bluuebunny/crossref_metadata_2025 huggingface dataset:
Extraction of Aflatoxins B1 and G1 from Maize by Using Aqueous Sodium Dodecyl Sulfate
Authors: Maragos Chris M
Published: February 2020

Aflatoxins are potent carcinogens produced by certain Aspergillus fungi. The aflatoxins were first discovered in the 1960s, and since then have been found to be distributed worldwide in a variety of commodities, foods, and feeds. Many of the early techniques for detecting aflatoxins involved extraction with halogenated solvents. With the increased availability and use of reversed-phase solid-phase extraction cartridges and the availability of immunoaffinity columns, aqueous mixtures of nonhalogenated solvents have been frequently used. To further reduce the need for solvents, we examined the effects of eliminating solvents during the extraction of maize, using aqueous mixtures of the detergent sodium dodecyl sulfate. After extraction and filtration, aflatoxins B1 (AFB1)and G1 (AFG1) were isolated by using commercially available immunoaffinity columns. The isolated AFB1 and AFG1 were derivatized with trifluoroacetic acid before separation by liquid chromatography with fluorescence detection. In spiked maize, the limits of detection were 0.5 and 1 ng/g for AFB1 and AFG1, respectively. Recoveries of AFB1 from maize spiked at 120 ng/g averaged 87.5 (range, 76.399.0), with an average repeatability relative standard deviation (RSDr) of 4.0. Recoveries of AFG1 from maize spiked at 220 ng/g averaged 80.4 (range, 70.385.8), with an average RSDr of 3.5. This is the first reported demonstration of an effective solvent-free extraction of aflatoxins from maize at ambient pressure, and this extraction procedure may serve to help reduce solvent consumption during aflatoxin analysis.
Determination of Sulfur Amino Acids in Foods as Related to Bioavailability
Authors: Rutherfurd Shane M , Moughan Paul J
Published: February 2020

During the processing of feedstuffs and foods, methionine can be oxidized to methionine sulfoxide and methionine sulfone, and cysteine can be oxidized to cysteic acid. Methionine sulfone and cysteic acid are nutritionally unavailable, but methionine sulfoxide can be utilized, at least to some degree. The degree of utilization depends on the levels of methionine, cysteine, and methionine sulfoxide in the diet, but there is no consensus in the literature on the quantitative impact of these dietary constituents on methionine sulfoxide utilization. Methionine and cysteine are most often determined after quantitative oxidation to methionine sulfone and cysteic acid, respectively, using performic acid oxidation prior to hydrolysis. However, this method may overestimate the methionine content of processed foods, as it will include any methionine sulfoxide and methionine sulfone present. A selection of analytical methods has been developed to allow the separate determination of the 3 oxidized forms of methionine, the merits of which are discussed in this review. An additional consideration for determining methionine and cysteine bioavailability is that not all dietary methionine and cysteine is digested and absorbed from the small intestine. Selected methods designed to determine the extent of digestion and absorption are discussed. Finally, a concept for a new assay for determining methionine bioavailability, which includes determining the digestibility of methionine and methionine sulfoxide as well as the utilization of methionine sulfoxide, is presented.
High-Performance Thin-Layer Chromatography Densitometric Method for the Quantification of Harmine, Harmaline, Vasicine, and Vasicinone in Peganum harmala
Authors: Pulpati Harsha , Biradar Yogesh S , Rajani Mandapati
Published: February 2020

Peganum harmala Linn. seed is a reputed drug of the Indian systems of medicine. We report a simple high-performance thin-layer chromatography (HPTLC) densitometric method for the quantification of 4 alkaloids, viz., harmine, harmaline, vasicine, and vasicinone from P. harmala seed. The 4 compounds were resolved in ethyl acetatemethanolammonia (7 1 0.3, v/v/v) mobile phase. The method was validated for precision, repeatability, and accuracy. Instrumental precision was 0.27, 1.53, 0.39, and 1.15% [relative standard deviation (RSD)] and repeatability of the method was 1.01, 0.79, 0.13, and 1.62% RSD for harmine, harmaline, vasicine, and vasicinone, respectively. Accuracy of the method was checked by a recovery study conducted at 3 different levels, and the average recovery was 97.88% for harmine, 97.69% for harmaline, 98.38% for vasicine, and 98.28% for vasicinone. The 4 compounds were quantified in P. harmala seed using the method, and it was found to contain 0.44, 0.096, 0.25, and 0.0007% (w/w) of each, respectively. The proposed HPTLC densitometric method for the quantification of the 4 compounds was found to be simple, precise, specific, sensitive, and accurate. It can be used for routine quality control of P. harmala seed and has the ability to quantify the 4 marker compounds in the formulations containing P. harmala. It also can be used to quantify any of these marker compounds in other herbal drugs.
Polymeric Matrix Membrane Sensors for Stability-Indicating Potentiometric Determination of Oxybutynin Hydrochloride and Flavoxate Hydrochloride Urogenital System Drugs
Authors: Heba Mohamed , Ramadan Nesrin , El-Laithy Moustafa
Published: February 2020

Four polyvinyl chloride (PVC) matrix membrane electrodes responsive to 2 drugs affecting the urogenital systemoxybutynin hydrochloride (OX) and flavoxate hydrochloride (FX)were developed, described, and characterized. A precipitation-based technique with tungstophosphate (TP) and ammonium reineckate (R) anions as electroactive materials in a PVC matrix with an OX cation was used for electrode 1 and 2 fabrication, respectively. Electrode 3 and 4 fabrication was based on use of the precipitation technique of FX cation with tetrakis (4-chlorophenyl) borate and R anions as electroactive materials. Fast and stable Nernstian responses in the range 1 1021 106 M for the 2 drugs over the pH range 58 revealed the performance characteristics of these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The method was applied to FX and OX in their pharmaceutical formulations and in human plasma samples. The 4 proposed sensors were found to be specific for the drugs in the presence of up to 60 of their degradation products. Validation of the method according to the quality assurance standards showed suitability of the proposed electrodes for use in the quality control assessment of these drugs. The recoveries for determination of the drugs by the 4 proposed selective electrodes were 99.5 0.5, 100.0 0.4, 99.9 0.4, and 100.1 0.4 for sensors 14, respectively. Statistical comparison between the results obtained by this method and the official method of the drugs was done, and no significant difference found.
Colorimetric Determination of Sildenafil Citrate (Viagra) Through Ion-Associate Complex Formation
Authors: Amin Alaa S , Moustafa Moustafa E , El-Dosoky Reham M S
Published: February 2020

A simple, quick, accurate, and sensitive colorimetric method is described for the determination of sildenafil citrate (SLD). The method is based on the reaction of SLD with Congo Red, Sudan II, and Gentian Violet in buffered aqueous solutions at pH 2.5, 6.5, and 11.0, respectively, to give highly colored soluble ion-associate complex species; the colored products are quantitated colorimetrically at 523, 554, and 569 nm, respectively. The various experimental conditions were optimized. The stoichiometric ratio was found to be 1:1 for all ion associates; the calculated logarithmic stability constants were 8.51, 7.79, and 5.58, respectively. Beer's law was obeyed over the concentration range of 0.27.0 g/mL, whereas the Ringbom optimum concentration range was 0.46.5 g/mL. Values for molar absorptivity, Sandell sensitivity, and detection and quantification limits were also calculated. The proposed method was successfully applied to the determination of SLD in Viagra tablets and in serum samples by using the technique of standard additions with mean accuracy values of 100.06 1.14, 99.87 0.70, and 99.86 0.97 for Viagra tablets and 99.88 0.60, 99.90 0.90, and 100.24 0.80 for serum samples, respectively.
Utilization of Picolinaldehyde-4-phenyl-3-thiosemicarbazone in Sodium Dodecylsulfate Micelles for the Spectrophotometric Determination of Iron, Vanadium, and Cobalt Following Partial Least-Squares Regression Analysis
Authors: Balouch Aamna , Memon Najma , Bhanger Muhammad I , Khuhawar Muhammad Y
Published: February 2020

Partial least-squares regression was applied for the simultaneous determination of iron, vanadium, and cobalt after complexation with picolinaldehyde-4-phenyl-3-thiosemicarbazone (PAPT) in the presence of anionic sodium dodecylsulfate (SDS) micelles. These 3 complexed metal ions exhibited overlapping spectra in the 390510 nm region with a maximum absorbance at 415 nm at pH 3.0 and enhanced absorbance in the presence of SDS. The data for the simultaneous determination of these metal ions were analyzed using a simple partial least-squares (SIMPLS) algorithm. Formation constants (log Kf) were found to be 4.65, 3.29, and 4.85 for PAPT complexes of Fe, V, and Co, respectively, and the detection limits for Fe, V, and Co were 0.013, 0.002, and 0.010 g/mL, respectively. Common anions and cations did not interfere with the proposed method. The method was validated by calculating root mean square error of cross-validation, root mean square error of calibration, and root mean square error of prediction and was applied to determine these 3 metal ions in real crude oil samples.
Variability Among Four Laboratories of the Filter Bag Technique to Determine Acid and Neutral Detergent Fiber Contents in Ruminant Feeds from Argentina
Authors: Fay José P , Guaita María S , Danelón José L , Chifflet Sonia , Wawrzckiewicz Marisa , Díaz Carolina , Ross Deborah A , Fernndez Héctor M
Published: February 2020

The objective of this work was to evaluate the filter bag technique (FBT) in an ANKOM 200 fiber analyzer to assess its accuracy for the determination of acid and neutral detergent fiber (ADF and NDF, respectively) contents in common ruminant feeds from the temperate region of Argentina. The evaluation was done in a ring test of 4 laboratories. The 3 Argentine laboratories were from the College of Agronomy, University of Buenos Aires, the College of Agricultural Sciences of the Catholic University of Argentina, and the Balcarce Agricultural Experiment Station of the National Institute of Agricultural Technology (INTA). The fourth laboratory was from the Department of Animal Science of Cornell University, Ithaca, NY. The feeds utilized were soybean meal expeller, whole sunflower seed, corn grain, herbages of alfalfa, ryegrass, tall wheatgrass, weeping lovegrass, guinea and barley grasses, and silages of corn and of a natural grassland. Results indicated that values obtained in the 4 laboratories were consistent regardless of the laboratory where the analyses were performed. It was concluded that the FBT in the ANKOM instrument gave satisfactory results when used for the determination of both ADF and NDF across samples having a wide range of fiber contents, and that the among-laboratories variability of this methodology was low.
Validation of a Modification to Performance-Tested MethodSM 010403: Microwell DNA Hybridization Assay for Detection of Listeria spp. in Selected Foods and Selected Environmental Surfaces
Authors: Alles Susan , Peng Linda X , Mozola Mark A
Published: February 2020

A modification to Performance-Tested MethodSM 010403, GeneQuence Listeria Test (DNAH method), is described. The modified method uses a new media formulation, LESS enrichment broth, in single-step enrichment protocols for both foods and environmental sponge and swab samples. Food samples are enriched for 2730 h at 30C, and environmental samples for 2448 h at 30C. Implementation of these abbreviated enrichment procedures allows test results to be obtained on a next-day basis. In testing of 14 food types in internal comparative studies with inoculated samples, there were statistically significant differences in method performance between the DNAH method and reference culture procedures for only 2 foods (pasteurized crab meat and lettuce) at the 27 h enrichment time point and for only a single food (pasteurized crab meat) in one trial at the 30 h enrichment time point. Independent laboratory testing with 3 foods showed statistical equivalence between the methods for all foods, and results support the findings of the internal trials. Overall, considering both internal and independent laboratory trials, sensitivity of the DNAH method relative to the reference culture procedures was 90.5. Results of testing 5 environmental surfaces inoculated with various strains of Listeria spp. showed that the DNAH method was more productive than the reference U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) culture procedure for 3 surfaces (stainless steel, plastic, and cast iron), whereas results were statistically equivalent to the reference method for the other 2 surfaces (ceramic tile and sealed concrete). An independent laboratory trial with ceramic tile inoculated with L. monocytogenes confirmed the effectiveness of the DNAH method at the 24 h time point. Overall, sensitivity of the DNAH method at 24 h relative to that of the USDA-FSIS method was 152. The DNAH method exhibited extremely high specificity, with only 1 false-positive reactions overall.
Application of Graphitized Carbon Black to the QuEChERS Method for Pesticide Multiresidue Analysis in Spinach
Authors: Li Li , Li Wei , Qin Dongmei , Jiang Shuren , Liu Fengmao
Published: February 2020

A modified QuEChERS method was optimized to determine 66 pesticide residues in spinach using gas chromatography with mass spectrometric detection in selected-ion monitoring mode. Graphitized carbon black (GCB) at different levels (0, 5, 10, 15, 20, and 25 mg) was used to adsorb the pigments in spinach extracts. Best recoveries with less colored extract samples for all pesticides analyzed were obtained in the presence of 10 mg GCB. Under the optimized condition, analyses of spiked samples were performed at 3 different levels. Correlation coefficients, R2, in the linear range tests were better than 0.99. Average recoveries ranged from 66 to 104, with the relative standard deviation below 16. The limits of quantitation ranged from 50 to 250 g/kg.
Determination of Ultratrace Amounts of Ce3 in the Presence of Sm3, La3, Dy3, and Yb3 in Water and Soils by Inductively Coupled Plasma-Optical Emission Spectroscopy After Preconcentration with Thio-Functionalized MCM-41 at Controlled
pH
Authors: Saberyan Kamal
Published: February 2020

A method is presented for the selective preconcentration and determination of ultratrace amounts of Ce3 ions by inductively coupled plasma-optical emission spectroscopy in the presence of Sm3, La3, Dy3, Yb3, and common interfering ions. In this method, thio-functionalized MCM-41 is used in the preconcentration step. Extraction efficiency and the influence of sample matrix, pH of sample solution, type and minimum amount of tripping acid, and flow rates were investigated. The preconcentration is pH-dependent, and the best results were obtained in the pH range of 8.510.3. The maximum capacity of 2 mg absorbent was found to be 170 4 g. The detection limit of the measurements after the preconcentration step was found to be 114 ng Ce3/L.
Development and Validation of an LC Method for Simultaneous Determination of Amiloride Hydrochloride and Hydrochlorothiazide in Human Urine
Authors: Elshanawane Abdalla A , Mostafa Samia M , Elgawish Mohamed S
Published: February 2020

An HPLC method with photometric detection has been developed for determination of a binary mixture of amiloride hydrochloride and hydrochlorothiazide in human urine using chlorthalidone as the internal standard. Reversed-phase chromatography was performed at room temperature on a cyanopropyl column with the mobile phase consisting of a 10 mM KH2PO4 solution (pH 4.5)methanol (70 + 30, v/v) at a flow rate of 1 mL/min. The detector was set at 214 nm. The total analysis time was 10 min. The method was validated in terms of accuracy, precision, absolute recovery, freeze-thaw stability, bench-top stability, and re-injection reproducibility. The procedure shows good accuracy, repeatability, and selectivity. Moreover, the method was applied directly to urine that had not undergone prior treatment. The intra- and interday coefficients of variation for all compounds were below 4, and the method was highly accurate, with a relative error for all compounds that was below 8. No interference from endogenous compounds in urine samples was found. The proposed method, which is rapid, simple, and does not require any separation steps, has been successfully applied to the assay of human urine containing amiloride hydrochloride and hydrochlorothiazide.
Analysis Method Study on 839 Pesticide and Chemical Contaminant Multiresidues in Animal Muscles by Gel Permeation Chromatography Cleanup, GC/MS, and LC/MS/MS
Authors: Pang Guo-Fang , Cao Yan-Zhong , Fan Chun-Lin , Jia Guang-Qun , Zhang Jin-Jie , Li Xue-Min , Liu Yong-Ming , Shi Yu-Qiu , Li Zeng-Yin , Zheng Feng , Lian Yu-Jing
Published: February 2020

The paper reports the study of gel permeation chromatography (GPC), gas chromatography/mass spectrometry (GS/MS), and column chromatography tandem MS (LC/MS/MS) for 839 pesticides and chemical contaminants, through which a GPC data bank has been established for 744 pesticides, a GC/MS data bank for 541 pesticides, and an LC/MS/MS data bank for 464 pesticides. On the basis of this study, a new method for quantitative determination of 587 pesticide residues in animal muscles such as beef, mutton, pork, chicken, and rabbit has been established using GPC cleanup followed by GC/MS and LC/MS/MS. In the method, 10 g animal samples were mixed with 20 g sodium sulfate and extracted twice with 35 mL cyclohexaneethyl acetate (1 + 1) by blender homogenization followed by centrifugation, filtration, and concentration. An equivalent of 5 g sample was injected into a 400 25 mm S-X3 GPC column, with cyclohexaneethyl acetate (1 + 1) as the mobile phase at a flow rate of 5 mL/min. The 2240 min fraction was collected for subsequent analysis. For the 478 pesticides determined by GC/MS, the portions collected from GPC were concentrated to 0.5 mL and exchanged twice with 5 mL hexane. For the 379 pesticides determined by LC/MS/MS, the portions collected from GPC were dissolved with acetonitrilewater (60 + 40) after taking the extract to dryness with nitrogen gas. At the limit of quantification (LOQ) and 10 LOQ fortification levels of 0.116 000 g/kg, recoveries were within 40130, among which 563 pesticide recoveries were between 60 and 130, accounting for 96 of the compounds; 24 analytes were recovered between 40 and 60, accounting for 4 of the compounds. The relative standard deviation was below 30 for all 587 pesticides. The limits of detection for the method were 0.11600 g/kg. In comparison with GC/MS, LC/MS/MS increased the detection sensitivity 21000 times for 236 pesticides.
Simultaneous Enrichment-Separation of Metal Ions from Environmental Samples by Solid-Phase Extraction Using Double-Walled Carbon Nanotubes
Authors: Soylak Mustafa , Unsal Yunus Emre
Published: February 2020

A solid-phase extraction (SPE) method has been developed using a column filled with double-walled carbon nanotubes for the preconcentrationseparation of Co(II), Cu(II), Ni(II), Pb(II), Fe(III), and Mn(II) ions. Experimental parameters, including pH of the solution, sample volume, flow rate of the sample solution and eluents, etc., were investigated. Quantitative recoveries for the anayte ions were obtained at pH 9.0 with 2 M HNO3 eluent at a flow rate of 2 mL/min. The influences of matrix ions were also investigated. The preconcentration factor was 100. Addition and recovery experiments for analyte ions in real water samples gave good results. The validity of the presented SPE method was tested by analysis of HR-1 Humber River Sediment certified reference material for each element.
Simultaneous Determination of Residual Thiamphenicol and Florfenicol in Foods of Animal Origin by HPLC/Electrospray Ionization-MS/MS
Authors: Chou Kuang Yu , Cheng Tsung Yao , Chen Ching Mei , Hung Pei Ling , Tang Yu Yun , Chung-Wang Yueh Jong , Shih Yang-Chih
Published: February 2020

A simple and reliable method using HPLC/MS/MS has been developed for determination of thiamphenicol and florfenicol in foods of animal origin, such as pork, porcine liver, porcine kidney, beef, bovine liver, fish, and chicken. The HPLC separation was performed on a Waters XTerra phenyl column (100 2.1 mm, 3.5 m) with a gradient mobile phase system of 0.1 formic acidmethanol at a flow rate 0.35 mL/min. Negative ionization produced the molecular ions at m/z 354 and 356 for thiamphenicol and florfenicol, respectively. Two characteristic transition reactions (m/z 354185, 290 and m/z 356336, 185) in the selected reaction monitoring mode were tested for detection and confirmation of thiamphenicol and florfenicol simultaneously. The analytes were extracted with ethyl acetate and defatted with n-hexane by liquidliquid extraction. The recoveries of thiamphenicol and florfenicol by the developed method were 72.597.6. The limits of determination were 1.0 ng/g (ppb) for both compounds.
New Nonextractive and Highly Sensitive High-Performance Liquid Chromatographic Method for Determination of Paroxetine in Plasma After Offline Precolumn Derivatization with 7-Chloro-4-Nitrobenzo-2-Oxa-1,3-Diazole
Authors: Darwish Ibrahim A , Al-Majed Abdulrahman A , Mahmoud Ashraf M , Khalil Nasr Y
Published: February 2020

New nonextractive and simple offline precolumn derivatization procedures have been proposed, for the first time, for the trace determination of paroxetine (PXT) in human plasma by HPLC with fluorescence detection. Trimetazidine (TMZ) was used as an internal standard. Plasma samples were treated with acetonitrile for protein precipitation and then derivatized with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole in borate buffer of pH 8 at 70C for 30 min. Separations of the derivatized PXT and TMZ were performed on a Nucleosil CN column using a mobile phase consisting of acetonitrile10 mM sodium acetate buffer (pH 3.5)methanol (47 + 47 + 6, v/v) at a flow rate of 1.0 mL/min. The derivatized samples were excited at 470 nm and monitored at an emission wavelength of 530 nm. Under the optimum chromatographic conditions, a linear relationship with good correlation coefficient (r 0.9998, n 7) was found between the peak area ratio and PXT concentrations in the range of 5600 ng/mL. The LOD and LOQ were 1.37 and 4.14 ng/mL, respectively. The intraday and interassay precisions were satisfactory; the RSD did not exceed 4.2. The accuracy of the method was proved by recovery of PXT from spiked human plasma at levels of 97.28104.38 0.413.62. The proposed method had high throughput, as the analysis involved a simple sample pretreatment procedure and short run time (<10 min). The results demonstrated that the method would have a great value when it is applied in the therapeutic monitoring of PXT.
Validation and Application of High-Performance Liquid Chromatographic and Spectrophotometric Methods for Simultaneous Estimation of Nebivolol and Hydrochlorothiazide: A Novel Approach to Multivariate Calibrations by R-Software Environment
Authors: Gowda Nagaraj , Panghal Surender , Vipul Kalamkar , Rajshree Mashru
Published: February 2020

A fast, simple reversed-phase HPLC method and two spectrophotometric methods based on principal component regression and partial least squares calibrations were developed for determination of nebivolol (NEB) and hydrochlorothiazide (HCTZ) in formulations without prior separation or masking. The HPLC assay utilized a Phenomenex-Luna RP-18(2) 250 4.6 mm, 5 m column with acetonitrile0.03 aqueous formic acid, pH 3.3 (65 + 35, v/v), mobile phase at a flow rate of 1.0 mL/min, and UV detection at 277 nm. The retention times of NEB and HCTZ were 2.133 and 2.877 min, respectively. The total run time was <4 min. Chemometric calibrations were constructed by using an absorption data matrix corresponding to a concentration data matrix, with measurements in the range of 231310 nm ( 1 nm) in their zero-order spectra using 16 samples in a training set. The chemometric numerical computations were obtained by using R-Software Environment (Version 2.1.1). The proposed methods were validated for various International Conference on Harmonization regulatory parameters like linearity, range, accuracy, precision, robustness, LOD, LOQ, and HPLC system suitability. Laboratory-prepared mixtures and commercial tablet formulations were successfully analyzed using the developed methods. All results were acceptable and confirmed that the method is suitable for its intended use.
Determination of Furosine in Thermally Processed Foods by Hydrophilic Interaction Liquid Chromatography
Authors: Gökmen Vural , Serpen Arda , Morales Francisco J
Published: February 2020

Furosine, a marker of the impairment of lysine residues in protein, is formed during acid hydrolysis of the Amadori compound generated at the early stage of the Maillard reaction in thermally treated foods. An analytical method is described for the determination of furosine in thermally processed foods. The method entails acid hydrolysis of food, SPE cleanup with a hydrophilic-lipophilic sorbent, and hydrophilic interaction LC separation. The main advantage of the method is the separation of furosine by means of hydrophilic interaction LC analysis, which simply avoids ion-pairing agents during the chromatography for a complete baseline separation, or avoids the use of a metal-free chromatographic device. In addition, by combining microwave hydrolysis with hydrophilic interaction LC, the complete determination of furosine in a food sample takes approximately 2530 min. The LOD and the LOQ were 0.7 and 2.3 mg/kg, respectively, for furosine, based on S/Ns of 3 and 10, respectively. The recoveries ranged from 94.6 3.1 to 98.6 1.7 for spiking levels of 1001000 mg/kg sample. The method is easy to use and cost-effective, and gave reproducible results for both within-day and day-to-day tests.
Enzyme-Linked Immunosorbent Assay Kit for Beta-Lactoglobulin Determination: Interlaboratory Study
Authors: Štumr František , Gabrovská Dana , Rysová Jana , Hanák Petr , Plicka Jan , Tomková Kvta , Cuhra Petr , Kubk Martin , Barošvá Soňa , Karšulĺnová Lenka , Bulawová Hana , Brychta Josef
Published: February 2020

An interlaboratory study was performed in six laboratories to prove the validation of the ELISA method developed for quantitative determination of beta-lactoglobulin (BLG) in foods. The ELISA kit used for this study is based on rabbit polyclonal antibody. In-house validation of the kit did not produce false-positive results or cross-reactivity in a broad range of food matrixes containing no milk proteins. All participants obtained the BLG kit with a standard operational procedure, the list of the samples, samples, and a protocol for recording test results. The study included 14 food samples (extruded breakfast cereals, bread, two soy desserts, butter, chicken ham, chicken meat, wheat flour, long grain rice, jelly, two whey drinks, crackers, and bitter chocolate) and six spiked samples (two rice, two wheat flour, and two chicken meat). Nine samples of food matrixes containing no milk proteins showed BLG content lower than the first standard (0.15 mg/kg). Two samples of food matrixes with no milk proteins revealed BLG content higher than standard 3 (1.5 mg/100 g) and standard 4 (5.0 mg/100 g). Three food samples containing milk were tested as positive, and all spiked samples were evaluated as positive. The statistical tests (Cochran, Dixon, and Mandel) and analysis of variance were used to evaluate the interlaboratory study results. Repeatability and reproducibility limits, as well as LOQ (0.22 mg BLG/kg) and LOD (0.07 mg BLG/kg), for the kit were calculated.
Optimization of Ultrasonic-Assisted Acid Extraction of Mercury in Muscle Tissues of Fishes Using Multivariate Strategy
Authors: Shah Abdul Q , Kazi Tasneem G , Arain Mohammad B , Baig Jameel A , Afridi Hassan I , Jamali Mohammad K , Jalbani Nusrat , Kandhro Ghulam A
Published: February 2020

A simple and rapid ultrasound-assisted extraction procedure was developed for the determination of total mercury (Hg) in muscle tissues of freshwater fish species. A Plackett-Burman experimental design was used as a multivariate strategy for the evaluation of the effects of variables, such as presonication time (without ultrasonic stirring), sonication time, ultrasonic bath temperature, nitric acid concentration, hydrochloric acid concentration, and sample mass of muscle tissues. Some variables showed a significant effect on recovery, and they were further optimized by a 23 + star central composite design that involved 16 experiments. The validation was carried out by analysis of certified reference material DORM-2 (dog fish muscles); for comparative purposes, an acid digestion induced by microwave energy was used. Cold vapor atomic absorption spectrometry was used for the determination of total Hg. No significant differences were established between the analytical results and the certified values (paired t-test at P > 0.05). The LOD and LOQ of Hg were 0.133 and 0.445 g/kg, respectively, which demonstrated the high sensitivity of the proposed procedure for the determination of Hg at trace levels. The Hg concentrations in the muscle tissues of 10 freshwater fish species were found in the range of 35.367.8 g/kg on a dried basis, which were within the permissible limit of the World Health Organization.
Determination of a Two-Tailed 100(1-α)% Upper Limit on the Relative Error in the Laboratory-to-Laboratory Standard Deviation Obtained from an Interlaboratory Study
Authors: McClure Foster D , Lee Jung K
Published: February 2020

For some classes of analytical methods, it is assumed that the error in the laboratory-to-laboratory standard deviation (sL) is appreciable. To demonstrate the magnitude of this error in sL for such methods, formulas were derived to obtain a two-tailed 100(1-α)% upper limit on the relative error in sL obtained from an interlaboratory study, assuming that the laboratory-to-laboratory variance (sL2) obtained in the validation of an analytical method is approximately normal and/or Chi-square distributed. This 100(1-α)% upper limit is referred to as a margin of relative error in sL (MRE(sL)). Monte Carlo simulations were performed, and the results compared satisfactorily with the formula calculations. To aid in designing future interlaboratory studies in which concern is focused on the magnitude of the uncertainty in sL, expressed as a proportion of the true value (σL), a formula was derived to determine the number of laboratories needed to attain a given MRE in sL for a stated number of replicates per laboratory.
Structural and Immunogenic Effects of Multiple Hapten Loading on Carrier Protein
Authors: Singh K Vikas , Khanna Pooja , Suri C Raman , Garg Mohan L
Published: February 2020

Haptens are low-molecular-weight compounds that are usually nonimmunogenic in nature. These compounds are, in general, conjugated with carrier proteins to elicit an immune response for antibody production. In this work, we report the effect of multiple hapten loading on carrier protein after conjugation by monitoring the structural and immunogenic properties of the protein. Biochemical conjugation of carboxylated hapten (atrazine derivative) to bovine serum albumin via ε-amino groups of lysine residues was monitored by the intrinsic fluorescence intensity of tryptophan residues of protein. A significant blue shift of emission maxima confirmed the conformational changes with increasing molar ratio of hapten:protein. Circular dichroism spectroscopy suggested a decreasing trend for α-helical and increased formation of β-sheet structures in hapten-loaded protein. A further insight was sought by using molecular modeling methods for understanding of structural changes in the native protein post-hapten conjugation. A sequential approach for hapten loading on the carrier confirmed that initial binding could affect the possible binding sites for subsequent incorporation of hapten molecules. These changes play a major role in the immunogenic response of hapten-carrier conjugate. The approach taken to develop this model is promising, and can be generalized for studies with other protein-hapten combinations.
Extraction Efficiencies of Heavy Metals in Hydroethanolic Solvent from Herbs of Commerce
Authors: Sullivan James , Greenfield Jackie , Cumberford Greg , Grant Jim , Stewart Jeremy
Published: February 2020

Heavy metal contamination of herbal products is a major concern in the herbal and dietary supplement industry. Heavy metal exposure is well-documented to cause a variety of adverse human health effects and to negatively impact our environment. The Final Rule for Dietary Supplements for current good manufacturing practice regulation, 21 U.S. Food and Drug Administration Code of Federal Regulations 111, requires dietary supplement manufacturers to establish herbal purity limits for heavy metal contaminants considered safe for human consumption. Heavy metals may enter into the herbal manufacturing process via bioaccumulation from the harvest site or during postharvest processing phases, such as drying and/or liquid extraction. Traditionally, herbalists have used hydroethanolic solvents to extract herbal biomasses in pure food-grade ethanolwater combinations with solvent polarities capable of removing a wide range of hydrophilic and lipophilic constituents. The presented data demonstrate that hydroethanolic solvents are not completely efficient in the extraction of heavy metal accumulations from plant matrixes; and can act as an effective decontamination step in herbal product processing.
Kinetic Spectrophotometric Determination of Ciprofloxacin in a Pharmaceutical Preparation
Authors: Aslan Serap Saglik , Demir Betul
Published: February 2020

Two kinetic spectrophotometric methods were developed for determination of ciprofloxacin (CIP) in a pharmaceutical preparation. The methods are based on oxidation of CIP with potassium permanganate in alkaline media and measurement of the enhancement in the absorbance of manganate ion at 603 nm by spectrophotometry. The calibration graphs were constructed using the initial rate and fixed time methods. The linearity range for concentrations of CIP was found to be 4.020.0 g/mL. The RSD values for intraday and interday precision were 0.050.50 and 0.070.63, respectively. The procedures were applied successfully for determination of CIP in commercial tablets. The results compared well with those from a reference HPLC method. The proposed methods can be recommended for routine analysis of CIP in QC laboratories.
Comparison of Analytical Methods to Determine Sodium Content of Low-Sodium Foods
Authors: Ehling Stefan , Tefera Sebhat , Earl Robert , Cole Shannon
Published: February 2020

U.S. nutrition labeling regulations require the declaration of sodium content on food products. Accurate and reproducible determination of Na in foods with low Na content (<140 mg/serving) is challenging because of laboratory contamination. Within-laboratory performance of inductively coupled plasma/MS (ICP/MS), flame atomic absorption spectrophotometry (FAAS), ion-selective electrode (ISE), and potentiometric titration of chloride ion were evaluated in 17 low-sodium foods. For 13 types of food, statistically significant differences (P < 0.05) exist between the within-day and/or interday means obtained by ICP/MS, FAAS, and ISE. Median within-day and interday precent RSD values were 2.7 and 6.1, 3.5 and 3.2, and 5.6 and 6.2, respectively, by ICP/MS, FAAS, and ISE. The fewest matrix effects were found with ICP/MS, followed by FAAS, and ISE. FAAS gave higher results in a variety of matrixes when compared to ICP/MS and/or ISE. ISE did not perform well in fatty foods or at very low Na concentrations. Manufacturers' Nutrition Facts Panel sodium declarations exceeded levels found by analysis in >70 of the foods. Analysis of chloride content does not produce reliable Na estimates in low-sodium foods, even when added sodium chloride is present. Methodological issues and contamination sources are discussed.
Single-Laboratory Validation of a Method for the Determination of Phenols and Phenates in Disinfectant Formulations by Liquid Chromatography with UV Detection
Authors: Phillips Tommy , Burns Adrian , Mcmanus Kenneth , Bontoyan Warren
Published: February 2020

A single-laboratory validation study was conducted for an LC method using UV detection for the simultaneous determination of the active ingredients o-phenylphenol (OPP), p-tert-amylphenol (PTAP), and o-benzyl-p-chlorophenol (OBPCP) in disinfectant formulations. Samples were extracted, the extracts diluted with acidified methanol, and the active ingredients separated by LC with a gradient mobile phase and quantified by using UV detection at 285 nm. For each active ingredient, the RSD was 3.7, and the intermediate reproducibility was 3.4. The active ingredient content of the spiked samples analyzed in this study ranged from 0.075 to 10.1 for the individual phenol active ingredients. The average recovery ranges were 86.7104.9, 82.8115.6, and 91.6114.7 for the active ingredients OPP, PTAP, and OBPCP, respectively, for the concentration range of 0.07510.1. This method, with a relatively short chromatographic run time (about 15 min), proved to be reliable and convenient for analyses of products or samples containing all or a combination of these phenol active ingredients.
Determination of Molecular Weight of Silk Fibroin by Non-Gel Sieving Capillary Electrophoresis
Authors: Wei Wei , Zhang Yaopeng , Shao Huili , Hu Xuechao
Published: February 2020

A simple non-gel sieving capillary electrophoresis (NGSCE) method was established to determine the MW of silk fibroin using CE. The background electrolyte with a pH of 8.8 was based on three components: polyethylene glycol, tris(hydroxymethyl)aminomethane, and sodium dodecyl sulfate (SDS). NGSCE showed a good linear relationship with satisfactory reproducibility between the migration time and the MW of standard proteins. It was found that the regenerated silk fibroin had an MW around 83 kDa with a wide MW distribution (MWD). This absolute value is lower than the result obtained from SDS-polyacrylamide gel electrophoresis due to the different principles of the methods, but their similar MWD shapes indicated that NGSCE could be a feasible, highly sensitive, rapid method for determination of the MW of silk fibroin.
Development and Validation of a Micellar High-Performance Liquid Chromatographic Method for Determination of Risedronate in Raw Material and in a Pharmaceutical Formulation: Application to Stability Studies
Authors: Walash Mohamed , Metwally Mohamed , Eid Manal , El-Shaheny Rania
Published: February 2020

A micellar HPLC method was developed for analysis of the antiosteoporosis drug risedronate. The analysis was carried out using a 250 4.6 mm id, 5 m particle size C18 Waters Symmetry column. The mobile phase consisted of 0.02 M sodium dodecyl sulfate + 0.3 triethylamine + 10 n-propanol, prepared in 0.02 M orthophosphoric acid. The pH of the mobile phase was adjusted to pH 6.0, and it was pumped at a flow rate of 0.7 mL/min with UV detection at 262 nm. The method showed good linearity in the range of 280 g/mL, with an LOD of 0.40 g/mL (1.31 106 M) and an LOQ of 1.21 g/mL. The suggested method was successfully applied for the analysis of risedronate in raw material and a tablet formulation, with average recoveries of 99.91 1.30 and 101.52 0.30, respectively. The stability-indicating capability of the proposed method was proved using forced degradation. By changing the pH of the mobile phase to 4.0, the oxidative degradation product could be separated from risedronate.
Separation and Preconcentration of Trace Amounts of Gold(III) Ions Using Modified Multiwalled Carbon Nanotube Sorbent Prior to Flame Atomic Absorption Spectrometry Determination
Authors: Afzali Daryoush , Ghaseminezhad Sima , Taher Mohammad Ali
Published: February 2020

Multiwalled carbon nanotubes are attractive as sorbents for SPE because they can be used for enrichment of organic compounds and metal ions at trace levels. In this study, multiwalled carbon nanotubes were oxidized with concentrated HNO3, and then the oxidized multiwalled carbon nanotubes were modified with 5-(4-dimethylaminobenzyliden)-rhodanine. The modified multiwalled carbon nanotubes were used as a solid sorbent for separation and preconcentration of trace amounts of Au(III) ions. The sorption of Au(III) ions was quantitative in the pH range of 2.05.0, whereas quantitative desorption occurred instantaneously with 5.0 mL 2.0 M Na2S2O3. The eluted solution was aspirated directly into the flame for atomic absorption spectrometry. The proposed method resulted in an enrichment factor of 94. The RSD of the method was 1.11 (n = 10, 2.0 g/mL) and the LOD was 0.15 ng/mL. The calibration curve for Au(III) was linear between 0.53 ng/mL and 36.0 g/mL in the initial solution, with an R2 value of 0.9999. The sorbent capacity of the modified multiwalled carbon nanotubes was 7.3 mg Au(III)/g sorbent. The influences of the experimental parameters, including sample pH, sample flow rate, eluent volume and flow rate, sample volume, and interference of some ions on the recoveries of the Au ions, were investigated. The proposed method was applied for preconcentration and determination of Au in different samples.
Analysis of Triclosan and Triclocarban in Soil and Biosolids Using Molecularly Imprinted Solid Phase Extraction Coupled with HPLC-UV
Authors: Verma Kusum S , Xia Kang
Published: February 2020

A molecularly imprinted polymer (MIP) able to selectively bind triclosan (TCS) and triclocarban (TCC), commonly used antibacterial agents in many consumer products, was prepared using noncovalent molecular imprinting methods. The prepared MIP was evaluated as a selective sorbent in SPE for sample cleanup before HPLC-UV analysis of TCS and TCC in soil and biosolid samples. The MIP was also compared with commercially available C18 SPE sorbent. The molecularly imprinted SPE (MISPE) developed in this study was more efficient than C18 SPE for the cleanup of extracts of soil and biosolid samples prior to the analysis of TCC and TCS using HPLC-UV. The LOQ values for both TCC and TCS in the soil samples were determined to be 40 g/kg; in the biosolid samples, the LOQ values were 100 and 300 g/kg for TCC and TCS, respectively. Compared to C18 SPE, using MISPE for sample cleanup may result in a significant reduction of analytical cost, because one MIP can be reused up to 35 times and HPLC-UV instead of HPLC/MS can be used for instrumental analysis following sample cleanup by MISPE.
Tradition- and Science-Based Quality Control of Chinese MedicinesIntroducing the Phyto-True System
Authors: Leung Albert Y
Published: February 2020

The current QC practice of quantifying presumed active chemicals or arbitrarily selected chemical markers is of doubtful value in assessing multicomponent complex traditional Chinese medicines (CMs) and often leads to an inconsistent or irreproducible research and clinical outcome. Consequently, the first and most important step in the QC of CMs (or other botanical medicines) whose exact active chemical components are unknown is to use analytical techniques that can comprehensively define the totality of the components/attributes making up their identity and quality. One of the most versatile techniques is HPTLC. Using HPTLC, along with other simple techniques such as FTIR spectroscopy and UV-Vis spectroscopy combined with complementary gene expression profiling, we have been able to correctly identify CM materials, detect adulterants, and differentiate closely related materials and botanical species. Our research has resulted in the introduction of the concept and specimens of Phyto-True Reference Material (PTRM™), aka Representative Botanical Reference/Research Material (RBRM™), now commercially available, and a novel patent-pending technology (Phyto-True™ system) that can serve as a starting point for the meaningful QC of traditional CMs so far not possible for these complex materials. Examples will be highlighted to demonstrate this new concept.
Study on Triterpenoic Acids Distribution in Ganoderma Mushrooms by Automatic Multiple Development High Performance Thin Layer Chromatographic Fingerprint Analysis
Authors: Yan Yu-Zhen , Xie Pei-Shan , Lam Wai-Kei , Chui Eddie , Yu Qiong-Xi
Published: February 2020

GanodermaLingzhi in Chineseis one of the superior Chinese tonic materia medicas in China, Japan, and Korea. Two species, Ganoderma lucidum (Red Lingzhi) and G. sinense (Purple Lingzhi), have been included in the Chinese Pharmacopoeia since its 2000 Edition. However, some other species of Ganoderma are also available in the market. For example, there are five species divided by color called Penta-colors Lingzhi that have been advocated as being the most invigorating among the Lingzhi species; but there is no scientific evidence for such a claim. Morphological identification can serve as an effective practice for differentiating the various species, but the inherent quality has to be delineated by chemical analysis. Among the diverse constituents in Lingzhi, triterpenoids are commonly recognized as the major active ingredients. An automatic triple development HPTLC fingerprint analysis was carried out for detecting the distribution consistency of the triterpenoic acids in various Lingzhi samples. The chromatographic conditions were optimized as follows: stationary phase, precoated HPTLC silica gel 60 plate; mobile phase, tolueneethyl acetatemethanolformic acid (15 + 15 + 1 + 0.1); and triple-development using automatic multiple development equipment. The chromatograms showed good resolution, and the color images provided more specific HPTLC fingerprints than have been previously published. It was observed that the abundance of triterpenoic acids and consistent fingerprint pattern in Red Lingzhi (fruiting body of G. lucidum) outweighs the other species of Lingzhi.
Development and Validation of a High-Performance Liquid Chromatographic Method for Determination of Eprosartan in Bulk Drug and Tablets
Authors: Patel Harsha U , Suhagia Bhanubhai N , Patel Chhaganbhai N
Published: February 2020

A simple, precise, and accurate isocratic RP-HPLC method was developed and validated for determination of eprosartan in bulk drug and tablets. Isocratic RP-HPLC separation was achieved on a Phenomenex C18 column (250 4.6 mm id, 5 m particle size) using the mobile phase 0.5 formic acidmethanolacetonitrile (80 25 20, v/v/v, pH 2.80) at a flow rate of 1.0 mL/min. The retention time of eprosartan was 7.64 0.05 min. The detection was performed at 232 nm. The method was validated for linearity, precision, accuracy, robustness, solution stability, and specificity. The method was linear in the concentration range of 10400 g/mL with a correlation coefficient of 0.9999. The repeatability for six samples was 0.253 RSD; the intraday and interday precision were 0.210.57 and 0.330.71 RSD, respectively. The accuracy (recovery) was found to be in the range of 99.86100.92. The drug was subjected to the stress conditions hydrolysis, oxidation, photolysis, and heat. Degradation products produced as a result of the stress conditions did not interfere with detection of eprosartan; therefore, the proposed method can be considered stability-indicating.