bluuebunny/crossref_metadata_2025 huggingface dataset:
Bariatric surgery and risk of alcohol use disorder: a register-based cohort study
Authors: Bramming Maja , Becker Ulrik , Jørgensen Maja B , Neermark Søren , Bisgaard Thue , Tolstrup Janne S
Published: July 2020

Background

Bariatric surgery has been associated with altered alcohol metabolism. We examined whether patients undergoing bariatric surgery have a higher risk of developing alcohol use disorder (AUD) compared with individuals with obesity who have not received bariatric surgery.

Methods

In this prospective cohort study, we followed 13 430 patients undergoing bariatric surgery (95% gastric bypass) between 2005 and 2013 and a reference group of 21 021 individuals with obesity for a median of 6.9 years (5th-95th percentile: 4.0–9.8). Four different approaches were used to account for baseline differences between the two groups: (i) adjustment; (ii) inverse probability of treatment weighting (IPTW); (iii) 1:1 matching based on propensity scores; and (iv) before-and-after analysis comparing the bariatric surgery group with itself 5 years before and after surgery. Cox proportional hazard modelling was used to estimate hazard ratios of AUD defined from national registers.

Results

When applying the IPTW approach, the hazard ratio (HR) of AUD for bariatric surgery patients was 7.29 [95% confidence interval (CI): 5.06–9.48] compared with individuals without surgery. When employing different approaches (adjustment for baseline variables, matching on propensity scores, before-and-after analyses), results were of similar magnitude. Analysis stratified by time after surgery revealed a higher risk of AUD already within the first year following surgery [HR: 2.77 (95% CI: 1.39–5.53)].

Conclusions

Patients undergoing bariatric surgery have a higher risk of developing AUD compared with individuals without bariatric surgery. The higher risk observed in this group of patients cannot be explained by differences in baseline characteristics such as socioeconomic factors. Despite the higher risk of AUD, only few individuals developed AUD. Individuals with disabling obesity should therefore not rule out surgery based on these results but rather be aware of negative implications.
On the Distribution of Periods of Holomorphic Cusp Forms and Zeroes of Period Polynomials
Authors: Nordentoft Asbjørn Christian
Published: July 2020

In this paper, we determine the limiting distribution of the image of the Eichler–Shimura map or equivalently the limiting joint distribution of the coefficients of the period polynomials associated to a fixed cusp form. The limiting distribution is shown to be the distribution of a certain transformation of two independent random variables both of which are equidistributed on the circle $\mathbb{R}/\mathbb{Z}$, where the transformation is connected to the additive twist of the cuspidal $L$-function. Furthermore, we determine the asymptotic behavior of the zeroes of the period polynomials of a fixed cusp form. We use the method of moments and the main ingredients in the proofs are additive twists of $L$-functions and bounds for both individual and sums of Kloosterman sums.
Grappling with Dr. Strangelove’s “Wargasm” Fantasy
Authors: Payne Rodger A
Published: July 2020

Dr. Strangelove continues to be viewed as one of the most acclaimed films of all-time. Likewise, international relations (IR) experts commonly list the film among the most essential IR-themed movies. The IR scholars who discuss Dr. Strangelove as a text or recommend it for courses generally claim that it can be used to explain nuclear deterrence, the security dilemma, mutually assured destruction, Cold War competition, and various other traditional serious concerns of the field. They also recognize that the satirical film is critical of nuclear strategy. This article considers Dr. Strangelove’s sexual subtext, involving important metaphors and symbols that IR scholars characteristically ignore. Yet, for decades, film critics and scholars from other disciplines have identified and emphasized the importance of the film's comedic “sexual framework” and concluding “wargasm.” Director Stanley Kubrick even acknowledged these key elements in private correspondence. The film suggests that the national security establishment's masculine view of the utility of nuclear weapons and deterrence are comparable to absurd male sexual fantasies. Feminist IR scholars frequently note that mainstream scholars largely ignore their critique of masculine views of the discipline and nuclear strategy. The article concludes that scholars in the field should both prioritize Dr. Strangelove’s sexual subtext and rely upon feminist contributions to help understand those elements.
Coupling of Size-Exclusion Chromatography to Liquid Chromatography/Mass Spectrometry for Determination of Trace Levels of Thifensulfuron-Methyl and Tribenuron-Methyl in Cottonseed and Cotton Gin Trash
Authors: Stry James J , Amoo Jennifer S , George Steve W , Hamilton-Johnson Teresa , Stetser Ellen
Published: July 2020

Size-exclusion chromatography (SEC) was coupled to reversed-phase liquid chromatography/mass spectrometry for the determination of thifensulfuron-methyl and tribenuron-methyl in cottonseed and cotton gin trash. The limit of quantitation was 20 parts per billion (ppb), and the limit of detection was 6 ppb. The analytes were extracted by homogenization in a buffer solution. The extracts underwent a solvent exchange into methanol and were injected onto an SEC column. As the analytes eluted from the SEC column, the eluate was diverted onto a reversed-phase column for additional separation of the analytes and their detection via mass spectrometry. This method is unique because the samples are not cleaned up before analysis, the analytes are injected in methanol, and the entire analysis is completed in 30 min. Average recoveries and standard deviations for thifensulfuronmethyl and tribenuron-methyl in cotton gin trash were 91 ± 6% and 88 ± 5%, respectively. Average recoveries and standard deviations for thifensulfuron-methyl and tribenuron-methyl in cottonseed were 91 ± 11% and 99 ± 12%, respectively. This is an effective method for the detection and determination of thifensulfuron-methyl and tribenuronmethyl in cotton.
Determination of Phenolic Sympathomimetic Drugs in Pharmaceutical Samples and Biological Fluids by Flow-Injection Chemiluminescence
Authors: Aly Fatma A , Al-Tamimi Salma A , Alwarthan Abdulrahman A
Published: July 2020

A rapid and highly sensitive flow-injection chemiluminometric method was developed for determination of 3 sympathomimetic drugs, namely, etilefrine hydrochloride, isoxsuprine hydrochloride, and prenalterol hydrochloride. The method is based on chemiluminescence induced by oxidation of drugs with acidified potassium permanganate in the presence of formic acid as a carrier. The calibration graphs were linear over the concentration ranges 0.2–9, 0.2–12.5, and 0.025–1.25 μg/mL for the 3 compounds, respectively. The method was applied successfully in determining the drugs in dosage forms and in biological fluids. A proposal for the reaction pathway is suggested.
Identification and Determination of Oxytetracycline, Tiamulin, Lincomycin, and Spectinomycin in Veterinary Preparations by Thin-Layer Chromatography/Densitometry
Authors: Krzek Jan , Kwiecień Anna , Starek Małgorzata , Kierszniewska Anna , Rzeszutko Włodzimierz
Published: July 2020

A thin-layer chromatographic/densitometric method was developed for the identification and quantitation of oxytetracycline, tiamulin, lincomycin, and spectinomycin in veterinary preparations. Silica gel-coated thin layer chromatography plates and 2 mobile phases were used to separate these constituents. The appropriate compositions of the suitable mobile phases were established: 10% citric acid solution–n-hexane–ethanol (80 + 1 + 1, v/v) and n–butanol–ethanol–chloroform– 25% ammonia (4 + 5 + 2 + 5, v/v). Along with Rf values and spot colors, direct UV and visual densitometric measurements were used for identification. Similar measuring ranges were used for quantitative analysis to obtain repeatable and reliable results for the preparations examined. The results of the quantitative analysis are characterized by a small confidence interval and are close to the declared contents of active constituents: oxytetracycline 30.01 ± 0.38 g at λ = 350 nm and 30.24 ± 0.86 g at λ = 430 nm; tiamulin, 10.19 ± 0.86 g at λ = 450 nm; lincomycin, 2.27 ± 0.08 g at λ = 278 nm; and spectinomycin, 2.18 ± 0.07 g at λ = 421 nm. The recoveries for all antibiotics ranged from 100.01 to 102.54%.
Derivative Spectrophotometric Analysis of 4-Quinolone Antibacterials in Formulations and Spiked Biological Fluids by Their Cu(II) Complexes
Authors: Rizk Mohammed , Belal Fathalla , Ibrahim Fawiza , Ahmed Soad , Sheribah Zeinab A
Published: July 2020

A derivative UV-spectrophotometric analytical procedure was developed for determination of three 4-quinolone antibacterials: norfloxacin (NFX), ciprofloxacin (CFX), and sparfloxacin (SFX). The method depends on the complexation of Cu(II) with the studied compounds in aqueous medium. A third order, measurement was applied for their quantification. A linear correlation was established between the amplitude of the peak and concentration for all the studied drugs in the range of 15–80, 35–120, and 200–700 ng/mL, with minimum detectability (S/N = 2) of 1.0, 1.3, and 5.1 ng/mL for NFX, CFX, and SFX, respectively. The method was successfully applied for accurate, sensitive, and selective determination of the studied drugs in bulk and tablets formulation with average percentage recoveries of 99.22 ± 0.55 to 100.33 ± 1.60. The results obtained were favorably compared with those of the reference method. The method was also used to determine sparfloxacin in spiked human plasma and urine. The results obtained were satisfactory, accurate, and precise.
Determination of Clenbuterol Residues in Bovine Urine by Optical Immunobiosensor Assay
Authors: Haughey Simon A , Baxter G Andrew , Elliott Christopher T , Persson Bjorn , Jonson Carin , Bjurling Peter
Published: July 2020

Clenbuterol (CBL) is an orally active β2-adrenoceptor agonist which has been used in veterinary medicine as a broncodilator and an agent of uterine relaxation. It has however become better known as a drug used illegally to promote growth in farm animals. A rapid an sensitive biosensor assay was developed to detect CBL residues in bovine urine. The method involved a simple extraction procedure using tert-butyl methyl ether followed by analysis on the biosensor with results obtained against a buffer calibration curve. The assay allowed up to 88 samples to be analyzed per working day, with each cycle on the biosensor taking approximately 7 min to complete. The limit of detection (LOD) was determined as 0.27 ng/mL using 20 EU reference blank urine samples. The intra-assay Sr ranged from 4.7–7.6% for 3 control samples while the interassay Sr ranged from 9.2–12.7%. The recovery was found to be approximately 95%. A series of incurred urine samples were assayed and the results compared by Enzyme immunoassay (EIA), radio-immunoassay (RIA), and gas chromatography/mass spectrometry (GC/MS) analysis.Urine samples taken from local abattoirs were also analyzed by the biosensor method and by EIA analysis. The antibody used in the biosensor test exhibited high cross reactivity with at least 7 other β-agonists allowing detection of these compounds at less than 1 ng/mL in bovine urine.
Sensitivity and Specificity of the BAX® for Screening/Listeria monocytogenes Assay: Internal Validation and Independent Laboratory Study
Authors: Hochberg Alan M , Roering Ann , Gangar Vidhya , Curiale Michael , Barbour W Mark , Mrozinski Peter M
Published: July 2020

In this study to certify the BAX® for Screening/Listeria monocytogenes assay (DuPont Qualicon, Wilmington, DE), an internal evaluation was conducted on 16 food types that were simultaneously analyzed with the BAX system (BAX), and the ISO method for the detection of L. monocytogenes (ISO). No statistically significant difference in performance between the BAX and ISO methods was observed. Inclusivity/exclusivity testing showed that the BAX system was able to detect 97 of 97 (100%) of L. monocytogenes strains tested. None of 56 other Listeria species or non-Listeria tested gave a reproducible positive BAX result. Ruggedness testing demonstrated that performance of the assay was not affected by reasonable variability in the operating parameters. BAX was then submitted for independent laboratory validation. In this phase, BAX was compared with standard culture methods for the detection of L. monocytogenes in chicken (USDA-FSIS), crab meat (BAM), and milk (AOAC). This study validated product claims of sensitivity and specificity >98% in accordance with AOAC Performance Tested MethodSM requirements.
Identical Flow Injection Spectrophotometric Manifold for Determination of Protein, Phosphorus, Calcium, Chloride, Copper, Manganese, Iron, and Zinc in Feeds or Premixes
Authors: Liu Jing-Fu , Feng Ying-Di , Jiang Gui-Bin
Published: July 2020

A simple procedure using an identical manifold was developed for determination of nitrogen (protein) phosphorus, calcium, chloride, copper, manganese, iron, and zinc in feeds and feedstuffs. By changing appropriate reagents and detection wavelength, these 8 elements were determined successively with a simple identical double-line flow injection (FI) manifold. FI spectrophotometric determinations were made by the blue indophenol reaction for ammonium, the molybdenum blue method for phosphate, the cresolphthalein complexone procedure for calcium, and the mercuric thiocyanate procedure for chloride. The chromogenic reagents for copper, iron, manganese, and zinc determination were bis(cyclohexanone)oxalydihydrazone (Cuprizone), 1,10-phenanthroline, formaldoxime, and xylenol orange, respectively. Sample digestion catalyst, FI manifold, and some chemical parameters were optimized. The proposed procedure had a sampling rate of 90/h for each analyte. The determination ranges (mg/L) were 10–60 for N, 1–15 for P and Ca, 5–40 for Cl, and 0.5–15 for Cu, Fe, Mn, and Zn, respectively. Results of the analyses of animal feed and feedstuff samples by this procedure did not differ significantly from those obtained by proven manual methods.
Development and Validation of a Method Using On-Line Solid-Phase Extraction and Liquid Chromatography with Ultraviolet Detection for the Determination of Bisphenol A, Octylphenol, and Nonylphenol in Groundwater
Authors: Careri Maria , Elviri Lisa , Mangia Alessandro
Published: July 2020

Alkylphenols are nonbiodegradable metabolites arising from various pathways of aerobic and anaerobic degradation of the nonionic surfactants alkylphenol ethoxylates. A method based on the use of on-line solid-phase extraction (SPE) and liquid chromatography (LC) with UV detection was developed to determine bisphenol A, octylphenol, and nonylphenol at trace levels in water. The on-line coupled SPE procedure automatically enables an approximately 300-fold preconcentration of analytes, which can be further enhanced by an increase in applied sample volume. By using C18 cartridges, recoveries of >90% were obtained for all the analytes. A validation procedure was carried out with a groundwater sample to ensure the quality of the results; performance criteria such as detection limits (LODs), quantitation limits (LOQs), linearity, and precision were evaluated. LODs and LOQs in the range of 0.17–0.36 and 0.35–1.88 μg/L, respectively, were found; for all the analytes, linearity was established over 2 orders of magnitude (r2 >0.997, n = 54). The intraday repeatability values expressed as relative standard deviations were <5.3%; a nested analysis of variance was performed to verify the influence of 3 different factors, i.e., different days, extraction procedure, and LC replicate injection, on data precision.
Analysis of Cyanobacterial Toxins by Physicochemical and Biochemical Methods
Authors: Codd Geoffrey A , Metcalf James S , Ward Clive J , Beattie Kenneth A , Bell Steven G , Kaya Kunimitsu , Poon Grace K
Published: July 2020

Cyanobacteria (blue-green algae) produce a wide range of low molecular weight metabolites that include potent neurotoxins, hepatotoxins, and cytotoxins. The accumulation of such toxins in freshwaters, and in brackish and marine waters presents hazards to human and animal health by a range of exposure routes. A review is presented of developments in the detection and analysis of cyanobacterial toxins, other than bioassays, including application of physicochemical, immunoassays, and enzyme-based methods. Analytical requirements are considered with reference to recently derived guideline levels for the protection of health and to the availability, or otherwise, of purified, quantitative cyanobacterial toxin standards.
Quantitation of Antihistamines in Pharmaceutical Preparations by Liquid Chromatography with a Micellar Mobile Phase of Sodium Dodecyl Sulfate and Pentanol
Authors: Gil-Agustí Mayte , Monferrer-Pons Llorenç , Esteve-Romero Josep , García-Alvarez-Coque María Celia
Published: July 2020

A reversed-phase liquid chromatographic procedure with a micellar mobile phase of sodium dodecyl sulfate (SDS), containing a small amount of pentanol, was developed for the control of 7 antihistamines of diverse action in pharmaceutical preparations (tablets, capsules, powders, solutions, and syrups): azatadine, carbinoxamine, cyclizine, cyproheptadine, diphenhydramine, doxylamine, and tripelennamine. The retention times of the drugs were <9 min with a mobile phase of 0.15M SDS–6% (v/v) pentanol. The recoveries with respect to the declared compositions were in the range of 93–110%, and the intra- and interday repeatabilities and interday reproducibility were <1.2%. The results were similar to those obtained with a conventional 60 + 40 (v/v) methanol–water mixture, with the advantage of reduced toxicity, flammability, environmental impact, and cost of the micellar-pentanol solutions. The lower risk of evaporation of the organic solvent dissolved in the micellar solutions also increased the stability of the mobile phase.
Application of sec-Butanol to the Derivatization of Hydroxyfuranones
Authors: Nawrocki Jacek , Andrzejewski Przemysław , Jeleń Henryk
Published: July 2020

This paper reports the use of sec-butanol for the derivatization of chlorinated hydroxyfuranones. The following hydroxyfuranones were investigated: 3,4-dichloro-5-hydroxy-2(5H)-furanone, 3,4-dibromo-5-hydroxy-2(5H)-furanone, 3-chloro-4-(chloromethyl)-5-hydroxy-2(5H)-furanone, and 3-chloro-4-methyl-5-hydroxy-2(5H)-furanone. Their derivatization products were analyzed by gas chromatography/mass spectrometry. The sec-butyl derivatives of the hydroxyfuranones investigated yield ions that are less abundant than those obtained for the corresponding isopropyl derivatives. However, sec-butyl derivatives are easily detectable in especially dirty matrixes because they produce double peaks in the chromatogram. The ion intensity of the first peak in the pair is lower than that of the second peak, but both are characterized by the same spectrum. The formation of multiple peaks is related to the formation of diastereoisomers during derivatization.
Validation of a Method for the Determination of Multiclass Pesticide Residues in Fruit Juices by Liquid Chromatography/Tandem Mass Spectrometry after Extraction by Matrix Solid-Phase Dispersion
Authors: Perret Daniela , Gentili Alessandra , Marchese Stefano , Sergi Manuel , D'Ascenzo Giuseppe
Published: July 2020

A multiresidue method was developed and validated for the determination of pesticide residues (omethoate, dimethoate, carbendazim, propoxur, thiabendazole, carbaryl, pirimicarb, azinphos-methyl, methidathion, and iprodione) in fruit juices. The samples were extracted by matrix solid-phase dispersion with diatomaceous earth and analyzed by liquid chromatography/tandem mass spectrometry. The method detection limits were <0.2 ppb for all pesticides; the relative standard deviations for analyses of samples fortified over the range of 2–50 ng/g were <9%, and the recoveries for each pesticide were all between 77 and 102%. The proposed method was used to analyze 21 commercial fruit juices; pesticide residues were found in 71% of the samples.
Derivative Spectrophotometric Determination of Nitrate in Plant Tissue
Authors: Lastra Olga C
Published: July 2020

A derivative spectrophotometric method was developed to determine NO3– –N in plant tissues. The method is based on measurement of the first-derivative spectrum of nitrosalicylic acid in basic solution. The nitrosalicylic acid was obtained by reaction of samples with salicylic acid in concentrated sulfuric acid and was used by Cataldo et al. in nonderivative spectrophotometry. The main strength of this technique is the lack of matrix background interference, typical of plant extracts in traditional spectrophotometric methods. This method is fast, inexpensive, easy-to-apply, and highly selective. The calibration graph was linear in the range of 0.1 and 1.0 mg/L N as NO3–. Average recovery in real matrixes (lettuce and spinach) was 102.6%; average standard deviation was 3.3. This method has been applied to leaves of 4 types of lettuce.
Comparison of Cholesterol Oxidation Product Preparation Methods for Subsequent Gas Chromatographic Analysis
Authors: Rodriguez-Estrada Maria Teresa , Costa Arianna , Pelillo Marco , Caboni Maria Fiorenza , Lercker Giovanni
Published: July 2020

An evaluation was made of the stability of cholesterol hydroperoxides (CHPs) under the analytical conditions and preparation methods commonly used for determination and quantification of cholesterol oxidation products (COPs). CHPs were prepared by photoxidation and separated by silica thin-layer chromatography. CHPs were individually collected by normal-phase liquid chromatography and then subjected either to reduction or to cold saponification. The corresponding hydroxyl derivatives were generated by reduction, whereas cold saponification gave rise predominantly to 7-ketocholesterol. In another test, silylated and non-silylated CHPs were separately injected into a gas chromatograph at 310°C, collected, and re-injected into a gas chromatography-mass spectrometry system. The silylated CHPs were more stable than the non-silylated ones, giving 7-ketocholesterol, 7α-and 7β-hydroxycholesterol as main degradation products. Two unknown degradation peaks were detected in both silylated and nonsilylated CHPs, having 384 as main m/z fragment. The study of their mass spectra led to the conclusion that peaks A and B correspond to 6α- and 6β-hydroxycholesterol, respectively.
Diet and Metabolic Syndrome: Where Does Resistant Starch Fit In?
Authors: Tapsell Linda C
Published: July 2020

Metabolic syndrome is a term linking the clinical profiles of some of the world's major health problems today: obesity, heart disease, and diabetes. It is predicated on dietary patterns, and particularly on the delivery of fuel. The effects may be seen first in the development of abdominal obesity and insulin resistance leading to Type 2 diabetes mellitus and coronary heart disease. This review examines the role resistant starch might play in the prevention and management of these conditions. Beginning with a definition of resistant starch, a critical review of the scientific literature is presented. Current knowledge suggests that resistant starch in the diet may assist in the prevention and management of conditions associated with the metabolic syndrome via its potential effects on delaying the delivery of glucose as fuel with subsequent fat utilization and appetite control benefits. There is still a great deal of research to be undertaken in this area, but it is clearly warranted, given the position of starches in the global food supply and the potential impact on population health.
Variation of Analytical Results for Peanuts in Energy Bars and Milk Chocolate
Authors: Trucksess Mary W , Whitaker Thomas B , Slate Andrew B , Williams Kristina M , Brewer Vickery A , Whittaker Paul , Heeres James T
Published: July 2020

Peanuts contain proteins that can cause severe allergic reactions in some sensitized individuals. Studies were conducted to determine the percentage of recovery by an enzyme-linked immunosorbent assay (ELISA) method in the analysis for peanuts in energy bars and milk chocolate and to determine the sampling, subsampling, and analytical variances associated with testing energy bars and milk chocolate for peanuts. Food products containing chocolate were selected because their composition makes sample preparation for subsampling difficult. Peanut-contaminated energy bars, noncontaminated energy bars, incurred milk chocolate containing known levels of peanuts, and peanut-free milk chocolate were used. A commercially available ELISA kit was used for analysis. The sampling, sample preparation, and analytical variances associated with each step of the test procedure to measure peanut protein were determined for energy bars. The sample preparation and analytical variances were determined for milk chocolate. Variances were found to be functions of peanut concentration. Sampling and subsampling variability associated with energy bars accounted for 96.6% of the total testing variability. Subsampling variability associated with powdered milk chocolate accounted for >60% of the total testing variability. The variability among peanut test results can be reduced by increasing sample size, subsample size, and number of analyses. For energy bars the effect of increasing sample size from 1 to 4 bars, subsample size from 5 to 20 g, and number of aliquots quantified from 1 to 2 on reducing the sampling, sample preparation, and analytical variance was demonstrated. For powdered milk chocolate, the effects of increasing subsample size from 5 to 20 g and number of aliquots quantified from 1 to 2 on reducing sample preparation and analytical variances were demonstrated. This study serves as a template for application to other foods, and for extrapolation to different sizes of samples and subsamples as well as numbers of analyses.
Carrier Tests to Assess Microbicidal Activities of Chemical Disinfectants for Use on Medical Devices and Environmental Surfaces
Authors: Springthorpe V Susan , Sattar Syed A
Published: July 2020

For well over a decade, many deficiencies have been identified in current AOAC methods used to assess the microbicidal activities of chemical disinfectants on medical devices and environmental surfaces. This report discusses the development of quantitative carrier tests (QCT) designed to address these concerns. Decontamination of surfaces with dried inocula is invariably more difficult than when microorganisms are in suspension. For medical device as well as environmental decontamination, microbicides are used on contaminated surfaces, thus making it necessary to evaluate their microbicidal action on representative carrier materials contaminated with a dried challenge microorganism(s). Our approach is a 2-tiered QCT. The first tier (QCT-1) uses relatively ideal conditions to assess performance of the microbicide for screening purposes; the test uses smooth glass surfaces and quantities of disinfectant in excess of those likely to be experienced in the field. The second tier of testing (QCT-2) is more stringent because it uses (1) disks of brushed stainless steel as carriers, (2) only 50 μL of the test formulation on each carrier as compared to 1 mL in QCT-1, and (3) an added soil load to simulate the presence of residual body fluids or accumulated surface dirt. This review also discusses the factors that affect disinfection of medical devices and environmental surfaces in the context of the methodology used to evaluate the potency of microbicides. Specific recommendations for discussion are included, and performance criteria are suggested based on a risk-reduction approach for different classes of disinfectants. The focus is on improving the relevance of the test methodology to actual field use of disinfectants for devices and facilities in health care, and potentially in other settings. It is hoped that this review and its recommendations will initiate needed discussion and resolution of the many issues identified.
Reduction of Exposure to Acrylamide: Achievements, Potential of Optimization, and Problems Encountered from the Perspectives of a Swiss Enforcement Laboratory
Authors: Grob Koni
Published: July 2020

The most important initiatives taken in Switzerland to reduce exposure of consumers to acrylamide are the separate sale of potatoes low in reducing sugars for roasting and frying, the optimization of the raw material and preparation of french fries, and campaigns to implement suitable preparation methods in the gastronomy and homes. Industry works on improving a range of other products. Although these measures can reduce high exposures by some 80%, they have little effect on the background exposure resulting from coffee, bread, and numerous other products for which no substantial improvement is in sight. At this stage, improvements should be achieved by supporting voluntary activity rather than legal limits. Committed and consistent risk communication is key, and the support of improvements presupposes innovative approaches.
Rapid and Easy Identification of Illicium verum Hook. f. and Its Adulterant Illicium anisatum Linn. by Fluorescent Microscopy and Gas Chromatography
Authors: Joshi Vaishali C , Srinivas Pullela V , Khan Ikhlas A
Published: July 2020

Illicium verum Hook. f. is used as an herbal tea to treat colic pain in infants. Reports suggest that Star anise herbal tea may be adulterated with Illicium anisatum Linn. A short and rapid method using microscopy and gas chromatography (GC) was developed to detect I. anisatum Linn., an adulterant in the powdered mixture of I. verum. Anatomical differences in the epicarp cells of I. verum and I. anisatum fruits were clearly defined as examined under fluorescent microscopy and scanning electron microscopy. A GC method was developed for quick identification of possible I. anisatum adulteration with I. verum.
Multiresidue Determination of Organophosphorus Pesticides in Ginkgo Leaves by Accelerated Solvent Extraction and Gas Chromatography with Flame Photometric Detection
Authors: Yi Xionghai , Lu Yitong
Published: July 2020

A rapid and simple method using accelerated solvent extraction and solid-phase extraction cleanup was developed and validated for the determination of 15 organophosphorus pesticides in ginkgo leaves by capillary gas chromatography with flame photometric detection. The pesticides were extracted at 100°C under 1500 psi pressure in <20 min. The average recovery from 10 g ginkgo leaves, fortified at 3 levels ranging from 0.05 to 1.00 mg/kg, was 95.2% with a relative standard deviation of 4.6%. The limits of detection ranged from 1.11 × 10−3 mg/kg (dimethoate) to 4.44 × 10−3 mg/kg (dichlorvos). The proposed method showed acceptable accuracy and precision while minimizing environmental concerns, time, and labor. Furthermore, the method could be easily applied to the monitoring of these 15 organophosphorus pesticides in ginkgo leaves.
Flame Atomic Absorption Spectrometric Determination of Trace Amounts of Nickel after Extraction and Preconcentration onto Natural Modified Analcime Zeolite Loaded with 2-(5-Bromo-2-Pyridylazo)-5-Diethylaminophenol
Authors: Afzali Darush , Taher Mohammad Ali , Mostafavi Ali , Mahani Mohammad Khayatzadeh
Published: July 2020

Nickel is a moderately toxic element compared with other transition metals. However, inhalation of nickel and its compounds leads to serious problems, including cancer of the respiratory system and a skin disorder, nickel-eczema. Thus, attention has focused on the toxicity of nickel at low concentrations, and the development of reliable, analytical approaches for the determination of trace amounts of nickel is needed. This paper describes a simple, rapid, and sensitive flame atomic absorption spectrometric method for the determination of trace amounts of nickel in various samples after adsorption of its 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex on a modified Analcime column in the pH range of 7.5–10.5. The retained analyte on the Analcime is recovered with 5.0 mL 2M nitric acid and determined by flame atomic absorption spectrometry. The detection limit is 20 ng/mL, and the calibration curve is linear for analyte concentrations in the range of 0.1–8 μg/mL final solution, with a correlation coefficient of 0.9993. Eight replicate determinations of nickel at 2 μg/mL in the final solution gave an absorbance of 0.1222, with a relative standard deviation (RSD) of ±1.2%. The interference of a large number of anions and cations was studied, and the proposed method was used for the determination of nickel in various standard reference samples. The accuracy of the proposed method was evaluated by analyzing standard reference samples, and the results were satisfactory (recoveries of >96%; RSD of <3.5%).
The Impact of Processing on the Nutritional Quality of Food Proteins
Authors: Meade Susie J , Reid Elizabeth A , Gerrard Juliet A
Published: July 2020

During many food processing regimens, food proteins may undergo a variety of chemical modifications. Despite the enormous consumption of processed foods worldwide, much remains to be learned about the exact nature of these modifications. This is partly due to the complex nature of the changes involved, and partly to the problems of analysis imposed by the intractable nature of the food matrix. Such difficulties are compounded by the paucity of chemically based analytical tests that accurately measure amino acid availability in biologically relevant terms. In this review, we explore the known changes that proteins and amino acids undergo during food processing and the consequences of these changes on the physical and nutritional qualities of the food. We also examine the impact of these protein derivatizations for the analysis of food proteins and amino acids, and highlight areas that require future research.
Determination of Residual Clopidol in Chicken Muscle by Capillary Gas Chromatography/Mass Spectrometry
Authors: He Limin , Liu Yahong , Zeng Zhenling , Huang Xianhui , Liu Rong
Published: July 2020

Clopidol was extracted from chicken with acetonitrile, and the extract was evaporated to about 5 mL. The concentrated solution was centrifuged and applied to a glass column filled with basic alumina. The column was eluted with methanol and the methanol was evaporated to dryness. Theresidue was derivatized with Sylon BFT™ and analyzed by gas chromatography/mass spectrometry (GC/MS). Mass characteristics of trimethylsilyl derivative of clopidol were interpreted manually. The selected-ion monitoring mode was performed at m/z 191, 248, 263, and 265. A sensitive, reproducible GC/MS method was developed for monitoring residues of clopidol in chickens. All recoveries of the drug from chicken muscle fortified at 1, 10, and 100 ng/g were >65%, and relative standard deviations were <15%. The detection limit was about 0.5 ng/g, and the quantitation limit was the lower limit of the standard curve, which was about 1 ng/g.
Estimation of Pioglitazone Hydrochloride and Metformin Hydrochloride in Tablets by Derivative Spectrophotometry and Liquid Chromatographic Methods
Authors: Shankar Madhira B , Modi Vaibhav D , Shah Dimal A , Bhatt Kashyap K , Mehta Rajendra S , Geetha Madhira , Patel Binita J
Published: July 2020

Two simple and accurate methods of analysis to determine pioglitazone hydrochloride (PIO) and metformin hydrochloride (MET) in combined dosage forms were developed using second-derivative spectrophotometry and reversed-phase liquid chromatography (LC). PIO and MET in combined preparations (tablets) were quantified using the second-derivative responses at 227.55 nm for PIO and 257.25 nm for MET in spectra of their solutions in a mixture of methanol and acetonitrile (30 + 70). The calibration curves were linear [correlation coefficient (r) = 0.9984 for PIO and 0.9986 for MET] in the concentration range of 8–40 μg/mL for PIO and 4–12 μg/mL for MET. In the LC method, analysis was performed on a Hypersil ODS-C18 column with 5 μm particle size using the mobile phase acetonitrile-water-acetic acid (75 + 25 + 0.3), adjusted to pH 5.5 with liquor ammonia, at a flow rate of 0.5 mL/min. Measurement was made at a wavelength of 230 nm. Both the drugs were well resolved on the stationary phase, and the retention times were 8.5 min for PIO and 16.0 min for MET. The calibration curves were linear (r = 0.9933 for PIO and 0.9958 for MET) in the concentration range of 4–20 μg/mL for PIO and MET. Both methods were validated, and the results were compared statistically. They were found to be accurate, precise, and specific. The methods were successfully applied to the estimation of PIO and MET in combined tablet formulations.
Enumeration of Total Coliforms and E. coli in Foods by the SimPlate® Coliform and E. coli Color Indicator Method and Conventional Culture Methods: Collaborative Study
Authors: Feldsine Philip T , Lienau Andrew H , Roa Nerie H , Green Shannon T ,   Collaborators:, Braut-Taormina J , Braymen C , Chavey C , Cohen A , Deans A , Delancey S , Elems C , Forgey R , Gonzalez E , Hall V , Huang M C J , Humes L , Johnson F , Kerdaji K , King J , Kipker L , Lau D , Nogle J , Peters C , Pinkston J , Porter M , Potter L , Rogers S , Stephens J , Skorupa G , Taylor R , Tuncan E , Vought K , Vrana D
Published: July 2020

The relative effectiveness of the SimPlate® Coliform and E. coli Color Indicator (CEc-CI) method was compared to the AOAC 3-tube Most Probable Number (MPN) methods for enumerating and confirming coliforms and Escherichia coli in foods (966.23 and 966.24). In this study, test portions were prepared and analyzed according to the conditions stated in both the AOAC methods and SimPlate directions for use. Six food types were artificially contaminated with coliform bacteria and E. coli: frozen burritos, frozen broccoli, fluid pasteurized milk, whole almond nut meats, cheese, and powdered cake mix. Method comparisons were conducted. Overall, the SimPlate method demonstrated <0.3 log difference for total coliform and E. coli counts compared to the AOAC reference methods for the majority of food types and levels analyzed. In all cases, the repeatability and reproducibility of the SimPlate CEc-CI method were not different from those of the reference methods and in certain cases, were statistically better than those of the AOAC 3-tube MPN methods. These results indicate that the SimPlate CEc-CI method and the reference culture methods are comparable for enumeration of both total coliforms and E. coli in foods.
Real-Time Determination of Microbial Activity of Pasteurized Fluid Milk Using a Novel Microrespirometer Method
Authors: Ren Zhao , Hsieh Yun-Hwa P
Published: July 2020

The effectiveness of the rapid CO2 evolution rate (CER) method was evaluated by using a novel noninstrumental microrespirometer to determine the microbial activity of pasteurized milk and comparing it with traditional culturing methods in homogeneous milk samples. Three different kinds of milk (skim, 1% fat, and whole) stored at 2 temperatures (4° and 7°C) were measured daily for CER, aerobic plate count (APC), and psychrotrophic bacterial count. The mean initial rates of CO2 evolution for all 3 samples stored at the 2 temperatures ranged from 3.42 to 3.71 μL/h/mL and increased to 29 μL/h/mL and above on the final day of the experiment. Regression analysis showed a high correlation (R = 0.98–0.99) between the APC and CER results in combined milk samples. A cut-off value of CER (25 μL/h/mL) for milk spoilage at refrigeration temperatures was identified. The real-time CER method shows promise as a potential alternative to the traditional culture method.
Determination of Magnesium in Foods by Single-Sweep Polarography
Authors: Xiangchun Zhou , Lirong Wang , Yan Zeng , Guanghan Lu , Peng Zhen
Published: July 2020

In KOH, the Mg(II)bromopyrogallol red (BPR) complex produced a very sensitive polarographic wave at 1.30 V. The wave height was linear with the concentration of Mg(II) in the range of 0.05 to 2 μg/mL. The detection limit was 0.01 μg/mL. The electrochemical behavior of Mg(II)BPR was studied by electrochemical and spectrophotometric methods. Experiments proved that the polarographic wave of Mg(II)BPR was due to the reduction of BPR in the Mg(II)BPR complex. The method, which was sensitive, selective, and simple to perform, was used to determine magnesium in foods, and the results were consistent with those obtained by atomic absorption spectroscopy.
Determination of Nitroimidazole Residues in Porcine Urine by Liquid Chromatography/TandemMass Spectrometry
Authors: Xia Xi , Li Xiaowei , Shen Jianzhong , Zhang Suxia , Ding Shuangyang , Jiang Haiyang
Published: July 2020

A reliable and sensitive method was developed for determination of nitroimidazoles in porcine urine. Sample preparation involves an extraction with ethyl acetate, followed by a solid-phase extraction cleanup step. The final extract is injected into the liquid chromatography/tandem mass spectrometry system in the positive-ion electrospray ionization mode. A C8 column with water and acetonitrile as the mobile phase is used for chromatographic separation under gradient conditions. Overall average recoveries ranged from 83 to 107%. The limits of detection ranged from 0.03 to 0.05 ng/mL, and the limits of quantitation, from 0.1 to 0.2 ng/mL.
Single-Laboratory Validation of a Method for the Determination of Furan in Foods by Using Static Headspace Sampling and Gas Chromatography/Mass Spectrometry
Authors: Nyman Patricia J , Morehouse Kim M , McNeal Timothy P , Perfetti Gracia A , Diachenko Gregory W
Published: July 2020

A headspace gas chromatography/mass spectrometry method was developed and validated in-house for the determination of furan in foods. The method of standard additions with d4-furan as the internal standard was used to quantitate furan. The limit of detection and limit of quantitation (LOQ) values ranged from 0.2 and 0.6 ng/g, respectively, in apple juice to 0.9 and 2.9 ng/g, respectively, in peanut butter. Recoveries were obtained at 0.5, 1, 2, and 3 times the LOQ. At 1, 2, and 3 times the LOQ, the recoveries ranged from 89.4 to 108%, and the relative standard deviations ranged from 3.3 to 17.3% for all the matrixes. For apple juice, chicken broth, and infant formula, the averaged coefficients of determination from the linear regression analyses were >0.99 with each food fortified at 0.5, 1, 2, and 3 times the LOQ. The coefficients of determination were >0.99 for green beans and 0.96 for peanut butter with the foods fortified at 1, 2, and 3 times the LOQ. Within-laboratory precision was determined by comparing the amounts of furan found in 18 samples by 2 analysts on different days with different instruments. For most of the foods, the difference between the amounts found by each analyst was <18%. The method was used to conduct a survey of >300 foods. The furan levels found ranged from none detected to 174 ng/g.
Single-Laboratory Validation of the Biosense Direct Competitive Enzyme-Linked Immunosorbent Assay (ELISA) for Determination of Domoic Acid Toxins in Shellfish
Authors: Kleivdal Hans , Kristiansen Sven-Inge , Nilsen Mona V , Briggs Lyn
Published: July 2020

Method validation was conducted for an enzyme-linked immunosorbent assay (ELISA) for the determination of domoic acid (DA) toxins, known to give amnesic shellfish poisoning (ASP) symptoms, in shellfish. The calibration curve range of the assay is approximately 10260 pg/mL, with a dynamic working range for DA toxins in shellfish from 0.01 to at least 250 mg/kg. The ASP ELISA showed no significant cross-reactivity to structural analogs, and proved to be robust to deliberate alterations of the optimal running conditions. The shellfish matrix effects observed with mussels, oysters, and scallops were eliminated by diluting shellfish extracts 1:200 prior to analysis, leading to a limit of detection at 0.003 mg/kg. Thirteen blank shellfish homogenates were spiked with certified mussel material containing DA to levels in the range of 0.125 mg DA/kg, and analyzed in quadruplicate on 3 different days. The relative standard deviation (RSD) under intra-assay repeatability conditions ranged from 6.5 to 13.1%, and under interassay repeatability conditions the RSD ranged from 5.7 to 13.4%, with a mean value of 9.3%. The recoveries ranged from 85.5 to 106.6%, with a mean recovery of 102.2%. A method comparison was conducted with liquid chromatography with ultraviolet detection, using naturally contaminated scallop samples (n = 27) with DA levels at 0244 mg/kg. The overall correlation coefficient was 0.960 and the slope of the regression was 1.218, indicating a good agreement between the methods.
Development of a Capillary Electrophoresis Method for the Enantioselective Estimation of Primaquine in Pharmaceutical Formulations
Authors: Elbashir Abdalla A , Saad Bahruddin , Mohamed Ali Abdussalam Salhin , Saleh Muhammad Idiris
Published: July 2020

A capillary electrophoresis (CE) method has been developed that allows the separation and estimation of primaquine enantiomers using hydroxypropyl--cyclodextrin (HP--CD) as a chiral selector. The influence of chemical and instrumental parameters on the separation, such as type and concentration of CD, buffer concentration, buffer pH, applied voltage, capillary temperature, and injection time, were investigated. Good separation of the racemic mixture of primaquine was achieved using a fused-silica capillary (52.5 cm effective length 50 m id) and a background electrolyte composed of tris-phosphate buffer solution (50 mM, pH 2.5) containing 15 mM HP--CD as a chiral selector. The recommended applied voltage, capillary temperature, and injection time were 15 kV, 25C, and 6 s, respectively. Within-day and interday reproducibility of peak area and migration time gave relative standard deviation values ranging from 1.053.30. Good recoveries (range of 96.8104.9) were obtained from the determination of placebos that were spiked with 0.251.00 mg/L primaquine. The proposed CE method was successfully applied to the assay of primaquine diphosphate in pharmaceutical formulations (tablets).
Adams-Harbertson Protein Precipitation-Based Wine Tannin Method Found Invalid
Authors: Brooks Larry , McCloskey Leo , Mckesson Doug , Sylvan Marshall
Published: July 2020

The poor precision of the Adams-Harbertson wine tannin assay which was proposed for commercial winemaking, thereby creating the real possibility of quality control problems, is documented. The method is a version of the Hagerman and Butler protein precipitation-based tannin method. An extensive invalidation of the assay results with luxury wine data shows that the assay cannot distinguish bottled wine with reasonable accuracy. Five laboratories used Adams-Harbertson to assay 9 replicates each, of 3 bottled wines (n 135) found in California supermarkets, with tannin concentrations of nominally 500 and 1000 ppm by high-performance liquid chromatography (HPLC). Reliability exceeded the 5 industry requirement by nominally 5 times (z-score based on 5 distribution). Coefficient of variation was 27, making the standard deviation range 54 for Pinot Noir, 34 for Merlot, and 44 for Cabernet Sauvignon. Validity exceeded the 100 requirement. Intralaboratory validity recovery was 5563. Interwinery validity was 71178 of the mean for Pinot Noir, 81144 for Merlot, and 83164 for Cabernet Sauvignon. Range as a function of the mean was 89 for Pinot Noir, 55 for Merlot, and 67 for Cabernet Sauvignon. Expect intermethod validity to be nominally 50, i.e., percent recovery to HPLC. These statistically significant errors were predicted by the literature. First-order error is related to the tannin-protein equilibrium constant (Ka), as suggested by the original author, Hagerman, and the protein equivalence point error as suggested by Silber. This does not obviate second-order errors for tannin-protein analytical chemistry. Winemakers using the measurements risk making wines that are relatively more tannic than the measurements report.