bluuebunny/crossref_metadata_2025 huggingface dataset:
Conservation seed physiology of the ciénega endemic, Eryngium sparganophyllum (Apiaceae)
Authors: Wolkis Dustin , Blackwell Steve , Villanueva Shyla Kaninaualiʻi
Published: February 2020

Knowledge of seed dormancy and optimal propagation techniques is crucial for successful ex situ restoration and reintroduction projects, and determining the seed storage behaviour of a species is critical for the long-term conservation of seeds, further supporting future ex situ efforts. Eryngium sparganophyllum (Apiaceae) is a globally critically endangered plant species endemic to ciénega wetlands of southwest North America. To support in situ and ex situ conservation efforts of E. sparganophyllum, we asked (i) how does the embryo: seed (E:S) ratio change over time once imbibed, (ii) how does germination respond with varying periods of exposure to cold (5°C) and warm (25°C) stratification, and concentrations of gibberellic acid (GA3). By answering these questions, (iii) can dormancy class be inferred, and (iv) what storage behaviour category is exhibited? To answer these questions, we collected seeds in Southern Arizona from one of the few remaining wild populations. We measured embryo growth and tested the effects of cold (0–18 weeks) and warm (0 and 4 weeks) stratification, and 0–1000 ppm gibberellic acid on germination. We also tested the effects of cold (−80°C) dry (~20% equilibrium relative humidity) storage on germination. We found that (i) embryos grow inside seeds prior to germination; (ii) compared to control, cold stratification for at least 6 weeks increased germination and warm stratification had no effect; (iii) 1000-ppm GA3 had the highest germination success; (iv) therefore this species exhibits morphophysiological dormancy; and (v) seeds are orthodox and can therefore be conserved using conventional storage methods. This information will aid managers in the propagation of E. sparganophyllum that is crucial for in situ reintroduction and restoration projects, and seed banking represents a critical ex situ conservation strategy for the preservation of this species.
Distributive Justice for Behavioural Welfare Economics
Authors: Mandler Michael
Published: February 2020

The incompleteness of behavioural preferences can lead many or even all allocations to qualify as Pareto optimal. But the incompleteness does not undercut the precision of utilitarian policy recommendations. Utilitarian methods can be applied to groups of goods or to the multiple social welfare functions that arise when individual preferences are incomplete, and policymakers do not need to provide the preference comparisons that individuals are unable to make for themselves. The utilitarian orderings that result, although also incomplete, can generate a unique optimum. Non-separabilities in consumption reduce this precision but in all cases the dimension of the utilitarian optima drops substantially relative to the Pareto optima.
Preventing the White Death: Tuberculosis Dispensaries
Authors: Egedesø Peter Juul , Hansen Casper Worm , Jensen Peter Sandholt
Published: February 2020

Tuberculosis (TB) is a leading cause of death worldwide and while treatable by antibiotics since the 1940s, drug resistant strains have emerged. This article estimates the effects of the establishment of a pre-antibiotic public health institution, known as a TB dispensary, designed to prevent the spread of the disease. Our annual difference-in-differences estimation reveals that the rollout of the dispensaries across Danish cities led to a 19% decline in the TB mortality rate, but no significant impacts on other diseases when performing placebo regressions. We next take advantage of the dispensaries explicit targeting on TB to setup a triple-differences model which exploits other diseases as controls and obtain a similar magnitude of the effect. As for the mechanism, the evidence highlights the dispensaries’ preventive actions, such as information provision. At an estimated cost as low as 68 dollars per saved life-year, this particular public-health institution was extraordinarily cost effective. Overall, our evidence suggests a policy for developing countries to combat drug resistant TB.
Increasing EFL learner self-confidence with visualization tasks
Authors: Al-Murtadha Mutahar
Published: February 2020

L2 linguistic self-confidence has been considered a constituent of L2 motivation, a predictor of L2 proficiency, and part of the willingness to communicate construct (WTC). However, little is known about how to increase it. This intervention study examined whether helping EFL learners visualize their ideal L2 selves enhances their L2 linguistic self-confidence. Two hundred and six Yemeni EFL learners formed the experimental and control groups. The experimental group received one visualization lesson a week for six weeks, whereas the control group received their regular lessons. The intervention structure followed the six steps of the Possible Selves Tree Program: discover, think, sketch, reflect, grow, and perform. A one-way analysis of covariance revealed that the self-confidence of the experimental group increased significantly. Qualitative data indicated that the intervention enhanced L2 linguistic self-confidence in four ways: considering the future, emulating L2 role models, increasing WTC, and using English and measuring progress. Pedagogical implications are provided.
‘The Dear Old Holy Roman Realm, How Does it Hold Together?’ Monetary Policies, Cross-cutting Cleavages and Political Cohesion in the Age of Reformation
Authors: Volckart Oliver
Published: February 2020

Research has rejected Leopold von Ranke’s hypothesis that the Reformation emasculated the Holy Roman Empire and thwarted the emergence of a German nation state for centuries. However, current explanations of the Empire’s cohesion that emphasize the effects of outside pressure or political rituals are not entirely satisfactory. This article contributes to a fuller explanation by examining a factor that so far has been overlooked: monetary policies. Monetary conditions within the Empire encouraged its members to cooperate with each other and with the emperor. Moreover, cross-cutting cleavages forced actors on different sides of the confessional divide to frame coherent and fact-oriented monetary-policy arguments. This helped generate trust among the estates involved in the discussions about a common currency between the 1520s and the 1550s and contributed to the success of the negotiations. Monetary policies thus helped bridge the religious divide that had opened within the Empire, and they therefore contributed to its political cohesion.
What did Paul Rohrbach Actually Learn in Africa? The Influence of Colonial Experience on a Publicist’s Imperial Fantasies in Eastern Europe*
Authors: Kettler Mark T
Published: February 2020

Paul Rohrbach was an influential publicist in Wilhelmine Germany. He also routinely used racial justifications to defend brutal policies for managing the indigenous populations of Germany’s African colonies. In recent years, scholars have interpreted Rohrbach’s promotion of colonialism as evidence that colonial ideas increasingly saturated German political and imperial discourse before and during the First World War. His work has thus been cited to support an emerging narrative of pathological continuity, which contends that Wilhelmine German imperialists reflexively drew upon colonial ideologies, experiences and models to inform increasingly repressive and violent plans to rule ethnically diverse space in Eastern Europe. This article argues that Paul Rohrbach has been misinterpreted. His career represents not the ease with which colonial ideas infiltrated German imperial discourse, but rather the severe reluctance of an ardent colonialist to employ colonial methods in European space. Drawing upon his writings on Africa and his discussions of German war aims in Eastern Europe during the First World War, this article demonstrates Rohrbach’s profound unwillingness to structure German imperial expansion in Russia’s Baltic provinces and Congress Poland according to colonial precedents. Differences in the perceived cultural and political sophistication of African, Baltic and Polish societies convinced Rohrbach that repressive and brutal colonial models of rule would be inefficient or counterproductive for achieving German objectives in Eastern Europe. Indeed, Rohrbach’s studies of colonialism actually reinforced his commitment to decentralization and respect for national diversity as essential instruments for governing politically sophisticated European societies. His experiences in Africa, in other words, steeled his confidence in multinational imperialism.
Measuring health conditions and behaviours in fishing industry participants and fishing communities using the Behavioral Risk Factor Surveillance Survey (BRFSS)
Authors: Speir Cameron , Ridings Corey , Marcum Jennifer , Drexler Michael , Norman Karma
Published: February 2020

We estimate physical health, mental health, and healthcare access conditions and behaviours among fishing industry participants from a public health survey in the United States. Human well-being is an increasingly important consideration in ecosystem models and fishery management. We use a standardized public health survey, the Behavioral Risk Factor Surveillance System, to estimate health-related aspects of well-being in fishing industry participants (including harvest, processing, and wholesaling sectors) in Washington state and compare to reference populations. We find that physical and mental health outcomes and healthcare access among fishing industry participants are broadly similar to other populations. However, fishing industry participants are more frequently affected by conditions that limit activity and tend to engage in potentially unhealthy behaviour at higher rates. Our work fills a gap on health-related well-being outcomes in the human dimensions of fisheries and demonstrates the role that public health surveys can play in the study of well-being in fishing communities.
Influences of different factors on the three-dimensional heat transfer of spiral-coil energy pile group with seepage
Authors: You Tian , Yang Hongxing
Published: February 2020

Energy pile group is an important component of ground source heat pumps with foundation piles as ground heat exchangers. Among different energy piles, those with spiral pipes have a large heat exchange area between the pipe and the concrete, achieving good heat exchanging performance and wide applications. To analyze the influence of geometrical parameters (pile layout, pile spacing and pile depth) and external parameter (groundwater velocity) on the heat transfer of spiral-coil energy pile groups, a three-dimensional analytical model of spiral-coil energy pile groups with seepage is used, considering the thermal interaction among different piles, the geometry of spiral pipe and the velocity of groundwater. The soil temperature distribution in the energy pile group is studied under conditions with different factors (pile layouts: 3 × 2, L shape and line shape; pile spacing distances: 3, 5 and 7 m; pile depths: 10, 30 and 50 m; and groundwater velocities: 0, 1.2 × 10−6 and 2.0 × 10−6 m/s). The 3-year outlet fluid temperature of energy pile group affected by the above different factors under different inlet fluid temperatures and velocities or soil thermal exchange ratios is investigated. Results show that for the low fluid velocity inside the piles, the influence of above factors on the thermal performance of energy piles is more obvious. Large groundwater velocity, line shape pile layout, large pile spacing distance and short pile depth can alleviate the long-term temperature variation caused by unbalanced soil heat exchange. This work will facilitate the research, design and application of the energy pile group in ground source heat pumps.
Liquid Chromatographic Method for Determination of Anilazine in Formulated Products: Collaborative Study
Authors: Slahck Stephen C ,   Collaborators:, Arruda J , Bennett O O , Cheuk H , Elliott R M , Fontanilla A O , Hodgins W E , Hunt J , Jung P D , Lonn P , Pearson P M L , Schuld M , Schulz R , Stroh S , Tomkins D F , Updyke J R
Published: February 2020

A liquid chromatographic method for the determination of anilazine (DYRENE®) in formulated products has been developed and subjected to a collaborative study involving 15 participating laboratories. Each collaborator was furnished with reference standard, internal standard, and blind duplicate samples of DYRENE 80% concentrate, 75% wettable powder (75 WP), 50 WP, and 4 flowable formulation. Samples are dissolved in acetonitrile and analyzed by reverse phase chromatography using octanophenone as an internal standard. Collaborators were instructed to evaluate the method by either peak area or peak height measurements. Seven laboratories performed the analyses using peak areas; 8 laboratories used peak heights. Peak area measurements for the wettable powder samples resulted in statistically high bias vs peak height measurements. This was apparently due to inconsistent integration parameters among collaborators. Difficulties in establishing the correct integration parameters are illustrated along with t-test values for the 2 measurement techniques. Coefficients of variation of the peak height values obtained on the 80 concentrate, 75 WP, 50 WP, and 4 flowable were 1.68,1.29,1.74, 1.87%, respectively. The method has been adopted official first action.
Determination of Aztreonam and L-Arginine Combination in Parenteral Formulations
Authors: Wahbi Abdel-Aziz M , Abounassif Mohammad A , Gad-Kariem El-Rasheed A , Ibrahim Mahmoud E , Aboul-Enein Hassan Y
Published: February 2020

A rapid, sensitive and precise liquid chromatographic method is presented for the determination of aztreonam alone, in the presence of its degradation product, and in a parenteral formulation containing L-arginine. A reverse phase column and 0.2M phosphate buffer (pH 6)-methanol (95 + 5) with mobile phase at a flow rate of 2 mL/min is used. The method is sensitive for the range of 10-50 μg/mL with a relative standard deviation of less than 2%. The method has been applied to a parenteral formulation containing aztreonam and L-arginine. L-Arginine is also determined by a nonaqueous titrimetric method.
Liquid Chromatographic Determination of Flucytosine in Capsules: Collaborative Study
Authors: Shostak Donald , Klein Clifford ,   Collaborators:, Cappon C , Falcone N , Hanus J P , Mahn F , O’Brien D T , Ting S , Williams B W
Published: February 2020

A liquid chromatographic method for the determination of flucytosine in capsules was collaboratively studied by 7 laboratories. The method uses a C18 reverse phase column, water-methanol-acetic acid mobile phase containing 1-octanesulfonic acid sodium salt, p-aminobenzoic acid as internal standard, and photometric detection at 285 nm. The mean recovery value (±SD) of flucytosine from a synthetic formulation representing capsules was 99.2 ± 1.72% (CV = 1.73%). Composited samples of 250 and 500 mg commercial capsules gave assay values of (mean ± SD) 103.17 ± 2.21 and 99.29 ± 1.29% of declared, respectively. CV values were 2.15 and 1.30%. Reproducibility and repeatability CVs were 2.19 and 1.50%, respectively, for the 250 mg capsules, and 1.34 and 0.63%, respectively, for the 500 mg capsules. The method has been adopted official first action.
Moisture Analysis of Forage by Near Infrared Reflectance Spectroscopy: Preliminary Collaborative Study and Comparison Between Karl Fischer and Oven Drying Reference Methods
Authors: Windham William R , Barton Franklin E , Robertson James A
Published: February 2020

A collaborative study of moisture analysis by neai infrared reflectance spectroscopy (NIRS) has been completed involving 5 laboratories and 20 forage samples. Near infrared reflectance spectroscopy calibrations for moisture were developed in the Associate Referee's laboratory from Karl Fischer (KF) and AOAC air oven (AO) (135°C for 2 h) moisture methods, respectively, and transferred to each collaborating laboratory's NIRS instrument. NIRS moisture data were validated with KF data from the Associate Referee's laboratory and AO data from each collaborating laboratory. The standard error of analysis of KF data by NIRS KF determination and AO data by NIRS AO determination ranged from 0.25 to 0.48% and from 0.74 to 1.88%, respectively. The standard errors between laboratories for NIRS KF and NIRS AO determinations were 0.2" and 0.39%, respectively. The standard error between moisture analyses by NIRS KF and NIRS AO calibrations, averaged across laboratories, was 0.42%. In addition, the standard error between laboratories for the AOAC AO method was 0.63%. The increase in standard error for the AOAC AO method was due to the random and systematic errors associated with the gravimetric techniques. The results indicate that NIRS analysis can accurately and precisely deterrr ine the moisture content of forages and forage crops because of th« very strong absorbance of water in the near infrared region.
Gas Chromatographic Determination of the Monosaccharide Composition of Plant Cell Wall
Preparations
Authors: Harris Philip J , Blakeney Anthony B , Henry Robert J , Stone Bruce A
Published: February 2020

A simplified procedure is described for determining the monosaccharide composition of plant cell wall ("fiber") preparations. The preparations are hydrolyzed using a 2-stage sulfuric acid method. The monosaccharides released are rapidly reduced and acetylated to produce alditol acetates, which are separated by capillary gas chromatography. This procedure has been applied to the analysis of fiber preparations from a variety of animal feeds. The monosaccharide composition of the fiber preparations varied among feeds from different sources, indicating the usefulness of this method in characterizing fiber preparations in nutritional studies.
Determination of /V-Nitrosodipropylamine in Trifluralin Emulsifiable Concentrates Using
Minicolumn Cleanup and Gas Chromatography with Thermal Energy Analyzer
Authors: Wotherspoon Dave , Hindle Ralph
Published: February 2020

A quick method for determining /V-nitrosodipropylamine (NDPA) levels in trifluralin emulsifiable concentrate formulations is described. At least 18 samples can be analyzed at one time in a minimum of fumehood space, with up to 90% savings on solvents and materials. A sample aliquot is mixed with a solution containing nitrosamine recovery standards, and nitrosamines are separated by minicolumn cleanup. Internal standard is added directly to the eluate containing the nitrosamines, and levels are determined by gas chromatography with thermal energy analyzer. Recoveries of spiked nitrosamines ranged from 98 to 102%. Coefficients of variation for samples containing 0.5 ppm NDPA are 13%. Minimum detectable limit, calculated as 3 times the noise, is 0.06 ppm. Comparison with the method formerly used by this laboratory shows no significant difference in the analytical results at 95% confidence limits, and control experiments were performed to ensure that there was no artifact formation of NDPA.
Liquid Chromatographic Determ [nation of Available Lysine in Soybean and Fish Meal
Authors: Rabasseda Joan , Rauret Gemma , Galceran Teresa M
Published: February 2020

A method for the determination of available lysine on the basis of the reactivity of the e-amino group with fluorodinitrobenzene (FDNB) has been optimized. Hydrolysis is performed in closed vessels in an autoclave. Conditions for different meals were established by using a modified sequential simplex method. Hydrolysis for 4 h was sufficient for the meals studied—soybean and fish. The use of liquid chromatography to determine available lysine was studied, and optimum conditions were established for separation and quantitation of e-DNB-lysine. The proposed method is faster, more accurate, and more precise than commonly used methods
Improved Method for Determination of Chlorothalonil and Related Residues in Cranberries
Authors: El-Nabarawy1 Ibrahim M , Carey William F
Published: February 2020

Tetrachloroisophthalonitrile (chlorothalonil) was applied under controlled conditions in 1985 to a cranberry bog for fungus control and for residue studies. Randomly selected samples of cranberries were analyzed for residues of chlorothalonil, its metabolite 4-hydroxy- 2,5,6-trichloroisophthalonitrile, hexachlorobenzene, and pentachlorobenzonitrile by extraction, methylation, Florisil column cleanup, and electron capture gas chromatography. Because of interferences in the GC determinative step, previously reported methodology was modified. The total residues found in the test samples were well below the permissible limit for the parent and related compounds.
Development of Porcine Rapid Identification Method (PRIME) by Modified
Agar-Gel Immunodiffusion
Authors: Cutrufelli Mark E , Mageau Richard P , Schwab Bernard , Johnston Ralph W
Published: February 2020

A porcine rapid identification method (PRIME) has been developed for detection of pork in a wide variety of meat products. The test is an adaptation of previously developed field screening immunodiffusion tests for beef and poultry detection. The PRIME test was demonstrated to be specific, sensitive, and accurate in the analysis of samples in the laboratory and in a commercial meat processing establishment.
Determination of Diacetyl in Butter as 2,3-Diaminonaphthalene Derivative, Using a Fluorometric Procedure or Reverse Phase Liquid Chromatography with Fluorescence Detection
Authors: Damiani Pietro , Burini Giovanni
Published: February 2020

Two procedures, one fluorometric and the other reverse phase liquid chromatographic, for determination of a derivative of diacetyl are described. Exploratory work on diacetyl standard solutions to establish the best conditions for the derivatization with 2,3-diaminonaphthalene (DAN) to yield 2,3-dimethylbenzo[g]-quinoxaline (DMBQ) is discussed, as well as the fluorescence characteristics of the DMBQ derivative. Diacetyl was determined in 10 commercial butter samples by the proposed procedures and by other known methods (determination of o-phenylenediamine and 3,3-diaminobenzidinederivatives). Recoveries from butter samples spiked with known amounts of diacetyl ranged from 96.9 to 101.8% (with CVs ranging from 0.3 to 2.1%) for the fluorometric procedure and from 96.9 to 102.7% (with CVs ranging from 0.5 to 2.4%) for the chromatographic procedure. These results agree well with those obtained with o-phenylenediamine and 3,3-diaminobenzidine methods on the same butter samples. The proposed methods have the advantages of improved detectability and specificity.
Determination of Polychlorinated Biphenyls in Sediments, Using Sonication Extraction and
Capillary Column Gas Chromatography-Electron Capture Detection with Internal Standard
Calibration
Authors: Dunnivant Frank M , Elzerman Alan W
Published: February 2020

A sonication technique is presented for the extraction of polychlorinated biphenyls (PCBs) from sediments. In addition, a quantitation scheme is described which allows peak-specific and, in many cases, congener-specific determination of PCBs. PCBs are quantitated by capillary column gas chromatography-electron capture detection, with internal standard calibration. Results utilizing sonication extraction were compared with those obtained by Soxhlet and steam distillation extractions of 3 U.S. Environmental Protection Agency (EPA) quality control sediment samples and 3 lake sediments known to be contaminated with PCBs. Environmental lake sediments were extracted wet, with no drying prior to extraction. Recoveries by each technique varied depending on the sediment sample being extracted and degree of chlorination of PCB congeners. With proper selection of extraction solvent, the sonication technique can recover amounts of PCBs equivalent to and sometimes greater than recoveries by the Soxhlet or steam distillation techniques. A 24-h quiescent period in the extraction solvent between 2 sonications improved extraction efficiency for 2 freeze-dried sediments but did not affect results obtained for 3 environmentally contaminated sediments that were extracted without drying. Replacement of Soxhlet extraction with the sonication technique results in reduced sample preparation time, decreased volumes of solvents and sample, and substitution of common laboratory glassware in place of fragile, expensive Soxhlet glassware. Sonication extraction can also improve precision compared with Soxhlet extraction
Fluorogenic Assay for Rapid Detection of Escherichia coli in Chilled and Frozen Foods:
Collaborative Study
Authors: Moberg Lloyd J , Wagner Mary K , Kellen Lisa A
Published: February 2020

A collaborative study was conducted to compare a proposed LSTMUG method with the AOAC official method for Escherichia coli detection. E. coli produces an enzyme, β-glucuronidase, which cleaves the substrate, 4-methyl-umbelliferyl-β-D-glucuronide (MUG), to yield a fluorescent end product. Incorporation of the MUG substrate into lauryl tryptose broth (LST) enables a rapid quantitative method for screening E. coli, which is detected by fluorescence of the medium under longwave UV light. In this collaborative study, 5 food samples, 2 frozen (entree sauce/gravy and dairy topping) and 3 chilled (hamburger, pork sausage, and cheese), were tested for E. coli detection by 17 collaborating laboratories. Results indicate that the LST-MUG method is equal to or better than the current AOAC method for detecting E. coli. The LST-MUG method has been adopted official first action
Survey of Vitamin Content of Fortified Milk
Authors: Tanner James T , Smith Jeffrey , Defibaugh Phillip , Angyal Gerald , Villalobos Melina , BUENO Martin P , Mcgarrahan Eugene T , Michael Wehr H , Muniz Juan F , Hollis Bruce W , Koh Younghan , Reich Peter , Simpson Kenneth L
Published: February 2020

This paper summarizes work done by 4 different laboratories on the vitamin content of milk. Riboflavin, vitamin A, and vitamin D were assayed in whole, 2%, and skim milks that had been fortified. In general, the adherence to label claim decreased with decreasing fat content. This may be due to methods and stage of vitamin addition prior to processing
Historical Perspectives on Methodology to Detect Listeria monocytogenes
Authors: Donnelly Catherine W
Published: February 2020

While recognized as a causative agent of illness in animals and humans for some time, the foodborne role of Listeria monocytogenes is a new and emerging one. This review briefly summarizes the historical developments in methodology used to detect the presence of L. monocytogenes. Although clinical procedures exist, these procedures do not consider isolation of Listeria from heavily contaminated environments. Federal agencies such as the U.S. Food and Drug Administration and the U.S. Department of Agriculture have defined protocols for the isolation of Listeria from dairy and meat products, respectively. Each of these protocols, and current problems common to all methods for the isolation of Listeria from food products, are discussed. Finally, future challenges with respect to improvement in our abilities to recognize, isolate, and rapidly identify Listeria in foods are presented
Microbial Diffusion Assay for Antibiotics in Feeds Using a Simplified Design
Authors: Brady Marietta Sue , Katz Stanley E
Published: February 2020

Results are compared for the microbiological analysis of antibiotics in feeds using the AOAC plate diffusion assay and the simplified 2-plate assay. Five antibiotics, bacitracin, chlortetracycline, oxytetracycline, penicillin, and streptomycin, were used to supplement feed extracts at levels of 100 and 25 μg antibiotic/g feed (bacitracin at 100 jug/g only). For bacitracin at the one level and for penicillin at both levels, the 2-plate design yielded significantly more accurate results than those of the AOAC assay. The same was true for the 25 μg/g level of oxytetracycline and the 100 μg/g level of streptomycin. For streptomycin at the 25 μg/g supplementation, the AOAC assay results showed better accuracy. There was no significant difference in results between the 2 designs for oxytetracycline at 100 fig/g and chlortetracycline at either level. The accuracy and precision of the results for the 2-plate design are equivalent to or better than those obtained using the AOAC design; in addition, the 2-plate assay is less labor-intensive, is more cost-effective, and is able to determine reasonable conditions of similarity.
Rapid Procedure for Determination of Nicarbazin Residues in Chicken Tissues
Authors: Parks Owen W
Published: February 2020

A procedure is described for the quantitation of nicarbazin residues in chicken tissues. The method includes extraction of tissue with chloroform-ethyl acetate-dimethyl sulfoxide (50 + 50 + 0.8), adsorption on neutral alumina, and subsequent elution of the residues with methanol-pH 6.0 phosphate buffer (1 + 1). Extracts are separated on a 15 cm, 5 μm C18 column with methanol-pH 6.0 phosphate buffer (6.5 + 3.5) as the mobile phase. The dinitrocarbanilide portion of the complex is detected and quantitated with an electrochemical detector in the reductive mode. Recoveries, based on dinitrocarbanilide, were greater than 95% in liver, breast, and thigh muscle tissues fortified with 0.25-8.0 ppm nicarbazin.
Apple Juice Composition: Sugar, Nonvolatile Acid, and Phenolic Profiles
Authors: Lee Hyoung S , Wrolstad Ronald E
Published: February 2020

Apples from Michigan, Washington, Argentina, Mexico, and New Zealand were processed into juice; the 8 samples included Golden Delicious, Jonathan, Granny Smith, and Mcintosh varieties. Liquid chromatography was used for quantitation of sugars (glucose, fructose, sucrose, and sorbitol), nonvolatile acids (malic, quinic, citric, shikimic, and fumaric), and phenolics (chlorogenic acid and hydroxymethylfurfural [HMF]). Other determinations included pH, °Brix, and L-malic acid. A number of compositional indices for these authentic juices, e.g., chlorogenic acid content, total malic - L-malic difference, and the HMF: chlorogenic ratio, were at variance with recommended standards. The phenolic profile was shown to be particularly influenced by gelatin fining, with peak areas decreasing by as much as 50%. The L-malic: total malic ratio serves as a better index for presence of synthetic malic acid than does the difference between the 2 determinations. No apparent differences in chemical composition could be attributed to geographic origin.
Stable Isotopic Carbon Composition of Apples and Their Subfractions—Juice, Seeds, Sugars, and Nonvolatile Acids
Authors: Lee Hyoung S , Wrolstad Ronald E
Published: February 2020

The 13C:12C ratios of 8 authentic apple juice samples and their subfractions were determined by mass spectrometry. Apples from Argentina, Mexico, New Zealand, and the United States were processed into juice; pulp was collected from the milled fruit and seeds were collected from the press-cake. Sugars, nonvolatile acids, and phenolics were isolated from the juice by treatment with ion-exchange resins and polyvinylpyrrolidone (PVPP). The mean value for all juice samples was — 24.2%o which is close to the values reported by other investigators. Juice from apples grown in Argentina, Mexico, and New Zealand did not differ from U.S. samples. The isotopic composition of the subfractions ranged from -22.0 to -31.0%o. The values for the pulp were essentially the same as for juice. The sugar fraction was slightly less negative than the juice; the nonvolatile acid and phenolic fractions were more negative. The levels of nonvolatile acids and phenolics in apple juice are low, however, so these compounds contribute little to overall δ13C values in juice.
Determination of Vitamin K1 in Powdered Infant Formulas, Using Supercritical Fluid
Extraction and Liquid Chromatography with Electrochemical Detection
Authors: Schneiderman Martin A , Sharma Avadhesh K , Mahanama Kariyawasam R R , Locke David C
Published: February 2020

Vitamin K, (phylloquinone) is extracted from commercial soy proteinbased and milk-based powdered infant formulas by using supercritical fluid extraction with C02 at 8000 psi and 60°C. Quantitative extraction requires only 15 min, and does not suffer from the problems associated with conventional solvent extraction of lipophilic materials from media such as formulas. Vitamin K, is determined in the extracts by using reverse-phase liquid chromatography (LC) with reductive mode electrochemical detection at a silver electrode polarized at —1.1 V vs SCE. LC run time is 9 min. The minimum detectable quantity is 80 pg, and response is linear over at least 5 orders of magnitude. Recovery of vitamin K, from a milk-based powdered formula was 95.6% with RSD of 7.4%, and from a soy protein-based product, 94.4% recovery with RSD of 6.5%.
Screening Method for Determination of High Levels of Cadmium, Lead, and Copper in Foods
by Polarized Zeeman Atomic Absorption Spectrometry Using Discrete Nebulization Technique
Authors: Saito Isao , Oshima Harumi , Kawamura Norihisa , Yamada Masuo
Published: February 2020

A screening method for determination of cadmium, lead, and copper in foods was developed. The sample (1-3 g) is digested with HN03- H2S04-HCI04 in a centrifuge tube attached to a straight glass tube that prevents loss of HN03 by volatilization. After digestion, potassium iodide, H2S04, and MIBK (4-methyl 2-pentanone) are added, and the metals are extracted with MIBK as metal iodides. The MIBK solution is injected and the metals are determined by flame polarized Zeeman atomic absorption spectrometry using a discrete nebulization technique. Recoveries of metals from fortified milk powder, unpolished rice, fish, beef, peanut butter, apple, and cabbage were satisfactory. The analytical results for NBS Oyster Tissue and NIES Pepperbush, Chlorella, and Mussel agreed with certified or reference values except lead in Pepperbush. The limits of quantitation for cadmium, lead, and copper were 0.01, 0.09, and 0.02 ppm, respectively. This method is simple and safe for routine analysis of high levels of cadmium, lead, and copper in foods.
Automated Microanalysis for Reducing Sugars, Sucrose, and Starch in Single Soybean
Leaflets
Authors: Hoogenboom Gerrit , Huck Morris G , Peterson Curt M , Goli Ankon
Published: February 2020

An automated enzymatic hydrolysis procedure was developed to analyze aqueous leaf extracts for soluble carbohydrates in the presence of chlorophyll. Following an initial estimate of free reducing substances in the extracts from individual soybean {Glycine max [L.] Merr. 'Braxton') leaflets, separate portions were incubated with invertase or amyloglucosidase. The increase in ferricyanide reduction after incubation with the enzyme was assumed to represent the concentration of sucrose or starch, respectively, in the original extract. Use of an autoanalyzer operating in a double-beam mode compensated for interference from chlorophyll and other endogenous pigments. Extraction efficiency was checked by successive boiling-water extractions, and enzymatic incubation conditions were verified by a series of internal calibration standards. After 3 successive boilingwater extractions of § min each, more than 95% of the soluble sucrose was removed from the leaflets. Although the conditions of these procedures were insufficient for quantitative removal of all soluble starch present in the soybean leaflet, they represent a compromise that yields an aqueous extract which is amenable to enzymatic assay while avoiding excessive degradation of labile carbohydrates during the extraction process. This method allowed for a rapid comparison between drought-stressed and non-stressed soybean leaflets, which were collected during field experiments and stored in a laboratory freezer for later analysis of osmotic potential and soluble carbohydrates, e.g., glucose, fructose, sucrose, and starch.
Determination of Intermediates and Side-Reaction Products in Tartrazine by
Ion-Pair Liquid Chromatography
Authors: Kirchmayr Klaus , Malissa Hans , Szolgyenyi Gerald P , Winsauer Karl
Published: February 2020

A reverse-phase ion-pair liquid chromatographic method was applied to the measurement of uncombined intermediates and side-reaction products in Tartrazine (FD&C Yellow No. 5). These compounds, sulfanilic acid, phenylhydrazine-p-sulfonic acid, pyrazolone-T, methyl and ethyl esters of pyrazolone-T, and 4,4'-(diazoamino)-dibenzenesulfonic acid, form strong ion pairs with the tetrabutylammonium (TBA) counterion, which are separated on an RP-18 column with a methanol-water solvent mixture under acidic conditions. Baseline resolution is attained with a 0.03 mol/L TBA concentration and a pH of 2.5. With a linear step flow program and 40°C column temperature, elution time is reduced to 20 min with no equilibration between individual runs. Performance data for quantitative measurement are given in terms of calibration curve linearity (r between 0.98 and 1.00 for all compounds studied) and method detection limit (from 0.004 to 0.022% as % per weight of Tartrazine).
Reverse-Phase Liquid Chromatographic Determination of Lysine in Complete Feeds and
Premixes, Using Manual Precolumn Derivatization
Authors: Cottingham Layna S , Smallidge Robert L
Published: February 2020

A sample portion is hydrolyzed with 6N HCl for 23 h and cooled, the pH is adjusted to 7.7 with NaOH, and the solution is diluted with pH 7.7 borate buffer. An aliquot of the sample extract is derivatized with 9-fluorenylmethyl chloroformate (9-FMC). Lysine is separated from other amino acids by isocratic reverse-phase liquid chromatography (LC) using fluorescence detection: 260 nm excitation and 313 nm emission. The mobile phase is acetonitrile-O.lM acetic acid (pH 4.2) buffer (53 + 47). Linearity is satisfactory over a range of 0.4-24 Mg/mL. Results from 9 feed samples (1.1-2.7% lysine) analyzed by both the LC method and an amino acid analyzer were not significantly different statistically. Recovery of standard lysine, spiked just before derivatization on these same 9 samples (in duplicate), was 100.9% with a coefficient of variation (CV) of 2.4%. A study of within-day and between-day method precision resulted in CVs of 1.1 and 1.8%, respectively. The variation of results was negligible when the method was tested for ruggedness on 7 factors.
Comparison of Four Methods for Digesting Food Samples for Determination of Trace Levels
of Cadmium by Flameless Atomic Absorption Spectrophotometry
Authors: Cabanis Marie T , Cassanas Genevieve , Cabanis Jean C , Brun Suzanne
Published: February 2020

We compared 4 digestion procedures, namely, sulfuric-nitric acid in an open flask, nitric acid under pressure, sulfuric-nitric acid with refluxing, and nitric-hydrochloric-peroxide with refluxing, for the determination of cadmium by flameless atomic absorption spectrophotometry in 3 foodstuffs: rice, beef, and cream cheese. The foodstuffs were homogenized and divided into several batches for analysis. The results were evaluated using a 2-way cross analysis of variance. The study revealed that the digestion procedure was a highly significant factor (P < 10 4) in the analysis of the 3 foods; whereas the nature of the foodstuffs was not significant for rice and meat and only slightly significant (P <10~2) for cream cheese. When the foodstuffs were spiked with a known amount of cadmium, we observed a loss of the metal when the sulfuric-nitric acid procedure in an open flask and the nitric-hydrochloric-peroxide digestion procedure were used. Taken together, the results of the present study indicate that the choice of the reagents used for digestion of foodstuffs is a crucial factor for cadmium determination by flameless atomic absorption spectrophotometry.
Analysis of Selected Elements in Tobacco by Wavelength Dispersive X-Ray Fluorescence
Spectrometry
Authors: Martin John M
Published: February 2020

A rapid method for the determination of 16 elements in tobacco by wavelength dispersive X-ray fluorescence spectrometry has been developed. The method is accurate and precise, and requires only 9 min per sample for quantitation. Sample preparation consists of placing a portion of dried, ground tobacco in a sample cup, and pressing at 25 tons pressure to make a compressed pellet. This pellet is then automatically analyzed by X-ray fluorescence for 16 elements. The results are stored on a computer disk for future recall and report generation.
Liquid Chromatographic Determination of Sulfamethazine in Feeds
Authors: Houglum Joel E , Larson Richard D , Neal Rose M
Published: February 2020

A reverse-phase liquid chromatographic method for the assay of sulfamethazine (SMZ) in feeds is described. Feed samples are extracted with 50% methanol solution, centrifuged, filtered, and diluted when necessary, and chromatographed on a C-18 column. Samples are eluted with a mobile phase of 20% methanol and 80% of a solution containing acetic acid and tetramethylammonium chloride. The average recovery from spiked samples was 97.2% with a coefficient of variation of 1.2%. Linearity was very good (correlation coefficient 0.9997). Within-day and between-day coefficients of variation averaged 1.3 and 2.6%, respectively. The results for samples assayed by this method compared closely with the results from the same extracts assayed by the AOAC colorimetric method
Simplified Method for Determination of Total Dietary Fiber in Foods
Authors: Li Betty W , Andrews Karen W
Published: February 2020

A simplified method, based on the same principles as the AOAC enzymatic-gravimetric method for determining total dietary fiber (TDF) (43.A14-43.A20), has been tested on 12 food samples which had been used in other collaborative studies. TDF values obtained in our laboratory for these 2 methods were in good agreement (y = 0.96x + 0.39; r = 0.999). The simplified method uses a single incubation period and only 1 enzyme (amyloglucosidase), and thus yields smaller blank and ash corrections but a higher protein correction.
Liquid Chromatographic Determination of Glibenclamide in Human Plasma
Authors: Othman Sadeq , Shaheen Omar , Jalal Ibraheem , Abdullah Awidi , Al-Turk Walid
Published: February 2020

The oral hypoglycemic agent glibenclamide was determined in human plasma by liquid chromatography (LC). Samples, with internal standard added, are extracted with dichloromethane. The organic phase is evaporated, and the residue is reconstituted in mobile phase for injection onto the LC column. Intra- and inter-day variability of the method was assessed at high and low levels of the drug. Although coefficients of variation were similar for both intra- and inter-day studies at both levels, CVs were smaller at the higher concentration level. Recovery of the drug was good at both high and low levels. The minimum level of detection was 5 ng/mL.
Evaluation by Enzyme-Linked Immunosorbent Assay of Cleanup for Thin-Layer
Chromatography of Aflatoxin B 1in Corn, Peanuts, and Peanut Butter
Authors: Chu Fun S , Lee Rachel C , Trucksess Mary W , Park Douglas L
Published: February 2020

A simple, rapid enzyme-linked immunoassay (ELISA) was used to evaluate the performance of each step (extraction, filtration, solvent partition, and silica gel column chromatography) of a solvent-efficient thin-layer chromatographic (TLC) method which is undergoing interlaboratory collaborative study for the determination of aflatoxin B1 in corn, raw peanuts, and peanut butter. The apparent average recoveries using the ELISA method were about 30 to 50% higher than those using the TLC method if only the amount of B, added to the samples was used in the calculations. After the cross-reaction of the antibody with other aflatoxins added to the samples was considered, the amounts recovered approached the levels of aflatoxins added in all 3 commodities tested. With no cleanup treatment, ELISA recoveries at aflatoxin B, levels above 7.5 ng/g were 84, 79, and 103% for corn, raw peanuts, and peanut butter, respectively. The coefficients of variation were between 5.2 and 25.2%. With each cleanup step in the TLC method, ELISA detected a progressive decrease in recovery from 150.5 to 105.3% (before correction for the presence of other aflatoxins) or from 93.5 to 65.4% (after correction for other aflatoxins) of B1 added to the samples. The ELISA data support the conclusion obtained from previous studies that cleanup treatments were not necessary in the ELISA. When large amounts of other aflatoxins are present, an understanding of the cross-reactivity of antibody with other aflatoxins in the ELISA is essential for final interpretation of the data.
Liquid Chromatographic Determination of Aflatoxins in Feedstuffs Containing Citrus Pulp
Authors: Paulsch Walter E , Sizoo Eric A , Van Egmond Hans P
Published: February 2020

A liquid chromatographic (LC) method was developed for the determination of aflatoxins in feedstuffs containing citrus pulp. The feedstuff sample is extracted with chloroform, followed by Sep-Pak Florisil cartridge cleanup and Sep-Pak C18 cartridge cleanup. The final eluate (water-acetone, 85 + 15, v/v) is submitted to reverse-phase liquid chromatography with water-methanol-acetonitrile (130 + 70 + 40, v/v/v) as mobile phase and postcolumn derivatization with iodine. Citrus components are removed from the extract efficiently. The limit of detection for aflatoxin B1 is< 1 μg/kg. Other aflatoxins can also be detected and measured. Recoveries of aflatoxins B1 B2, G,1 and G2 for dairy rations spiked at 13, 5, 10, and 4 μg/kg were 87, 86, 81, and 82%, respectively. Corresponding coefficients of variation were 3.1, 3.6, 5.2, and 3.8%, respectively.
UV Spectrophotometric Determination of Hydralazine Hydrochloride in Tablets:
Collaborative Study
Authors: Mopper Barry
Published: February 2020

A UV spectrophotometric method for the determination of hydralazine hydrochloride in tablets was collaboratively studied by 5 laboratories. The method is based on conversion of hydralazine to a tetrazolo [5,l-a]phthalazine derivative which shows an absorption maximum at about 274 nm. Each collaborator received blind duplicate samples of 2 commercial powdered composites from 10 and 100 mg tablets, and 1 synthetic tablet formulation. Each collaborator also received a set of 10 tablets for determination of content uniformity. The pooled mean recovery of hydralazine hydrochloride from the synthetic formulation was 101.2 ± 0.94%. The mean assay values for 10 and 100 mg tablets were 95.6 ± 0.98 and 101.0 ± 0.73% of the declared amounts, respectively, with corresponding CV values of 1.02 and 0.73%. The pooled mean for individual tablet assay was 99.8 ± 3.26% of the declared value, with a CV of 3.29%. The method has been adopted official first action
Dimetridazole Residues in Pork Tissue. II. Application of Liquid Chromatographic Method to
Monitor Elimination of Drug and its Major Metabolite
Authors: Carignan Germain , Macintosh Agnes I , Skakum William , Sved Stephen
Published: February 2020

A study was conducted to monitor the elimination of dimetridazole (DMZ) and its major metabolite 2-hydroxymethyl-l-methyl-5-nitroimidazole (HMMNI) in swine plasma and tissue, using a liquid chromatographic method with electrochemical detector sensitive to 0.5 ppb. The study consisted of 2 experiments. In the preliminary experiment, one young female piglet was fed medicated ration containing 125 ppm dimetridazole (DMZ) for 2 weeks, followed by a withdrawal period using regular ration for 5 days. Another, control, piglet was given regular diet throughout. Plasma concentrations of DMZ and its most important residue, HMMNI, were measured daily at 2 h after the morning feeding and, on days 8 and 15, several times during the day. The 2 h concentrations after 3 days loading ranged from 47 to 77 ppb for DMZ and 424 to 1081 ppb for HMMNI. A daily cycle in the plasma levels was seen for both substances. Upon withdrawal of medication, elimination of drug and metabolite was biexponential with a terminal half-life of 6.7 h. In the second experiment, 5 piglets were medicated as above and slaughtered 2, 6, 12,25, and 49 h after withdrawal of the medication; the concentration of DMZ and HMMNI was measured in plasma, muscle, kidney, and liver. DMZ in the plasma amounted to 22 and 1.8 ppb at 2 and 6 h, while HMMNI declined from 535 ppb at 2 h to 0.75 ppb at 25 h. Most values for both substances found in muscle were close to those in the plasma; in kidney they amounted to 9-17% of the plasma levels. Very little HMMNI and no DMZ was found in the liver at 2 h. No drug or metabolite could be detected at 49 h in any of the tissues studied