC and TLC methods were investigated. The developed methods are selective, simple, and easily applicable.
Validation Study of a Rapid ELISA for Detection of Aflatoxin in Corn
Authors: Lupo Anthony , Roebuck Chris , Dutcher Monica , Kennedy Justina , Abouzied Mohamed
Published: February 2020

Neogen Corp. developed the Veratox aflatoxin test kit for the detection of total aflatoxin. The purpose of this study was to validate the method under the requirements of the AOAC Research Institute Performance Tested MethodsSM (PTM) program. There are several AOAC Official MethodsSM for total aflatoxin detection in corn (994.08, 990.33, 979.18, 993.17, 990.32, 993.16, 991.31, and 990.74), varying between rapid and analytical-based methods and one rapid method that has been performance tested by the AOAC Research Institute (PTM 030701). However, the widely used reference method is AOAC Official MethodSM994.08, which is an HPLC method and is referred to as the reference method in this paper. Although considered the reference method, the HPLC procedure is complicated and requires the investment of both expensive equipment and a highly skilled technician. A rapid (e.g., ELISA) test kit to be validated by the AOAC Research Institute is needed.
Determination of trans Vitamin K1 in Infant and Medical Nutritional Products Using AOAC Method 999.15 with Modified Preparation and Extraction Procedures and C30 Bonded Phase Chromatography: Single-Laboratory Validation
Authors: Schimpf Karen J , Thompson Linda B , Schmitz Daniel J
Published: February 2020

Modifications were made to AOAC Official MethodSM 999.15 to extend its applicability to specialty infant formulas containing hydrolyzed proteins and free amino acids, and to medical and adult nutritional products. Minor changes to the sample preparation procedure and chromatographic separation improved vitamin K1 recoveries and reduced chromatographic interferences in these types of matrixes. Currently AOAC Method 999.15 is applicable only to the determination of total vitamin K1 (phylloquione) in infant formula and milk (fluid, ready-to-feed, and powdered) containing >1 g vitamin K1/100 g solids. AOAC Method 999.15 recoveries of vitamin K1 were improved by altering sample sizes, extraction solvents and amounts, and the reagent addition order and amount of water or aqueous solutions added. The chromatographic separation of vitamin K1 in medical nutritional products containing canola and marine oils was improved, and trans vitamin K1 was separated from the biologically inactive cis isomer in all products with a C30 3 m column and a 100 methanol mobile phase. With these modifications to the extraction procedure and chromatographic separation, AOAC Method 999.15 demonstrated acceptable precision and accuracy for the quantitation of trans vitamin K1 in specialty infant formulas containing hydrolyzed proteins and free amino acids, and medical and adult nutritional products. A single-laboratory validation of these minor modifications was completed. Fourteen different product matrixes were analyzed during validation. The intermediate precision averaged 4.15 RSD (range 2.525.81 RSD), and recovery data averaged 100.1 (range 92.2109).
Investigation of Matrix Effects for Some Pesticides in Waters by On-line Solid-Phase Extraction-Liquid Chromatography Coupled with Triple Quadrupole Linear Ion-Trap Mass Spectrometry and the Use of Postcolumn Introduction
Authors: Gru Yvan , Colin Ronan , Le Cloirec Pierre
Published: February 2020

The effect of analytical conditions on on-line SPE-LC/MS/MS was investigated. Real matrix-induced signal suppression or enhancement due to the ionization process was simulated by using postcolumn introduction experiments. Results were compared with global matrix effects that occur during a routine analysis. Four pesticides were studied: carbendazim, fenuron, thiabendazole, and vamidothion. These compounds have different behaviors in terms of matrix effects. Good correlations were shown, demonstrating that the main matrix effect is due to the ionization step. Good results were also obtained for the RSD values (<5 for routine analysis and <35 for postcolumn introduction).
Determination of Bioactive Compounds in Cortex Phellodendri by High-Performance Liquid Chromatography
Authors: Yang Qi , Zhang Feng , Gao Shou-Hong , Sun Lian-Na , Chen Wan-Sheng
Published: February 2020

An HPLC method combined with a photodiode array detector was developed for quantitative determination of five bioactive compounds that belong to two subclasses, including limonin, phellodendrine, jatrorrhizine, palmatine, and berberine in Cortex Phellodendri. The analysis was performed on an Agilent Diamonsil C18 column (4.6 250 mm, 5 m) using a gradient of acetonitrile and 0.3 aqueous diethylamine phosphate (v/v), a flow rate of 0.8 mL/min, and a detection wavelength of 220 nm. The calibration curve was linear over the range of 2.5100.0 g/mL for both phellodendrine and jatrorrhizine, 5.0200.0 g/mL for palmatine, and 7.5300.0 g/mL for both berberine and limonin. The average recoveries ranged from 97.56 to 102.53 with RSD 1.00. Samples from different geographical locations were analyzed to evaluate the applicability of the established method, and the results indicated that the method was efficient, sensitive, and reliable for determining limonin and four alkaloids in Cortex Phellodendri.
Development and Validation of an HPLC-DAD Analytical Procedure for Quality Control of Damiana (Turnera diffusa), Using an Antioxidant Marker Isolated from the Plant
Authors: PéRez-Meseguer Jonathan , Garza-JuáRez Aurora , Salazar-Aranda Ricardo , Salazar-Cavazos Ma Luz , dela Torre RodríGuez Yael C , Rivas-Galindo VeróNica , De Torres Noemí Waksman
Published: February 2020

Damiana is a shrub used as a dietary supplement and as an additive in several foods. This report presents the first validated analytical method for QC of products made from damiana. Through bioassay-guided fractionation, the compound showing the best antioxidant activity, determined using 2,2-diphenyl-1-picryl-hydrazyl assay in TLC, was purified and identified as 8-C--[6-deoxy-2-O-(-1-rhamnopyranosyl)-xylo- hexopyranos-3-uloside] (CI50 5.56 g/mL). This is the only natural source from which this compound has been reported, and has been found in all native damiana samples analyzed. Therefore, it was used as a biomarker to develop an HPLC-diode-array detection analytical procedure using the first-order derivative of the chromatograms. Separation was achieved using an AccQ Tag C18 150 3.9 mm (4 m) column, with a gradient of methanol and 0.1 trifluoroacetic acid in water. The method was shown to be accurate, sensitive, and reproducible, providing a useful quantitative means to apply QC to damiana products.
Validated HPLC Determination of the Two Fixed Dose Combinations (Chlordiazepoxide Hydrochloride and Mebeverine Hydrochloride; Carvedilol and Hydrochlorothiazide) in Their Tablets
Authors: Haggag Rim S , Shaalan Rasha A , Belal Tarek S
Published: February 2020

Simple, rapid, and selective RP-HPLC methods with UV detection were developed for simultaneous determination of chlordiazepoxide hydrochloride and mebeverine hydrochloride (Mixture I) and carvedilol and hydrochlorothiazide (Mixture II). The chromatographic separation in both mixtures was achieved by using an RP-C8 (octylsilyl) analytical column. For Mixture I, a mobile phase composed of acetonitrile0.05 M disodium hydrogen phosphatetriethylamine (50 + 50 + 0.2, v/v/v), pH 2.5, was used; the detector wavelength was 247 nm. For Mixture II, the mobile phase consisted of acetonitrile0.05 M disodium hydrogen phosphate (50 + 50, v/v), pH 4.0, and the detector was set at 220 nm. Quantification of the analytes was based on measuring their peak areas. Both mixtures were resolved in less than 6 min. The reliability and analytical performance of the proposed HPLC procedures were statistically validated with respect to linearity, range, precision, accuracy, selectivity, robustness, LOD, and LOQ. The linear dynamic ranges were 2.5150 and 2.5500 g/mL for chlordiazepoxide HCl and mebeverine HCl, respectively, and 0.25200 and 0.25150 g/mL for carvedilol and hydrochlorothiazide, respectively. The validated HPLC methods were successfully applied to the analysis of their commercial tablet dosage forms, for which no interfering peaks were encountered from common pharmaceutical adjuvants.
Preparation and Characterization of Standard Reference Material 1849 Infant/Adult Nutritional Formula
Authors: Sharpless Katherine E , Lindstrom Richard M , Nelson Bryant C , Phinney Karen W , Rimmer Catherine A , Sander Lane C , Schantz Michele M , Spatz Rabia O , Thomas Jeanice Brown , Turk Gregory C , Wise Stephen A , Wood Laura J , Yen James H
Published: February 2020

Standard Reference Material (SRM) 1849 Infant/Adult Nutritional Formula has been issued by the National Institute of Standards and Technology (NIST) as a replacement for SRM 1846 Infant Formula, issued in 1996. Extraction characteristics of SRM 1846 have changed over time, as have NIST's analytical capabilities. While certified mass fraction values were provided for five constituents in SRM 1846 (four vitamins plus iodine), certified mass fraction values for 43 constituents are provided in SRM 1849 (fatty acids, elements, and vitamins) and reference mass fraction values are provided for an additional 43 constituents including amino acids and nucleotides, making it the most extensively characterized food-matrix SRM available from NIST.
Quantitative Evaluation of Benzene, Toluene, and Xylene in the Larvae of Drosophila melanogaster by Solid-Phase Microextraction/Gas Chromatography/Mass Spectrometry for Potential Use in Toxicological Studies
Authors: Mudiam Mohana Krishna Reddy , Singh Mahendra Pratap , Chowdhuri Debapratim Kar , Murthy Ramesh Chandra
Published: February 2020

A simple, rapid, and solvent-free method for quantitative determination of benzene, toluene, and Xylene in exposed Drosophila larvae was developed using headspace solid-phase microextraction (HS-SPME) coupled to GC/MS. Larvae fed on standard Drosophila food mixed with benzene, toluene, and Xylene for 48 h were homogenized in Milli-Q water. Extraction of benzene, toluene, and Xylene was performed at 65C for 30 min on the SPME fiber (silica-fused). Subsequently, the fiber was desorbed in the GC injection port, followed by GC/MS analysis in the selected-ion monitoring mode. An external calibration curve was used for the quantification of benzene, toluene, and Xylene in the exposed organism. Recoveries were in the range of 78-82% (intraday) and 76-81% (interday) in larvae, and 9196 (intraday) and 87-92% (interday) in the diet. LOD with an S/N of 3:1 and LOQ with an S/N of 10:1 were in the range of 0.010.023 and 0.0340.077 µg/L, respectively. Percent RSD values for benzene, toluene, and Xylene were in the range of 0.500.81 (intraday) and 0.891.23 (interday) for retention time, and 2.163.85 (intraday) and 2.994.95 (interday) for peak concentration, showing good repeatability. This method was sensitive enough to quantitate benzene, toluene, and Xylene in small exposed organisms like Drosophila larvae. The SPME/GC/MS method developed may have wider applications in various in vivo toxicological studies.
Screening and Quantitative Confirmatory Method for the Analysis of Glucocorticoids in Bovine Milk Using Liquid Chromatography-Tandem Mass Spectrometry
Authors: Malone Edward M , Elliott Chris T , Kennedy David G , Regan Liam
Published: February 2020

An LC/MS/MS method was developed and validated for the simultaneous identification, confirmation, and quantification of 12 glucocorticoids in bovine milk. The method was validated in accordance with the criteria defined in Commission Decision 2002/657/EC. The developed method can detect and confirm the presence of dexamethasone, betamethasone, prednisolone, flumethasone, 6α-methylprednisolone, fluorometholone, triamcinolone acetonide, prednisone, cortisone, hydrocortisone, clobetasol propionate, and clobetasol butyrate in bovine milk. Milk samples are extracted with acetonitrile; sodium chloride is subsequently added to aid partition of the milk and acetonitrile mixture. The acetonitrile extract is then subjected to liquidliquid purification by the addition of hexane. The purified extract is evaporated to dryness and reconstituted in a wateracetonitrile mixture, and determination is carried out by LC/MS/MS. The method permits analysis of up to 30 samples in 1 day.
Determination of Pesticide Residues in Sewage Sludge: A Review
Authors: Tadeo José L , Sánchez-Brunete Consuelo , Albero Beatriz , Garcí-Valcárcel Ana I
Published: February 2020

Pesticides are widely applied to protect plants from diseases, weeds, and insect damage, and they usually come into contact with soil where they may undergo a variety of transformations and provide a complex pattern of metabolites. Spreading sewage sludge on agricultural lands has been actively promoted by national authorities as an economic way of recycling. However, as a byproduct of wastewater treatment, sewage sludge may contain pesticides and other toxic substances that could be incorporated into agricultural products or be distributed in the environment. This article reviews the determination of pesticides in sewage sludge samples. Sample preparation including pretreatment, extraction, and cleanup, as well as the subsequent instrumental determination of pesticide residues, are discussed. Extraction techniques such as Soxhlet extraction, ultrasound-assisted extraction, pressurized liquid extraction, supercritical fluid extraction, and matrix solid-phase dispersion and their most recent applications to the determination of pesticides in sewage sludge samples are reviewed. Determination of pesticides, generally carried out by GC and HPLC coupled with different detectors, especially MS for the identification and quantification of residues, is summarized and discussed.
Use of Pressurized Liquid Extraction for the Simultaneous Analysis of 28 Polar and 94 Non-polar Pesticides in Agricultural Soils by GC/QqQ-MS/MS and UPLC/QqQ-MS/MS
Authors: Vidal José luis martínez , Sánchez Juan Antonio Padilla , Plaza-bolaños Patricia , Frenich Antonia Garrido , Romero-González Roberto
Published: February 2020

Due to the wide range of pesticides that can be used in agriculture, the development of fast multiresidue methods that simultaneously determine polar and non-polar pesticides is greatly demanded. This study shows the development and validation of a multiresidue method for the analysis of 98 non-polar pesticides and 28 polar pesticides in soil. A simultaneous extraction step by pressurized liquid extraction was utilized. The optimum results were obtained using ethyl acetatemethanol (3:1, v/v) with 2 min of preheat time and 85C as the extraction temperature. The final determination of non-polar pesticides was performed by GC, whereas polar pesticides were determined by ultra-performance liquid chromatography (UPLC). Both GC and UPLC were coupled to triple-quadrupole analyzers operating in tandem MS. The optimized extraction procedure was validated. The average extraction recoveries were in the range 72108 (10 g/kg) and 71106 (50 g/kg), with RSD values 26. The matrix effect was also evaluated, and matrix-matched standard calibration was finally applied for quantification. The suitability of the method was also checked by the analysis of a certified reference material. Furthermore, 26 real soil samples were analyzed by the proposed methods in order to assess their applicability. Several pesticides (e.g., bifenthrin, triadimefon, or endosulfan) were found in the samples.
Quantitative Analysis of Eugenol in Clove Extract by a Validated HPLC Method
Authors: Yun So-Mi , Lee Myoung-Heon , Lee Kwang-Jick , Ku Hyun-Ok , Son Seong-Wan , Joo Yi-Seok
Published: February 2020

Clove (Eugenia caryophyllata) is a well-known medicinal plant used for diarrhea, digestive disorders, or in antiseptics in Korea. Eugenol is the main active ingredient of clove and has been chosen as a marker compound for the chemical evaluation or QC of clove. This paper reports the development and validation of an HPLC-diode array detection (DAD) method for the determination of eugenol in clove. HPLC separation was accomplished on an XTerra RP18 column (250 4.6 mm id, 5m) with an isocratic mobile phase of 60 methanol and DAD at 280 nm. Calibration graphs were linear with very good correlation coefficients (r2 > 0.9999) from 12.5 to 1000 ng/mL. The LOD was 0.81 and the LOQ was 2.47 ng/mL. The method showed good intraday precision (RSD 0.080.27) and interday precision (RSD 0.321.19). The method was applied to the analysis of eugenol from clove cultivated in various countries (Indonesia, Singapore, and China). Quantitative analysis of the 15 clove samples showed that the content of eugenol varied significantly, ranging from 163 to 1049 ppb. The method of determination of eugenol by HPLC is accurate to evaluate the quality and safety assurance of clove, based on the results of this study.
Development and Validation of a New HPLC-UV Method for the Simultaneous Determination of Triclabendazole and Ivermectin B1a in a Pharmaceutical Formulation
Authors: Shurbaji Maher , Al Rub Mohamad H Abu , Saket Munib M , Qaisi Ali M , Salim Maher L , Abu-Nameh Eyad S M
Published: February 2020

A rapid, simple, and sensitive RP-HPLC analytical method was developed for the simultaneous determination of triclabendazole and ivermectin in combination using a C18 RP column. The mobile phase was acetonitrilemethanolwateracetic acid (56 36 7.5 0.5, v/v/v/v) at a pH of 4.35 and flow rate of 1.0 mL/min. A 245 nm UV detection wavelength was used. Complete validation, including linearity, accuracy, recovery, LOD, LOQ, precision, robustness, stability, and peak purity, was performed. The calibration curve was linear over the range 50.09150.26 g/mL for triclabendazole with r = 0.9999 and 27.0181.02 g/mL for ivermectin with r = 0.9999. Calculated LOD and LOQ for triclabendazole were 0.03 and 0.08 g/mL, respectively, and for ivermectin 0.07 and 0.20 g/mL, respectively. The intraday precision obtained was 98.71 with RSD of 0.87 for triclabendazole and 100.79 with RSD 0.73 for ivermectin. The interday precision obtained was 99.51 with RSD of 0.35 for triclabendazole and 100.55 with RSD of 0.59 for ivermectin. Robustness was also studied, and there was no significant variation of the system suitability of the analytical method with small changes in experimental parameters.
Simultaneous Analysis of 70 Pesticides Using HPLC/MS/MS: A Comparison of the Multiresidue Method of Klein and Alder and the QuEChERS Method
Authors: Riedel Melanie , Speer Karl , Stuke Sven , Schmeer Karl
Published: February 2020

Since 2003, two new multipesticide residue methods for screening crops for a large number of pesticides, developed by Klein and Alder and Anastassiades et al. (Quick, Easy, Cheap, Effective, Rugged, and Safe; QuEChERS), have been published. Our intention was to compare these two important methods on the basis of their extraction efficiency, reproducibility, ruggedness, ease of use, and speed. In total, 70 pesticides belonging to numerous different substance classes were analyzed at two concentration levels by applying both methods, using five different representative matrixes. In the case of the QuEChERS method, the results of the three sample preparation steps (crude extract, extract after SPE, and extract after SPE and acidification) were compared with each other and with the results obtained with the Klein and Alder method. The extraction efficiencies of the QuEChERS method were far higher, and the sample preparation was much quicker when the last two steps were omitted. In most cases, the extraction efficiencies after the first step were approximately 100. With extraction efficiencies of mostly less than 70, the Klein and Alder method did not compare favorably. Some analytes caused problems during evaluation, mostly due to matrix influences.
Development and Validation of Stability-Indicating HPLC Method for the Simultaneous Determination of Paracetamol, Tizanidine, and Diclofenac in Pharmaceuticals and Human Serum
Authors: Siddiqui Farhan Ahmed , Arayne M Saeed , Sultana Najma , Qureshi Faiza
Published: February 2020

A method is described for the simultaneous determination of paracetamol, tizanidine, and diclofenac in mixtures. The method was based on HPLC separation of the three drugs followed by UV detection at 254 nm. The separation was carried out on a Hypersil ODS, C18 (250 × 4.6 mm id, 10 μm particle size) column using the mobile phase aqueous 0.2% ammonium carbonate–methanol (60 + 40, v/v) at a flow rate of 1 mL/min. The linear regression analysis data were used for the regression curve in the range of 170–10,000 ng/mL for paracetamol, 120–10,000 ng/mL for tizanidine, and 20–10,000 ng/mL for diclofenac. No chromatographic interference from tablet excipients was found. In order to check the selectivity of the proposed method, degradation studies were carried out using hydrolysis (acid, basic, and neutral), thermolysis, and oxidation. The developed method, after being validated in terms of precision, robustness, recovery, LOD, and LOQ, was successively applied to the analysis of pharmaceutical formulations and human serum.
Determination of Dodine in Fruit Samples by Liquid Chromatography Electrospray Ionization-Tandem Mass Spectrometry
Authors: Le Grand Rozenn , Saint-Marcoux Franck , Dulaurent Sylvain , Sauvage François-Ludovic , Moesch Christian , Lachâtre Gérard
Published: February 2020

A rapid and sensitive LC/electrospray ionization-MS/MS method has been developed for the determination of dodine in fruit samples. Based on a liquid–liquid extraction of 10 g solid fruit homogenate using an acetone–dichloromethane– hexane mixture and acetate ammonium buffer (pH 4.5), this LC/MS/MS procedure was characterized by recoveries above 50%, with good intra-assay precision (RSD <13%) and interassay precision (RSD <18%) for seven different matrixes (apple, apricot, cherry, peach, pear, plum, and quince). This method was validated from 5 to 500 μg/kg according to standard guidelines. Its LOD (1 μg/kg) and LOQ (5 μg/kg) were in accordance with recommendations of the European legislation defined for infant food [maximum residue level (MRL) = 10 μg/kg]. The whole procedure was finally tested on 1022 fruit samples intended for commercialization, both infant food samples and samples not intended in particular for babies. In this study, dodine was detected in 27 samples; none exhibited a concentration higher than the MRL.
Surface Plasmon Resonance Biosensor for Determination of Tetrodotoxin: Prevalidation Study
Authors: Vaisocherová Hana , Taylor Allen D , Jiang Shaoyi , Hegnerová Kateřina , Vala Milan , Homola Jiří , Yakes Betsy Jean , Deeds Jonathan , DeGrasse Stacey
Published: February 2020

A label-free surface plasmon resonance biosensor method was applied to determine tetrodotoxin (TTX) in pufferfish matrixes using an antibody inhibition assay format. A prevalidation study was conducted to demonstrate the assay performance characteristics, such as selectivity, LOD, LOQ, repeatability, reproducibility, and accuracy. Three participating laboratories reported standard curves in buffer and pufferfish matrix. A set of blind samples with TTX spiked into buffer as well as in 10 pufferfish extract were analyzed. Additionally, three blind naturally contaminated samples were analyzed, and the results were compared to those obtained using a reference method (HPLC/electrospray ionization-selected reaction monitoring-MS). The developed method was demonstrated to be capable of detecting TTX in pufferfish matrix standard samples in a broad concentration range (29000 ng/mL) with an LOD of 1.5 ng/mL. Between-laboratory recovery values were in the range of 51190 with a mean of 107, and 64180 with a mean of 103 for TTX-spiked samples in buffer and pufferfish matrix, respectively. Between-laboratory recoveries were in the satisfactory range of 101119 for naturally contaminated samples. This robust, rapid, and noninvasive method may serve as an attractive alternative to established methods for detection of TTX in pufferfish extracts.
Robust and Sensitive High-Performance Liquid Chromatographic-UV Detection Technique for the Determination of Tigecycline in Rabbit Plasma
Authors: Zorpas Kostas M , Valsami Georgia N , Vryonis Evangelos V , Skoutelis Athanasios T , Archontaki Helen A
Published: February 2020

An isocratic HPLC method with detection at 248 nm was developed and fully validated for the determination of tigecycline in rabbit plasma. Minocycline was used as an internal standard. A Hypersil BDS RP-C18 column (250 × 4.6 mm, 5 μm particle size) was used with the mobile phase phosphate buffer (pH 7.10, 0.070 M)–acetonitrile (76 + 24, v/v) at a flow rate of 1.0 mL/min. The elution time of tigecycline and minocycline was approximately 8.1 and 9.9 min, respectively. Calibration curves of tigecycline were linear in the concentration range of 0.021–3.15 μg/mL in plasma. The LOD and LOQ in plasma were estimated as 7 and 21 ng/mL, respectively. The intraday and interday precision values of the method were in the range of 5.0–7.1 and 5.6–9.1%, while the corresponding accuracy values were in the ranges of 92.8–111.1 and 97.6–102.3%, respectively. At the LOQ, the intraday precision was 18.7%, while intraday and interday accuracy values were 97.3 and 98.0%, respectively. Robustness of the proposed method was studied using a Plackett-Burman experimental design. A pharmacokinetic profile is presented for confirmation of the applicability of the method to pharmacokinetic studies.
Use of Multiwalled Carbon Nanotube Disks for the SPE of Some Heavy Metals as 8-Hydroxquinoline Complexes
Authors: Soylak Mustafa , Unsal Yunus Emre
Published: February 2020

A multiwalled carbon nanotube disk was used for the SPE of some toxic heavy metals from environmental samples. Metal ions were adsorbed on the disk as 8-hydroxquinoline complexes, then quantitatively desorbed from the disk by using 10 mL 2 M HNO3. The effects of analytical parameters, including pH, sample volume, and ﬂow rates, on the recoveries of Cd(II), Co(II), Ni(II), Pb(II), Fe(III), Cu(II), and Zn(II) were investigated. The inﬂuences of some 1A and 2A group elements and some other ions as concomitant ions on the recoveries of analyte ions were also examined. The LODs of the presented preconcentration-separation system for the analyte ions were found to be in the range of 1.0–5.2 µg/L. In order to validate the procedure, SRM 1577B Bovine Liver, IAEA 336 Lichen, and HR-1 Humber river sediment certifed reference materials were analyzed. The proposed method has been applied to the determination of understudy elements in some pharmaceutical samples and natural water samples from different sites in Turkey.
Nonhost Status of Commercial Sweet Granadilla (Passiflora ligularis) in Peru to Ceratitis capitata (Diptera: Tephritidae) and Anastrepha fraterculus
Authors: Dolores Orlando S , Layme Javier M , Huaynate Carlos C
Published: February 2020

The host status of sweet granadilla (Passifflora ligularis Juss.) to Ceratitis capitata (Wiedemann) and Anastrepha fraterculus (Wiedemann) in Peru was determined. Experiments were conducted in Pasco (Peru) in four different orchards, over 2 yr (2016 and 2017), two orchards per year. Choice (granadilla plus natural host) and no-choice foraging behavior trials were conducted using sleeves under field conditions, and forced infestation was examined in laboratory cages, with five females per fruit. The development time of C. capitata was determined, and the oviposition behavior of C. capitata and A. fraterculus was examined. Three fruit maturity stages of intact (n = 1,320) and punctured (n = 1,320) granadilla fruits were examined. Adult C. capitata (n = 4,418) and A. fraterculus (n = 2,484) were trapped in the orchards, and commercial granadilla fruits (n = 1,940) sampled and dissected. Fruit fly infestation was not found in any intact granadilla fruits. Larvae and pupae were found inside punctured granadilla only in fruits broken after 20 d, and adults only emerged when those pupae were removed from the fruit. Ceratitis capitata development time was longer in punctured granadilla than that in host fruit. In the oviposition test, A. fraterculus and C. capitata did not lay eggs in intact granadilla, and C. capitata laid eggs in punctured fruits but larvae were not found. Because of the resistance mechanisms of the pericarp, commercial fruits of Passiflora ligularis are not a natural host of C. capitata and A. fraterculus in Peru.
Rock physical characterisation of microstructural fabrics and elastic anisotropy for a shale oil reservoir
Authors: Liu Xiwu , Guo Zhiqi , Zhang Qibin , Liu Yuwei , Chen Haifeng
Published: February 2020

Rock physics models are constructed to describe elastic anisotropy of various fabrics in shales. A method is developed to invert elastic properties of the clay mixture in shales. Inversion results indicate that the clay mixture has abnormally low Vs and consequently leads to a very high Vp/Vs ratio, which is related to the presence of the soft interparticle medium in the clay mixture. Accordingly, a model is constructed to describe anisotropy clay mixture that consists of layering distributed illite-smectite particles, and a more compliant interparticle medium that has a bulk modulus similar to that of water and smaller nonzero shear modulus. Rock physical modelling indicates that an increase in the fraction of the soft interparticle medium (f-soft) leads to a dramatic increase in Vp/Vs ratios of the clay mixture. Meanwhile, the fraction of illite (f-illite) also shows a significant impact on elastic anisotropy of the clay mixture. Accordingly, a rock physical inversion scheme is further proposed to estimate the parameters f-soft and f-illite. Finally, based on these inverted parameters, elastic anisotropy values of various fabrics at different scale, including illite-smectite platelet, clay mixture, solid matrix of shale and shale rock, are computed by the constructed rock physics model. The estimated anisotropy parameters reveal lamination textures and can help in the evaluation of mechanical properties of shale reservoirs. Also, the obtained anisotropy parameters can provide an accurate velocity model for seismic modelling, seismic data processing and inversion.
Temporal patterns of waterhole use as a predator avoidance strategy
Authors: Amoroso Caroline R , Kappeler Peter M , Fichtel Claudia , Nunn Charles L
Published: February 2020

Animals that depend on water sources in dry environments must balance their water demands with predation risk. In settings of water scarcity, predators may strategically exploit prey’s dependence on water; prey may adjust their use of water sources either spatially or temporally to avoid overlapping with predators. To examine the spatiotemporal dynamics of predators and prey at water sources, we studied the use of semipermanent waterholes in the dry season by red-fronted lemurs (Eulemur rufifrons), a primate species that exhibits flexible circadian activity patterns and inhabits a dry deciduous forest in western Madagascar. We hypothesized that lemurs avoid predators in their spatiotemporal use of waterholes. We analyzed the patterns of camera trap activations at waterholes by red-fronted lemurs and their two main predators: fossa (Cryptoprocta ferox) and Madagascar harrier hawks (Polyboroides radiatus). We found that red-fronted lemurs were unlikely to use waterholes at times of day when predators were commonly present, and that the distributions of times of waterhole use differed between red-fronted lemurs and each of their predator species. Red-fronted lemurs frequently used waterholes that were also used by predators within the same week in part because the predators used a variable set of water resources. In this system, predators did not appear to exploit waterholes for the high density of red-fronted lemurs attracted to them, but instead likely used waterholes primarily to meet their own water demands. Our findings suggest that when predators and prey share water sources, prey may adjust their behavior to reduce their risk of overlap with predators, including through avoidance of indirect cues of predation, such as waterholes at particular times of day.
Sugar Feeding Patterns for Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) Mosquitoes in South Texas
Authors: Olson Mark F , Garcia-Luna Selene , Juarez Jose G , Martin Estelle , Harrington Laura C , Eubanks Micky D , Badillo-Vargas Ismael E , Hamer Gabriel L
Published: February 2020

Effective mosquito surveillance and management depend on a thorough understanding of the biology and feeding patterns unique to species and sex. Given that a propensity to sugar feed is necessary for some mosquito surveillance and newer control strategies, we sought to document the amount of total sugar in wild Aedes aegypti (L.) and Culex quinquefasciatus (Say) captured from five different locations in the Lower Rio Grande Valley (LRGV) of South Texas over 2 yr. We used Biogents Sentinel 2 (BGS2) traps in year 1 and aspirators, BGS2, and CDC resting traps in years 2 and 3 to collect adult mosquitoes. The hot anthrone test was used to quantify total sugar content in each mosquito. Additionally, the cold and hot anthrone tests were used to distinguish fructose content from total sugars for mosquitoes captured in 2019. Overall, Ae. aegypti females had significantly lower total sugar content than Ae. aegypti males as well as both sexes of Cx. quinquefasciatus. However, the percentage of Ae. aegypti positive for fructose consumption was four to eightfold higher than Ae. aegypti previously reported in other regions. The difference between locations was significant for males of both species, but not for females. Seasonality and trapping method also revealed significant differences in sugar content of captured mosquitoes. Our results reinforce that sugar feeding in female Ae. aegypti is less than Cx. quinquefasciatus, although not absent. This study provides necessary data to evaluate the potential effectiveness of sugar baits in surveillance and control of both Ae. aegypti and Cx. quinquefasciatus mosquitoes.
Vaccination against Japanese encephalitis with IC51: systematic review on immunogenicity, duration of protection and safety
Authors: Kling Kerstin , Harder Thomas , Younger Zane , Burchard Gerd , Schmidt-Chanasit Jonas , Wichmann Ole
Published: February 2020

Japanese encephalitis is a disease caused by a flavivirus which is transmitted by mosquitos in endemic countries. Considering the potentially severe outcomes of the disease, vaccination is recommended for those at risk of exposure. During recent years, IC51 (IXIARO®, JESPECT®, JEVAL®) has increasingly been used to protect travellers from Europe and the USA. However, no systematic review exists that summarizes the currently available evidence on the immunogenicity and safety of this vaccine.

We conducted a systematic review on the immunogenicity and safety of IC51, using the databases PubMed, MEDLINE, EMBASE and ClinicalTrials.gov (search date: 31 August 2019). Data extracted from included studies were grouped by outcomes and stratified by population and setting. Risk of bias (ROB) was assessed using the RoB 2 tool for randomized controlled trials (RCTs) and ROBINS-I for non-randomized studies. Due to high heterogeneity, meta-analysis was not performed.

A total of 32 studies from 16 countries met the inclusion criteria (15 RCTs, 17 non-randomized studies). ROB was serious or high in the majority of studies. Seroprotection rates ranged from 93 to 100% in adults (seven studies) and from 91 to 100% in children (four studies). In the study involving adults aged 64 years and older, seroprotection was 65% with higher rates in persons who were previously vaccinated against tick-borne encephalitis virus. Safety was investigated in 27 studies. Rates of serious adverse events were below 5% in all age groups, with the majority not being causally related to the vaccine.

IC51 is a safe vaccine with good seroprotective abilities in persons aged >2 months to <64 years. The body of evidence, however, is weakened by a large amount of heterogeneity in study and clinical trial methodology. Further well-designed RCTs with special risk groups are needed.
Sky Quality Meter and satellite correlation for night cloud-cover analysis at astronomical sites
Authors: Cavazzani S , Ortolani S , Bertolo A , Binotto R , Fiorentin P , Carraro G , Saviane I , Zitelli V
Published: February 2020

The analysis of night cloud cover is very important for astronomical observations in real time, considering a typical observation time of about 15 minutes, and to provide statistics. In this article, we use the Sky Quality Meter (SQM) for high-resolution temporal analysis of the La Silla and Asiago (Ekar Observatory) sky: 3 and 5 minutes respectively. We investigate the annual temporal evolution of the natural contributions of the sky at a site not influenced by artificial light at night (ALAN) and at one highly influenced. We also make a correlation between GOES and Aqua satellite data and ground-based SQM data to confirm the relationship between the SQM data and cloud cover. We develop an algorithm that allows the use of the SQM for night cloud detection and reach correlations with the nighttime cloud cover detected by the GOES and Aqua satellites of 97.2 per cent at La Silla and 94.6 per cent at Asiago. Our algorithm also classifies photometric (PN) and spectroscopic nights (SN). We measure 59.1 per cent PN and 21.7 per cent SN for a total percentage of clear nights of 80.8 per cent at La Silla in 2018. The respective Ekar Observatory values are 31.1 per cent PN, 24.0 per cent SN and 55.1 per cent of total clear night time. Application to the SQM network would involve the development of long-term statistics and large data forecasting models for site testing and real-time astronomical observation.
Broadband X-ray analysis of 1E 1740.7−2942: constraints on spin, inclination, and a tentative black hole mass
Authors: Stecchini Paulo E , D’Amico F , Jablonski F , Castro M , Braga J
Published: February 2020

1E 1740.7−2942 is one of the strongest hard X-ray emitters in the Galactic Centre region, believed to be a black hole in a high-mass X-ray binary system. Although extensively studied in X-rays, many aspects about the underlying nature of the system are still unknown. For example, X-ray data analyses of 1E 1740.7−2942 to date have not yet unveiled the signature of a reflection component, whose modelling could be used to estimate parameters such as the spin of the black hole and inclination of the disc. We report here on the determination of these parameters from the analysis of the reflection component present in a public NuSTAR observation which has not been subject to any previous study. We include XMM–Newton and INTEGRAL data to build a combined spectrum, enabling a joint analysis of both the disc and comptonization components. Results point to a relatively high inclination disc ≳ 50° (3 σ) and a near-maximum speed rotating black hole. The former is in agreement with a previous radio study and the latter is reported here for the first time. Lastly, we follow the methodology of recent efforts to weigh black holes with only X-ray spectra and find results that suggest a black hole mass of about 5 M⊙ for 1E 1740.7−2942.
Case Series: Unilateral Amygdala Ablation Ameliorates Post-Traumatic Stress Disorder Symptoms and Biomarkers
Authors: Bijanki Kelly R , van Rooij Sanne J H , Ely Timothy D , Stevens Jennifer S , Inman Cory S , Fasano Rebecca E , Carter Sierra E , Winters Sterling J , Baman Justin R , Drane Daniel L , Jovanovic Tanja , Willie Jon T
Published: February 2020

BACKGROUND

Post-traumatic stress disorder is a severe psychobiological disorder associated with hyperactivity of the amygdala, particularly on the right side. Highly selective laser ablation of the amygdalohippocampal complex is an effective neurosurgical treatment for medically refractory medial temporal lobe epilepsy that minimizes neurocognitive deficits relative to traditional open surgery.

OBJECTIVE

To examine the impact of amygdalohippocampotomy upon symptoms and biomarkers of post-traumatic stress disorder.

METHODS

Two patients with well-documented chronic post-traumatic stress disorder who subsequently developed late-onset epilepsy underwent unilateral laser amygdalohippocampotomy. Prospective clinical and neuropsychological measurements were collected in patient 1. Additional prospective measurements of symptoms and biomarkers were collected pre- and post-surgery in patient 2.

RESULTS

After laser ablation targeting the nondominant (right) amygdala, both patients experienced not only reduced seizures, but also profoundly abated post-traumatic stress symptoms. Prospective evaluation of biomarkers in patient 2 showed robust improvements in hyperarousal symptoms, fear potentiation of the startle reflex, brain functional magnetic resonance imaging responses to fear-inducing stimuli, and emotional declarative memory.

CONCLUSION

These observations support the emerging hypothesis that the right amygdala particularly perpetuates the signs and symptoms of post-traumatic stress disorder and suggests that focal unilateral amydalohippocampotomy can provide therapeutic benefit.
Family ownership
Authors: Villalonga Belén , Amit Raphael
Published: February 2020

This article reviews the existing literature about the most prevalent form of corporate ownership around the world: ownership by individuals—particularly founders—and families. We summarize the existing evidence about the prevalence and persistence of family ownership around the world, along with its impact on performance—both financial and non-financial—relative to other types of corporate ownership. We discuss how and why these empirical facts and findings come about—why owners in general, and family owners in particular, are critical drivers of firm behaviour and performance, and how they are able to exercise their influence over corporations in which other shareholders, such as institutional investors, and other stakeholders can also play an important role.