bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Liquid Chromatographic Methods for Determination of Quinocetone and Its Main Metabolites in Edible Tissues of Swine and Chicken
Authors: Huang Lingli , Xiao Aiguo , Fan Shengxian , Yin Juyi , Chen Pin , Liu Dengcai , Qiu Yinsheng , Wang Yulian , Yuan Zonghui
Published: February 2020

Quinocetone (QCT), a new antimicrobial growth promotant of quinoxalines, can effectively improve the growth and feed efficiency of food animals with more safety than is provided by olaquindox and carbadox. To clarify its metabolism and residue levels in animals, a liquid chromatographic method with UV-Vis detection was developed for the determination of QCT and its main metabolites, desoxyquinocetone (DQCT) and 3-methyl-quinoxaline-2-carboxylic acid (MQCA), in muscle, liver, kidney, and fat of swine and chicken. For sample pretreatment, QCT and DQCT were extracted with ethyl acetate and purified with iso-octane; after alkaline hydrolysis of the tissue, MQCA was extracted with ethyl acetate and citric acid buffer (pH 6.0), and the extract was purified over a cation-exchange column (AG MP-50 resin). Detection was at 312 and 320 nm for QCT and DQCT, respectively, and at 320 nm for MQCA. The observed limit of detection for the 3 compounds was 0.025 μg/g in various tissues. The methods were linear over the concentrations range of 0.01-0.64 μg/mL with mean recoveries of approximately 71–86% and relative standard deviations of about 4–12% at the levels of 0.05, 0.10, and 0.20 μg/g. The method is highly selective and can be applied to the determination of QCT and its main metabolites in animal tissues, which would accelerate the pharmacokinetic and residue study of QCT in food animals.
Spectrophotometric Methods for the Determination of the Antidepressant Drug Paroxetine Hydrochloride in Tablets
Authors: Önal Armağan , Kepekçi Evrim.Ş , Öztunç Aysel
Published: February 2020

Simple, sensitive, and accurate visible spectrophotometric methods are described for the determination of paroxetine hydrochloride (PA) in tablets. Among them, the first 3 methods are based on the ion-pair complexes of PA formed with bromothymol blue (BTB), bromophenol blue (BPB), and bromocresol green (BCG) in aqueous acidic buffers. The complex species extracted into chloroform were quantitatively measured at 414 nm with BTB and BCG and at 412 nm with BPB. Beer's law was obeyed over the concentration ranges of 2–20, 2–16, and 2–16 μg/mL, respectively. The fourth method described is based on a coupling reaction between PA and 7-chloro-4-nitrobenzofurazon (NBD-Cl) in borate buffer, pH 8.5, in which a yellow reaction product that was measured at 478 nm was formed. The Beer's law range for this method was 2–10 μg/mL. The last method developed describes the interaction of PA base, as an n-electron donor, with 7,7,8,8-tetracyanoquinodimethane (TCNQ), as a π-acceptor, in acetonitrile to give blue-colored TCNQ− radical anion with absorption maxima at 750 and 845 nm. Measured at 845 nm, the absorbance–concentration plot was rectilinear over the range of 1.5–15 μg/mL. The new methods developed were successfully applied to the determination of PA in tablets without any interference from common tablet excipients. The results of the methods were in good agreement with those obtained with an official liquid chromatographic method. This report describes first colorimetric methods for the determination of PA.
Evaluation of a Chromogenic Medium for Identification and Differentiation of Listeria monocytogenes in Selected Foods
Authors: Lauer Wendy F , Facon Jean-Pierre , Patel Asmita
Published: February 2020

Listeria monocytogenes continues to be a threat to food safety in the United States despite a “zero tolerance” policy. When Listeria species are identified by standard cultural methods, confirmation of L. monocytogenes takes days to complete. RAPID'L.Mono™ agar, developed by Bio-Rad Laboratories, is a chromogenic medium that differentiates L. monocytogenes from other species of Listeria by a simple color change reaction. Differentiation is based on the specific detection of phosphatidylinositol phospholipase C activity, resulting in a blue colony, and the inability of L. monocytogenes to metabolize xylose, resulting in the absence of a yellow halo. Detection principles of standard method agars, Oxford and PALCAM, are based on the ability of all species of Listeria to hydrolyze esculin. Thus, all species of Listeria have similar colony morphology on these agars, making differentiation of pathogenic L. monocytogenes from other nonhuman pathogens difficult. RAPID'L.Mono agar has been validated with surimi, mixed salad, brie, and processed deli turkey because of the prevalence of L. monocytogenes in these foods. Sensitivity and specificity for this medium was determined to be 99.4 and 100%, respectively. Overall method agreement of RAPID'L.Mono with standard culture methods (U.S. Department of Agriculture/Food Safety and Inspection Service; U.S. Food and Drug Administration/Bacteriological Analytical Manual; and AOAC INTERNATIONAL) was excellent, with enrichment protocols 24 h shorter than those of standard methods.
Characterization and Event Specific-Detection by Quantitative Real-Time PCR of T25 Maize Insert
Authors: Collonnier Cécile , Schattner Alexandra , Berthier Georges , Boyer Francine , Coué-Philippe Géraldine , Diolez Annick , Duplan Marie-Noëlle , Fernandez Sophie , Kebdani Naïma , Kobilinsky André , Romaniuk Marcel , Beuckeleer Marc de , Loose Marc de , Windels Pieter , Bertheau Yves
Published: February 2020

T25 is one of the 4 maize transformation events from which commercial lines have so far been authorized in Europe. It was created by polyethylene glycol-mediated transformation using a construct bearing one copy of the synthetic pat gene associated with both promoter and terminator of the 35S ribosomal gene from cauliflower mosaic virus. In this article, we report the sequencing of the whole T25 insert and the characterization of its integration site by using a genome walking strategy. Our results confirmed that one intact copy of the initial construct had been integrated in the plant genome. They also revealed, at the 5′ junction of the insert, the presence of a second truncated 35S promoter, probably resulting from rearrangements which may have occurred before or during integration of the plasmid DNA. The analysis of the junction fragments showed that the integration site of the insert presented high homologies with the Huck retrotransposon family. By using one primer annealing in the maize genome and the other in the 5′ end of the integrat ed DNA, we developed a reliable event-specific detection system for T25 maize. To provide means to comply with the European regulation, a real-time PCR test was designed for specific quantitation of T25 event by using Taqman® chemistry.
Novel Reference Gene, High-mobility-group protein I/Y, Used in Qualitative and Real-Time Quantitative Polymerase Chain Reaction Detection of Transgenic Rapeseed Cultivars
Authors: Weng Haibo , Yang Litao , Liu Zhili , Ding Jiayu , Pan Aihu , Zhang Dabing
Published: February 2020

With the development of transgenic crops, regulations to label the genetically modified organisms (GMOs) and their derived products have been issued in many countries. Polymerase chain reaction (PCR) methods are thought to be reliable and useful techniques for qualitative and quantitative detection of GMOs. These methods are generally needed to amplify the transgene and compare the amplified results with that of a corresponding reference gene to get the reliable results. Specific primers were developed for the rapeseed (Brassica napus), High-mobility-group protein I/Y (HMG-I/Y) single-copy gene and PCR cycling conditions suitable for the use of this sequence as an endogenous reference gene in both qualitative and quantitative PCR assays. Both methods were assayed with 15 different rapeseed varieties, and identical amplified products were obtained with all of them. No amplification was observed when templates were the DNA samples from the other species of Brassica genus or other species, such as broccoli, stem mustard, cauliflower, Chinese cabbage, cabbage, sprouts, Arabidopsis thaliana, carrot, tobacco, soybean, mung bean, tomato, pepper, eggplant, plum, wheat, maize, barley, rice, lupine, and sunflower. This system was specific for rapeseed. Limits of detection and quantitation in qualitative and quantitative PCR systems were about 13 pg DNA (about 10 haploid genomes) and about 1.3 pg DNA (about 1 haploid genome), respectively. To further test the feasibility of this HMG-I/Y gene as an endogenous reference gene, samples containing transgenic rapeseed GT73 with the inserted glyphosate oxidoreductase (GOX) gene were quantitated. These demonstrated that the endogenous PCR detection systems were applicable to the qualitative and quantitative detection of transgenic rapeseed.
Detection of Genetically Modified Corn (Bt176) in Spiked Cow Blood Samples by Polymerase Chain Reaction and Immunoassay Methods
Authors: Petit Laetitia , Baraige Fabienne , Bertheau Yves , Brunschwig Philippe , Diolez Annick , Duhem Koenraad , Duplan Marie-Noëlle , Fach Patrick , Kobilinsky André , Lamart Stephen , Schattner Alexandra , Martin Patrice
Published: February 2020

The fate of DNA and protein transgenic sequences in products derived from animals fed transgenic crops has recently raised public interest. Sensitive molecular tests targeting the Bt176 genetic construct and the transgenic Cry1Ab protein were developed to determine whether plant sequences, especially transgenic sequences, are present in animal products. A protocol for total DNA extraction and purification from cow whole blood samples was first drawn up and assessed by spiking with known amounts of DNA from Bt176 maize. The limit of detection for transgenic sequences (35S promoter and Bt176-specific junction sequence) was determined by both the polymerase chain reaction–enzyme-linked immunosorbent assay (PCR–ELISA) and the 5′-nuclease PCR assay. Four additional PCR systems were built to substantiate the results. The first detects a mono-copy maize-specific sequence (ADH promoter). Two others target multi-copy sequences from plant nucleus (26S rRNA gene) and chloroplast (psaB gene). The last one, used as a positive control, targets a mono-copy animal sequence (αs1-casein gene). Both methods detected a minimum spiking at 25 copies of Bt176 maize/mL in 10 mL whole blood samples. The sandwich ELISA kit used detected down to 1 ng transgenic Cry1Ab protein/mL spiked whole blood.
Determination of Penicillin G in Feeds by Liquid Chromatography with Solid-Phase Extraction
Authors: Gramse Matthew J , Jacobson Paul E
Published: February 2020

A liquid chromatographic method was developed for the determination of penicillin G in feeds. The method involves extraction of penicillin G with methanol, concentration under a stream of nitrogen, and cleanup using Phenomenex Strata-X solid-phase extraction cartridge. Analyte separation and quantification were achieved by gradient reversed-phase liquid chromatography and ultraviolet absorbance at 230 nm. Average spike recoveries for samples prepared at 3 spiking levels (25, 50, and 200 g/ton) were 96.3, 92.1, and 88.6%, respectively. The overall method precision at each of the 3 spiking levels was ≤5.39% relative standard deviation. The limits of detection and quantititation (g/ton formulation) were 3.89 and 13.0 g/ton, respectively.
Development of Methods for Determination of the Residues of 15 Pesticides in Medicinal Herbs Isatis indigotica Fort. by Capillary Gas Chromatography with Electron Capture or Flame Photometric Detection
Authors: Tang Feng , Yue Yongde , Hua Rimao , Ge Shimei , Tang Jie
Published: February 2020

Two multiresidue methods were developed for the determination of 15 pesticides (organochlorines, organphosphorus compounds, pyrethroids, and fungicides) in medicinal herbs Isatis indigotica Fort. and its formulations. The analytical procedure is based on ultrasonic assisted extraction and liquid-liquid extraction (LLE). After solvents were added, the raw material or granule sample was sonicated in an ultrasonic water bath and then centrifuged, filtered, and cleaned up by LLE. The infusion sample was extracted with petroleum ether by LLE. The pesticide residues were determined by capillary gas chromatography with electron-capture or flame photometric detection. Recoveries with the method at concentrations between 0.4 μg/kg and 10 μg/kg ranged from 70.2 to 119.5% for raw material, 73.2 to 105.1% for granule formulation, and 72.8 to 113.3% for infusion formulation. The relative standard deviation values were <20% for all of the pesticides studied. The pesticide detection limits were within the ranges 0.3–0.5 μg/L for endosulfan, 3–7.5 μg/L for pyrethroids, 0.7–32.5 μg/L for organophosphorus pesticides, and 0.1–0.6 μg/L for the other pesticides. The proposed methods are simple and rapid and provide simultaneous determination of pesticide residues in Isatis indigotica Fort. with acceptable recoveries and repeatability and an adequate limit of determination.
Real-Time Polymerase Chain Reaction Detection of Cauliflower mosaic virus to Complement the 35S Screening Assay for Genetically Modified Organisms
Authors: Cankar Katarina , Ravnikar Maja , Žel Jana , Gruden Kristina , Toplak Nataša
Published: February 2020

Labeling of genetically modified organisms (GMOs) is now in place in many countries, including the European Union, in order to guarantee the consumer's choice between GM and non-GM products. Screening of samples is performed by polymerase chain reaction (PCR) amplification of regulatory sequences frequently introduced into genetically modified plants. Primers for the 35S promoter from Cauliflower mosaic virus (CaMV) are those most frequently used. In virus-infected plants or in samples contaminated with plant material carrying the virus, false-positive results can consequently occur. A system for real-time PCR using a TaqMan minor groove binder probe was designed that allows recognition of virus coat protein in the sample, thus allowing differentiation between transgenic and virus-infected samples. We measured the efficiency of PCR amplification, limits of detection and quantification, range of linearity, and repeatability of the assay in order to assess the applicability of the assay for routine analysis. The specificity of the detection system was tested on various virus isolates and plant species. All 8 CaMV isolates were successfully amplified using the designed system. No cross-reactivity was detected with DNA from 3 isolates of the closely related Carnation etched ring virus. Primers do not amplify plant DNA from available genetically modified maize and soybean lines or from different species of Brassicaceae or Solanaceae that are natural hosts for CaMV. We evaluated the assay for different food matrixes by spiking CaMV DNA into DNA from food samples and have successfully amplified CaMV from all samples. The assay was tested on rapeseed samples from routine GMO testing that were positive in the 35S screening assay, and the presence of the virus was confirmed.
Experimental Evaluation of Different Precision Criteria Applicable to Microbiological Counting Methods
Authors: Lombard Bertrand , Cornu Marie , Lahellec Cecile , Feinberg Max H
Published: February 2020

The dispersion of microbiological counting measurements, when repeating the analysis on the same material both within a laboratory (repeatability) and between laboratories (reproducibility) can be characterized by the organization of interlaboratory studies, where several sets of identical test materials are sent to several laboratories. Using the example of data generated by an interlaboratory study on enumeration of Listeria monocytogenes in foods by the standardized reference method (colony-count technique), 2 types of robust estimators of reproducibility standard deviations, based on the median, were examined, in comparison with the classical estimators, based on the mean. Experimental evaluation indicated that the 3 approaches gave consistent results for most of the combinations. The usual log10 transformation of the enumeration results was also questioned before these calculations were conducted.
Sensitive Determination of Anionic Surfactants in Water with Trans-4-[4′-(N-methyl-N-hydroxylethylamino)-cinnamyl-N-9-(4′-(2,2′:6′,2″-terpyridine))-phenylmethylene]pyridine Bromide by the Light-Absorption Ratio Variation Approach
Authors: Yang Jia-Xiang , Gao Hong-Wen , Hu Zhang-Jun , Jiang Min-Hua
Published: February 2020

The light-absorption ratio variation approach was described and applied to the determination of anionic surfactants (AS) in water with a novel chromophore, Trans 4-[4′-(N-methyl-N-hydroxylethylamino)-cinnamyl-N-9-(4′-(2,2′:6′,2″-terpyridine))-phenylmethylene]pyridine bromide (BTMHCTPP). The complexations between BTMHCTPP and sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS) at pH 3.85 were characterized by the break point approach. Results have shown that both 1BTMHCTPP:1SDS and 1BTMHCTPP:1SDBS complexes were formed, and that ΔAr (ΔAr = light-absorption ratio variation) is linear for the range of AS between 0.05 and 1.00 mg/L. The limits of detection (3σ) are 0.045 mg/L for SDS and 0.040 mg/L for SDBS. The complexation is selective in the presence of EDTA, and it has been applied to the analysis of water samples with satisfactory results.
Bioactive Peptides Derived from Food
Authors: Rutherfurd-Markwick Kay J , Moughan Paul J
Published: February 2020

As interest in the ability of functional foods to impact on human health has grown over the past decade, so has the volume of knowledge detailing the beneficial roles of food-derived bioactive peptides. Bioactive peptides from both plant and animal proteins have been discovered, with to date, by far the most being isolated from milk-based products. A wide range of activities has been described, including antimicrobial and antifungal properties, blood pressure-lowering effects, cholesterol-lowering ability, antithrombotic effects, enhancement of mineral absorption, immunomodulatory effects, and localized effects on the gut. Although there is still considerable research to be performed in the area of food-derived bioactive peptides, it is clear that the generation of bioactive peptides from dietary proteins during the normal digestive process is of importance. Therefore, it will become necessary when determining dietary protein quality to consider the potential effects of latent bioactive peptides that are released during digestion of the protein.
Determination of Pantothenic Acid in Foods by Optical Biosensor Immunoassay
Authors: Haughey Simon A , O'Kane Anthony A , Baxter G Andrew , Kalman Andras , Trisconi Marie-José , Indyk Harvey E , Watene Gaylene A
Published: February 2020

An optical biosensor inhibition immunoassay was developed using a specific pantothenic acid-binding protein for the quantitation of free pantothenic acid (vitamin B5) in foodstuffs. Samples were prepared by a simple extraction procedure in buffer, and vitamin content was estimated against authentic calibrants in the same buffer. Performance parameters included a working range of 10–5000 ng/mL, a limit of detection of 4.4 ng/mL, precision relative standard deviation of 5.4–7.1% over a range of concentrations, and recoveries >95% in the matrixes tested. A wide range of foodstuffs, including National Institute of Standards and Technology reference samples, were tested in 3 independent laboratories and the results were compared with microbiological assay and liquid chromatography/mass spectrometry (LC/MS) methods. The results indicate that the biosensor technique is appropriate for the estimation of pantothenic acid in a wide range of foodstuffs.
A Simple Determination of Mizoribine in Human Plasma by Liquid Chromatography with UV Detection
Authors: Kaji Hiroaki , Maiguma Takayoshi , Inukai Yoko , Ono Hiroshige , Taniguchi Ritsuko , Makino Kazutaka , Tagawa Yoshinobu , Teshima Daisuke
Published: February 2020

A simple liquid chromatography (LC) method was developed for determination of the therapeutic level of mizoribine in human plasma. After precipitation of plasma proteins with 6% perchloric acid, mizoribine was determined by LC with spectophotometric detection. The peak height for mizoribine was linearly related to its concentrations, which ranged from 0.09 to 3.13 μg/mL. Therefore, the limit of quantitation was considered to be 0.09 μg/mL. The accuracy was 104.96–107.37%. The intra- and interday relative standard deviation values were in the range of 1.10–3.25%. The detection limit was 0.025 μ g/mL, defined as a signal-to-noise ratio of 3. The plasma concentrations of mioribine were not related to the dosage. Because mizoribine was mainly excreted in the urine, the plasma concentrations of mizoribine might be affected by a change in renal function. Therefore, the mizoribine concentration in blood should be monitored and the dosage adjusted, depending on the condition of renal function. It was suggested that the present method may be applied well in the therapeutic drug monitoring for mizoribine.
Optimization of Two Flow-Injection Spectrophotometric Methods for the Determination of Indapamide in Pharmaceutical Dosage Forms
Authors: Rodríguez Juan C , Barciela Julia , García Sagrario , Herrero Carlos , Peña Rosa M
Published: February 2020

Multivariate experimental design has been used to optimize 2 flow-injection spectrophotometric methods for the determination of indapamide in pharmaceutical dosage forms, both pure and commercial tablets. The methods are based on the oxidation of this drug with iron (III) in acidic medium and the subsequent formation of an intensive orange-red complex between the liberated iron (II) and 2,2′-bipyridyl or 1,10-phenanthroline reagents. Plackett-Burman designs were applied as a screening method to evaluate the most significant factors with few experiments. Central composite 23+ star designs were performed to evaluate the response surfaces. The methods have been fully validated and were applied successfully to the determination of indapamide in pure and pharmaceutical forms with good accuracy and precision. Therefore, the 2 proposed procedures are simple, inexpensive, and rapid flow methods for the routine determination of indapamide in pharmaceutical preparations.
A New Process for Preparation of Soybean Protein Concentrate with Hexane-Aqueous Ethanol Mixed Solvents
Authors: Zhang Wei-Nong , Liu Da-Chuan
Published: February 2020

A new process for the preparation of soybean protein concentrate (SPC) by directly extracting full-fat soy flour with a mixture of hexane and aqueous ethanol was established. Compared with conventional methods, it has some advantages, such as saving energy and reducing protein denaturation caused by heat action during solvent recovery, because this process saves one step of solvent recovery. The effects of aqueous ethanol concentration and the mixure ratio (hexane to ethanol) on the degree of protein denaturation and product quality were investigated, on the basis of which the orthogonal tests were performed. The optimum technical parameters were obtained by analyzing the results of the orthogonal tests with statistical methods. We found that SPC can be obtained by extracting full-fat soy flour under the following conditions: mixture ratio hexane: 90% ethanol, 9:1, v/v; extraction temperature, 45°C; ratio of solid to solvents, (1:2 w/v); and 5 repeated extractions (15 min each time). The results of quality analysis showed that solubility of the product was improved significantly [nitrogen solubility index (NSI) 46.6%] compared with that for ethanol washing of protein concentrate (NSI 8.7%).
Sample Preparation Improvement in Polycyclic Aromatic Hydrocarbons Determination in Olive Oils by Gel Permeation Chromatography and Liquid Chromatography with Fluorescence Detection
Authors: Martinez-López Sandra , Morales-Noé Asuncion , Pastor-Garcia Agustin , Morales-Rubio Angel , Guardia Miguel de la
Published: February 2020

The determination of 15 polycyclic aromatic hydrocarbons (PAHs) in olive oil samples has been improved in order to obtain a fast methodology with a low limit of detection through the combination of liquid–liquid extraction with acetonitrile and preparative gel permeation chromatography (GPC) prior to the injection of purified extracts into a C18 column. Acetonitrile–water was used as the mobile phase with a gradient from 50 to 95%, w/w, acetonitrile in 30 min. The oven temperature was maintained at 15°C, and fluorometric detection was made at a fixed excitation wavelength of 264 nm and variable, optimal emission wavelength for each analyte ranging from 352 nm for 11-H-benzo(b)fluorene to 500 nm for indeno(1,2,3-cd)pyrene. Recovery for all the compounds studied varied from 75 to 111%, and limit of detection values from 0.05 ng/g for benzo(k)fluoranthene to 0.48 ng/g for indeno(1,2,3-cd)pyrene, corresponding to 0.09 ng/g benzo(a)pyrene. Results were compared with those obtained by liquid–liquid extraction followed by a cleanup on silica and a direct GPC treatment of oil samples diluted in dichloromethane, 2 other methodologies that are appropriate for quantifying PAHs in olive oils. However, the proposed method improves the determination limits, reduces the time of analysis, and provides a highly stable baseline for sample chromatograms.
Liquid Chromatography with Mass Spectrometry—Detection of Lipophilic Shellfish Toxins
Authors: Stobo Lesley A , Lacaze Jean-Pierre C L , Scott Alasdair C , Gallacher Susan , Smith Elizabeth A , Quilliam Michael A
Published: February 2020

A rapid multiple toxin method based on liquid chromatography with mass spectrometry (LC/MS) was developed for the detection of okadaic acid (OA), dinophysistoxin-1 (DTX-1), DTX-2, yessotoxin (YTX), homoYTX, 45-hydroxy-YTX, 45-hydroxyhomo-YTX, pectenotoxin-1 (PTX-1), PTX-2, azaspiracid-1 (AZA-1), AZA-2, and AZA-3. Toxins were extracted from shellfish using methanol–water (80%, v/v) and were analyzed using a C8 reversed-phase column with a 5 mM ammonium acetate–acetonitrile mobile phase under gradient conditions. The method was validated for the quantitative detection of OA, YTX, PTX-2, and AZA-1 in 4 species (mussels, Mytilus edulis; cockles, Cerastoderma edule; oysters, Crassostrea gigas; king scallop, Pecten maximus) of shellfish obtained from United Kingdom (UK) waters. Matrix interferences in the determination of the toxins in these species were investigated. The validated linear range of the method was 13–250 μg/kg for OA, PTX-2, and AZA-1 and 100–400 μg/kg for YTX. Recovery and precision ranged between 72–120 and 1–22%, respectively, over a fortification range of 40–160 μg/kg for OA, PTX-2, and AZA-1 and 100–400 μg/kg for YTX. The limit of detection, reproducibility, and repeatability of analysis showed acceptable performance characteristics. A further LC/MS method using an alkaline hydrolysis step was assessed for the detection of OA, DTX-1, and DTX-2 on their esterified forms. In combination with the LC/MS multiple toxin method, this allows detection of all toxin groups described in Commission Decision 2002/225/EC.
Quantitative Evaluation of 28 Mineral Elements by Inductively Coupled Plasma/Mass Spectrometry and Its Application in Source Identification of Indian Opium
Authors: Mudiam Mohanakrishna R , Kumar Sanjukta A , Mahadevan Sudhershanan , Ghosh Priyankar , Sarin Rajendra K , Beedu Sashidhar R
Published: February 2020

An analytical method based on inductively coupled plasma/mass spectrometry (ICP/MS) was developed for the determination of 28 mineral elements (Cr, Mn, Co, Ni, Cu, Zn, Ga, Sr, Cd, Ag, Ba, Pb, Bi Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in Indian opium samples. The detection limits were found to be in the range of 0.0008–0.45 ng/mL. The recoveries of spiked samples for each element were found to be in the range of 83–106%, with a precision of less than 9%. A total of 124 opium samples from India were analyzed for the distribution pattern of the 28 mineral elements. Quantitative elemental data were subjected to chemometric analysis in order to determine an optimal classifier to evaluate the source of Indian opium. The study indicated that mineral elements might not be the suitable discriminators for the discrimination of licit opium-growing divisions of India. However, the methodology developed and the analytical data on elemental profile may find important forensic application in discriminating Indian opium with that of licit and illicit opium originating from different geographical regions of world.
Quantitative Determination of β-Asarone in Calamus by High-Performance Thin-Layer Chromatography
Authors: Widmer Valeria , Schibli Anne , Reich Eike
Published: February 2020

A quantitative high-performance thin-layer chromatographic method for determination of β-asarone in Calamus rhizome was developed and validated. The method is suitable for proper identification of Acorus calamus. Through the use of caffeine-modified silica gel as the stationary phase and toluene–ethyl acetate (93 + 7, v/v) as the mobile phase, β-asarone is baseline separated from its isomer α-asarone. Scanning densitometry with absorption measurement at 313 nm allows specific, accurate, and precise quantification of β-asarone. The working range of 40 to 200 ng absolute of the target substance is sufficient to establish whether a given sample passes the limit test of 0.5% maximum as required by the Swiss Pharmacopoeia.
Analysis of Phenothiazines in Human Body Fluids Using Disk Solid-Phase Extraction and Liquid Chromatography
Authors: Marumo Akemi , Kumazawa Takeshi , Lee Xiao-Pen , Fujimaki Koichiro , Kuriki Ayako , Hasegawa Chika , Sato Keizo , Seno Hiroshi , Suzuki Osamu
Published: February 2020

Seven phenothiazine derivatives, perazine, perphenazine, prochlorperazine, propericiazine, thioproperazine, trifluoperazine, and flupentixol, have been found to be extractable from human plasma and urine samples using disk solid-phase extraction (SPE) with an Empore C18 cartridge. Human plasma and urine (1 mL each) containing the 7 phenothiazine derivatives were mixed with 2 mL of 0.1M NaOH and 7 mL distilled water and then poured into the disk SPE cartridges. The drugs were eluted with 1 mL chloroform– acetonitrile (8 + 2) and determined by liquid chromatography with ammonium formate/formic acid–acetonitrile gradient elution. The detection was performed by ultraviolet absorption at 250 nm. The separation of the 7 phenothiazine derivatives from each other and from impurities was generally satisfactory using a SymmetryShield RP8 column (150 × 2.1 mm id, 3.5 μm particle size). The recoveries of the 7 phenothiazine derivatives spiked into plasma and urine samples were 64.0–89.9% and 65.1–92.1%, respectively. Regression equations for the 7 phenothiazine derivatives showed excellent linearity, with detection limits of 0.021–0.30 mg/mL for plasma and 0.017–0.30 μg/mL for urine. The within-day and day-to-day coefficients of variation for both samples were commonly below 9.0 and 14.9%, respectively.
Determination of Cefdinir by a Stability-Indicating Liquid Chromatographic Method
Authors: Mehta Tushar N , Subbaiah Gunta , Pundarikakshudu Kilambi
Published: February 2020

A simple, fast, specific, stability-indicating, and precise reversed-phase liquid chromatographic method was developed for the determination of Cefdinir in its different dosage forms, i.e., capsules and suspensions. The method was developed and optimized by analyzing the placebo preparation, formulations, and degraded samples of the drug substance according to the International Conference on Harmonization. The proposed method can successfully separate the drug from degradation products formed under stress conditions along with pharmaceutical ingredients such as preservatives. The developed method was used successfully to determine Cefdinir in capsules and Insta-use suspensions. The developed method was found to be linear for a concentration range of 6–14 μg/mL. Average recoveries obtained with the method were 99.3 ± 0.4 and 99.6 ± 0.4% for Insta-use suspensions and capsules, respectively. The method was shown to be specific, precise, and robust.
Determination of Chlormequat and Mepiquat in Foods by Liquid Chromatography/Mass Spectrometry or Liquid Chromatography/Tandem Mass Spectrometry: Interlaboratory Study
Authors: Alder Lutz , Startin James R ,   Collaborators:, Alonso S , Anspach T , Brewin S , Broekaert C , Christiansen A , DeKok A , Frase U , Fresvig M , Hemmerling Ch , Hermansson E , Hiemstra M , Hogendoorn E , Kolb J , Kombal R , Melk Ch , Polonji B , Quirijns J K , Ross L , Saint-Joly Ch , Scherbaum E , van Damme D , Welter A , Wüst B
Published: February 2020

Interlaboratory validation studies have been performed on 2 methods for the determination of chlormequat (CLQ) and mepiquat (MPQ). Both methods used identical extraction procedures and stable isotope internal standardization but differed in the use of liquid chromatography/mass spectrometry (LC/MS) or LC/tandem mass spectrometry (LC/MS/MS) for the determination, the amount of internal standard used, and the expected limit of detection. After addition of deuterated internal standards, CLQ and MPQ were extracted with methanol–water and determined by LC/MS or LC/MS/MS with positive electrospray ionization. Eight European laboratories participated in the LC/MS method study, analyzing mushroom, pear, wheat flour, and fruit puree with residues of CLQ in the range 0.040–1.19 mg/kg and of MPQ in the range 0.041–0.39 mg/kg. For CLQ, the Horwitz ratio (HoRat) values for individual test materials/levels were in the range 0.85–1.13 with amean of 1.00, showing good method performance. For MPQ, the Ho values for mushroom, pear (both levels), and wheat flour were in the range 0.83–0.94, again indicating good method performance. For the determination of MPQ in infant food (fruit puree) at 0.041 mg/kg, the Ho was 1.7 when a value of 0 reported by one participant was excluded. In the LC/MS/MS study, in which 11 laboratories participated, a separate sample set was analyzed with residues of CLQ in the range 0.007–1.03 mg/kg and of MPQ in the range 0.008–0.72 mg/kg. Ho values for CLQ were in the range 0.27–1.36 and for MPQ in the range 0.51–2.10, all corresponding to acceptable method performance.
Development of EPA Method 535 for the Determination of Chloroacetanilide and Other Acetamide Herbicide Degradates in DrinkingWater by Solid-Phase Extraction and Liquid Chromatography/TandemMass Spectrometry
Authors: Shoemaker Jody A , Bassett Margarita V
Published: February 2020

U.S. Environmental Protection Agency (EPA) Method 535 has been developed in order to provide a method for the analysis of Alachlor ESA and other acetanilide degradation products, which are listed on EPA's 1998 Drinking Water Contaminant Candidate List. Method 535 uses solid-phase extraction with a nonporous graphitized carbon sorbent to extract the ethane sulfonic acid (ESA) and oxanilic acid degradates of propachlor, flufenacet, dimethenamid, alachlor, acetochlor, and metolachlor from finished drinking water matrixes. Separation and quantitation of the target analytes are achieved with liquid chromatography/tandem mass spectrometry. Dimethachlor ESA and butachlor ESA were chosen during the method development as the surrogate and internal standard. Drinking water samples were dechlorinated with ammonium chloride without adversely affecting the analyte recoveries. Typical mean recoveries of 92116% in deionized water and 89116% in ground water were observed with relative standard deviations of <5%.
Determination of Organophosphorus Pesticide Residues in the Roots of Platycodon grandiflorum by Solid-Phase Extraction and Gas Chromatography with Flame Photometric Detection
Authors: Yi Xionghai , Hua Qing , Lu Yitong
Published: February 2020

Asimple and rapid sample preparation method using accelerated solvent extraction and solid-phase extraction (SPE) cleanup for determining organophosphorus (OP) pesticides in the roots of Platycodon grandiflorum was developed. The OP pesticides were concentrated by use of an SPE cartridge (ENVI-Carb) and quantitatively analyzed and confirmed by capillary gas chromatographywith flame photometric detection. The pesticides were eluted from the cartridges with 20mL acetonitriletoluene (3 1, v/v). The averag recovery from 10 g P. grandiflorum roots, fortified at 3 levels ranging from 0.04 to 1.00 mg/kg, was 91.9 with a relative standard deviation of 4.3. The limits of detection ranged from 1.16 103 mg/kg (dimethoate) to 4.64 103 mg/kg (dichlorvos). The proposed method showed acceptable accuracy and precision while minimizing environmental concerns, time, and labor.
Chemical Fingerprinting of Gardenia jasminoides Fruit Using Direct Sample Introduction and Gas Chromatography with Mass Spectrometry Detection
Authors: Yan Shikai , Xin Wenfeng , Luo Guoan , Wang Yiming , Cheng Yiyu
Published: February 2020

A rapid, rugged, and inexpensive approach is described to develop chemical fingerprints of volatile and semivolatile fractions in herbal medicine. The method is based on the combination of direct sample introduction and gas chromatography (GC) analysis with mass spectrometry detection. In comparison with routine methods, the proposed approach provides the most informative fingerprint and does not demand time-consuming extraction, pretreatment, and cleanup procedures. The approach was applied to establish the GC fingerprint of gardenia fruit (Gardenia jasminoides Ellis), in which 39 components were identified. With the help of principal components analysis, the obtained fingerprint could reveal the variation in and within different herb samples as affected by season and developmental state (wild or cultivated). The results indicated that the proposed approach could serve as a rapid, simple, and effective technique for the quality control of herbal medicines.
Determination of Phenylephrine Hydrochloride, Chlorpheniramine Maleate, and Methscopolamine Nitrate in Tablets or Capsules by Liquid Chromatography with Two UV Absorbance Detectors in Series
Authors: Cieri Ugo R
Published: February 2020

A procedure is presented for the simultaneous determination of phenylephrine HCl (PE), chlorpheniramine maleate (CM), and methscopolamine nitrate in commercial tablets or capsules by liquid chromatography (LC) with 2 UV absorbance detectors in series. Reference and sample solutions are prepared in methanol. LC separations are performed on a 7.5 cm Novapak silica column. The mobile phase is prepared by mixing 930 mL methanol with 70 mL of a 0.5% aqueous solution of 1-pentanesulfonic acid, sodium salt. The injection volume is 20 L; the flow rate is approximately 1 mL/min. Retention times are approximately 1.5 min for PE, 3 min for CM, and 6 min for methscopolamine nitrate. One detector determines the first 2 compounds at 265 nm, but the third compound does not produce a detectable peak. The other detector set at 210 nm generates peaks for all 3 compounds, but only methscopolamine is within the recorder range; the other 2 compounds are exceedingly off scale. If it is not feasible or desirable to arrange 2 UV absorbance detectors in series, separate determinations can be made, one for the first 2 compounds and the other for the third component of the mixture. Two commercial samples of tablets and 2 commercial samples of capsules were analyzed by the proposed method. Recovery studies were also conducted with amounts of the 3 compounds ranging from 80 to 120% of the quantities present in the sample solutions.
Sterol Oxidation in Meat- and Fish-Based Homogenized Baby Foods Containing Vegetable Oils
Authors: Zunin Paola , Salvadeo Paola , Boggia Raffaella , Evangelisti Filippo
Published: February 2020

Sterol oxidation was evaluated in commercial meat- and fish-based homogenized baby foods containing vegetable oil. Gas chromatography coupled with mass spectrometry (GC/MS) was used for the analytical determination of 7-ketocholesterol and 7-ketositosterol, which were chosen as markers of sterol oxidation in lipids of animal origin and vegetable origin, respectively. Cholestanetriol was also quantified, because its negative effects on atherogenesis and other biological processes are well known. In meat-based samplesg/serving. The 7-ketocholesterol and 7-ketositosterol were 2289 and 1140 g/serving, respectively, whereas the 7-ketocholesterol/cholesterol percent ratio was and 11-40 g/serving, respectively, whereas the cholestanetriol levels were 738 g/serving. The 7-ketocholesterol/cholesterol percent ratio was characteristic of each kind of meat and related to the levels of unsaturated fatty acids of animal lipids. In fish-based samples, the cholestanetriol and 7-ketocholesterol levels per serving were significantly lower than in meat samples, but in fish fillets they were about 2025, instead of 40, of the ingredients. The values of the 7-ketocholesterol/ cholesterol percent ratio in fish-based products were close to the values computed for chicken or turkey-based products. The detected values of cholestanetriol showed that the addition of vegetable oil enhances the development of the indirect bimolecular pathway of cholesterol oxidation, which was even more favorable in fish-based products.
Genetics-Based Methods for Detection of Salmonella spp. in Foods
Authors: Mozola Mark A
Published: February 2020

Genetic methods are now at the forefront of foodborne pathogen testing. The sensitivity, specificity, and inclusivity advantages offered by deoxyribonucleic acid (DNA) probe technology have driven an intense effort in methods development over the past 20 years. DNA probe-based methods for Salmonella spp. and other pathogens have progressed from time-consuming procedures involving the use of radioisotopes to simple, high throughput, automated assays. The analytical sensitivity of nucleic acid amplification technology has facilitated a reduction in analysis time by allowing enriched samples to be tested for previously undetectable quantities of analyte. This article will trace the evolution of the development of genetic methods for detection of Salmonella in foods, review the basic assay formats and their advantages and limitations, and discuss method performance characteristics and considerations for selection of methods.
Modeling and Risk Assessment for Salmonella in Meat and Poultry
Authors: Lammerding Anna M
Published: February 2020

Microbial risk assessment is rapidly becoming a well-recognized concept in the management of food- and waterborne microbial hazards. The process of conducting a risk assessment is a structured, systematic approach to integrate and evaluate information from diverse sources concerning the origin and fate of pathogens along the food chain and to determine the magnitude of public health risks. Quantitative modeling of the sources, prevalence, numbers, and behavior of food chain pathogens, such as Salmonella, and of the host/pathogen interaction and consequences are providing scientific information and insights useful for decision makers in managing the safety of the food supply.
Peer Validation of a Method to Confirm Chloramphenicol in Honey by Liquid Chromatography-TandemMass Spectrometry
Authors: Quon Dugane , Carson Mary C , Nochetto Cristina , Heller David N , Butterworth Fred
Published: February 2020

Chloramphenicol (CAP) is extracted from an aqueous dilution of honey using ethyl acetate. The extracts are evaporated and redissolved in water. CAP is then extracted from the aqueous solutions using reversed-phase solid-phase extraction cartridges. CAP is eluted from the reversed-phase cartridges with acetonitrilewater and re-extracted into ethyl acetate. The ethyl acetate is evaporated, and the residue is reconstituted in an aqueous solution. Extracts are chromatographed using a reversed-phase column and analyzed by electrospray negative mode tandem mass spectrometry. Four product ions of precursors m/z 321 or 323 are monitored. The method meets confirmation criteria recommended by the U.S. Food and Drug Administration and 4-point identification criteria established by the European Union. With slight modifications to accommodate different equipment, the method was validated in 2 laboratories.
High-Performance Thin-Layer Chromatography Densitometric Method for Simultaneous Quantitation of Phyllanthin, Hypophyllanthin, Gallic Acid, and Ellagic Acid in Phyllanthus amarus
Authors: Dhalwal Kamlesh , Biradar Yogesh S , Rajani Mandapati
Published: February 2020

Whole plant of Phyllanthus amarus Linn. is a reputed drug of the Indian systems of medicine that is used as hepatoprotective agent. A simple high-performance thin-layer chromatography (HPTLC) densitometric method has been developed for the simultaneous quantitation of phyllanthin, hypophyllanthin, gallic acid, and ellagic acid in the whole plant of P. amarus. They were found at levels of 0.37, 1.16, 0.36, and 0.17% (w/w), respectively. The method was validated for precision, repeatability, and accuracy. Instrumental precision was found to be 0.54, 0.93, 0.08, and 0.78% (coefficient of variation, CV); repeatability of the method was 1.01, 0.79, 0.98, and 1.06% (CV) for phyllanthin, hypophyllanthin, gallic acid, and ellagic acid, respectively. Accuracy of the method was determined by a recovery study conducted at 3 different levels, and the average recovery was found to be 99.09% for phyllanthin, 99.27% for hypophyllanthin, 98.69% for gallic acid, and 100.49% for ellagic acid. The proposed HPTLC method was found to be simple, precise, specific, sensitive, and accurate and can be used for routine quality control of raw material of P. amarus and formulations containing P. amarus. It also has the applicability in quantitating any of these marker compounds in other drugs.
Spectrophotometric Determination of Acyclovir and Ribavirin in Their Dosage Forms
Authors: El-Din Mohie Khaled Sharaf , El-Brashy Amina Mohammed , Sheribah Zeinab Awad , El-Gamal Rania Mohammed
Published: February 2020

Two simple, accurate, and reliable spectrophotometric methods have been developed for the determination of 2 antiviral drugs, acyclovir (ACV) and ribavirin (RBV), in their pharmaceutical formulations. These methods are based on oxidation of the 2 drugs with either cerium (IV) ammonium sulfate (Method A) or potassium persulfate (Method B). The products of oxidation in both methods are coupled with 3-methylbenzothiazolin 2-one hydrazone, producing a deep blue color with a maximum absorption wavelength at 630 nm. In Method A, the absorbanceconcentration plots were linear over the ranges of 550 and 1060 μg/mL with detection limits of 0.18 μg/mL (8 × 107 M) and 0.63 μg/mL (2.58 × 106 M) for ACV and RBV, respectively. In Method B, the ranges were 545 and 2050 μg/mL with detection limits of 0.11 μg/mL (4.88 × 107 M) and 1.40 μg/mL (5.73 × 106 M) for the 2 drugs, respectively. The molar absorptivities were 4.1 × 103 and 3.65 × 103 L/mol/cm in Method A and 5.03 × 103 and 3.97 × 103 L/mol/cm in Method B for the 2 drugs, respectively. The proposed methods were applied successfully for the determination of the 2 drugs in their pharmaceutical formulations. The percentage recoveries standard deviation were 99.57 ± 0.86 and 100.82 ± 0.46 for ACV; 99.41 ± 1.08 and 100.35 ± 1.03 for RBV. The results obtained were compared statistically with those given by official methods and showed no significant differences regarding accuracy and precision.