bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Postcolumn Methodology for Determination of Paralytic Shellfish Toxins in Shellfish Tissue
Authors: Rourke Wade A , Murphy Cory J , Pitcher Ginette , van de Riet Jeffery M , Burns B Garth , Thomas Krista M , Quilliam Michael A
Published: February 2020

A rapid liquid chromatographic (LC) method with postcolumn oxidation and fluorescence detection (excitation 330 nm, emission 390 nm) for the determination of paralytic shellfish toxins (PSTs) in shellfish tissue has been developed. Extracts prepared for mouse bioassay (MBA) were treated with trichloroacetic acid to precipitate protein, centrifuged, and pH-adjusted for LC analysis. Saxitoxin (STX), neoSTX (NEO), decarbamoylSTX (dcSTX), and the gonyautoxins, GTX1, GTX2, GTX3, GTX4, GTX5, dcGTX2, and dcGTX3, were separated on a polar-linked alkyl reversed-phase column using a step gradient elution; the N-sulfocarbamoyl GTXs, C1, C2, C3, and C4, were determined on a C-8 reversed-phase column in the isocratic mode. Relative toxicities were used to determine STX-dihydrochloride salt (diHCl) equivalents (STXeq). Calibration graphs were linear for all toxins studied with STX showing a correlation coefficient of 0.999 and linearity between 0.18 and 5.9 ng STX-diHCl injected (equivalent to 3.9128 g STXeq/100 g in tissue). Detection limits for individual toxins ranged from 0.07 g STXeq/100 g for C1 and C3 to 4.1 g STXeq/100 g for GTX1. Spike recoveries ranged from 76 to 112 in mussel tissue. The relative standard deviation (RSD) of repeated injections of GTX and STX working standard solutions was <4. Uncertainty of measurement at a level of 195 g STXeq/100 g was 9, and within-laboratory reproducibility expressed as RSD was 4.6 using the same material. Repeatability of a 65 g STXeq/100 g sample was 3.0 RSD. Seventy-three samples were analyzed by the new postcolumn method and both AOAC Official Methods for PST determination: the MBA (y = 1.22x + 13.99, r2 = 0.86) and the precolumn LC oxidation method of Lawrence (y = 2.06x + 12.21, r2 = 0.82).
Determination of Organotins in Aquatic Food by Gas Chromatography with Pulsed Flame Photometric Detection
Authors: Yun-Feng Zhao , Kong-Xiang Zhao , Yong-Ning Wu
Published: February 2020

A method based on gas chromatography (GC)-pulsed flame photometric detection (PFPD) was developed to determine the levels of organotins in aquatic food. After being purified by gel-permeation chromatography in ethyl actatetetrahydrofuran, the organotin compounds were derivatized by pentylmagnesium bromide. The derivative products were injected into the GC system and detected by PFPD (sulfur mode). The method was validated by analysis of the certified reference material and spiked samples. Recoveries of organotins ranged from 84.1 to 116.6 with relative standard deviation between 1.3 and 16.0 when spiked at levels of 2, 10, and 40 g/kg. The limits of detection varied from 0.1 to 1.2 g/kg for shellfish and 0.1 to 0.5 g/kg for fish. The proposed method was suitable for determining organotins in aquatic foods.
Development and Validation of Column High-Performance Liquid Chromatographic and Derivative Spectrophotometric Methods for Determination of Levofloxacin and Ornidazole in Combined Dosage Forms
Authors: Patel Satish A , Prajapati Arun M , Patel Paresh U , Patel Natubhai J , Vaghmasi Jayesh B
Published: February 2020

The manuscript describes validated reversed-phase column high-performance liquid chromatographic (RP-HPLC) and first-derivative UV spectrophotometric methods for the estimation of levofloxacin (LFX) and ornidazole (ORNI) in combined dosage forms. The RP-HPLC separation was achieved on a Phenomenex C18 column (250 mm 4.6 mm id, 5 m) using KH2PO4 buffer (pH 6.8)methanolacetonitrile (70 + 15 + 15, v/v/v) mobile phase at a flow rate of 1.5 mL/min and ambient temperature (25 2C). Quantification was achieved with photodiode array detection at 295 nm over the concentration range of 110 g/mL for both LFX and ORNI, with mean recovery of 101.7 0.23 and 99.23 1.57, respectively, by the RP-HPLC method. The derivative spectrophotometric method was based on the determination of both the drugs at their respective zero crossing point (ZCP). The first-order derivative spectra were obtained at N =1 (scaling factor), = 2.0 nm (wavelength interval), and the determinations were made at 310 nm (ZCP of ORNI) for LFX and 295 nm (ZCP of LFX) for ORNI over the concentration range of 240 g/mL for both LFX and ORNI. Mean recovery was 99.46 0.96 and 100.9 0.72, respectively, by the first-derivative UV spectrophotometric method. Standard and sample solutions were prepared with methanol as the solvent in both of the methods. These methods were found to be simple, accurate, precise, and sensitive and were applicable for the simultaneous determination of LFX and ORNI in combined dosage forms.
Effect of Matrix on Recovery of Biogenic Amines in Fish
Authors: Richard Nicole , Pivarnik Lori , Ellis P Christopher , Lee Chong
Published: February 2020

Biogenic amines, such as putrescine, cadaverine, and histamine, in fish can be indicators of spoilage and/or safety. Methanol extraction used for AOAC Official Methods 996.07 and 977.13 has resulted in low amine recoveries in fish. Extraction methodology was evaluated to improve recovery from fish tissue. Samples were evaluated for recovery of known quantities of biogenic amines added to tissue prior to extraction. Addition of 25 0.4 N HCl to the 75 methanolwater extraction solvent (according to AOAC Official Methods 996.07 and 977.13) resulted in higher recoveries (P <0.05) of the biogenic amines. Putrescine recovery increased from 44 2 to 100 14 in flounder and scup, and from 53 21 to 119 27 in mackerel and butterfish; cadaverine recovery increased from 47 4 to 106 15 (flounder/scup) and 58 24 to 113 9 (mackerel/butterfish); histamine recovery increased from 54 13 to 89 28 (mackerel). MeOH extraction resulted in comparable recovery from canned tuna, indicating that protein denaturation from processing may eliminate possible matrix interference. Acidification of the solvent resulted in a more complete extraction of the added amines to fresh/frozen fish tissue. This finding could indicate that current extraction procedures may cause biogenic amines to be underestimated.
BIOPEP Database and Other Programs for Processing Bioactive Peptide Sequences
Authors: Minkiewicz Piotr , Dziuba Jerzy , Iwaniak Anna , Dziuba Marta , Darewicz Magorzata
Published: February 2020

This review presents the potential for application of computational tools in peptide science based on a sample BIOPEP database and program as well as other programs and databases available via the World Wide Web. The BIOPEP application contains a database of biologically active peptide sequences and a program enabling construction of profiles of the potential biological activity of protein fragments, calculation of quantitative descriptors as measures of the value of proteins as potential precursors of bioactive peptides, and prediction of bonds susceptible to hydrolysis by endopeptidases in a protein chain. Other bioactive and allergenic peptide sequence databases are also presented. Programs enabling the construction of binary and multiple alignments between peptide sequences, the construction of sequence motifs attributed to a given type of bioactivity, searching for potential precursors of bioactive peptides, and the prediction of sites susceptible to proteolytic cleavage in protein chains are available via the Internet as are other approaches concerning secondary structure prediction and calculation of physicochemical features based on amino acid sequence. Programs for prediction of allergenic and toxic properties have also been developed. This review explores the possibilities of cooperation between various programs.
Application of Mass Spectrometry to the Characterization and Quantification of Food-Derived Bioactive Peptides
Authors: del Mar Contreras María , López-Expósito Iván , Hernández-Ledesma Blanca , Ramos Mercedes , Recio Isidra
Published: February 2020

Biologically active peptides are of particular interest in food science and nutrition because they have been shown to play different physiological roles, including antihypertensive, opioid, antimicrobial, and immunostimulating activities. Because these peptides are generated by protein hydrolysis or fermentation, they can represent only minor constituents in a highly complex matrix and therefore, identification of biologically active peptides in food matrixes is a challenging task in food technology. In this context, mass spectrometry (MS) has developed into a necessary tool to assess quality and safety of food and, more recently, to determine the presence and behavior of functional components such as these bioactive peptides. This review highlights the existing methods based on MS to identify, characterize, and quantify food-derived biologically active peptides, taking into account the different ionization sources used for the analysis of these high-value food components. The quantitative determination of bioactive peptides in food products or biological fluids is also discussed.
Quantitative Analysis of Three Chiral Pesticide Enantiomers by High-Performance Column Liquid Chromatography
Authors: Wang Peng , Liu Donghui , Gu Xu , Jiang Shuren , Zhou Zhiqiang
Published: February 2020

Methods for the enantiomeric quantitative determination of 3 chiral pesticides, paclobutrazol, myclobutanil, and uniconazole, and their residues in soil and water are reported. An effective chiral high-performance liquid chromatographic (HPLC)-UV method using an amylose-tris(3,5-dimethylphenylcarbamate; AD) column was developed for resolving the enantiomers and quantitative determination. The enantiomers were identified by a circular dichroism detector. Validation involved complete resolution of each of the 2 enantiomers, plus determination of linearity, precision, and limit of detection (LOD). The pesticide enantiomers were isolated by solvent extraction from soil and C18 solid-phase extraction from water. The 2 enantiomers of the 3 pesticides could be completely separated on the AD column using n-hexane isopropanol mobile phase. The linearity and precision results indicated that the method was reliable for the quantitative analysis of the enantiomers. LODs were 0.025, 0.05, and 0.05 mg/kg for each enantiomer of paclobutrazol, myclobutanil, and uniconazole, respectively. Recovery and precision data showed that the pretreatment procedures were satisfactory for enantiomer extraction and cleanup. This method can be used for optical purity determination of technical material and analysis of environmental residues.
Determination of Nebivolol Hydrochloride and Hydrochlorothiazide in Tablets by First-Order Derivative Spectrophotometry and Liquid Chromatography
Authors: Shah Dimal A , Bhatt Kashyap K , Mehta Rajendra S , Baldania Sunil L
Published: February 2020

Two simple and accurate methods for analysis of nebivolol hydrochloride (NEB) and hydrochlorothiazide (HCTZ) in their combined dosage forms were developed using first-order derivative spectrophotometry and reversed-phase liquid chromatography (LC). NEB and HCTZ in their combined dosage forms (tablets) were quantified using first-derivative responses at 294.6 and 334.6 nm in the spectra of their solutions in methanol. The calibration curves were linear in the concentration range of 840 g/mL for NEB and 1060 g/mL for HCTZ. LC analysis was performed on a Phenomenex Gemini C18 column (250 4.6 mm id, 5 m particle size) in the isocratic mode with 0.05 M potassium dihydrogen phosphateacetonitrilemethanol (30 + 20 + 50, v/v/v; pH 4) mobile phase at a flow rate of 1 mL/min. Detection was made at 220 nm. Both of the drugs and the internal standard (ezetimibe) were well resolved with retention times of 5.1 min for NEB, 2.9 min for HCTZ, and 8.2 min for ezetimibe. The calibration curves were linear in the concentration range of 114 g/mL for NEB and 0.328 g/mL for HCTZ. Both methods were validated and found to be accurate, precise, and specific, and results were compared statistically. Developed methods were successfully applied for the estimation of NEB and HCTZ in their combined dosage forms.
Determination of Mepiquat Chloride Residues in Cotton and Soil by Liquid Chromatography/Mass Spectrometry
Authors: Liu Xin-Gang , Dong Feng-Shou , Li Shuo , Zheng Yong-Quan
Published: February 2020

A liquid chromatographic/mass spectrometric (LC/MS) method is reported for the determination of the onium-type plant growth regulator mepiquat chloride in cotton and soil. The pesticide was extracted from the sample with ethanol and water containing 2 NH4Cl. The extract was cleaned up on a solid-phase extraction C18 column, and the pesticide was determined by LC/MS. The average recoveries were 85.993.8, 81.391.7, and 78.194.7, with corresponding relative standard deviations of 3.49.6, 3.712.3, and 4.09.8, from soil, cotton leaves, and cotton seeds, respectively. A coefficient of determination of R2 0.9964 was obtained for the analyte calibration graph, from 0.05 to 100 g/mL. Decision limits, CC, and detection capability, CC, were calculated. Electrospray ionization LC/MS in the positive-ion mode (ESI+) was used to detect mepiquat chloride in extracts of soil, cotton leaves, and cotton seeds. The ion at m/z 114 in the mass spectrum was monitored.
Estimation of Berberine in Ayurvedic Formulations Containing Berberis aristata
Authors: Rout Kedar Kumar , Pradhan Subhalaxmi , Mishra Sagar Kumar
Published: February 2020

A sensitive, simple, rapid, and efficient high-performance thin-layer chromatographic (HPTLC) method has been developed and validated for the analysis of berberine in marketed Ayurvedic formulations containing Berberis aristata DC for regulatory purposes. Chromatography of methanolic extracts of these formulations was performed on silica gel 60 F254 aluminum-backed TLC plates of 0.2 mm layer thickness. The plate was developed up to 66 mm with the ternary-mobile phase butanolacetic acidwater (8 + 1 + 1, v/v/v) at 33 5C with 5 min of tank saturation. The marker, berberine, was quantified at its maximum absorbance of 350 nm. The limit of detection and limit of quantitation values were found to be 5 and 10 ng/spot. The linear regression analysis data for the calibration plot showed a good linear relationship with correlation coefficient 0.9994 in the concentration range of 10 to 50 ng/spot for berberine with respect to peak area. The instrumental precision was found to be 0.49 coefficient of variation (CV), and repeatability of the method was 0.73 CV. Recovery values from 98.27 to 99.11 indicate excellent accuracy of the method. The developed HPTLC method is very accurate, precise, and cost-effective, and it has been successfully applied to the assay of marketed formulations containing B. aristata for determination of berberine.
Standardization of the Ayurvedic Formulation Haridra Khanda Using High-Performance Thin-Layer Chromatography-Densitometry
Authors: Kumar Rout Kedar , Parida Sagarika , Kumar Mishra Sagar
Published: February 2020

The present study aimed to standardize the Ayurvedic preparation Haridra Khanda containing Curcuma longa as a major ingredient. Various physicochemical parameters such as alcohol-soluble extractive, water-soluble extractive, total ash, and acid-insoluble ash were determined according to the Ayurvedic Pharmacopoeia of India. Microscopic evaluation of the formulation revealed the presence of various diagnostic cell structures of C. longa. Trace metal analysis indicated the absence of toxic metals such as As, Cd, Hg, and Pb. High-performance thin-layer chromatographic (HPTLC) fingerprint patterns at multiple wavelengths (254, 366, and 430 nm) identified the number of components present at each wavelength. The bioactive markers curcumin (C1), demethoxycurcumin (C2), and bisdemethoxycurcumin (C3) were quantified by using a simple, rapid, and efficient HPTLC method using plates precoated with silica gel 60F254 stationary phase. The instrumental precision [coefficient of variation (CV)] was 0.51, 0.64, and 0.79% and the repeatability of the method (CV) was 0.89, 1.11, and 0.95%, respectively, for C1 to C3. Limits of detection and quantitation for compounds C1 to C3 were 20, 20, and 15 ng and 50, 40, and 50 ng, respectively. Response was a linear function in the ranges of 50350, 40240, and 50300 ng with correlation coefficient (r) 0.9998, 0.9995, and 0.9992, respectively, for C1 to C3. The mean recovery values of 99.63 (C1), 98.65 (C2), and 98.97% (C3) indicated the excellent accuracy of the method. It is shown that HPTLC can be applied successfully for the marker evaluation of the formulation containing C. longa.
High-Performance Thin-Layer Chromatography Densitometric Method for the Simultaneous Determination of Three Phenolic Acids in Syzygium aromaticum (L.) Merr. & Perry
Authors: Rastogi Subha , Pandey Madan M , Rawat Ajay K S
Published: February 2020

A simple, precise, and rapid high-performance thin-layer chromatographic (HPTLC) method has been developed for the simultaneous determination of 3 phenolic acids, i.e., gallic acid, caffeic acid, and syringic acid, in the dried buds of Syzygium aromaticum, commonly known as clove. HPTLC was performed on silica gel 60F254 plates with tolueneethyl acetateformic acid (8 2 1) mobile phase and densitometric scanning at 280 nm. The method was validated for selectivity, linearity, precision, and repeatability. Instrumental precision coefficient of variation (CV) was 0.88, 0.93, and 0.98% and repeatability of the method (CV) was 0.76, 0.64, and 0.69% for gallic acid, caffeic acid, and syringic acid, respectively. The linear concentration ranges were 4003200 ng/spot with a correlation coefficient of 0.993 for gallic acid, 4403520 ng/spot with a correlation coefficient of 0.994 for caffeic acid, and 4004000 ng/spot with a correlation coefficient of 0.993 for syringic acid. The average recoveries of gallic acid, caffeic acid, and syringic acid were 96.3, 95.7, and 92.4%, respectively. Gallic acid, caffeic acid, and syringic acid were present at levels of 1.58, 0.06, and 0.05% (w/w), respectively, in S. aromaticum. This method is simple, accurate, precise, and economical and can be used for routine quality control.
High-Performance Thin-Layer Chromatographic Analysis of Selected Organophosphorous Pesticide Residues in Tea
Authors: Yue Yongde , Zhang Rong , Fan Wei , Tang Feng
Published: February 2020

The separation of 9 organophosphates (monocrotophos, quinalphos, triazophos, parathion-methyl, isofenphos-methyl, temephos, parathion, phoxim-ethyl, and chlorpyrifos) by high-performance thin-layer chromatography (HPTLC) with automated multiple development was studied. The HPTLC method was developed and validated for analysis of residues of phoxim-ethyl and chlorpyrifos in tea. The sample was extracted with acetonitrile and cleaned up by ENVI-CARB solid-phase extraction. The extract was directly applied as bands to glass-backed silica gel 60F254 HPTLC plates. The plates were developed with dichloromethanehexane (1 1, v/v) in a glass twin-trough chamber. Evaluation of the developed HPTLC plates was performed densitometrically. The results indicated that the detection limits of phoxim and chlorpyrifos were 5.0 109 and 1.0 108 g, respectively. Recoveries of the pesticides from tea by this analytical method were 90.7105.5%, and relative standard deviations were 7.313.5%. The precision and accuracy of the method were generally satisfactory for analysis of pesticide residues in tea.
High-Performance Thin-Layer Chromatography/Mass Spectrometry for Rapid Analysis of Neutral Glycosphingolipids
Authors: Miyazaki Masao , Yonesige Azusa , Matsuda Junko , Kuroda Yasuhiro , Kojima Naoya , Suzuki Akemi
Published: February 2020

Direct coupling of high-performance thin-layer chromatography (HPTLC) to matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MS) was shown to be a reliable and reproducible method to obtain structural information and fundamental properties of glycosphingolipids (GSLs).We report a protocol for the preparation of neutral GSL extracts frommouse tissues and demonstrate the applicability of HPTLC/MS to these preparations. The protocol consists of lipid extraction and ion exchange chromatography followed by a mild alkaline treatment and a reversed-phase cartridge extraction. Possible structures for each GSL are proposed based on HPTLC/MS analyses. This fast and simple method can be used to screen neutral GSL extracts obtained from tissues and cells without isolation and purification into individual GSLs.
Effect of Selected Metal Ions on the Photodegradation of Ciprofloxacin in the Solid Phase
Authors: Hubicka Urszula , Krzek Jan
Published: February 2020

The photodegradation of ciprofloxacin in the solid phase was investigated by using the chromatographic-densitometric method in the presence and absence of selected metal ions. It was shown that both ion concentration and ion type have an effect on the degradation process that leads to the generation of 2 new products with Rf values of approximately 0.45 and 0.56, which are different from the Rf of approximately 0.68 for ciprofloxacin. It was found that Cu2 and Fe3 ions have the strongest effect on ciprofloxacin photodegradation compared with photodegradation carried out without these ions and also with photodegradations carried out in the presence of Zn2, Cr3, Ni2, and Co2 ions. To identify the photodegradation products, we used amine-specific chromatographic reactions, UV spectra recorded directly from the chromatograms, and proton nuclear magnetic resonance and IR spectroscopic methods. The chemical structures of the degradation products were found to be 7-[(2-aminoethyl)amino]-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid and 7-amino-1-cyclopropyl-6- fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid.
Determination of Ergot Alkaloids: Purity and Stability Assessment of Standards and Optimization of Extraction Conditions for Cereal Samples
Authors: Krska Rudolf , Berthiller Franz , Schuhmacher Rainer , Nielsen Kristian F , Crews Colin
Published: February 2020

Results obtained from a purity study on standards of the 6 major ergot alkaloids ergometrine, ergotamine, ergosine, ergocristine, ergocryptine, and ergocornine and their corresponding epimers are discussed. The 6 ergot alkaloids studied have been defined by the European Food Safety Authority as those that are the most common and physiologically active. The purity of the standards was investigated by means of liquid chromatography with diode array detection, electrospray ionization, and time-of-flight mass spectrometry (LC-DAD-ESI-TOF-MS). All of the standards assessed showed purity levels considerably above 98 apart from ergocristinine (94), ergosine (96), and ergosinine (95). Also discussed is the optimization of extraction conditions presented in a recently published method for the quantitation of ergot alkaloids in food samples using solid-phase extraction with primary secondary amine (PSA) before LC/MS/MS. Based on the results obtained from these optimization studies, a mixture of acetonitrile with ammonium carbonate buffer was used as extraction solvent, as recoveries for all analyzed ergot alkaloids were significantly higher than those with the other solvents. Different samplesolvent ratios and extraction times showed just minor influences in extraction efficacy. Finally, the stability of the ergot alkaloids in both raw cereals and cereal-based processed food extracts was studied. According to these studies, extracts should be prepared and analyzed the same day or stored below ambient temperatures. Barley and rye extracts, which were stored at 4 and 15C after PSA cleanup, proved to be stable overnight. However, storage over a period of 14 days at 4C resulted in significant epimerization, which was most pronounced in rye and particularly for ergocornine, ergocryptine, and ergocristine.
ASimple 2-Directional High-Performance Thin-Layer Chromatographic Method for the Simultaneous Determination of Curcumin, Metanil Yellow, and Sudan Dyes in Turmeric, Chili, and Curry Powders
Authors: Dixit Sumita , Khanna Subhash K , Das Mukul
Published: February 2020

A method using simple extraction and 2-directional high-performance thin-layer chromatography (HPTLC) was developed for the simultaneous determination of curcumin, metanil yellow, and sudan dyes in turmeric, chili, and various mixed curry powder formulations. The method offers resolution (Rf) of turmeric pigments, namely, curcumin (0.77), demethoxycurcumin (0.69), bis(demethoxy)curcumin (0.61), and the synthetic dye metanil yellow (0.05) by the first-directional mobile phase, chloroformmethanol (9 1, v/v). The resolution (Rf) of sudan I (0.30) and sudan IV (0.23) was achieved by the second-directional mobile phase, toluenehexaneacetic acid (50 50 1, v/v/v). Natural pigments of both turmeric and chili showed no interference in the detection and quantification of synthetic colors. The limit of detection and limit of quantification values for curcumin, metanil yellow, sudan I, and sudan IV were 17.39, 42.90, 15.45, and 7.01 and 52.71, 130.0, 46.80, and 21.24 ng/spot, respectively. Analysis of a few market samples showed the presence of metanil yellow (1.54.6 mg/g), sudan I (4.812.1 mg/g), and sudan IV (0.92.0 mg/g) in loose turmeric and chili samples, whereas the curcumin content in turmeric and mixed curry powder samples ranged from 6.5 to 36.4 and from 0.3 to 1.9 mg/g, respectively. The method is relatively simple, offers reasonable sensitivity, and can be used to screen a large number of samples.
Determination of Trace Amounts of Cu2, Ni2, and Mn2 Ions After Preconcentration onto PAN-Immobilized Organo Nanoclay as a New Sorbent
Authors: Afzali Daryoush , Mostafavi Ali
Published: February 2020

The application of organo nanoclay 1-(2-pyridylazo)-2-naphthol (PAN)-immobilized as a new, easily prepared, and stable solid sorbent for preconcentration of trace amounts of Cu2, Ni2, and Mn2 ions in aqueous solution is presented. The organo nanoclay was prepared by adding tetradecyldimethylbenzylammonium chloride onto montmorillonite and then saturating with PAN. A simple, rapid, selective, sensitive, and economical method was developed for the simultaneous separation of trace amounts of copper, nickel, and manganese in aqueous medium using PAN as an analytical reagent. The sorption was quantitative in the pH range of 69.5, and quantitative desorption occurred instantaneously with 5.0 mL 3 M HNO3. Linearity was maintained at 0.2637 ng/mL for copper, 152 ng/mL for nickel, and 0.221 ng/mL for manganese in the original solution. The detection limits were 0.04 ng/mL for Cu(II), 0.15 ng/mL for Ni(II), and 0.03 ng/mL for Mn(II) in the original solution (2bl; standard deviation and bl blank). Various parameters, such as the effect of pH, breakthrough volume, and interference of a large number of anions and cations, have been studied, and the proposed method was used to determine these metal ions in water and standard samples. Determination of these metal ions in standard samples showed that the proposed method has good accuracy.
Determination of Aconitum Alkaloids in Dietary Supplements and Raw Botanical Materials by Liquid Chromatography/UV Detection with Confirmation by Liquid Chromatography/Tandem Mass Spectrometry: Collaborative Study
Authors: Wong Siu-Kay ,   Collaborators:, Che C T , Guo H-Z , Ji S , Kim J-H , Leung K S Y , Lo C K , Richards A , Schaneberg B T , Sudberg; S , Sullivan D , Wang W , Wong Y C , Zhang L-X , Zheng F-Y
Published: February 2020

An interlaboratory study was conducted to evaluate a method for the determination of 3 Aconitum alkaloids, viz., aconitine, mesaconitine, and hypaconitine, in raw botanical material and dietary supplements. The alkaloids were extracted with diethyl ether in the presence of ammonia. After cleanup by solid-phase extraction to remove matrix interferences, the alkaloids were determined by reversed-phase liquid chromatography (LC)/UV detection at 235 nm with confirmation by LC/tandem mass spectrometry (MS/MS). A total of 14 blind duplicates were successfully analyzed by 12 collaborators. For repeatability, the relative standard deviation (RSDr) values ranged from 1.9 to 16.7, and for reproducibility, the RSDR values ranged from 6.5 to 33. The HorRat values were all <2 with only one exception at 2.3. All collaborating laboratories had calibration curves with correlation coefficients of >0.998. In addition, 6 collaborators performed the confirmation and were able to verify the identities of the alkaloids by using LC/MS/MS.
Spectrophotometric Determination of Doxazosin Mesylate in Tablets by Ion-Pair and Charge-Transfer Complexation Reactions
Authors: Aydomu Zeynep , Barla Asli
Published: February 2020

Two accurate, easy spectrophotometric methods for the determination of doxazosin mesylate were described. The first method was based on the formation of ion-pair complexes with the acidic sulfophthalein dyes bromocresol purple (BCP) and bromophenol blue (BPB) in pH 3.3 and 4.5 citratephosphate buffer, respectively. The formed complexes were extracted into dichloromethane, and their absorbance was measured at 403 and 410 nm for BCP and BPB, respectively. The second method was based on the charge transfer reaction of the drug as an n-electron donor with either 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) as -acceptors, to give colored radical anions. The absorbances of products were measured at 457 nm in acetonitrile and 838 nm in methanol for DDQ and TCNQ, respectively. Under the optimum reaction conditions, Beer's law was obeyed with a good correlation coefficient (r = 0.99970.9999) in the concentration ranges 3.018.0, 3.020.0, 15.095.0, and 10.0100.0 g/mL for the BCP, BPB, DDQ, and TCNQ methods, respectively. Limits of detection of the BCP, BPB, DDQ, and TCNQ methods were 0.314, 0.408, 1.935, and 1.610 g/mL, respectively. The limits of quantification were 1.045, 1.360, 6.449, and 5.367 g/mL, respectively. The parameters molar absorptivity, precision, accuracy, recovery, robustness, and stability constant were studied. The proposed methods were successfully applied for determination of the drug in tablets with good accuracy and precision. Statistical comparison of the results with those obtained by a reported method showed good agreement and indicated no significant difference in accuracy and precision.
Multiresidue Mycotoxin Analysis in Corn Grain by Column High-Performance Liquid Chromatography with Postcolumn Photochemical and Chemical Derivatization: Single-Laboratory Validation
Authors: Ofitserova Maria , Nerkar Sareeta , Pickering Michael , Torma Laszlo , Thiex Nancy
Published: February 2020

A multiresidue method was developed and validated for simultaneous analysis of 5 families of mycotoxins in corn grain. Deoxynivalenol (DON); aflatoxins B1, B2, G1, G2; ochratoxin A; zearalenone; and fumonisins FB1 and FB2 are extracted from corn grain samples with watermethanol, and extracts are cleaned up using immunoaffinity and solid-phase extraction columns. The column high-performance liquid chromatographic method uses postcolumn photochemical derivatization for detection of aflatoxins and derivatization with o-phthalaldehyde for detection of fumonisins. Mean recoveries and relative standard deviation values () over studied fortification levels for the chosen matrixes were: DON 89.9, 8.7; aflatoxin B1 85, 9.4; aflatoxin B2 82.4, 9.7; aflatoxin G1 74.8, 13.5; aflatoxin G2 79.2, 10.0; fumonisin B1 96.2, 8.0; fumonisin B2 84.5, 6.4; zearalenone 91.7, 11.5; and ochratoxin A 87.4, 15.8. The method performance criteria, including specificity, accuracy, repeatability, operational range, and detection limits, were found to be within specifications set by the Feed Additives and Contaminants Group of the AOAC Agricultural Materials Community.
Validated Column High-Performance Liquid Chromatographic Method for Determination of Aspirin and Clopidogrel in Combined Tablets in the Presence of Degradation Products Formed Under ICHRecommended Stress Conditions
Authors: Kachhadia Pankaj K , Doshi Ashish S , Joshi Hitendra S
Published: February 2020

The development and validation of a column high-performance liquid chromatographic assay method for the determination of aspirin and clopidogrel in tablet formulation are described. The combination formulation was subjected to International Conference on Harmonization-recommended stress conditions. Separation of the drugs from the degradation products formed under stress conditions was achieved on an octasilyl (C8) column using 0.3 orthophosphoric acidacetonitrile (65 + 35, v/v) mobile phase. The method was validated for specificity, linearity, limits of detection and quantification, precision, accuracy, and robustness. The method was found to be specific against placebo interference and during the forced degradation. The response was linear in the concentration range of 30.0120.0 g/mL for aspirin and 15.060.0 g/mL for clopidogrel, with a correlation coefficient of 0.9999 for both. The relative standard deviation values for intra- and interday precision were <2.0. The accuracy was between 99.12 and 99.83 for aspirin and 98.20 and 100.35 for clopidogrel. Stress testing showed degradation products that were well-separated from the parent compound, confirming the stability-indicating capacity of the method.
Estimation of Pitavastatin Calcium in Tablet Dosage Forms by Column Liquid Chromatography and Ultraviolet Spectrophotometry
Authors: Panchal Hiral J , Suhagia Bhanubhai N , Patel Madhabhai M , Patel Bhavesh H
Published: February 2020

Two simple and accurate methods for the determination of pitavastatin calcium (PIT) in tablet dosage forms were developed and validated using column liquid chromatography (LC) and UV spectrophotometry. The LC separation was achieved on a Phenomenex Luna C18 column (250 mm, 4.6 mm id, 5 m) in the isocratic mode using acetonitrilewatertriethylamine (80 + 19.8 + 0.2, v/v/v), adjusted to pH 3.5 0.05 with orthophosphoric acid, as the mobile phase at a flow rate of 1.5 mL/min. The retention time was 5.70 min. Both the methods were performed at 238 nm, the wavelength of maximum absorbance of PIT in methanol. In the LC method, quantification was achieved with a photodiode array detector over the concentration range of 0.12.5 g/mL with a mean recovery of 100.26 0.75. In the UV method, quantification was achieved over the concentration range of 220 g/mL with mean recovery of 99.65 1.24. Both methods were validated, and the results were compared statistically. They were found to be simple, specific, accurate, and precise. The methods were successfully applied for the determination of PIT in tablet dosage form without any interference from common excipients.
Determination of Deoxynivalenol in Soft Wheat by Immunoaffinity Column Cleanup and LC-UV Detection: Interlaboratory Study
Authors: Neumann Gary , Lombaert Gary A , Kotello Susan , Fedorowich Nicole ,   Collaborators:, Abdelaal E , Cea J , Kurz K , Malone B , Marley E , Mischke C , Panzarini G , Patel S , Roscoe M , Savard M , Solfrizzo M , Trelka R , Vargas E
Published: February 2020

An interlaboratory study was conducted to assess the applicability of a previously validated method for the analysis of deoxynivalenol (DON) in cereal and cereal products to soft wheat in the range of >0.13.0 g/g. The study evaluated a generic method to determine DON at levels that bracket the existing Canadian guidelines for DON in soft wheat destined for use in baby foods and nonstaple foods. Collaborators selected one of 2 approved brands of DON immunoaffinity column for cleanup and their choice of qualified C18 liquid chromatographic (LC) column. Separation was by LC with UV detection. Blind duplicates from 5 levels of naturally contaminated wheat and a pair of spiked wheat samples were successfully analyzed by 12 laboratories in 8 countries. For samples naturally contaminated with DON from <0.12.2 g/g, the relative standard deviation of repeatability (RSDr) ranged from 3.1 to 14.8. For reproducibility, the RSDR ranged from 21.0 to 32.9 and the HorRat range was 1.0 to 1.9. Recoveries of 0.5 g/g DON spiked into wheat ranged from 66 to 98, with an average of 84. The RSDr was 5.4, the RSDR was 12.6, and the HorRat value was 0.7.
Determination of Oxytetracycline/Oxytetracycline Hydrochloride in Animal Feed, Fish Feed, and Veterinary Medicinal Products by Liquid Chromatography with Fluorescence Detection: Collaborative Study
Authors: Thiex Nancy J , Larson Richard ,   Collaborators:, Ahmed M S , Albert K , Babin Y , Campbell H , Campbell M , DeAtley A , Eigen S , Elson K , Farrow M , Firman M , Jamieson J , Jobin D , Kibbey J , Kirby P , Larson R , Marshall D , Mathis J , McManus K , Menefee L , Olson L , Panagiotis S , Raines J , Rowe D , Sabbatini J Z , Singh D , Smith C , Stenske M A , van Rhijn H , Williams S M
Published: February 2020

A method for determining oxytetracycline (OTC) in animal feed, fish feed, and veterinary medicinal products at medicated use and contamination levels was collaboratively studied. The method is applicable to the analysis of animal feeds and mineral premixes containing levels 2 mg/kg, and fish feed containing levels 10 mg/kg. Oxytetracycline hydrochloride (OTC.HCl) is extracted from ground feed material in acidmethanol solution using mechanical agitation. After centrifugation for 5 min at 1230 g, an aliquot of the extract is diluted with water and/or acidmethanol so that the concentration of OTC.HCl is approximately the same as that in the working standard, and the solutions contain at least 50 water. Injectable veterinary medicinal materials (also called animal remedy materials) are diluted with water and/or extractant to reach the target concentration. The extracts are filtered and analyzed by reversed-phase liquid chromatography with fluorescence detection with excitation at 390 nm and emission at 512 nm. Twenty-eight test samples of medicated feeds, supplements, and drug premixes, including 4 test samples for trace-level analysis, were sent to 17 collaborators in Canada, The Netherlands, and the United States. Results were received from 11 laboratories. The RSDr values (within-laboratory repeatability) ranged from 1.26 to 9.21; RSDR values (among-laboratory reproducibility) ranged from 2.14 to 12.9, and HorRat values ranged from 0.54 to 3.02. It is recommended that this method be adopted AOAC Official First Action.
Determination of 17-Ethynylestradiol, Carbamazepine, Diazepam, Simvastatin, and Oxybenzone in Fish Livers
Authors: Kwon Jeong-Wook , Armbrust Kevin L , Vidal-Dorsch Doris , Bay Steven M , Xia Kang
Published: February 2020

A method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed for the determination of 17-ethynylestradiol in fish liver; a second method using LC/MS was developed for the determination of carbamazepine, diazepam, simvastatin, and oxybenzone in fish liver. The fish liver samples were extracted and cleaned up by using liquid-liquid extraction and solid-phase extraction before the extracts were analyzed by LC/MS or LC/MS/MS with electrospray negative and positive ionization. Recoveries of the 5 target compounds from spiked catfish liver ranged from 72 2 to 100 3. Limits of quantification for the 5 compounds were between 4.2 and 12.3 ng/g (wet weight). Ten turbot (Pleuronichthys verticalis) liver samples were analyzed; levels of 17-ethynylestradiol, carbamazepine, simvastatin, and oxybenzone were below the detection limits. Diazepam was detected in all 10 fish liver samples at concentrations ranging from 23 to 110 ng/g (wet weight).
Evaluation of Analytical Methods for the Determination of Moisture, Crude Protein, Crude Fat, and Crude Fiber in Distillers Dried Grains with Solubles
Authors: Thiex Nancy
Published: February 2020

A number of analytical methods for constituents commonly measured in distillers dried grains (DDG) are practiced in laboratories serving the agricultural sector. A large interlaboratory variability among results has been observed in the industry. Methods for moisture, crude fat, and crude fiber are empirical, thus part of this variability can be attributed to the use of different methods of analysis. A study was organized and supported by the American Feed Industry Association, the Renewable Fuels Association, and the National Corn Grain Association to evaluate the efficacy, applicability, and the intralaboratory variation of a number of methods for moisture, crude protein, crude fat, and crude fiber in DDG with solubles (DDGS). The moisture methods included in the study are AOAC 930.15, AOAC 934.01, AOAC 935.29, AOAC 2003.06, and National Forage Testing Association (NFTA) 2.2.2.5; the crude protein methods studied are AOAC 990.03 and AOAC 2001.13; the crude fat methods studied are AOAC 945.16, AOAC 954.02, AOAC 2003.05, and AOAC 2006.06; and the crude fiber methods studied are AOAC 978.10 and AOCS Ba 6a-05. A second study was undertaken to assess existing interlaboratory variation of the same methods in 23 laboratories. Based on the results of these studies, the sponsoring associations established recommended reference methods for use in commercial trade of DDGS. The reference methods selected are NFTA 2.2.2.5 for moisture, AOAC 990.03 and AOAC 2001.11 for crude protein, AOAC 945.16 for crude fat, and AOAC 978.10 for crude fiber.
Development of Chromatographic Methods for Determination of Agrimoniin and Related Polyphenols in Pharmaceutical Products
Authors: Fecka Izabela
Published: February 2020

Thin-layer chromatography (TLC) and liquid chromatography (LC) methods were developed for the qualitative and quantitative determination of agrimoniin, pedunculagin, ellagic acid, gallic acid, and catechin in selected herbal medicinal products from Rosaceae: Anserinae herba, Tormentillae rhizoma, Alchemillae herba, Agrimoniae herba, and Fragariae folium. Unmodified silica gel (TLC Si60, HPTLC LiChrospher Si60) and silica gel chemically modified with octadecyl or aminopropyl groups (HPTLC RP18W and HPTLC NH2) were used for TLC. The best resolution and selectivity were achieved with the following mobile phases: diisopropyl etheracetoneformic acidwater (40 30 20 10, v/v/v/v), tetrahydrofuranacetonitrilewater (30 10 60, v/v/v), and acetoneformic acid (60 40, v/v). Concentrations of the studied herbal drugs were determined by using a Chromolith Performance RP-18e column with acetonitrilewaterformic acid as the mobile phase. Determinations of linearity, range, detection and quantitation limits, accuracy, precision, and robustness showed that the HPLC method was sufficiently precise for estimation of the tannins and related polyphenols mentioned above. Investigations of suitable solvent selection, sample extraction procedure, and short-time stability of analytes at storage temperatures of 4 and 20C were also performed. The percentage of agrimoniin in pharmaceutical products was between 0.57 and 3.23.
Determination of Fenitrothion in River Water and Commercial Formulations by Adsorptive Stripping Voltammetry with a Carbon Ceramic Electrode
Authors: Majidi Mir Reza , Asadpour-Zeynali Karim , Nazarpur Mohammad
Published: February 2020

A sol-gel carbon ceramic electrode (CCE) without any assigned electron transfer mediator or specific reagents was used for the determination of fenitrothion by square-wave adsorptive stripping voltammetry. Fenitrothion strongly adsorbs on a CCE surface, which enables the development of facile electrochemical quantitative methods. Operational parameters such as pH value, initial potential value, and pulse frequency were optimized, and the stripping voltammetric performance was studied by using square-wave voltammetry. Square-wave adsorptive stripping voltammetry was used to obtain calibration curves with 2 linear ranges, 0.0050.1 and 0.150 M; the lower linear range was used to calculate the detection limit, 0.0016 M (5 min adsorption). The effect of interference species on the determination of fenitrothion was also studied. The inherent stability, high sensitivity, low detection limit, and low cost of analysis are the advantages of this sensor. The present method was successfully applied to the determination of fenitrothion in a commercial formulation and river water samples. Analysis of real water samples by using the sensor demonstrated the feasibility of applying the sensor to the on-site monitoring of organophosphate compounds.
Multiresidue Analysis of 102 Organophosphorus Pesticides in Produce at Parts-per-Billion Levels Using a Modified QuEChERS Method and Gas Chromatography with Pulsed Flame Photometric Detection
Authors: Schenck Frank , Wong Jon , Lu Chenseng , Li Jing , Holcomb Jim R , Mitchell LaTonya M
Published: February 2020

A multiresidue method for the analysis of organophosphorus pesticides in fresh produce at levels down to 1.0 g/kg (ppb) has been developed using a modification of the QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure. The procedure entails extraction of pesticides from the sample with acetonitrile, salting-out with magnesium sulfate (MgSO4) and sodium chloride, and cleanup of the resulting extracts with dispersive solid-phase extraction using primary-secondary amine, graphitized carbon black, and MgSO4. Fortification studies were performed for 102 organophosphorus pesticides at 1.0, 10, and 100 ppb in 4 different pesticide-free commodities (grape, orange, spinach, and tomato). Recoveries ranged from 63125, with >80 being achieved for most of the pesticides tested in each commodity. The procedure was applied to the analysis of 400 produce samples collected from a cohort of children that participated in the Children's Pesticide Exposure Study and the Longitudinal Dietary Pesticide Exposure Study in which selected 24 h duplicate food items were collected throughout a 12-month period. Residues of 15 of the 102 pesticides were detected at levels ranging from <1 to 526 ppb.
Validation of a Solid-Phase Extraction and Ultra-Performance Liquid Chromatographic Tandem Mass Spectrometric Method for the Detection of 16 Glucocorticoids in Pig Tissues
Authors: Shao Bing , Cui Xiaoliang , Yang Yi , Zhang Jing , Wu Yongnin
Published: February 2020

A sensitive analytical method has been developed and validated for simultaneous determination of 16 glucocorticoid (fluorometholone, flumethasone, triamcinolone, aldosterone, clobetasol propionate, methylprednisolone, fluocinolone acetonide, hydrocortisone, prednisone, dexamethasone, beclomethasone, prednisolone, budesonide, triamcinolone acetonide, fludrocortisone acetate, and cortisone) residues in pig tissues (muscle, liver, and kidney). These biosamples were hydrolyzed with -glucuronidase/arylsulfatase enzyme and passed through a Supelclean ENVI-Carb graphitized carbon black solid-phase extraction cartridge, followed by further purification using aminopropyl cartridges. Analytes were separated on an ultra-performance liquid chromatography BEH C18 column followed by tandem mass spectrometry (MS) with an electrospray ion source. The MS data acquisition was performed in the negative multireaction monitoring mode by a time-scheduled multireaction monitoring program. The assay for the 16 glucocorticoids were linear over the range of 1250 g/L for pork, liver, and kidney, with correlation coefficient >0.99. Estimated detection limits for the target analytes ranged from 0.03 to 0.30 g/kg, and limits of quantitation ranged from 0.10 to 1.00 g/kg. Recoveries of the glucocorticoids (spiked at levels of 0.4 and 2.0 g/kg) ranged from 81.0 to 112.3, with relative standard deviations between 2.6 and 16.6.