bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Refluxing, Ultrasonic- and Microwave-Assisted Extraction of Dihydromyricetin from Ampelopsis grossedentata
Authors: Li Hui , Li Yanan , Zhang Yongkang , Shi Hui , Hu Wenbin , Zhang Zhaohui
Published: February 2020

Three techniquesrefluxing extraction (RE), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE)for extraction of dihydromyricetin from Ampelopsis grossedentata, family Vitaceae, were evaluated. A 70 methanolwater solution was used as extraction solvent, and extracts obtained were analyzed by high-performance liquid chromatography (HPLC). Results showed that the MAE method was the most efficient in the shortest time, followed by RE and UAE. Maximum extraction efficiency of dihydromyricetin was obtained by using the MAE technique, which needs only 10 min, whereas UAE and RE require 40 and 300 min, respectively, to gain higher extraction efficiency of dihydromyricetin. The time needed for MAE was 30 times less than that needed for RE. Extracts obtained by using different methods were shown by HPLC analysis to possess similar chemical constituents, and extraction reproducibility was satisfactory for these techniques. Compared with UAE and RE, the MAE is a better alternative extraction technique for large-scale speedy extraction of dihydromyricetin from this plant.
Simultaneous Determination of Some Phenothiazine Derivatives in Human Blood by Headspace Solid-Phase Microextraction and Gas Chromatography with Nitrogen-Phosphorus Detection
Authors: Shinmen Natsuko , Lee Xiao-Pen , Kumazawa Takeshi , Hasegawa Chika , Ishiwata Yasuhiro , Sato Keizo , Seno Hiroshi , Suzuki Osamu
Published: February 2020

Chlorpromazine, levomepromazine, promazine, triflupromazine, and trimeprazine were simultaneously determined in human whole blood and plasma by combining headspace solid-phase microextraction and gas chromatography with nitrogenphosphorus detection. Extraction efficiency for the phenothiazine derivatives was 0.0130.117 for both sample types. Regression equations were linear [correlation coefficient (r) 0.99510.9999] within the range 2.5200 ng/0.5 mL for triflupromazine and trimeprazine, and 6.3200 ng/0.5 mL for chlorpromazine, levomepromazine, and promazine. The limit of detection for each compound was 0.23.9 ng/0.5 mL whole blood and plasma. Intraday and interday coefficients of variation for all phenothiazines in both human samples were commonly <15 and 20, respectively. We also report the determination of levomepromazine in human plasma after oral administration.
Solid-Phase Microextraction for the Determination of Volatile Compounds in the Spoilage of Raw Ground Beef
Authors: Pérez Rosa Ana , Rojo Maria Dolores , Gonzlez Gema , Lorenzo Cristina De
Published: February 2020

A method using solid-phase microextraction (SPME) and gas chromatography/mass spectrometry was developed and applied to the determination of volatile compounds generated in meat, at different times, from ground beef stored under refrigeration. Selection of the extractive fiber, extraction time, and headspace (HS) or direct extraction was optimized for the determination of volatile compounds from ground meat. Various fibers were investigated, and carboxen/polydimethylsiloxane was selected for these analyses. The HS analysis of the solid sample by HS-SPME produced a higher volatile signal than did direct-SPME. The meat samples were stored under refrigeration and analyzed after 0, 3, and 6 days of storage. These analyses at different times showed important changes in the volatile profile of the evaluated samples. The ketones 3-hydroxy-2-butanone and 2,3-butanedione, and the alcohol 3-methyl-1-butanol were the most representative compounds generated during the meat storage. In general, compounds associated with a butter off-flavor were detected during the storage of raw ground beef.
Quantitative Identification of Pesticides as Target Compounds and Unknowns by Spectral Deconvolution of Gas Chromatographic/Mass Spectrometric Data
Authors: Robbat Albert , Hoffmann Andreas , Namara Kevin Mac , Huang Yongli
Published: February 2020

The results of gas chromatography/mass spectrometry (MS), with Ion Signature Technology, Inc. (North Smithfield, RI) quantitative deconvolution software, are discussed for pesticides identified both as target compounds by using retention and MS data and as unknowns by using only mass spectra. Target compound analysis of 32 pesticides, surrogates, and an internal standard added to lemon oil over a wide concentration range produced precision and accuracy that are well within the acceptable criteria of 25 and 50 for complex samples. When 112 pesticides were added to orange oil and searched as unknowns, 110 of the 112 compounds were correctly identified, with an average pesticide recovery of 101 19. The injection volume of the orange oil fortified with pesticides was selected so that 4 ng per compound was injected on column. No false negatives were found, because ion signals for the 2 unidentified pesticides were not acquired by the instrument in either the standard mixture or the oil. No false positives were detected, although >750 widely different compounds were included in the library search.
A New Method for Application of the Water-Soluble Dye SPADNS in a Carbon Paste Electrode for Determination of Trace Amounts of Copper
Authors: Rohani Tahereh , Taher Mohammad Ali
Published: February 2020

2-(P-sulfophenylazo)-1,8-dihydroxy-3,6-naphthalene disulfate (SPADNS) was adsorbed on surfactant modified zeolite type A by electrostatic interaction in the aqueous phase. The dye was strongly retained and not easily leached from the surfactant-modified zeolite matrix. This compound was incorporated into a carbon paste electrode for anodic stripping voltammetric determination of trace amounts of copper. The calibration plot was linear over the copper concentration range 2.0800 g/L. The detection limit was found to be 0.4 g/L Cu(II), and for 5 successive determinations of 50 and 150 g/L Cu(II) the relative standard deviations were 1.6 and 1.2, respectively. The modified electrode prepared in this study could be used for the determination of Cu(II) in water samples and human hair with good results.
Extraction of Aucubin from Seeds of Eucommia ulmoides Oliv. Using Supercritical Carbon Dioxide
Authors: Li Hui , Hu Jiangyu , Ouyang Hui , Li Yanan , Shi Hui , Ma Chengjin , Zhang Yongkang
Published: February 2020

Supercritical CO2 was used as solvent for the extraction of aucubin from the seeds of Eucommia ulmoides Oliv. The co-solvent composition was tested and extraction conditions were optimized. Results showed that the best co-solvent was a waterethanol mixture (1 + 3, v/v), and the highest yield was obtained when the extraction was performed under 26 MPa at extraction and separation temperatures of 55 and 30C for 120 min, using 6 mL co-solvent/g material at a CO2 flow rate of 20 L/h. In a comparison of the supercritical CO2 and Soxhlet extraction methods, the Soxhlet method needed 3 h to extract 10 g material, whereas the supercritical CO2 extraction technique needed only 2 h to extract 100 g material, thus showing a high extraction capability. The supercritical CO2 extraction produced a higher yield, with a lower cost for the extraction. Owing to the advantages of low extraction temperature, high yield, and ease of separating the product from the solvent, supercritical CO2 extraction is likely to be developed into an ideal technique for the extraction of aucubin, a compound with thermal instability, from the seeds of this plant.
Development and Validation of a Column High-Performance Liquid Chromatographic Method for Determination of Sibutramine in Capsules
Authors: Diefenbach Isabel Cristina Fração , Friedrich Milene , Santos Marcos Roberto Dos , Bittencourt Celso Figueiredo
Published: February 2020

The development and validation of a reversed-phase liquid chromatographic (LC) method for the determination of sibutramine hydrochloride monohydrate in capsules is described. An isocratic LC analysis was performed on a reversed-phase RP-18 column (250 4.6 mm id, 5 m particle size). The mobile phase consisted of methanolwatertriethylamine (80 + 20 + 0.5, v/v/v), with pH adjusted to 5.65 with 85 phosphoric acid, and was pumped at a constant flow rate of 1.0 mL/min. Measurements were made at a wavelength of 223 nm. The calibration curve was linear over the range of 1540 g/mL [correlation coefficient (r2) = 0.9998]. The relative standard deviation (RSD) value for intraday precision was 0.84. The RSD value for interday precision was 0.90. Recoveries ranged from 99.64 to 100.66. No interferences from the excipients were observed. Because of its simplicity and accuracy, the method is suitable for routine quality control analysis of sibutramine in capsules.
Evaluation of Modified PCR Quantitation of Genetically Modified Maize and Soybean Using Reference Molecules: Interlaboratory Study
Authors: Kodama Takashi , Kuribara Hideo , Minegishi Yasutaka , Futo Satoshi , Watai Masatoshi , Sawada Chihiro , Watanabe Takahiro , Akiyama Hiroshi , Maitani Tamio , Teshima Reiko , Furui Satoshi , Hino Akihiro , Kitta Kazumi
Published: February 2020

Real-time polymerase chain reaction (PCR)-based quantitative methods were previously developed and validated for genetically modified (GM) maize or soy. In this study, the quantification step of the validated methods was modified, and an interlaboratory study was conducted. The modification included the introduction of the PCR system SSIIb 3 instead of SSIIb 1 for the detection of the taxon-specific sequence of maize, as well as the adoption of colE1 as a carrier included in a reference plasmid solution as a replacement for salmon testis. The interlaboratory study was conducted with the ABI PRISM 7700 and consisted of 2 separate stages: (1) the measurement of conversion factor (Cf) value, which is the ratio of recombinant DNA (r-DNA) sequence to taxon-specific sequence in each genuine GM seed, and (2) the quantification of blind samples. Additionally, Cf values of other instruments, such as the ABI PRISM 7900 and the ABI PRISM 7000, were measured in a multilaboratory trial. After outlier laboratories were eliminated, the repeatability and reproducibility for 5.0 samples were <15.8 and 20.6, respectively. The quantitation limits of these methods were 0.5 for Bt11, T25, and MON810, and 0.1 for GA21, Event176, and RR soy. The quantitation limits, trueness, and precision of the current modified methods were equivalent to those of the previous methods. Therefore, it was concluded that the modified methods would be a suitable replacement for the validated methods.
A Novel Method for Speciation of Chromium: Coprecipitation Without Carrier Element by Using a Triazole Derivative
Authors: Duran Celal , Bulut Volkan N , Ozdes Duygu , Gundogdu Ali , Soylak Mustafa
Published: February 2020

A coprecipitation method has been established for speciation of chromium(III) and chromium(VI) in real samples. The procedure is based on the coprecipitation of Cr(III), by using a new organic coprecipitant, 3-phenyl-4-o-hydroxybenzylidenamino-4,5-dihydro-1,2,4-triazole-5-one, without adding any carrier element. After reduction of Cr(VI) by concentrated H2SO4 and ethanol, the method was applied to the determination of total Cr. The level of Cr(VI) was calculated by the difference of total Cr and Cr(III) levels. For optimum recovery of Cr(III), different analytical factors such as pH, amount of coprecipitant, centrifugation rate and time, and effect of sample volume, were investigated. The influences of some anions, cations, and transition metals on the recoveries were also investigated, and no significant interferences were observed. The preconcentration factor was 100. The detection limit based on 3 times standard deviation () of the blank (n = 10) for Cr(III) was 0.50 g/L. In order to evaluate the accuracy of the method, certified reference materials (CRM-TMDW-500 Drinking Water and National Institute of Standards and Technology Standard Reference Material 1573a Tomato Leaves) were analyzed, and the results obtained were in good agreement with certified values. The presented procedure was applied for Cr speciation in various solid and liquid samples with successful results.
Development and Validation of a Reversed-Phase High-Performance Liquid Chromatographic Method for the Simultaneous Determination of Amiloride Hydrochloride, Atenolol, Hydrochlorothiazide, and Chlorthalidone in Their Combined Mixtures
Authors: Elshanawane Abdalla A , Mostafa Samia M , Elgawish Mohamed S
Published: February 2020

A high-performance liquid chromatographic method was developed for the simultaneous determination of 2 ternary mixtures containing amiloride hydrochloride, atenolol, hydrochlorothiazide, and chlorthalidone used in hypertension therapy. The use of cyanopropyl column results in satisfactory separation of both mixtures. The mobile phase consisted of 10 mM KH2PO4 buffer (pH 4.5) and methanol in a ratio of (75 25 v/v), at a flow rate of 1 mL/min. UV detector was operated at 275 nm. Calibration graphs were linear in the concentration ranges of 210, 20200, 10100, and 550 g/mL for amiloride hydrochloride, atenolol, hydrochlorothiazide, and chlorthalidone, respectively. Intraday and interday precision values (relative standard deviation) were <1.13 for mixture I (amiloride hydrochloride, atenolol, chlorthalidone), and <0.93 for mixture II (amiloride hydrochloride, atenolol, hydrochlorothiazide). The method was successfully applied for the determination of the 2 combinations in laboratory-prepared mixtures and commercial pharmaceutical formulation with high accuracy and precision. Statistical comparison of the results with those of the published methods showed excellent agreement and indicates no significant difference between them.
Determination of Bromine in Regulated Foods with a Field-Portable X-Ray Fluorescence Analyzer
Authors: Anderson David L
Published: February 2020

A field-portable X-ray fluorescence analyzer, factory-calibrated for soil analysis, was used to measure bromine (Br) mass fractions in reference materials, flour, bakery products, malted barley, selected U.S. Food and Drug Administration Total Diet Study foods, and other food products. By using a calibration based on instrumental neutron activation analysis results for Br in reference materials, accurate quantitative results, confirmed by z-scores, could be obtained for mass fractions of about 255 mg/kg. These results confirmed accuracy of results (with larger uncertainties) obtained by applying a simple correction factor to the analyzer's output value. Results showed that very short analysis times (<2 min) would be needed to screen foods for Br content at regulatory levels for brominated and enriched brominated flour (24 mg/kg Br) and whole wheat flour and bakery products (36 mg/kg Br). Feasibility for determination of Br in malted barley at the regulatory level (75 mg/kg Br) was demonstrated, but quantitative results at that level could not be assured because no reference material with a suitable mass fraction was available. Br mass fractions for all foods tested were well below regulatory levels.
Adsorptive Cathodic Stripping Voltammetric Determination of Dexamethasone in Formulations and Biological Fluids
Authors: Ghoneim Enass M , El-Attar Mona A , Ghoneim Mohamed M
Published: February 2020

The electrochemical behavior of dexamethasone at a hanging mercury drop electrode (HMDE) in a universal buffer series of pH 210 was studied using cyclic voltammetry. Based on the interfacial adsorptive character of dexamethasone onto the HMDE (electrode surface coverage 1.4 1010mol/cm2), a fully validated simple square-wave adsorptive cathodic stripping voltammetric method is described for its determination in bulk form with a limit of detection (LOD) of 3.1 109 M. The described method was successfully applied to analysis of dexamethasone in its pharmaceutical formulations (deltasone tablets and fortecortin ampule) and in spiked samples of human urine, bovine urine, and protein-free bovine milk. The achieved LODs of dexamethasone in human urine, bovine urine, and protein-free bovine milk were 1.5 108, 2 108, and 9 109 M, respectively. The mean percentage recoveries of 4 107 M dexamethasone in bulk form, spiked human urine, bovine urine, and bovine milk, based on the average of 3 replicate measurements, were 99.8 0.25, 100.4 0.96, 99.6 0.79, and 100.1 0.26, respectively.
Validated Method for Determination of Eight Banned Nitroimidazole Residues in Natural Casings by LC/MS/MS with Solid-Phase Extraction
Authors: Sun Hanwen , Wang Fengchi , Ai Lianfeng , Guo Chunhai , Chen Ruichun
Published: February 2020

A sensitive method based on solid-phase extraction-liquid chromatography-tandem mass spectrometry interfaced with electrospray ionization (SPE-LC-MS/MS-ESI) was developed for the simultaneous determination of 8 banned nitroimidazole (NOZ) drugs including metronidazole (MNZ), ronidazole (RNZ), dimetridazole (DMZ), tinidazole, ornidazole, secnidazole, metronidazole-OH (MNZOH, the metabolite of MNZ), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI, the metabolite of RNZ and DMZ) in natural casings. After extraction with ethyl acetate and evaporation, the NOZs were reconstituted in ethyl acetate and purified on a strong cation-exchange SPE column, and then LC/MS/MS analysis was performed by positive ESI applying multiple reaction monitoring of 2 transition reactions for each compound. The method was validated according to the European Union requirements (Commission Decision 2002/657/EC). Specificity, linearity, decision limit (CC), detection capability (CC), accuracy, and precision were determined. Average recoveries of the 8 NOZs from natural animal casing fortified at 3 levels (0.1, 0.5, and 1 g/kg) ranged from 87.3 to 116.5. The calculated CC for NOZs ranged from 0.029 to 0.049 g/kg, and CC ranged from 0.049 to 0.083 g/kg. Repeatability was in the range of 3.3510.1, and within-laboratory reproducibility was <10.3.
Optimized HPLC Method for Analysis of Polar and Nonpolar Heterocyclic Amines in Cooked Meat Products
Authors: Gibis Monika
Published: February 2020

A simple, precise, and specific column high-performance liquid chromatographic (HPLC) method with UV absorption diode array and fluorescence detection has been developed by optimizing a previously described method for the simultaneous quantification of 15 polar and nonpolar heterocyclic amines (HAs) in fried meat products. The HPLC determination could be improved due to the application of a silica-based reversed-phase column with octadecyl groups (TSK-gel Super ODS) and a particle size of 2 m. The separation of HAs in the complex meat matrix was performed with a 21 min mobile phase gradient. The method was validated for instrumental precision, repeatability, and selectivity and compared with a previously published method. After liquid adsorption of the basic sample mixture on diatomaceous earth, HAs were extracted with ethyl acetate. For cleanup, solid-phase extraction (silica propylsulfonic acid and octadecyl cartridges) and different washing steps were applied. Both nonpolar and polar HAs were determined in one fraction. The calibration curves of all HAs were linear for the applied detection system (correlation coefficient = 0.9900.995). The recoveries, with the exception of 3-amino-1-methyl-5H-pyrido [4,3-b]indole (Trp-P-2), were between 42 and 98 from meat samples spiked in a range of 1.5 to 3.3 ng/g for fluorescence-active and 4.3 to 8 ng/g for UV-active HAs. For quantification of HAs, the standard addition method was used for adjustment of different characteristics of HAs in the extraction. In fried meat samples (chicken breast and beef patties), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f] quinoxaline(4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), norharmane, and harmane were found in a concentration range of 0.02 to 14.3 ng/g.
A Novel Method for the Quantification of Quinic Acid in Food Using Stable Isotope Dilution Analysis
Authors: Erk Thomas , Bergmann Hannah , Richling Elke
Published: February 2020

Organic acids play an important role in the flavor and taste of plant-derived foods. Quinic acid (QA) is one of the major acids. In the past, several methods like HPLC/UV, GC, and capillary electrophoresis were used for identification and quantification of QA. For the first time, a novel, sensitive, and selective method for the quantification of QA in food using stable isotope dilution analysis with HPLC/MS/MS has been established. Uniformly labeled 13C-QA was used as a standard to reduce sample preparations and to overcome matrix and ionization effects. The method was used to determine the QA content of red wines, instant coffees, and cloudy apple juices. QA contents of instant coffees were 64.4 and 63.6 g/kg powder. The concentrations in red wines were 24.0 and 25.1 mg/L, and 1493.3 and 1705.2 mg/L in cloudy apple juices.
Determination of Seven Flavonoids in Ixeridium gracile (DC.) Shih by High-Performance Liquid Chromatography
Authors: Chen Juan , Ma Xue-Mei , Shi Yan-Ping
Published: February 2020

A high-performance liquid chromatographic technique coupled with photodiode array detection was proposed for the simultaneous determination of 7 flavonoids, i.e., quercetin, kaempferol, 7-hydroxyflavanone, 7-methoxyflavanone, 2,4-dihydroxychalcone, 2,4-dihydroxydihydrochalcone, and 7,2-dihydroxy-3, 4-dimethoxyisoflavane, in extracts of the plant Ixeridium gracile. Optimum separation was obtained by using a reversed-phase C18 method. Because of the different UV characteristics of these components, 5 detection wavelengths were used for the quantitative analysis. All of the flavonoids showed good linearity (r > 0.9999). The limit of detection and limit of quantitation values for the analytes ranged from 0.06 to 0.46 g/mL and from 0.18 to 1.48 g/mL, respectively. The method was validated by evaluating repeatability, precision, stability, and accuracy. Five different extraction and purification procedures were investigated for preparation of the sample solution. The optimized method was applied to the determination of flavonoids in I. gracile and was found to be efficient.
Automated Chemiluminometric Screening of Counterfeit Drugs of the Antituberculosis Agent Pyrazinamide
Authors: Prior João A V , Santos João L M , Lima José L F C
Published: February 2020

Finding counterfeit drugs presents a growing challenge in preventing these products from entering health systems and causing serious consequences for consumers, drug manufacturers, and governments. In this investigation a simple, low-cost, and expeditious chemiluminometric approach, relying on a fully automated multipumping flow system for screening pharmaceutical preparations of the antituberculosis drug pyrazinamide, was implemented. The developed chemiluminescent method was based on the scavenging effect of pyrazinamide on the oxidation of luminol by hydrogen peroxide in alkaline medium. For analytical signal monitoring, a homemade chemiluminescence detector relying on a photomultiplier module was developed. Linear calibration plots for pyrazinamide concentrations between 10 and 70 mg/L were obtained (R = 0.9931) with good precision (RSD < 0.99; n = 21). The limit of detection was 5.79 mg/L, and the sampling rate was about 150 determinations per hour.
A Cloud Point Extraction Procedure for Preconcentration/Flame Atomic Absorption Spectrometric Determination of Silver, Zinc, and Lead at Subtrace Levels in Environmental Samples
Authors: Ghaedi Mehrorang , Shokrollahi Ardeshir , Niknam Khodabakhsh , Niknam Ebrahim , Derki Somayyeh , Soylak Mustafa
Published: February 2020

A cloud point extraction (CPE) procedure was presented for the preconcentration of silver, zinc, and lead ions in various samples. The complexes of these metal ions with 2-(((1H-benzo[d]imidazol-2-yl)methoxy)methyl)-1H-benzo[d]imidazole (BIMMBI) are quantitatively extracted into the Triton X-114-rich phase after centrifugation. A solution of 1.0 M HNO3 in methanol was added to the surfactant-rich phase as the effective eluant before analysis by flame atomic absorption spectrometry. The influence of effective parameters such as the concentrations of BIMMBI, Triton X-114, and HNO3, pH, bath temperature, centrifuge rate, and time on method sensitivity and efficiency was optimized. Detection limits of 2.8, 1.7, and 1.1 ng/mL for Pb2+, Ag+, and Zn2+, respectively, along with a preconcentration factor of 30 and enrichment factors of 33, 48, and 53 for Pb2+, Ag+, and Zn2+, respectively, were obtained. The present CPE method is suitable for accurate and precise determination of trace amounts of analyte ions in complex matrixes. The proposed CPE procedure was applied to the determination of these ions in biological, natural water, wastewater, soil, and blood samples.
Nontargeted Multicomponent Analytical Screening of Plastic Food Contact Materials Using Fast Interpretation of Deliverables via Expert Structure-Activity Relationship Software
Authors: Rothenbacher Thorsten , Schwack Wolfgang
Published: February 2020

Plastic packaging materials may release compounds into packed foodstuffs. To identify potential migrants of toxicological concern, resins, and multilayer foils (mainly polyethylene) intended for the production of food contact materials were extracted and analyzed by GC/mass spectrometry. To identify even compounds of low concentrations, AMDIS software was used and data evaluation was safeguarded by the Kovats retention index (RI) system. In this way, 46 compounds were identified as possible migrants. The expert structure-activity relationship software DEREK for Windows was utilized to evaluate all identified substances in terms of carcinogenicity, genotoxicity, thyroid toxicity, and miscellaneous endpoints for humans. Additionally, a literature search for these compounds was performed with Sci-Finder, but relevant data were missing for 28 substances. Seven compounds with adverse toxicological effects were identified. In addition, the RIs of 24 commercial additive standards, measured with a GC capillary column of intermediate polarity, are given.
Validation Study of a Receptor-Based Lateral Flow Assay for Detection of Beta-Lactam Antibiotics in Milk
Authors: Abouzied Mohamed , Sarzynski Michael , Walsh Aaron , Wood Heather , Mozola Mark
Published: February 2020

Avalidation study designed tomeet the requirements of the AOAC Research Institute and the U.S. Food and Drug Administration (FDA), Center for Veterinary Medicine, was conducted for a receptor-based, immunochromatographic method (BetaStar US) for detection of beta-lactam antibiotic residues in raw, commingled bovine milk. The assay was found to detect amoxicillin, ampicillin, cephapirin, cloxacillin, and penicillin G at levels below the FDA tolerance/safe levels but above the maximum sensitivity thresholds established by the National Conference on Interstate Milk Shipments. Results of the Part I (internal) and Part II (independent laboratory) dose-response studies using spiked samples were in very close agreement for all five drugs tested, with differences between the Part I and Part II 90/95 sensitivity values ranging from 0 to 1 ppb. The test was able to detect all five drugs at the approximate 90/95 sensitivity levels when present as incurred residues in milk collected from cows that had been treated with the specific drug. Asixth drug, ceftiofur, was found to be undetectable at levels of 500 ppb (as total ceftiofur metabolites from incurred residues in milk samples). The selectivity of the assay was 100, because no false-positive results were obtained in tests of >1000 control milk samples. The assay was found to be applicable to the testing of frozen raw milk samples. Results of ruggedness experiments established the operating parameter tolerances for the BetaStar US assay. Results of cross-reactivity testing established that the assay detects certain other beta-lactam drugs (dicloxacillin and ticarcillin), but it does not cross-react with any of 30 drugs belonging to other classes. Abnormally high bacterial or somatic cell counts in rawmilk produced no interference with the ability of the test to detect beta-lactams at tolerance/safe levels.
Simultaneous Determination of Five Benzimidazoles in Feeds Using High-Performance Capillary Electrophoresis
Authors: Shen Jianzhong , Tong Jing , Jiang Haiyang , Rao Qinxiong , Li Na , Guo Liming , Ding Shuangyang
Published: February 2020

A high-performance capillary electrophoretic method for determination of five benzimidazoles (thiabendazole, albendazole, fenbendazole, mebendazole, oxfendazole) in animal feeds was developed. Separation was carried out in an 80.5 cm 75 m id fused-silica uncoated capillary and injected by hydrodynamic injection (35 mbar 8 s) at a wavelength detection of 295 nm. The drugs were completely resolved in 50 mmol/L citric acid buffer (pH 1.9) with 30 kV at a temperature of 25C. Linear range was 180 g/mL; limits of detection for the analytes were less than 2 mg/kg; the overall recoveries for benzimidazoles were >73, with coefficients of variation below 10.
High-Performance Liquid Chromatographic Fingerprint for Quality Control of Terminalia arjuna Containing Ayurvedic churna Formulation
Authors: Chitlange Sohan S , Kulkarni Prajakta S , Patil Dada , Patwardhan Bhushan , Nanda Rabindra K
Published: February 2020

Because Ayurvedic herbal preparations contain a myriad of compounds in complex matrixes, it is difficult to establish quality control standards for raw materials and to standardize finished Ayurvedic drugs. A novel, accurate, and valid fingerprint method was developed using HPLC for quality control of a traditional Ayurvedic Arjuna churna formulation, which is used as a cardiotonic drug. Comprehensive comparison of chromatograms of standardized formulation of Arjuna churna and marketed formulations revealed eight characteristic peaks in chromatograms, which unambiguously confirmed the presence of authentic raw material used in the formulation on the basis of their retention time values and UV data. An HPLC fingerprint was also developed for total sapogenins present in Terminalia arjuna. The six common peaks observed in chromatograms of isolated sapogenins, standardized formulations, and marketed formulations can serve as a quality control tool for qualitative estimation of total saponin glycosides present in an Arjuna churna formulation.
Construction of New Iodide Ion-Selective Electrodes Based on New Ionophores: Comparison of the Effect of Structures and Additives on Electrode Response
Authors: Shokrollahi Ardeshir , Ghaedi Mehrorang , Kianfar Ali Hossain , Montazerozohori Morteza , Najibzadeh Marziyeh
Published: February 2020

New iodide ion-selective electrodes based on bis(2-methyl-3-phenyl-propenylidene)1,2-propanediamine) mercury(II) bromide [Hg(BMPPMB)Br2], bis (5-bromo salicylaldehyde) ethylenediimine vanadyl(IV) [VO(5-Br Salen)], and bis(5-bromo salicylaldehyde) ethylenediimine uranyl(VI) [UO2(5-Br Salen)] carriers are described. The electrodes exhibited Nernstian slopes of 58.3 1.0, 58.5 1.4, and 59.0 1.2 mV/decade for Hg(BMPPMB)Br2, VO(5-Br Salen), and UO2(5-Br Salen) iodide ion concentration in the range of 1.0 1060.1 M, with detection limits of about 0.6, 0.5, and 0.3 M, respectively. The potentiometric responses of the electrodes were independent of pH over the range 1.710.6, 2.211.3, and 2.111.1, with satisfactory reproducibility. The electrodes had response times of 5 s and could be used for at least 84, 80, and 100 days for Hg(BMPPMB)Br2, VO(5-Br Salen), and UO2(5-Br Salen), respectively, without any considerable divergence in their potential responses.
Rapid Method for the Determination and Confirmation of Fluoroquinolone Residues in Catfish Using Liquid Chromatography/Fluorescence Detection and Liquid Chromatography-Tandem Mass Spectrometry
Authors: McMullen Sarah E , Schenck Frank J , Vega Victor A
Published: February 2020

A simplified method for the extraction and determination of four fluoroquinolone (FQ) residues (ciprofloxacin, enrofloxacin, sarafloxacin, and difloxacin) in catfish is presented. In this method, the FQ residues were extracted with acidified acetonitrile, and the extract was defatted with dispersive C18 solid-phase extraction (SPE) sorbent or hexane. A portion of the extract was evaporated and reconstituted in the mobile phase. The quantitative determination was accomplished with LC-fluorescence detection (FLD), and the confirmation was by LC-MS/MS. Fortifications of catfish tissue were carried out at 0.5x, x, 2x, and 4x, where x = 5 ppb (U.S. Food and Drug Administration current regulatory target level). Recoveries for the LC/FLD determination of five replicates (for both cleanup routes) at each level ranged from 64 to 98, with RSD values <8. The method quantitation limits for all residues were <1 ng/g. The LC-MS/MS analysis of the same extracts confirmed all FQ residues at all levels. This method is an improvement over existing methodologies since additional cleanup steps, such as cation exchange SPE column cleanup, are not utilized. The C18 dispersive SPE method represents a novel cleanup approach for FQs in fish tissue.
Streamlined Methods for the Resolution and Quantification of Fatty Acids Including Trans Fatty Acid Isomers in Food Products by Gas Chromatography
Authors: Golay Pierre-Alain , Giuffrida Francesca , Dionisi Fabiola , Destaillats Frédéric
Published: February 2020

To support labeling, claims, and authenticity of food products, industry needs reliable methods for the analysis of fatty acids, including Trans fatty acids (TFA). In finished products, precise quantification of TFA can be problematic due to the occurrence of various positional and geometrical isomers originating from different sources, such as animal fats or processed vegetable oils and fats. The risk of underestimating TFA amounts is particularly high when inappropriate GC conditions are used. Complex sample preparation procedures involving purification of TFA isomers by silver ion chromatography have been well-documented and used for research purposes. However, in the food industry, time and cost constraints do not permit multiple analytical steps; therefore, streamlined methods are necessary. Direct methods include preparation of fatty acid methyl esters directly from food samples without prior extraction. The appropriate resolution is obtained using high-resolution GC with a highly polar 100 m capillary column, and quantification is achieved using experimentally determined response. We found that it is possible to quantify TFA in the range of 0.01 to 5.00 g/100 g of lipids in a wide range of food products. In addition, the use of direct transmethylation, response factors, and high-resolution GC allow accurate quantification of other fatty acids, including polyunsaturated and long-chain polyunsaturated fatty acids.
Qualitative Polymerase Chain Reaction Methods for Detecting Major Food Allergens (Peanut, Soybean, and Wheat) by Using Internal Transcribed Spacer Region
Authors: Hirao Takashi , Watanabe Satoshi , Temmei Yusuke , Hiramoto Masayuki , Kato Hisanori
Published: February 2020

Allergen detection methods for peanut, soybean, and wheat were developed by designing PCR primer pairs for specific amplification of a fragment of the internal transcribed spacer (ITS) region reported for Arachis spp. for peanut, Glycine spp. for soybean, and Triticum and Aegilops spp. for wheat. The target species for detection included not only cultivated, but also wild and ancestor species, which were thought to be potentially allergenic. The ability of the resultant primer pairs to detect the target species was verified using genomic DNA extracted from A. hypogaea for peanut and G. max for soybean; T. aestivum, T. turgidum, T. durum, T. aestivum-rye amphidiploid, T. monococcum, T. timopheevi, Ae. speltoides, and Ae. squarrosa for wheat. The LODs were 50500 fg of target DNA, which were comparable to those of the most sensitive PCR methods previously reported. The results from the present work, as well as those from our previous work on buckwheat and kiwifruit, prove that the ITS region, for its high copy number and interspecific diversity, is particularly useful as the target of allergen detection methods.
Application of Headspace Sorptive Extraction and Gas Chromatographic/Mass Spectrometric and Chemometric Methods to the Quantification of Pine Nuts and Pecorino in Pesto Genovese
Authors: Zunin Paola , Leardi Riccardo , Boggia Raffaella
Published: February 2020

Headspace sorptive extraction and GC/MS, coupled with chemometric tools, were used to predict the amounts of pine nuts and Pecorino in Pesto Genovese, a typical Italian basil-based pasta sauce. Two groups of samples were prepared at different times and with ingredients from different batches for building the predicting models and testing their performances. Principal component analysis and partial least-squares regression (PLS) were applied to the chromatographic data. The 24 most-predictive variables were selected, and the application of PLS to the training set samples led to two models that explained approximately 70 of the variance in cross-validation, with prediction errors of 0.1 g for Pecorino and 0.6 g for pine nuts, thus confirming the reliability of the analytical method and the predicting ability of the models. The results obtained for the test set samples were not completely satisfactory, with a prediction error and a bias of 5.0 and 4.1 g, respectively, for Pecorino and corresponding values of 4.1 and 2.0 g for pine nuts. This preliminary study shows that the analytical methods used can allow construction of models with high predictive ability only if the great variability of the headspace composition of the ingredients and the effect of Twister are considered.
Considerations in the Development of Biomarkers of Copper Status
Authors: Bertinato Jesse , Zouzoulas Athina
Published: February 2020

Copper (Cu) is an essential nutrient, but a harmful metal in excess. As part of the North American Dietary Reference Intakes, the Recommended Dietary Allowance for Cu was set using a combination of biomarkers of Cu deficiency, including plasma Cu and ceruloplasmin concentrations, erythrocyte Cu/Zn superoxide dismutase activity, and platelet Cu concentration. Liver damage was the sole indicator used in setting the Tolerable Upper Intake Level. Some studies suggest that these conventional biomarkers may not be sensitive enough to detect marginal reductions or excesses of Cu that could pose a health risk. The insensitivity of conventional biomarkers casts uncertainty as to the prevalence of Cu deficiency or overload in the population and in the accuracy of current nutritional reference values for Cu. Numerous biochemical changes have been associated with alterations in Cu status, and many potential biomarkers of Cu nutriture have been proposed; yet, conventional biomarkers are still the most frequently used, underscoring the need for research efforts to substantiate the use of novel biomarkers. In this report, biomarkers of Cu status are reviewed and practical considerations in the development of novel biomarkers are discussed as diagnostic tools for assessing Cu status in humans.
A Stability-Indicating High-Performance Liquid Chromatographic Method for the Determination of Methocarbamol in Veterinary Preparations
Authors: Rosasco María A , Ceresole Rita , Forastieri Clara C , Segall Adriana I
Published: February 2020

An isocratic HPLC method was developed and validated for the quantitation of methocarbamol in the presence of its degradation products. Quantitation was achieved using a reversed-phase C18 column at ambient temperature with mobile phase consisting of methanolwatertetrahydrofuran (25 + 65 + 10, v/v). The flow rate was 0.9 mL/min. The detection was by UV light at 274 nm. The proposed method was validated for selectivity, precision, linearity, and accuracy. The assay method was found to be linear from 159.0 to 793.2 g/mL (3.2 to 15.9 g injected). All validation parameters were within the acceptable range. The developed method was successfully applied to estimate the amount of methocarbamol in a veterinary injection.
Single-Laboratory Validation of an NMR Method for the Determination of Aloe Vera Polysaccharide in Pharmaceutical Formulations
Authors: Davis Bryce , Goux Warren J
Published: February 2020

This report presents a single-laboratory-validated NMR method for determining the quantity of aloe vera polysaccharide in product formulations. The ratio of signal intensities of the acetyl methyl protons to methyl protons of an internal reference varied linearly with concentration (r2 > 0.99) with a lower LOQ of 0.2 g/100 mL for two commercial aloe polysaccharide standards, Acemannan Hydrogel (AH) and Immuno10 (I10). The assay was used to quantify these standards in two nonacetylated polysaccharide matrices, dextrin and arabinogalactan, and in a pharmaceutical product. The concentrations of AH in samples containing the polysaccharide matrices agreed within 7 of values determined on the basis of weight and showed within- and between-run RSD values of <3.5. The assay of I10 in the pharmaceutical product was within 7 of the expected values over a range from 50 to 125 of the targeted I10 concentration, with a between- run RSD of <7. The assay showed no interference from other added polysaccharides or from other components of the pharmaceutical formulation and was independent of the molecular size distribution of the aloe polysaccharide present. The NMR assay can be used to validate aloe polysaccharide contained in a product and to follow any chemical degradation that may occur over time.
Membrane Electrodes for the Determination of Pyridostigmine Bromide
Authors: El-Kosasy Amira M , Salem Maissa Y , El-Bardicy Mohamed G , Abd El-Rahman Mohamed K
Published: February 2020

Two pyridostigmine bromide (PB) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH), based on the interaction between the drug solution and the dissociated COOH groups in the PVC-COOH. One of the sensors was fabricated by using PVC-COOH only as anionic site without incorporation of an ionophore (sensor 1). The second sensor was constructed by using 2-hydroxy propyl -cyclodextrin as an ionophore (sensor 2). Linear responses of PB within a concentration range of 103102 and 105102 M, with slopes of 51.9 0.31 and 56.7 0.40 mV/decade over pH range of 510 were obtained using sensors 2 and 1, respectively. The proposed method displayed useful analytical characteristics for determination of PB in tablets with average recoveries of 100.22 0.62, and 100.15 0.72, and in plasma with average recoveries of 99.14 1.19 and 99.79 0.72, for sensors 2 and 1, respectively. The utility of 2-hydroxy propyl -cyclodextrin as an ionophore has a significant influence on increasing both membrane sensitivity and selectivity of sensor 2 in comparison with sensor 1. The methods were also used to determine the intact drug in the presence of its degradate, and thus could be used as stability-indicating methods. The results obtained by the proposed procedures were statistically analyzed and compared with those obtained by the U.S. Pharmacopeia method. No significant difference for either accuracy or precision was observed.
Development of an Ultraviolet Spectrophotometric Method for the Determination of Ceftiofur Sodium Powder
Authors: E Souza marinês J , Canedo Natália , Souza Filho Paulo S , Bergold Ana M
Published: February 2020

A UV spectrophotometric method was developed for determination of ceftiofur sodium in the drug substance and sterile powder for injection. The method validation, which yielded good results, included evaluation of the range, linearity, intraand interday precision, accuracy, recovery, specificity, robustness, LOQ, and LOD. The UV spectrophotometric determinations were performed at 292 nm. Good linearity was obtained between 2.5 and 20.0 g/mL. A prospective validation showed that the method is linear (r = 0.9999) and precise, with RSD values of 0.3 for product A and 0.4 for product B. The intraand interday precision values were <2 for all samples analyzed. Comparison of UV spectrophotometry and LC by analysis of variance and Student's t-test showed no significant difference between methodologies. Moreover, the accuracy and precision obtained with the UV method correlated well with the values obtained with the LC method, and this correlation suggests that UV spectrophotometric analysis can be an inexpensive, reliable, and less time-consuming alternative to chromatographic analysis. The results demonstrated the validity of the proposed method as a simple and useful alternative for the determination of ceftiofur in routine QC analyses.
Microdetermination of Emtricitabine in Human Plasma by Liquid Chromatography/Tandem Mass Spectrometry
Authors: Yadav Manish , Singhal Puran , Goswami Sailendra , Sharma Primal , Shrivastav Pranav S
Published: February 2020

A simple, precise, and rapid LC/MS/MS method was developed and validated for the quantification of emtricitabine in human plasma using lamivudine as the internal standard (IS). The method involves liquidliquid extraction of emtricitabine and the IS in diethyl etherethyl acetate (50 + 50, v/v) from 0.1 mL human plasma. A Kromasil C18 (150 4.6 mm, 5 m particle size) analytical column was used for the chromatographic separation under isocratic conditions. The parent product ion transitions for emtricitabine (m/z 248.0130.0) and the IS (m/z 230.1 112.0) were monitored on a triple-quadrupole mass spectrometer, operated in the multiple reaction monitoring positive ion mode. The method was validated over the concentration range of 29.23110 ng/mL for emtricitabine, with a total chromatographic run time of 1.5 min. Acceptable precision and accuracy were obtained for the concentrations used to prepare the standard curves. The applicability of the method was demonstrated by a pharmacokinetic study conducted with 43 healthy volunteers who were administered a capsule formulation containing 200 mg emtricitabine.
Determination of Total Iodine in Food Samples Using Inductively Coupled PlasmaMass Spectrometry
Authors: Benkhedda Karima , Robichaud André , Turcotte Stéphane , Béraldin Franca J , Cockell Kevin A
Published: February 2020

A method was developed and validated for the extraction and determination of total iodine (I) in food composite samples, representing different foods available on the Canadian market, by inductively coupled plasmamass spectrometry (ICP-MS). Prior to analysis, samples were digested in a closed microwave system using a mixture of nitric acid and perchloric acid. The detection limit for iodine determination was 29 ng/g and precisions of 10 and 1.3 were obtained for 10 replicate measurements of 100 and 1000 ng/g standards, respectively. The method was validated using Certified Reference Materials and spike recovery measurements in food samples and was applied for the determination of iodine in a variety of food composite samples from the Canadian Total Diet Study. The high sample throughput of ICP-MS makes the method suitable for analysis of large numbers of food samples with varying matrixes, such as for Total Diet Studies.