bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bioavailability and Speciation of Mineral Micronutrients: The Enzymolysis Approach
Authors: Hocquellet Pierre , L'Hotellier Marie-Dominique 
Published: February 2020

Abstract
Speciation analyses are essential to investigate the effects of dietary components on bioavailability of mineral micronutrients. Enzymolysis was used. An in vitro model simulating enzymatic activity in the gastrointestinal tract of monogastric species was developed and used to assess availability of Fe, Cu, Mn, and Zn in some foodstuffs. The solubility of each element in samples was measured by atomic absorption spectrometry after enzymatic treatment. Data are in good agreement with information obtained from earlier, more expensive nutritional surveys or in vivo experiments and, therefore, allow prediction of the tendency of a particular food to induce mineral deficiency. In addition, ligands responsible for inhibiting intestinal absorption were identified by determining the amount of metal released after treatment of the insoluble residue with an appropriate enzyme such as cellulase and phytase, used respectively to study fiber and phytate interactions. Enzymolysis may be useful for optimizing mineral supplementations though its nutritional significance is somewhat limited by the fact that it does not take into account the dynamic changes in the gastrointestinal tract. Enzymolysis is a prerequisite for further speciation studies of complex systems and in some instances is the only way for specifying physicochemical forms of elements.
Rapid and Alternative Screening Methods for Microbiological Analysis
Authors: Van Der Zee Henk , Huis In T Veld Jos H J 
Published: February 2020

Abstract
Automated analytical instruments for enumerating indicator organisms and diagnostic test kits for pathogens can be used in food microbiology to screen samples and to replace conventional cultural and confirmation steps. Such methods are now available for rapid detection or estimation of groups of (indicator) organisms, pathogenic microorganisms, bacterial toxins and mycotoxins, and molds. These alternative methods can be classified by the principles on which they are based: modified conventional methods, instrumental measurement of bacterial metabolism, bioluminescence, immunological techniques, DNA techniques, and combinations of these techniques. To meet user expectations, test kits must be accurate, sensitive, specific, rapid (24 h or less), easy to use, and laborsaving. They must also offer the possibility of computerization, a low detection limit, and low investment and running costs. The paper compares the ability of alternative methods to meet these criteria. Variations were found, depending on the techniques used and the target organism of the analysis. Economic reasons can determine whether alternative methods can be used routinely. Adoption of these screening systems also can be hampered by lack of internationally coordinated and accepted validation protocols.
New Universal Quartz Burner for Decomposition of Samples by the Wickbold Combustion Technique in Determination of Arsenic, Antimony, Selenium, Mercury, and Lead
Authors: Erber Dietmar , Cammann Karl , Roth JüRgen 
Published: February 2020

Abstract
A new universal quartz burner for the Wickbold decomposition method is investigated with respect to its fast and efficient decomposition of solid samples for determining volatile trace elements like arsenic, antimony, selenium, mercury, and lead. Decomposition is based on burning samples in an oxyhydrogen flame. The samples are transported into the flame in gaseous form by pyrolyzing the material in an oven heated to 1100C. During this decomposition step, a nitrogen stream loaded with carbon tetrachloride mobilizes the volatile elements, causing separation from the sample matrix. An effective precombustion in oxygen and a large turbulent flame improve decomposition conditions. Different certified inorganic and organic reference materials are pyrolyzed and combusted, and the combustion products are absorbed in water. Metals found in the absorption solutions are analyzed by flow injection/hydride generation/atomic absorption spectrometry. Data were analyzed by several statistical tests recommended for quality control purposes. The combination of a decomposition and detection method resulted in very low detection limits: 1.4 μg arsenic/kg, 0.8 pig antimony/kg, 1.8 μg mercury/kg, 1.4 μg lead/kg, and 1.6 μg selenium/ g can be detected without an extra enrichment step.
Identification and Quantitation of the Six Active Compounds in a Pyrethrin Standard
Authors: Moorman Richard , Nguyen Khanh T 
Published: February 2020

Abstract
Six biologically active insecticidal compounds in pyrethrum extract—pyrethrin I (Py I), jasmolin I (J I), cinerin I (C I), pyrethrin II (Py II), jasmolin II (J II), and cinerin II (C II)—have been identified and quantitated using a procedure combining the modified version of the AOAC mercury reduction Method 936.05 and capillary gas chromatography with flame ionization detection (GC-FID), GC with mass selective detection, and GC with infrared detection. This method involves hydrolysis of pyrethrum extract and subsequent measurement of monocarboxylic and dicarboxylic acids. Mass and infrared spectra are used to identify the 6 active compounds, and GC-FID is used to determine their purities. The use of this characterized standard is limited to a proposed capillary GC AOAC method that quantitates AAoctyl bicycloheptene dicarboximide (MGK264), pyrethrin, and butylcarbityl 6- propylpiperonyl ether (BPE) in technical materials, concentrates, and certain finished products.
Planar Chromatography for Quantitative Determination of Ampicillin Residues in Milk and Muscle
Authors: Abjean Jean-Pierre , Lahogue Véronique 
Published: February 2020

Abstract
A method involving protein precipitation with trichloroacetic acid and ampicillin hydrolysis with sodium hydroxide was developed for determination of ampicillin residue in milk and muscle. The hydrolysis product reacts in an acidic medium, in the presence of mercuric chloride, to form a fluorescent compound, which is extracted from the matrix with dichloromethane and concentrated on a silica Sep-Pak cartridge in a single step. After elution of the silica cartridge and evaporation of the solvent, the residue is recovered in 100 μL ethyl acetate, and 20 μL is deposited on a chromatoplate and chromatographed with ethyl acetate. The method allows determination of ampicillin residues in milk and muscle fortified at 4 μg/L and 50 μg/kg, respectively.
Determination of Nicarbazin in Eggs by Liquid Chromatography–Atmospheric Pressure Chemical Ionization Mass Spectrometry
Authors: Blanchflower W John , Hughes Peter J , Kennedy D Glenn 
Published: February 2020

Abstract
A method was developed to determine in eggs 2 components [4,6-dimethyl-2-hydroxypyrimidine and 1,3-bis(4-nitrophenyl)urea] of the anticoccidial drug nicarbazin, used to treat poultry. Samples were extracted with acetonitrile, and the extracts were washed with hexane and evaporated to dryness before analysis by liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization. By switching from positive to negative ion monitoring and using gradient elution, both components were measured within one run. The limit of quantitation of the assay was 10 ng/g for each component. The results of a preliminary feeding trial in which chickens were fed contamination levels of the drug are also reported.
Induction and Characterization of Multianalyte Antibodies Against Penicillins in Egg Yolk
Authors: de Leuw Peter , Kapa Georg , Petz Michael 
Published: February 2020

Abstract
Antibodies against penicillins were induced in eggs of laying hens after immunization with 6-aminopeniciIlanic acid (6-APA) coupled to keyhole limpet hemocyanin (KLH). Development of the antibody titer was monitored by an indirect enzyme-linked immunosorbent assay (ELISA), with 6-APA coupled to ovalbumin as antigen for coating microtiter plates. Different characteristics (time course, affinity) of the immune reaction were observed by testing eggs of individual hens. Titer values varied between 150 and 2000. Antibodies were isolated by polyethylene glycol precipitation and affinity chromatography, using a hapten sorbent with 6-APA as ligand. Glycine buffer, pH 3.0, was used to elute the immunoglobulins. Antibody specificity was determined in a competitive ELISA with 7 penicillins and the cephalosporin cephalexin as competitors. Cross reactivities for the penicillins were between 100 and 290% (6-APA = 100%). Cephalexin cross reacted only marginally (3%).
Survey of Organochlorine Pesticide Residues in Milk in Hong Kong (1993–1995)
Authors: Wong Siu-Kay , Lee Wai-On 
Published: February 2020

Abstract
A survey was conducted from 1993 through 1995 to monitor organochlorine pesticides and their metabolite residues in milk available in local Hong Kong markets. Of 252 samples analyzed, including pasteurized milk, fresh milk, and raw milk, 42 contained organochloride pesticide residues at levels exceeding the Extraneous Maximum Residue Limits of the Codex Committee on Pesticide Residues. DDE and HCH isomer levels were substantially higher than those found in a 1984–1987 survey, probably because the source of cow’s milk has shifted from local dairy industries to mainland China over the past decade. Although organochlorine pesticides such as DDT and HCH have been banned in China since 1983, residues of such compounds may still persist in the environment and cause contamination through the food chain.
Determination of vitamin a in milk and flour consumed by one- to four-year-old children in côte d'ivoire
Authors: Ake Michele , Mandrou Bernadette , Malan Anglade 
Published: February 2020

Abstract
As part of a United Nations Children's Found (UN¬ICEF) study, an analytical method is proposed for routine analysis of vitamin A in milk and flour consumed by 1- to 4-year-old children in Côte d'Ivoire. The method involves liquid-liquid extrac¬tion of sample followed by reversed-phase liquid chromatography (LC). The method has been vali¬dated and used to analyze various samples col¬lected at different locations and stored under unfa¬vorable conditions. Average vitamin A content was 575 μg/100 g for milk powder and 1350 μg/100 g for millet flour. Lower contents were found in corn flour (40-240 μg/100 g), and no vitamin A could be detected in rice flour
Preparation of Environmental Samples for Determination of Sulfonylurea Herbicides by Solid-Phase Extraction Using a Polymeric Sorbent
Authors: Young Michael S 
Published: February 2020

Abstract
An analytical procedure was developed for rapid determination of sulfonylurea herbicides in water or soil. Samples were prepared by solid-phase extraction using polymeric sorbents in cartridges and analyzed by liquid chromatography with photodiode array detection. Recoveries were consistent for all sample matrixes tested and were generally &gt;85%, except for tribenuron methyl (75%). Detection limits were &lt;100 ng/L for water samples
Liquid Chromatographic Method for Determining Thiodicarb in Technical Products and Formulations: CIPAC Collaborative Study
Authors: Hanks Alan R ,   Collaborators:, Abedi J , De Aguila E , Bodzian F , Chatpong  , Chechik E , Chmil V , Duverney-Prêt P , Förster R , Gau W , Hussain  , Itier M , lurascu T , Manso L , Pocaba V , Ruffin  , Ryckel B De , Santos  , Schreuder R H , Sriplakich C , Sweeney P J , Tam K C , Tengler H , Thuet E , Weber  , Werner T 
Published: February 2020

abstract
A liquid chromatographic method for determining thiodicarb in technical products and formulations was evaluated by 25 participants from 19 laboratories. Data from 19 laboratories were used in statistical analysis to characterize method performance.Two technical materials, a suspension concentrate, a wettable powder, and a water dispersable granule were analyzed. Thiodicarb was determined by reversed-phase liquid chromatography using a mobile phase of methanol and water. Chromatography was performed on a C8 column with detection at 254 nm. Quantitation was achieved by using an internal standard and peak area ratios.
Quantitation of Imidacloprid in Liquid and Solid Formulations by Reversed-Phase Liquid Chromatography:Collaborative Study
Authors: Macke Michelle M ,   Collaborators:, Ambrose Richard , Benke Lajos , Denning Ralph , Ryckel B de , Focht Charles , Laslo Bura , Manuweera Lalini , Ritland C L , Smilo A Richard , Stroh Steven , Tam K C , Tengler H , Xing Gu Yi 
Published: February 2020

abstract
A liquid chromatographic (LC) method was developed for quantitation of the synthetic insecticide imidacloprid in liquid and solid formulations. Samples are dissolved or extracted in solvent and analyzed by reversed-phase LC with propiophenone as internal standard. Fourteen laboratories in 7 countries participated in the collaborative study of the method. Each collaborator was provided with reference standard, internal standard, and matched-pair samples of imidacloprid technical, flowable, wettable powder, fertilizer, and granular formulations. Collaborators were instructed to use peak area measurements for quantitation. The reversed-phase LC method for determination of imidacloprid in liquid and solid formulations has been adopted first action by AOAC INTERNATIONAL.
A Rapid and Selective Method for Determining Potential Nitrosating Agents in Cosmetic Products by Chemiluminescence Detection of Nitric Oxide
Authors: Chou Hardy J , Yates Ronald L 
Published: February 2020

abstract
A method was developed for rapid and selective determination of potential nitrosating agents at the part-per-billion level in cosmetic products. These compounds are chemically reduced to nitric oxide, which is determined by its chemiluminescent reaction with ozone. Suspended materials and colors in cosmetic products do not interfere. Hence their removal before analysis is not required. A detection limit of 33 ppb, calculated as nitrite, was obtained. No false-positive interferences were observed from antifoaming agents, several AZ-nitroso compounds, and nitrate up to 20 ppm. Among cosmetic products surveyed, potential nitrosating agents were found at levels ranging from 113 to 5021 ppb. No consistent relationship was found between levels of potential nitrosating agents and N-nitrosamines in the same products. However, the highest levels of nitrosating agents were most often associated with the highest levels of N-nitrosamines known to be present in the products.
Determination of Reserpine and Rescinnamine in Rauwolfia serpentina Powders and Tablets: Collaborative Study
Authors: Ugo R Cieri ,   Collaborators:, Alexander Leland , Colon Miguel , Frost Danielle , Jhangiani Rita K , Takiar Neeru , Tam Nilsa , Walters Milda , Yuen Stella 
Published: February 2020

abstract
A liquid chromatographic (LC) method for determining reserpine and rescinnamine in Rauwolfia serpentina powders and tablets, which uses fluorescence detection, was subjected to a collaborative study. The procedure for extraction and purification is a simplified version of that used in the current official method for analysis of these products. LC separations are performed on a normal- phase column. The mobile phase is methanol to which a small volume of an aqueous solution of 1-pentanesulfonic acid sodium salt can be added to achieve desired elution characteristics. Reserpine and rescinnamine elute at approximately the same time but can be individually quantitated by appropriate settings of the fluorescence detector. Reserpine is determined at an excitation wavelength of 280 nm and an emission wavelength of 360 nm, because rescinnamine is completely nonfluorescent at these wavelengths. Rescinnamine is determined at an excitation wavelength of 330 nm and an emission wavelength of 435 nm, because reserpine is completely nonfluorescent at these wavelengths. The following materials were used for the study: one sample of United States Pharmacopeia (USP) standard R. serpentina powder, one tablet type labeled as containing 100 mg R. serpentina and 2 tablet types labeled as containing 50 mg R. serpentina. For each of the 4 materials, 2 pairs of blind duplicates were prepared. Three materials were analyzed in duplicate by 8 laboratories. One of the 2 tablets labeled to contain 50 mg ft serpentina was analyzed only by 7 of 8 participating laboratories. Average combined content of reserpine and rescinnamine was 0.144% for the USP raw material and 0.132, 0.135, and0.137% for the 3 commercial tablets. Reproducibility relative standard deviation values were 5.72, 5.93, 8.61, and 3.48% and repeatability relative standard deviation values were 2.57, 4.87, 3.19, and 1.99% for the 4 samples. The Associate Referee conducted a study to determine recoveries of reserpine plus rescinnamine by this method from mixtures simulating sample extracts. Average recovery of 15 determinations was 100.1%, with a relative standard deviation of 1.3%. The LC method for determination of reserpine and rescinnamine in R. serpentina powders and tablets has been adopted first action by AOAC INTERNATIONAL.
Stability-Indicating Spectrophotometric and Densitometric Methods for Determination of Some Cephalosporins
Authors: Kelani Khadiga , Bebawy Lories I , Abdel-Fattah Laila 
Published: February 2020

abstract
Two methods were developed for determination of intact ceftazidime (I), cefuroxime sodium (II), and cefotaxime sodium (III) in the presence of their degradation products. In the first method, first derivative spectrophotometry (D1) is used. The (D1) absorbance is measured at 268.6, 306, and 228.6 nm for I, II, and III, respectively. The first proposed method determines I, II, and III in concentration ranges of 5-50, 5-35, and 5-40 μg/mL, respectively, with corresponding mean accuracies of 99.7 ± 0.8, 100.1 ± 0.7, and 99.8 ± 0.8%. The method determines the intact drug in the presence of up to 90% degradation products for I, and II and up to 80% for III. The second method depends on the quantitative densitometric evaluation of thin-layer chromatograms of I, II, and III. It determines I, II, and III in concentration ranges of 4-16 μg for I and 2-12 μg for II and III, with mean accuracy's of 99.5 ± 0.8, 99.2 ± 0.7, and 99.7 ± 0.8% for I, II, and III, respectively. The second method retains its accuracy in the presence of up to 90% degradation products for the 3 drugs. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the official method.
Zero Control Reference Materials for Infant Formula Methods Development
Authors: Chase G William , Reid Anne P , Eitenmiller Ronald R , Long Austin R 
Published: February 2020

abstract
A zero control reference material (ZRM) for milk and soy-based infant formula was manufactured and characterized. The ZRM was free of retinyl palmitate and all-rac-α-tocopheryl acetate. The composition was similar to commercially available infant formula. The ZRM provides a valuable tool to ascertain method performance.
Determination of N-Octyl Bicycloheptene Dicarboximide, Pyrethrins, and Butylcarbityl 6-Propylpiperonyl Ether in Technical Materials, Concentrates, and Finished Products by Capillary Gas Chromatography: Collaborative Study
Authors: Nguyen Khanh T , Moorman Richard , Kuykendall Virginia ,   Collaborators:, Bura L , Erbe E E , Essig K , Galoux I M , Gentry G M , Kersten S , Kho C C , Kim C -H , Kumar G S , Lisowski G T , Manso D L , Ochieng C D , Ritland C , Sriplarich C , Sundquist D L , Tam K C , Vaida M , Weiping G 
Published: February 2020

abstract
Nineteen collaborating laboratories (including the authors') analyzed 6 blind, duplicate pairs of various technical materials, pyrethrum extracts, concentrates, and finished products by split injection capillary gas chromatography (GC) with flame ionization detection. This procedure simultaneously quantitates with speed, ease, accuracy, and precision all 6 insecticidal compounds in pyrethrum: pyrethrin I, jasmolin I, cinerin I, pyrethrin II, jasmolin II, and cinerin II, as well as butylcarbityl 6-propylpiperonyl ether (BPE, the predominant compound in technical piperonyl butoxide, also commonly known as piperonyl butoxide) and both the endo and exo isomers of N-octyl bicycloheptene dicarboximide (MGK 264). Repeatability ranged from 4.28 to 7.22% for total pyrethrins, from 2.41 to 7.04% for BPE, and from 2.20 to 4.91 % for total MGK 264. Reproducibility ranged from 5.22 to 9.71 % for total pyrethrins, from 4.37 to 7.04% for BPE, and from 2.66 to 6.01 % for total MGK 264. The capillary GC method for these insecticidal compounds in technical materials, concentrates, and finished products has been adopted first action by AOAC INTERNATIONAL.
Simple System for Rapid Determination of Carbon Dioxide Evolution Rates
Authors: Hsieh Yuch-Ping , Hsieh Yun-Hwa P 
Published: February 2020

abstract
Measurement of CO2 evolution rates is important and necessary for many biological investigations because the rate is a common indicator of biological activity. The CO2 evolution rate of a sample can be determined quickly and sensitively with an IR CO2 analyzer. Many existing systems for determining CO2 evolution rates are quite complicated and expensive. They usually require removal of moisture in the testing air stream and a special gas mixture for calibration. The switching devices that allow analysis of multiple samples sequentially also further complicate the system. We present here a simple system—constructed from a commercially available CO2 analyzer and simple laboratory supplies— that analyzes CO2 evolution rates of multiple samples sequentially without special calibration gas mixtures or preremoval of moisture in the testing gas. The sensitivity and measuring range of the system can be conveniently adjusted by varying the sizes of the sample and the sample bottle. The lower detection limit of the system is 1.5 μl_/h, and the testing range is from 2 to 500 μL/h. The system is also portable for field applications.
Compound-Specific Gas Chromatographic/Mass Spectrometric Analysis of Alkylated and Parent Poly cyclic Aromatic Hydrocarbons in Waters, Sediments, and Aquatic Organisms
Authors: Means Jay C 
Published: February 2020

abstract
Polycyclic aromatic hydrocarbons (PAHs) and their alkylated and heterocyclic analogs are ubiquitous contaminants in aquatic environments, including estuaries and marine systems. Methodology for compound-specific analysis of 63 parent, alkylated, and heterocyclic PAHs using gas chromatography/ mass spectrometry (GC/MS) in both scanning and selected-ion monitoring modes has been developed and applied to sediment, natural waters and effluents, and marine organisms including oysters, mussels, and fish. Relative response factors and relative retention times for the 63 alkylated, heterocyclic, and parent PAHs compared with 6 deuterated PAHs are given. Analyses of natural sea water samples, enriched at concentrations ranging from 5 to 100 ng/L, show good accuracy (8℅ mean difference at the 5 ng/L level) and precision (mean RSD of 9℅), and method detection limits are in the partsper- trillion range. Results for sediments and tissues of aquatic organisms exposed to petroleum contamination demonstrate that analysis of parent PAHs alone vastly underestimates levels in sediments and tissues and the potential toxic effects of such residues in food webs. Multiple analyses of a reference tissue material show good precision (mean RSD of 15℅) and accuracy (mean difference of 17℅) for both alkylated and parent PAHs.