bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein Quantification, Sandwich ELISA, and Real-Time PCR Used to Monitor Industrial Cleaning Procedures for Contamination with Peanut and Celery Allergens
Authors: Stephan Oliver , Weisz Nancy , Vieths Stefan , Weiser Tanja , Rabe Burghard , Vatterott Wolfgang
Published: February 2020

In the United States, peanut is one of the main sources of food allergens. Similarly, celery is a common allergenic food in Western Europe. Severe allergic reactions to both foods are common. Unexpected allergic reactions can occur after the consumption of celery-and peanut-free foods as a result of inadvertent cross-contaminations during manufacturing. Therefore, in cooperation with a flavor manufacturer, we monitored the cleaning process of slurry preparation equipment with regard to contaminations of follow-up products with celery and peanut compounds. Washing water samples taken after different cleaning steps and follow-up products were analyzed for the presence of celery and peanut traces with a celery-specific real-time polymerase chain reaction (PCR) and a peanut-specific sandwich enzyme-linked immunosorbent assay (ELISA). PCR and ELISA were compared with a nonspecific protein assay to evaluate whether the detection of protein traces can be a fast and cost-effective method for monitoring the effectiveness of wet cleaning procedures. Additionally, the allergenic potential of the celery and peanut mush, which were used as source material, were measured by a mediator release assay using a rat basophilic leukemia (RBL) cell line. In conclusion, the quantification of total protein in washing water was suitable for monitoring the cleaning process. Our study also revealed evidence that, in cases where wet cleaning is applicable, allergenic traces can be removed with high efficiency.
Identification and Estimation of the Levo Isomer in Raw Materials and Finished Products Containing Atropine and/or Hyoscyamine
Authors: Cieri Ugo R
Published: February 2020

The belladonna alkaloids atropine sulfate and hyoscyamine sulfate, occasionally used as anticholinergic and antimuscarinic agents, have identical molecular formulas but different stereo configurations. Hyoscyamine sulfate contains almost 100% of the levo isomer, whereas atropine sulfate is composed of equal parts of dextro and levo isomers. It is believed that the therapeutic properties of these alkaloids are due exclusively or primarily to the levo isomer. Currently available methods determine only the total amount of atropine (hyoscyamine) sulfate. A method has been developed and is reported for the identification and estimation of the levo and dextro isomers of atropine and hyoscyamine. Reference solutions are prepared in methanol at the following weights per 100 mL: 8.0 mg atropine sulfate; 4.0 mg hyoscyamine sulfate; 7.0 mg scopolamine hydrobromide; and 10.0 mg homatropine methylbromide. Samples of raw materials are similarly prepared in methanol, commercial products are also extracted or diluted with methanol, and solutions are filtered. Liquid chromatography is used for separations on a 25 cm Chirobiotic T2 column. The mobile phase is prepared by mixing 3.0 mL acetic acid and 2.0 mL triethylamine with 1000 mL methanol. The injection volume is 100 or 200 μL; the flow rate is about 0.35 mL/min. Fluorescence detection is at 255 nm excitation and 285 nm emission. Scopolamine hydrobromide and hyoscyamine eluted after 20 and 60 min, respectively. Atropine sulfate generated 2 peaks after 60 and 65 min. Homatropine methylbromide also produced 2 peaks after 70 and 85 min. Samples tested in this study included raw materials and commercial tablets or injections containing belladonna alkaloids. In all cases, the percentage calculated was that of the levo isomer relative to the total amount of atropine (hyoscyamine) present.
Determination of Metal Content in Valerian Root Phytopharmaceutical Derivatives by Atomic Spectrometry
Authors: Arce Silvia , Cerutti Soledad , Olsina Roberto , Gomez María R , Martínez Luis D
Published: February 2020

Phytopharmaceuticals containing Valerian are used as mild sleep-inducing agents. The elemental composition of 3 different marks of Valeriana officinalis roots commercially available in the Argentinian market, their teas, and a commercial tincture have been studied. The content of Al, Ca, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, V, and Zn was determined in phytopharmaceuticals by flame atomic emission/absorption spectrometry, electrothermal atomic absorption spectrometry, and ultrasonic nebulization coupled to inductively coupled plasma-optical emission spectrometry. Prior to analyses of the samples, a digestion procedure was optimized. The analytical results obtained for Fe, Al, Ca, and V in the solid sample study were within the range 100–1000 mg/kg, and for Mn, Zn, and Pb within the range 10–100 mg/kg. Cadmium was found at levels up to 0.0125 mg/kg.
Overview of Acrylamide Monitoring Databases
Authors: Lineback David , Wenzl Thomas , Ostermann Ole P , Calle Beatriz de la , Anklam Elke , Taeymans Dominique
Published: February 2020

Since high acrylamide levels in carbohydrate-rich food were reported in 2002, many research activities were started in order to gain knowledge on occurrence, formation, and prevention of this compound in food products. Among them, monitoring programs were conducted in many countries worldwide by official bodies as well as by the food industry. National and international bodies set up monitoring databases. In 2003, both the European Commission and the World Health Organization posted calls for data and placed their spreadsheets for the submission of data on the Web. The goal of the databases is to collect data for a reliable estimation of the exposure of consumers to acrylamide via the food chain. This paper describes the assessment of the data quality and outlines the composition of the data in the 2 databases, to date.
Liquid Chromatographic Analysis of Vitamin B6 in Reconstituted Infant Formula: Collaborative Study
Authors: Mann Dudley L , Ware George M , Bonnin Evelyn , Eitenmiller Ronald R ,   Collaborators:, Barna Eva , Christiansen Scott , Luc De Borde Jean , DeVries Jonathan , Gilliland Pamela , Hemmer Jane , Kalman Andras , Konings Erik , Levin David , Salvati Louis , Woollard David
Published: February 2020

A liquid chromatographic (LC) method was validated for the determination of total vitamin B6 in infant formula. Total vitamin B6 was quantified by converting the phosphorylated and free vitamers into pyridoxine. Pyridoxine was determined by ion pair reversed-phase LC with fluorescence detection. The method was subjected to an AOAC collaborative study involving a factory-manufactured, milk- and soy-based infant formula. Each was spiked at 3 concentrations in the range of 0–1 μg/g and sent as blind duplicate to participant laboratories. Nine laboratories returned valid data which were statistically analyzed for outliers and precision parameters. The repeatability relative standard deviation (RSDr) ranges were 2.0–4.0 and 3.5–5.9% for fortified milk- and soy-based formulas, respectively. The reproducibility relative standard deviation (RSDR) ranges were 8.2–8.4 and 6.7–11.2% for fortified milk- and soy-based formulas, respectively. HORRAT values ranged from 0.42 to 0.53, indicating that the precision of the method is acceptable. The mean RSDr:RSDR values were 0.60 and 0.55 for milk- and soy-based formulas, respectively. As expected, RSDs for the unfortified samples were higher, but their HORRAT values (0.81 and 2.06) helped define a realistic limit of quantitation as 0.05 μg/g. Recovery data were quantitative and varied between 81.4 and 98.0% (mean = 89.8%) for each of 6 spiked materials.
Determination of β-Agonists in Liver and Retina by Liquid Chromatography-Tandem Mass Spectrometry
Authors: Fesser Adrian C E , Dickson Leslie C , MacNeil James D , Patterson John R , Lee Stephen , Gedir Ronald
Published: February 2020

A liquid chromatography-tandem mass spectrometry (LC/MS/MS) method for the determination of bromobuterol, cimaterol, clenbuterol, clenpenterol, hydroxymethylclenbuterol, isoxsuprine, mabuterol, ractopamine, ritrodrine, salbutamol, terbutaline, and tulobuterol residues in bovine liver and retina is reported. This procedure uses enzymatic digestion, liquid–liquid extraction, and cleanup on Oasis HLB solid-phase extraction cartridges, followed by determination of the residues by LC-tandem quadrupole MS using atmospheric pressure chemical ionization in the positive ion mode. Overall average recoveries ranged from 23 to 76% for liver and 34 to 77% for retina. The mean values for samples fortified at levels between 0.5–2.0 μg/kg (liver) and 5–20 μg/kg (retina) agreed within 98–118% of the spiked levels, with coefficients of variation ranging from 6 to 20%. The decision limits, CCα, ranged from 0.1 to 0.3 μg/kg for liver, 1–3 μg/kg for retina, and detection capabilities, CCβ, from 0.2–0.5 μg/kg for liver and 2–5 μg/kg for retina.
Simultaneous Determination of Residues of Dipyrone and Its Major Metabolites in Milk, Bovine Muscle, and Porcine Muscle by Liquid Chromatography/Mass Spectrometry
Authors: Penney Lisa , Bergeron Caralee , Coates Brent , Wijewickreme Arosha
Published: February 2020

A new liquid chromatography/mass spectrometry (LC/MS) method for the determination of dipyrone (DIP) and the DIP-related residues 4-formylaminoantipyrine (FAA), 4-aminoantipyrine (AA), and 4-methylaminoantipyrine (MAA) in milk, bovine muscle, and porcine muscle is presented. The analytes are extracted from the sample with methanol and defatted with hexane. The methanol extracts are then concentrated and injected into the LC system. Compounds are determined by reversed-phase LC using an Inertsil ODS-3 column with ammonium formate-acetonitrile mobile phase and MS detection using positive-ion electrospray ionization. Calibration curves were linear between 0.02 and 0.20 μg/g matrix equivalent concentration for FAA, AA, and MAA, and between 0.2 and 2.0 μg/g for DIP. The relative standard deviations for measurements by the proposed method were <11% for milk and porcine samples, with slightly greater variability for bovine samples. Average recoveries ranged from 82 to 128%, depending on the compound and matrix involved. The method detection limits of FAA, AA, and MAA were <0.02 μg/g for all matrixes tested, while those of DIP were <0.13 μg/g. The proposed method is rapid, simple, and specific, allowing a single analyst to easily prepare over 20 samples in a regular working day.
Multiresidue Method for Determination of Algal Toxins in Shellfish: Single-Laboratory Validation and Interlaboratory Study
Authors: McNabb Paul , Selwood Andrew I , Holland Patrick T ,   Collaborators:, Aasen J , Aune T , Eaglesham G , Hess P , Igarishi M , Quilliam M , Slattery D , Van de Riet; J , Van Egmond H , Van den Top H , Yasumoto T
Published: February 2020

A method that uses liquid chromatography with tandem mass spectrometry (LC/MS/MS) has been developed for the highly sensitive and specific determination of amnesic shellfish poisoning toxins, diarrhetic shellfish poisoning toxins, and other lipophilic algal toxins and metabolites in shellfish. The method was subjected to a full single-laboratory validation and a limited interlaboratory study. Tissue homogenates are blended with methanol-water (9 + 1), and the centrifuged extract is cleaned up with a hexane wash. LC/MS/MS (triple quadrupole) is used for quantitative analysis with reversed-phase gradient elution (acidic buffer), electrospray ionization (positive and negative ion switching), and multiple-reaction monitoring. Ester forms of dinophysis toxins are detected as the parent toxins after hydrolysis of the methanolic extract. The method is quantitative for 6 key toxins when reference standards are available: azaspiracid-1 (AZA1), domoic acid (DA), gymnodimine (GYM), okadaic acid (OA), pectenotoxin-2 (PTX2), and yessotoxin (YTX). Relative response factors are used to estimate the concentrations of other toxins: azaspiracid-2 and -3 (AZA2 and AZA3), dinophysis toxin-1 and -2 (DTX1 and DTX2), other pectenotoxins (PTX1, PTX6, and PTX11), pectenotoxin secoacid metabolites (PTX2-SA and PTX11-SA) and their 7-epimers, spirolides, and homoYTX and YTX metabolites (45-OHYTX and carboxyYTX). Validation data have been gathered for Greenshell mussel, Pacific oyster, cockle, and scallop roe via fortification and natural contamination. For the 6 key toxins at fortification levels of 0.05–0.20 mg/kg, recoveries were 71–99% and single laboratory reproducibilities, relative standard deviations (RSDs), were 10–24%. Limits of detection were <0.02 mg/kg. Extractability data were also obtained for several toxins by using successive extractions of naturally contaminated mussel samples. A preliminary interlaboratory study was conducted with a set of toxin standards and 4 mussel extracts. The data sets from 8 laboratories for the 6 key toxins plus DTX1 and DTX2 gave within-laboratories repeatability (RSDr) of 8–12%, except for PTX-2. Between-laboratories reproducibility (RSDR) values were compared with the Horwitz criterion and ranged from good to adequate for 7 key toxins (HorRat values of 0.8–2.0).
Quantitative Determination of Coenyzme Q10 by Liquid Chromatography and Liquid Chromatography/Mass Spectrometry in Dairy Products
Authors: Strazisar Monika , Fir Maja , Golc-Wondra Alenka , Milivojevic Luka , Prosek Mirko , Abram Veronika
Published: February 2020

The dietary sources of CoQ10 and the evaluation of CoQ10 in dairy products were characterized. For quantitation of CoQ10 in food samples, 2 liquid chromatography (LC) methods with UV and mass spectrometry (MS) detections were developed. LC with UV detection was performed at 25°C on a Hyperclone ODS 5 μm 150 × 4.6 mm column with mobile phase consisting of methanol-ethanol-2-propanol (70 + 15 + 15, v/v/v). Flow rate was 1.0 mL/min. Retention time of CoQ10 was 10.9 ± 0.1 min. The method was sensitive [limit of detection (LOD) = 0.2 mg/kg], reproducible [relative standard deviation (RSD) = 3.0%), and linear up to 25 mg/kg (R > 0.999). LC/MS analysis was performed on a LUNA C18 3 μm, 150 × 4.6 mm column, using mobile phase consisting of ethanol-dioxane-acetic acid (9 + 1 + 0.01, v/v/v), flow rate was 0.6 mL/min, and the retention time of CoQ10 was 4.1 ± 0.1 min. Identification and quantitation were performed with a Finnigan-LCQ mass detector in positive atmospheric pressure chemical ionization mode. Mass spectra were obtained in selected-ion monitoring mode; molecular mass (M+H)+m/z 863.4 ± 1 was used for quantitative determination. MS detection is more sensitive than UV detection (LOD = 0.1 mg/kg), less reproducible (RSD = 4.0%), and linear in selected range. Analytical recoveries are 75–90% and depend on the ratio between the amount of fat in the matrix and the concentration of CoQ10 in the sample. Some soybean milk products were analyzed together with different cow, goat, and sheep milk products. Concentrations obtained with LC and LC/MS were compared with a few accessible results available from the literature. Concentrations varied from 0 ppm in soybean milk to nearly 2 ppm in fresh milk from local farms.
Validation of UV Spectrophotometric and Nonaqueous Titration Methods for the Determination of Carvedilol in Pharmaceutical Formulations
Authors: Ieggli Carine Viana Silva , Cardoso Simone Gonçalves , Belle Luziane Potrich
Published: February 2020

Ultraviolet (UV) spectrophotometric and nonaqueous volumetric methods are described for the determination of carvedilol in pharmaceutical formulations. Linearity, precision, and accuracy were evaluated according to the validation guidelines of the International Conference on Harmonizationand the United States Pharmacopeia for both methods. The UV spectrophotometric procedure was performed in ethanol at 244 nm. Good linearity was obtained between 2 and 7 μg/mL with a correlation coefficient of 0.9999. The intra- and interday precision values were <2% for all samples analyzed. The accuracy, determined from recovery studies, was between 97.5 and 102.2%. The other procedure was based on the volumetric quantitation of carvedilol in a nonaqueous medium with 0.01M perchloric acid and 1% violet crystal as the indicator. The validation of the volumetric method yielded good results that included linearity (r of >0.999), precision (relative standard deviations of <2% for intra- and interday precision), and accuracy (96.4–102.4%). The methods were applied to tablets and compounded capsules. Statistical analysis by analysis of variance showed no significant difference between the results obtained by the proposed methods.
Simultaneous Quantification of Adrenergic Amines and Flavonoids in C. aurantium, Various Citrus Species, and Dietary Supplements by Liquid Chromatography
Authors: Avula Bharathi , Upparapalli Sampath Kumar , Navarrete Andres , Khan Ikhlas A
Published: February 2020

An analytical method was developed for the simultaneous quantitative analysis of 6 amines and 20 flavonoids in fruits and extracts of 30 Citrus species, including C. aurantium, near-Citrus relatives, and dietary supplements by liquid chromatography with photodiode array detection. The separation was achieved with a Phenomenex Synergi Hydro reversed-phase column using gradient mobile phase of sodium acetate buffer (pH 5.5) and acetonitrile. Elution was run at a flow rate of 1.0 mL/min and UV at 254, 280, and 330 nm. Among the amines analyzed, synephrine, the main component, was present in the levels from 0.11 to 2.0 mg/g dry weight in 21 Citrus species and 0.07 to 18.62% in dietary supplements claiming to contain C. aurantium. The flavanones and flavones were analyzed in the same Citrus samples and were species-specific. The levels of flavones were very low compared with those of flavanones. The method facilitated the simultaneous quantification of 6 amines and 20 flavonoids in various Citrus species, the distinction between the different Citrus species, and the analysis of dietary supplements containing C. aurantium.
Determination of Zearalenone in Barley, Maize and Wheat Flour, Polenta, and Maize-Based Baby Food by Immunoaffinity Column Cleanup with Liquid Chromatography: Interlaboratory Study
Authors: MacDonald Susan J , Anderson Sharron , Brereton Paul , Wood Roger , Damant Andrew ,   Collaborators:, Aletrari M , Alonso S , Burdaspal P , Darroch J , Donnelly C , Durand T , Felguerias I , French R , Griffin J , Heide C , Herry M , Hollywood F , Howe A , Ioannou-Kakouri E , Johnson T , Kernaghan I , Krska R , Nisbet J , Pettersson H , Procter J , Rawcliffe P , Smith A , Smith W , Stangroom S , Stevens C , Swanson W , Sweet P , Thomas M , Waller J , Welsh P
Published: February 2020

An interlaboratory study was performed on behalf of the UK Food Standards Agency to evaluate the effectiveness of an affinity column cleanup liquid chromatography (LC) method for the determination of zearalenone (ZON) in a variety of cereals and cereal products at proposed European regulatory limits. The test portion is extracted with acetonitrile:water. The sample extract is filtered, diluted, and applied to an affinity column. The column is washed, and ZON is eluted with acetonitrile. ZON is quantified by reversed-phase LC with fluorescence detection. Barley, wheat and maize flours, polenta, and a maize-based baby food naturally contaminated, spiked, and blank (very low level) were sent to 28 collaborators in 9 European countries and 1 collaborator in New Zealand. Participants were asked to spike test portions of all samples at a ZON concentration equivalent to 100 μg/kg. Average recoveries ranged from 91–111%. Based on results for 4 artificially contaminated samples (blind duplicates) and 1 naturally contaminated sample (blind duplicate), the relative standard deviation for repeatability (RSDr) ranged from 6.9–35.8%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.4–38.2%. The method showed acceptable within- and between-laboratory precision for all 5 matrixes, as evidenced by HorRat values <1.7.
Liquid Chromatographic Determination of Fosthiazate Residues in Environmental Samples and Application of the Method to a Fosthiazate Field Dissipation Study
Authors: Tsiropoulos Nicholas G , Likas Dimitrios T , Karpouzas Dimitrios G
Published: February 2020

A method was developed and validated for the determination of residues of the organophosphorus nematicide fosthiazate in soil and water by using reversed-phase liquid chromatography with UV detection. Good recoveries (>85%) of fosthiazate residues were obtained from water samples (drinking water, groundwater, and liquid chromatography water) after passage of 0.5–2 L water through solid-phase extraction (SPE) C-18 cartridges and subsequent elution with ethyl acetate. Residues in soil were extracted with methanol–water (75 + 25, v/v) on a wrist-action shaker, and the extract was cleaned up on C-18 SPE cartridges before analysis. The method was validated by analysis of a range of soils with different physicochemical characteristics; recoveries exceeded 87% at fortification levels ranging from 0.02 to 5.0 mg/kg. The precision values obtained for the method, expressed as repeatability and reproducibility, were satisfactory (<11%). Fosthiazate detection limits were 0.025 μg/L and 0.005 mg/kg for water and soil samples, respectively. The decline in the levels of fosthiazate residues in soil was measured after application of fosthiazate to protected tomato cultivation. The dissipation of fosthiazate residues followed first-order kinetics with a calculated half-life of 21 days.
Quantitative Determination of Triterpenes from Amphiptherygium adstringens by Liquid Chromatography and Thin-Layer Chromatography and Morphological Analysis of Cuachalalate Preparations
Authors: Navarrete Andrés , Avula Bharathi , Joshi Vaishali C , Ji Xiuhong , Hersh Paul , Khan Ikhlas A
Published: February 2020

Amphiptherygium adstringens (Anacardiaceae/Julianaceae), local name cuachalalate, is used in folk medicine for the treatment of cholelithiasis, fevers, fresh wounds, hypercholesterolemia, gastritis, gastric ulcers, and cancer of the gastrointestinal tract. The development of column high-performance liquid chromatographyphotodiode array detector (LC-PDA) and high-performance thin-layer chromatography (HPTLC)densitometry methods for the determination of masticadienonic acid and 3-hydroxymasticadienonic acid in cuachalalate preparations is described in this paper. Good separation of the compounds could be achieved by both methods. Either might be preparable depending on the requirements. The LC separation was performed on a Phenomenex Synergi MAX-RP 80A reversed-phase column operated at 40C with detection at 215 nm. The plant materials were extracted with methanol by sonication. The triterpenes present in the plant material and commercial extracts were separated with an acetonitrilewater reagent alcohol isocratic system. The limit of detection was 0.10.2 g/mL. The relative standard deviation values for the determination of triterpenes in plant extracts were less than 1.00%. This is the first report of an analytical method developed for the quantitative analysis of triterpenes from Amphiptherygium adstringens by LC-PDA and HPTLC. The stem bark showed higher amounts of triterpenes, and low amounts in root and stem root. The microscopic description of the crude drug of cuachalalate was also provided.
Determination of Pesticides in Soy-Based Infant Formula Using Liquid Chromatography with Electrospray Ionization Tandem Mass Spectrometry
Authors: Wang Jian , Cheung Wendy
Published: February 2020

A sensitive method using liquid chromatography with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was developed and validated to quantify and confirm 13 pesticides, including aldicarb sulfoxide, aldicarb sulfone, oxamyl, methomyl, formetanate, 3-hydroxycarbofuran, carbendazim, thiabendazole, aldicarb, propoxur, carbofuran, carbaryl, and methiocarb, in soy-based infant formula. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring of 2 fragment ion transitions to provide a high degree of sensitivity and selectivity for both quantitation and confirmation. Different approaches to constructing calibration curves were compared and discussed to address issues of the extraction efficiency or recovery, and matrix effects. Matrix-matched standard calibration curves with the use of isoprocarb as an internal standard were finally used to achieve the best accuracy of the method. Under most circumstances, recoveries of 13 pesticides, spiked at 5.0, 25.0, and 45.0 g/kg, were close to 100%. The method detection limits (signal-to-noise ratio 3:1; g/kg) of 13 pesticides were 0.2 for thiabendazole and methiocarb, 0.6 for aldicarb, and 0.1 for the others.
Determination of Nifuroxazide and Drotaverine Hydrochloride in Pharmaceutical Preparations by Three Independent Analytical Methods
Authors: Metwally Fadia H , Abdelkawy Mohammed , Naguib Ibrahim A
Published: February 2020

Three new, different, simple, sensitive, and accurate methods were developed for quantitative determination of nifuroxazide (I) and drotaverine hydrochloride (II) in a binary mixture. The first method was spectrophotometry, which allowed determination of I in the presence of II using a zero-order spectrum with an analytically useful maximum at 364.5 nm that obeyed Beer's law over a concentration range of 2-10 μg/mL with mean percentage recovery of 100.08±0.61. Determination of II in presence of I was obtained by second derivative spectrophotometry at 243.6 nm, which obeyed Beer's law over a concentration range of 2-10 μg/mL with mean recovery of 99.82±1.46%. The second method was spectrodensitometry, with which both drugs were separated on a silica gel plate using chloroformacetonemethanolglacial acetic acid (6 + 3 + 0.9 + 0.1) as the mobile phase and ultraviolet (UV) detection at 365 nm over a concentration range of 0.2-1 μg/band for both drugs, with mean recoveries of 99.99 0.15 and 100.00 0.34% for I and II, respectively. The third method was reversed-phase liquid chromatography using acetonitrilewate (40 + 60, v/v; adjusted to pH 2.55 with orthophosphoric acid) as the mobile phase and pentoxifylline as the internal standard at a flow rate of 1 mL/min with UV detection at 285 nm at ambient temperature over a concentration range of 2-10 μg/mL for both drugs, with mean recoveries of 100.24±1.51 and 100.08±0.78% for I and II, respectively. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulations containing the above drugs with no interference from other dosage form additives. The validity of the suggested procedures was further assessed by applying the standard addition technique which was found to be satisfactory, and the percentage recoveries obtained were in accordance with those given by the EVA Pharma reference spectrophotometric method.
Chemical Fingerprinting of Valeriana Species: Simultaneous Determination of Valerenic Acids, Flavonoids, and Phenylpropanoids Using Liquid Chromatography with Ultraviolet Detection
Authors: Navarrete Andres , Avula Bharathi , Choi Young-Whan , Khan Ikhlas A
Published: February 2020

The roots and rhizomes of various valeriana species are currently used as a sleeping aid or mild sedative. A liquid chromatography method has been developed that permits the analysis of chlorogenic acid, lignans, flavonoids, valerenic acids, and valpotrates in various valerian samples. The best results were obtained with a Phenomenex Luna C18(2) column using gradient elution with a mobile phase consisting of water and 0.05% phosphoric acid and 2100% acetonitrilemethanol (1 + 1) with 0.05% phosphoric acid. The flow rate was 0.8 mL/min and ultraviolet detection was at 207, 225, 254, 280, and 325 nm. Different valerian species and commercial products showed remarkable quantitative variations. Chlorogenic acid (0.21.2%), 3 lignans, linarin (0.0020.24%), and valepotriates were detected in all the valeriana species analyzed. Highest amounts of valerenic acids were detected in V. officinalis L., trace amounts in V. sitchensis, and none in the other species analyzed.
Spectrophotometric Analysis of Selective Serotonin Reuptake Inhibitors Based on Formation of Charge-Transfer Complexes with Tetracyanoquinodimethane and Chloranilic Acid
Authors: Darwish Ibrahim A , Refaat Ibrahim H
Published: February 2020

A simple, accurate, and sensitive spectrophotometric method for analysis of selective serotonin reuptake inhibitors (SSRIs) has been developed and validated. The analysis was based on the formation of colored charge-transfer complexes between the intact molecule of SSRI drug as an n-electron donor and each of tetracyanoquinodimethane (TCNQ) or p-chloranilic acid (pCA) as electron acceptors. The formed complexes were measured spectrophotometrically at 842 and 520 nm for TCNQ and pCA, respectively. Different variables and parameters affecting the reactions were studied and optimized. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.99750.9996) were found between the absorbances and the concentrations of the investigated drugs in the concentration ranges of 450 and 20400 g/mL with TCNQ and pCA, respectively. With all the investigated drugs, TCNQ gave more sensitive assays than pCA; the limits of assay detection were 2.54.8 and 2040 g/mLwith TCNQ and pCA, respectively. The intra- and interassay precisions were satisfactory; the relative standard deviations did not exceed 2. The proposed procedures were successfully applied to the analysis of the studied drugs in pure form and pharmaceutical formulations with good accuracy; the recovery values were 98.4102.8 1.241.81. The results obtained from the proposed method were statistically comparable with those obtained from the previously reported methods.
Determination of Amlodipine in Pharmaceutical Dosage Forms by Liquid Chromatography and Ultraviolet Spectrophotometry
Authors: Malesuik Marcelo Donadel , Cardoso Simone Gonalves , Bajerski Lisiane , Lanzanova Fibele Analine
Published: February 2020

A liquid chromatography (LC) method and an ultraviolet (UV) spectrophotometricmethod were developed and validated for quantitative determination of amlodipine in tablets and compounded capsules. The isocratic LC analyses were performed on an RP18 column using a mobile phase composed of 0.1 (v/v) ortho-phosphoric acid (pH 3.0) acetonitrile (60 40, v/v) at a flow rate of 1.0 mL/min. The UV spectrophotometricmethodwas performed at 238 nm. The analytical methodswere validated according to International Conference on Harmonization Guidelines. The calibration graphswere linear correlation coefficient (r) > 0.999 in the studied concentration range of 1030 g/mL for LC and 1035 g/mL for UV spectrophotometry. The relative standard deviation values for intraday and interday precision studies were less than 2, and the accuracywas greater than 98 for bothmethods. The specificity of the LC method was proved using forced degradation. Statistical analyses showed no significant difference between the results obtained by the 2 methods. The proposed methods are precise and accurate and can be applied directly and easily to the oral pharmaceutical preparations of amlodipine.
An Analytical Method to Screen for Six Thyreostatic Drug Residues in the Thyroid Gland andMuscle Tissues of Food Producing Animals by Liquid Chromatography with Ultraviolet Absorption Detection and Liquid Chromatography/Mass Spectrometry
Authors: Asea Philip E , MacNeil James D , Boison Joe O
Published: February 2020

A method was developed and validated to screen for residues of the thyreostatic drugs, tapazole (TAP), mercaptobenzimidazole (MBI), thiouracil (TU), methylthiouracil (MTU), propylthiouracil (PrTU), and phenylthiouracil (PhTU) in bovine, equine, ovine, and porcine thyroid and muscle tissues at concentrations 5 ng/g using 2-methoxy-mercaptobenzimidazole (MeMBI) and dimethylthiouracil (DMTU) as internal standards. In this method, the drugs were solvent extracted from thyroid and muscle tissue and cleaned up on an amino-propyl solid-phase extraction (SPE) cartridge. The unretained fraction containing TAP and MBI and the internal standard, MeMBI, was collected as Fraction 1. The retained fraction containing TU, MTU, PrTU, PhTU, and the internal standard, DMTU, was eluted with 3 acetic acidisopropanol as Fraction 2. Fraction 1 was further cleaned up on an alumina B SPE cartridge and analyzed by gradient elution on a C18 high-performance liquid chromatography (HPLC) column with ultraviolet detection at wavelengths of 255 and 300 nm. Fraction 2 was taken to dryness, derivatized with 4-chloro-7-nitrobenzo-2-furazan at pH 8, and analyzed by gradient elution on a C18 LC column with mass spectrometry (MS) detection. Any presumptive positive test results were submitted for further analysis by LC/MS/MS. The validated method was applied to the analysis of over 300 thyroid tissue samples.
Determination of Aflatoxins and Ochratoxin A in Ginseng and Other Botanical Roots by Immunoaffinity Column Cleanup and Liquid Chromatography with Fluorescence Detection
Authors: Trucksess Mary , Weaver Carol , Oles Carolyn , D'Ovidio Kathleen , Rader Jeanne
Published: February 2020

Mycotoxins are toxic secondary metabolites produced by certain molds and are common contaminants of many important food crops, such as grains, nuts, and spices. Some mycotoxins are found in fruits, vegetables, and botanical roots. These contaminants have a broad range of toxic effects, including carcinogenicity, immunotoxicity, neurotoxicity, and reproductive and developmental toxicity. The public health concerns related to both acute and chronic effects of mycotoxins in animals have prompted more than 100 countries to establish regulatory limits for some of the well-known mycotoxins, such as the aflatoxins (AFL). Our research focused on method development for 2 of these toxins, AFL and ochratoxin A (OTA), in ginseng and other selected botanical roots. Methods using an immunoaffinity column (IAC) cleanup, liquid chromatographic separation, and fluorescence detection were modified and evaluated. Two types of IAC cleanup were evaluated: IAC for AFL, and IAC for both AFL and OTA. Three derivatization techniques to enhance the fluorescence of the AFL were compared: precolumn trifluoroacetic acid, postcolumn bromination, and postcolumn ultraviolet irradiation. No derivatization was needed for OTA. Results for AFL using the single analyte IAC cleanup and the 3 derivatization techniques were all comparable for ginseng and for other roots such as ginger, licorice, and kava-kava. Recoveries of added AFL for ginseng at levels from 2 to 16 ng/g were about 80%. Using IAC cleanup for both AFL and OTA recoveries of added AFL for ginseng at 416 ng/g were about 70%, and for ginger, licorice, and kava-kava were about 60%. Recoveries of added OTA for ginseng, ginger, and echinacea at 4 ng/g were about 55%.
Determination of Residues of 446 Pesticides in Fruits and Vegetables by Three-Cartridge Solid-Phase ExtractionGas Chromatography-Mass Spectrometry and Liquid Chromatography-Tandem Mass Spectrometry
Authors: Pang Gao-Fang , Fan Chun-Lin , Liu Yong-Ming , Cao Yan-Zhong , Zhang Jin-Jie , Li Xue-Min , Li Zeng-Yin , Wu Yan-Ping , Guo Tong-Tong
Published: February 2020

A method was developed for determination of residues of 446 pesticides in fruits and vegetables through the use of cleanup by a 3-cartridge solid-phase extractiongas chromatography/ mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). Fruit and vegetable samples (20 g) were extracted with 40 mL acetonitrile, salted out, and centrifuged. Half of the supernatant was passed into an Envi-18 cartridge, eluted with acetonitrile, and cleaned up with Envi-Carb and aminopropyl Sep-Pak cartridges in series after concentration of the eluates. Pesticides were eluted with acetonitriletoluene (3 + 1, v/v), and eluates were concentrated to 0.5 mL and then added into internal standards after solvent exchange with 2 mL hexane and used for determination of 383 pesticides by GC/MS. The other half of the supernatant was concentrated to 1 mL and cleaned up with Envi-Carb and aminopropyl Sep-Pak cartridges in series. Pesticides were eluted with acetonitriletoluene (3 + 1, v/v), and the eluates were concentrated to 0.5 mL, dried with nitrogen gas, diluted to 1.0 mL with acetonitrilewater (3 + 2, v/v), and used for determination of 63 pesticides by LC/MS/MS. The limit of detection for the method was 0.2600 ng/g depending on the individual pesticide. In the method, fortification recovery tests at high, medium, and low levels were conducted on 6 varieties of fruits and vegetables, i.e., apples, oranges, grapes, cabbage, tomatoes, and celery, with average recoveries falling within the range of 55.0-133.8% for 446 pesticides, among which average recoveries between 60.0-120.0% accounted for 99% of the results. The relative standard deviation was between 2.1-39.1%, of which a relative standard deviation of 2.1-25.0% made up 96% of the results. Experiments proved that the method was applicable for determination of residues of 446 pesticides in fruit and vegetables.
Surface Plasmon Resonance Biosensors for Detection of PathogenicMicroorganisms: Strategies to Secure Food and Environmental Safety
Authors: Bergwerff Aldert A , Van Knapen Frans
Published: February 2020

This review describes the exploitation of exclusively optical surface plasmon resonance (SPR) biosensors for the direct and indirect detection of pathogenic microorganisms in food chains and the environment. Direct detection is, in most cases, facilitated by the use of defined monoclonal or polyclonal antibodies raised against (a part of) the target pathogenic microorganisms. The antibodies were immobilized to a solid phase of the sensor to capture the microbe from the sample. Alternatively, antibodies were used in an inhibition-like assay involving incubation with the target organism prior to analysis of nonbound antibodies. The free immunoglobins were screened on a sensor surface coated with either purified antigens or with Fc or Fab binding antibodies. Discussed examples of these approaches are the determination of Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes. Another direct detection strategy involved SPR analysis of polymerase chain reaction products of Shiga toxin-2 genes reporting the presence of E. coli O157:H7 in human stool. Metabolic products have been exploited as biomarkers for the presence of amicrobial agent, such as enterotoxin B and a virulence factor for the occurrence of Staphylococcus aureus and Streptococcus suis, respectively. Indirect detection, on the other hand, is performed by analysis of a humoral immune response of the infected animal or human. By immobilization of specific antigenic structures, infections with Herpes simplex and human immunodeficiency viruses, Salmonella and Treponema pallidum bacteria, and Schistosoma spp. parasites were revealed using human, avian, and porcine sera and avian eggs. Bound antibodies were easily isotyped using an SPR biosensor to reveal the infection history of the individual. Discussed studies show the recent recognition of the suitability of this type of instrument for (rapid) detection of health-threatening microbes to food and environmental microbial safety.
Spreeta-Based Biosensor Immunoassays to Detect Fraudulent Adulteration in Milk and Milk Powder
Authors: Haasnoot Willem , Marchesini Gerardo R , Koopal Kees
Published: February 2020

Biacore biosensors (Biacore AB, Uppsala, Sweden) have proven to be robust analytical tools for the automated immunochemical detection of different adulterants and contaminants in milk and milk powder. However, the significant cost of the instruments is a disincentive for their wide application in food control laboratories. Therefore, a low-cost alternative optical biosensor (Spreeta, Texas Instruments, Attleboro, MA) was built into an affordable liquid handling system. Using this prototype biosensor, an inhibition immunoassay for bovine κ-casein was evaluated for the detection of cow's milk in ewe's and goat's milk and for the detection of bovine rennet whey powder in milk powder. Comparable sensitivities were obtained for both adulterants in the Spreeta-based prototype biosensor and a Biacore 3000 instrument. The limit of detection for cow's milk was 0.17% (v/v) and bovine rennet whey powder could be detected in milk powder above 1% (w/w). The Spreeta sensor was also useful in the control of fraudulent water additions to milk, simply by measuring differences in the bulk response.
Phytoestrogens as Bioactive Ingredients in Functional Foods: Canadian Regulatory Update
Authors: Lee Nora
Published: February 2020

This paper outlines the Canadian regulatory position on phytoestrogens as bioactive ingredients in functional foods.
Flax LignansAnalytical Methods and How They Influence Our Understanding of Biological Activity
Authors: Muir Alister D
Published: February 2020

Flaxseed (Linum usitatissimum L.) is a major source of dietary intake of lignans by virtue of the high concentrations (0.71.5) that are present in the seed. The principal lignan present in flaxseed is secoisolariciresinol diglucoside (SDG), which occurs as a component of a linear ester-linked complex in which the C6-OH of the glucose of SDG is esterified to the carboxylic acid of hydroxymethylglutaric acid. Also present in flaxseed and in resulting lignan extracts are significant quantities of 2 cinnamic acid glycosides. Our emerging understanding of the biological activity of flax lignans is based on studies using a variety of materials ranging from whole ground seed to pure SDG. The underlying assumption of most of these studies is that the biological activity of flax lignans results from their conversion to the mammalian lignans enterolactone (EL) and enterodiol (ED). There are, however, several intermediate compounds generated during the digestion and metabolism of flax lignans, including SDG and its aglycones and secoisolariciresinol (Seco), that are good candidates to be the principal bioactive molecule. This review will document the history of the development of lignan analytical methods and illustrate how analytical methods have influenced the interpretation of animal and human trials and our understanding of the biological activity of flax lignans.
Comparison of Microbiological and UV-Spectrophotometric Assays for Determination of Voriconazole in Tablets
Authors: Adams Andra I H , Steppe Martin , Frehlich Pedro E , Bergold Ana M
Published: February 2020

Two methods have been developed for the determination of voriconazole, a new antifungal drug, in tablets. A UV method, with detection at 255 nm, was compared with a diffusion agar bioassay, which used Sacharomyces cerevisiae ATCC 2601 as the assay organism. The developed methods were linear in the range of 3.0-12.0 and 12.0-24.0 μg/mL, for the microbiological and UV methods, respectively, both exhibiting a coefficient correlation of 0.9999. The UV method demonstrated an improved precision compared to the bioassay method (1.0 versus 2.4%). The average recovery, 99.8 and 100.9%, was suitable in both methods. The results obtained by these 2 methods were compared with those of a high-performance liquid chromatography (HPLC) method published previously, and no evidence of significant difference was observed. The proposed methods are appropriate for the determination of voriconazole in tablets and can be used in routine quality control.
Spectrophotometric Determination of Certain Antidepressants in Pharmaceutical Preparations
Authors: Önal ArmaĞan , Kepeki Ş. Evrim , Çetin S MÜge , ErtÜrk Sidika
Published: February 2020

Simple and reproducible spectrophotometric methods have been developed for determination of sertraline, fluoxetine, and venlafaxine in pharmaceutical preparations. The methods are based on the reactions between the studied drug substances and ion-pair agents (bromothymol blue, bromocresol green, or bromophenol blue) to produce yellow-colored ion-pair complexes in acidic buffers. After extracting in chloroform, the ion-pair complexes are spectrophotometrically determined at the optimum wavelength. Optimizations of the reaction conditions were carried out. Beer's law was obeyed within the concentration range from 1 to 15 μg/mL. The molar absorptivity, Sandell sensitivity, and detection and quantification limits were also determined. The developed methods were applied successfully for the determination of these drugs in some available commercial preparations. The results were compared statistically with those obtained from reported high-performance liquid chromatography methods.
Direct Determination of Lycopene Content in Tomatoes (Lycopersicon esculentum) by Attenuated Total Reflectance Infrared Spectroscopy and Multivariate Analysis
Authors: Halim Yuwana , Schwartz Steven J , Francis David , Baldauf Nathan A , Rodriguez-Saona Luis E
Published: February 2020

Lycopene is a potent antioxidant that has been shown to play critical roles in disease prevention. Efficient assays for detection and quantification of lycopene are desirable as alternatives to time- and labor-intensive methods. Attenuated total reflectance infrared (ATR-IR) spectroscopy was used for quantification of lycopene in tomato varieties. Calibration models were developed by partial least-squares regression (PLSR) using quantitative measures of lycopene concentration from liquid chromatography as reference method. IR spectra showed a distinct marker band at 957 cm1 for trans Carbon-Hydrogen (CH) deformation vibration of lycopene. PLSR models predicted the lycopene content accurately and reproducibly with a correlation coefficient (σ) of 0.96 and standard error of cross-validation <0.80 mg/100 g. ATR-IR spectroscopy allowed for rapid, simple, and accurate determination of lycopene in tomatoes with minimal sample preparation. Results suggest that the ATR-IR method is applicable for high-throughput quantitative analysis and screening for lycopene in tomatoes.
Proficiency Testing as a Tool to Assess the Performance of Visual TLC Quantitation Estimates
Authors: Risha Peter , Msuya Zera , Ndomondo-Sigonda Margareth , Layloff Thomas
Published: February 2020

The use of rapid and inexpensive nonlaboratory-based screening tests for drug quality assessments is recommended as a component of a drug quality assurance program in poor resource settings. We have established routine Minilab® test procedures to screen product quality and a proficiency testing program to determine the competency of the inspectors and reliability of results. Samples for the proficiency testing were prepared by pulverizing a standard reference tablet of the appropriate drug and making serial dilutions with starch to obtain concentrations of 0, 40, and 100%. The samples, which were labeled only with the drug name and an identifying letter, were given to inspectors for quality screening using Minilab procedures. In round 1 of the proficiency test, only 3 of 28 substandard samples were correctly identified. Round 2 of the proficiency test, which was administered after a performance qualification test for the analytical method, showed much improvement: 19 of 27 substandard drugs were correctly identified, while 5 out of 9 inspectors made the correct inference on the quality of 45 samples. However, in both rounds, 2 inspectors failed to identify substandard samples, indicating that their technical competencies need to be improved for the reliability of the results. Although the thin-layer chromatography screening methods provide a rapid means for drug quality assessment, they need to be put in the hands of competent users. The inclusion of a proficiency test in the screening program provides a measure of determining competency of the personnel and reliability of the results.