bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid Chromatographic Determination of Residual Nitrite/Nitrate in Foods: NMKL Collaborative Study
Authors: Merino Leonardo , Edberg Ulla , Fuchs Georg , Åman Per ,   Collaborators:, Corbari G , Dahlberg L , Da-Riz V , Eerola S , Gerard R , Grancher D , Jensen S , Kangro A , Kjolby A , Lundberg L , Marin M , Meland S , Muriel B , Nicolas M , Ravn T , Tuhkanen M , Vartiala T , Zieprath G 
Published: February 2020

Abstract
Nitrite and nitrate are used as additives in the food industry to provide color and taste and to control undesirable gas and flavor production by anaerobic bacteria by virtue of their antimicrobial properties. The analytical method that has been widely used to determine nitrite and nitrate involves the use of toxic cadmium. In response to a request from the Nordic Committee on Food Analysis, a study was performed to obtain an alternative chromatographic method to determine residual nitrite and nitrate in meat products. The study was done in 3 stages: (1) comparative evaluation of the performance of 3 liquid chromatographic methods, (2) internal validation of the selected ion chromatographic method, and (3) a collaborative study in which 17 laboratories from European countries participated. Furthermore, the applicability of the method to matrixes other than meat and meat products was demonstrated. The results of the collaborative study show that the European Prestandard prENV 12014-4 is well suited for the determination of nitrite and nitrate in different foods (e.g., meat products, vegetables, baby food, and cheese). The limits of detection for nitrite and nitrate ions are 1 and 10 mg/kg, respectively. Recoveries of residual nitrite/nitrate ranged from 96 to 108%. Repeatability and reproducibility were satisfactory.
Averaging the Closest Two out of Three Observations
Authors: Blodgett Robert J 
Published: February 2020

Abstract
The average of 3 observations is the standard method of estimating the location of their distribution. The average of the closest 2 out of 3 observations, although often used, has more variability than the average of all 3 observations for a standard normal distribution. One statistic uses a threshold to decide when to use the average of all 3 observations rather than the closest 2. With the standard normal, this statistic still has more variability than the average of all 3 observations.
Validation of an Immunoassay for Detection and Quantitation of a Genetically Modified Soybean in Food and Food Fractions Using Reference Materials: Interlaboratory Study
Authors: Lipp Markus , Anklam Elke , Stave James W ,   Collaborators:, Bahrs-Windsberger J , Barreto Crespo M T , Benvenuto E , Berben G , Brignon P , Busch U , Cordes C , Eklund E , El Jaziri M , Engel K H , Eriksen F , Eriksson S , Felinger A , Fogher C , Folch I , Garrett S , Hischenhuber C , Hörtner H , Jany K D , Krska R , Kruse L , Kuiper H A , Lobre C , Miraglia M , Mhller W , Nunes Costa J M , Oliveira L , Patel P , Pietsch K , Pöpping B , Remler P , Rentsch J , Schulze M , Sutton M , van Duijn G , van Kan F , Wurz A 
Published: February 2020

Abstract
An immunoassay for detection of a specific genetically modified soybean (Roundup-Ready®) was validated on dried soybean powder in an interlaboratory study. Different percentages of genetically modified soybeans in nonmodified soybean matrix were evaluated in a blind study. Thirty-eight laboratories from 13 countries participated. The immunoassay was evaluated for 2 endpoints: (1) To give a semiquantitative result, i.e., determination of a given sample above or below a given threshold, or (2) to compute a quantitative result, i.e., percentage of genetically modified soybeans in the sample. Semiquantitative results showed that a given sample which contained &lt;2% genetically modified soybeans was identified as below 2% with a 99% confidence level. Quantitative use of the assay resulted in a repeatability (r) and reproducibility (R) that were computed to be RSDr = 7% and RSDR = 10%, respectively, for a sample containing 2% genetically modified soybeans. Application of this method depends on availability of appropriate reference materials for a specific food matrix. Only matrix-matched reference materials can be used for analysis of food or food fractions.
Evaluation of a Dry, Rehydratable Film Method for Rapid Enumeration of Staphylococcus aureus
Authors: Mach Patrick A , Lindberg Kathryn G , Lund Marlys E 
Published: February 2020

Abstract
Results with the new 3M™ Petrifilm™ Rapid S. aureus Count (RSA) Plate method were compared with those of the classical Baird-Parker agar (BPA) method for detection and enumeration of Staphylococcus aureus. Studies on 219 bacterial strains demonstrated that the Petrifilm RSA plate is more sensitive than and as specific as the classical BPA method for confirmed identification of S. aureus. Counts of colonies from 71 pure cultures, 61 naturally contaminated food samples, and more than 750 artificially inoculated food samples showed that the Petrifilm RSA method was as effective as the classical BPA method for identification and enumeration of S. aureus. The Petrifilm RSA method gave results in one-third the time required for the classical method.
Flow Injection Spectrophotometric Determination of Copper, Iron, Manganese, and Zinc in Animal Feeds Using a Common Manifold
Authors: Liu Jing-Fu , Jiang Gui-Bin , Feng Ying-Di 
Published: February 2020

Abstract
A rapid and simple procedure was developed for the determination of copper, iron, manganese, and zinc in animal feeds using an identical flow injection spectrophotometric manifold but different chromogenic reagents and different detection wavelengths. Bis(cyclohexanone)oxalydihydrazone, formaldoxime, 1,10-phenanthroline, and xylenol orange were adopted as chromogenic reagents for Cu, Mn, Fe, and Zn, respectively. Detection conditions such as manifold parameters, buffer pH, reagent concentration, temperature, and acidity of sample solution were optimized. Analytical characteristics of the method and interference of metal ions commonly present in feeds were studied. By changing the reagents and detection wavelengths, which can be done quickly, the proposed low cost flow injection system can determine Cu, Fe, Mn, or Zn in the range of 0.5–10 mg/L with a sampling throughput of 120/h.
Spectrophotometric Determination of Ritodrine and Isoxsuprine Hydrochlorides Using 4-Aminoantipyrine
Authors: Revanasiddappa Hosakere D , Manju Bochhe Gowda 
Published: February 2020

Abstract
A simple, accurate, and rapid method for the quantitative determination of ritodrine hydrochloride (RTH) and isoxsuprine hydrochloride (ISH) in both pure and dosage forms, is described. The method is based on the development of pink colored product as a result of the condensation of 4-aminoantipyrine with phenols in the presence of an alkaline oxidizing agent. The resulting products are measured at 510 nm for both drugs, with molar absorptivities of 0.98 × 104 and 1.20 × 104 L/mol·cm for RTH and ISH, respectively. A study of the effect of commonly associated excipients revealed that they did not cause interference.
Confirmation of Moxidectin Residues in Cattle Fat by Liquid Chromatography/Mass Spectrometry
Authors: Stout Steven J , Wickremesinhe Enaksha , daCunha Adrian R , Khunachak Alisa 
Published: February 2020

Abstract
Moxidectin, a potent new endo- and ectoparasitic agent, is determined in cattle tissues by liquid chromatography (LC) with fluorescence detection. The original confirmatory method for moxidectin in cattle fat, the target tissue for regulatory purposes, was LC with mass spectrometry (MS) using thermospray (TSP) ionization and selected ion monitoring. As newer ionization techniques for LC/MS made TSP obsolete and with the availability of a new generation of benchtop LC/MS instrumentation, the confirmation of moxidectin in cattle fat was re-evaluated. The ionization techniques of atmospheric pressure chemical ionization versus electrospray ionization, the detection techniques of single-stage MS versus tandem MS, and the instrumentation of ion trap versus quadrupole were investigated. The final confirmatory method was based on full-scan single-stage MS. Even with full-scan detection, the analysis required at least 10-fold less extract than the original TSP method. The applicability of this new confirmatory method was demonstrated on both ion trap and quadrupole instruments.
Survey of Residual Tetracyclines in Kidneys of Diseased Animals in Aichi Prefecture, Japan (1985–1997)
Authors: Oka Hisao , Ito Yoko , Ikai Yashitomo , Matsumoto Hiroshi , Kato Keiichi , Yamamoto Isao , Shimizu Michihiko , Kawamura Norihisa , Miyazaki Yutaka , Nojiri Takayasu , Okumura Masanao , Ohmi Shin , Sato Takeo , Mori Giichiro 
Published: February 2020

Abstract
A survey was conducted to determine the incidence of tetracycline antibiotic (TCAs) residues in the kidneys of slaughtered animals that did not pass inspection for human consumption by the Japanese Food Sanitation Law and the Meat Inspection Law at the slaughterhouses in Aichi Prefecture, Japan, from April 1985 to March 1998. The kidneys were analyzed by the AOAC Official Method 995.09. Among 424 animals (147 cattle and 277 pigs), 131 (30.9%) were contaminated with TCAs, including 69 (16.3%) with chlortetracycline (CTC), 61 (14.4%) with oxytetracycline (OTC), 3 (0.7%) with tetracycline (TC), and 1 (0.2%) with doxycycline (DC). One sample (cattle kidney) was contaminated with both OTC and DC. The frequencies of OTC and TC residues were significantly higher ( p&lt; 0.05) in cattle than in pigs, whereas, the frequency of CTC was significantly higher ( p&lt; 0.01) in pigs. Pig kidney samples collected in 1991–1997 had significantly higher incidences of TCAs and CTC ( p&lt; 0.01) residues than those in 1985–1986.
Selective Separation and Simultaneous Determination of Trace Levels of Five Types of Fluorinated Quinolone Drugs by Thin-Layer Chromatography/Fluorescence Densitometry
Authors: Wang Pei-Lan , Chen Liang , Fan Ying-Fang 
Published: February 2020

Abstract
This paper reports the determination of trace levels of 5 types of fluorinated quinolone drugs, i.e., ciprofloxacin, norfloxacin, enoxacin, pefloxacin, and ofloxacin, by thin-layer chromatography (TLC)/fluorescence densitometry. The new analytical method uses 2-step TLC development, selective separation, and simultaneous determination of the 5 drugs. The method was also applied to the determination of recoveries of standards of the 5 drugs in plasma and urine samples. The results show that the method has a wide linear range, high repeatability, and good stability.
Rapid Determination of Nineteen Chlorophenols in Wood, Paper, Cardboard, Fruits, and Fruit Juices by Gas Chromatography/Mass Spectrometry
Authors: Diserens Jean-Marc 
Published: February 2020

Abstract
Although the use of pentachlorophenol (PCP) is prohibited in most countries, it is still widely found in the wood of pallets, containers, crates and in cardboard, paper, etc. Such material may contain not only PCP but other chlorophenols as well. Wooden crates and cardboard boxes are often used to store and transport fresh fruits. Consequently, chlorophenols present in the wood may contaminate the stored fruits by migration. To ascertain that packaging, storage material, and fruit raw materials are free from chlorophenol residues, we developed a rapid and sensitive method for the detection of 19 chlorophenols by gas chromatography/mass spectrometry (GC/MS). The test portions are directly extracted and acetylated in a solution of sodium carbonate in the presence of acetic anhydride and hexane. The hexane layer is analyzed, without further purification, by GC/MS in the selective-ion monitoring mode. The method allows the analysis of &gt;40 samples/day with detection limits of &lt;20 μg/kg for chlorophenols in wood, cardboard, and paper, and &lt;2 μg/kg for chlorophenols in fruits. Typical recoveries of all chlorophenols were 94% from paper, 115% from cardboard, 51% from wood (depending on the size of the chips or shavings), and 93% from fruit puree.
Spectrophotometric Determination of Sulfur Dioxide in Air, Using Thymol Blue
Authors: Gayathri Nagasundaram , Balasubramanian Natesan 
Published: February 2020

Abstract
A simple and sensitive spectrophotometric method was developed for the determination of trace amounts of sulfur dioxide. The method is based on the reaction of SO2 with a known excess of ICl as the oxidant. The unreacted ICl iodinates thymol blue under acidic conditions. The λmax of thymol blue is at 545 nm under acidic conditions, and on iodination λmax shifts to 430 nm. This shift results in a decrease in the absorbance at 545 nm. The amount of uniodinated thymol blue present depends on the concentration of unreacted ICl, which in turn depends on the SO2 concentration. The system obeys Beer's law in the range 0–30 μg SO2 in a final volume of 25 mL, having a molar absorptivity of 3.2 × 104 L/mol-cm with a relative standard deviation (RSD) of 2% at 24 μg SO2 (n = 10). The uniodinated dye can be extracted into 5 mL isoamyl alcohol under acidic conditions for measurement of absorbance. The extraction method obeys Beer's law in the range 0–5 mg SO2, having a molar absorpitivity of 4.16 × 104 L/mol-cm with an RSD of 1.9% at 4 μg SO2 (n = 10). The method has been successfully applied to the determination of atmospheric SO2.
Quantitative Determination of Paralytic Shellfish Poisoning Toxins in Shellfish by Using Prechromatographic Oxidation and Liquid Chromatography with Fluorescence Detection
Authors: Lawrence James F , Niedzwiadek Barbara 
Published: February 2020

Abstract
The prechromatographic oxidation LC method developed by Lawrence [J. Assoc. Off. Anal. Chem. 74, 404–409(1991)] for the determination of paralytic shellfish poisoning (PSP) toxins has been tested for the quantitative determination of PSP toxins in shellfish. All aspects of the method were studied and modified as necessary to improve its performance for routine regulatory purposes. The chromatographic conditions were changed to shorten analysis time. The oxidation reaction was tested for repeatability and the influence of the s ample matrix on quantitation. An important part of the study was to quantitatively evaluate an ion exchange (-COOH) cleanup step using disposable solid-phase extraction cartridges that separated the PSP toxins into 3 distinct groups for quantitation, namely the C toxins, the GTX toxins, and the saxitoxin group. The cleanup step was very simple and used increasing concentrations of aqueous NaCl for elution of the toxins. The C toxins were not retained by the cartridges and thus were eluted unretained with water. The GTX toxins (GTX1 to GTX6 as well as dcGTX2 and dcGTX3) eluted from the cartridges with 0.05M NaCl while the saxitoxin group (saxitoxin, neosaxitoxin, and dcsaxitoxin) required 0.3M NaCl for elution. Each fraction was analyzed by LC after oxidation with periodate or peroxide. All of the compounds could be separated and quantitatively determined in spiked samples of mussels, clams, and oysters. The nonhydroxylated toxins could be quantitated at concentrations as low as about 0.02 μg/g (2 μg/100 g) of tissue while the hydroxylated toxins could be quantitated at concentrations as low as about 0.1 μg/g (10 μg/100 g). Average recoveries of the toxins through the complete cleanup procedure were 85%or greater for spiked extracts of oysters and clams and greater than 73%for mussels.
Immunoassay Methods for Paralytic Shellfish Poisoning Toxins
Authors: Usleber Ewald , Dietrich Richard , Bürk Christine , Schneider Elisabeth , Märtlbauer Erwin 
Published: February 2020

Abstract
The current status of immunochemical techniques for analysis of paralytic shellfish poisoning (PSP) toxins is summarized. Important aspects regarding production of the biological reagents necessary for immunochemical methods, the characteristics of polyclonal and monoclonal antibodies against saxitoxin and neosaxitoxin, and the importance of test sensitivity and specificity are discussed. Applications of immunochemical techniques for PSP toxins include microtiter plate enzyme immunoasays and enzyme-linked immunofiltration assays for toxin detection, and immunoaffinity chromatography (IAC) for sample extract cleanup. A major advantage of enzyme immunoassay (EIA) is simplicity and rapidity of the test procedure, and higher sensitivity than other methods. However, quantitative agreement between EIA and mouse bioassay is dependent on antibody specificity and the toxin profile in the shellfish; thus, both over- and underestimation of total toxicity may occur. For screening purposes, however, EIAs offer major advantages over the mouse bioassay, which is criticized in Europe because of animal welfare. A major application of antibodies against PSP toxins is their use for extract cleanup by IAC, which gives highly purified extracts, thereby enhancing determination of PSP toxins by conventional physicochemical methods such as liquid chromatography. IAC can also be used to isolate PSP toxins for preparation of analytical standard solutions.
Atomic Absorption Spectrometric Determination of Chromium, Copper, Lead, Mercury, and Zinc in Sediments Collected in Bayou d'Inde, Southwestern Louisiana
Authors: Hardaway Carey , Gauthreaux Kermit , Sneddon Joseph , Beck James N 
Published: February 2020

Abstract
The concentrations of the metals chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), and zinc (Zn) were determined in sediment cores taken from Bayou d'Inde in southwestern Louisiana. Previous studies had reported elevated concentrations of these trace metals in sediments along this waterway. The current study, conducted more than a decade later, was designed to determine if these metals had migrated from the areas of highest concentrations. Concentrations as high as 400 mg/kg for Cr, 1100 mg/kg for Cu, 10 mg/kg for Hg, and 600 mg/kg for Pb and Zn were found. Areas of high concentrations of metals were isolated within a distance of about 1 km from the most highly contaminated areas in the bayou. Low concentrations of metals were found at the mouth of the bayou. Estimated sedimentation rates of 0.67–1.2 cm/yr were based on the burial of the sediments originally studied. The concentrations of the metals studied remained high and were also highly localized, both spatially and temporally.
Determination of Water (Moisture) and Dry Matter in Animal Feed, Grain, and Forage (Plant Tissue) by Karl Fischer Titration: Collaborative Study
Authors: Thiex Nancy J , Erem Terri van ,   Collaborators:, Amundson D , Boucher J , Clark A , Clark D , Coco P , Dow D , Fahey P , Hoffmann H , Mertens D , Morris H , Rittenhouse T , Wohla M 
Published: February 2020

Abstract
A Karl Fischer method for determining water (dry matter) in animal feed and forages was collaboratively studied. Water was extracted from animal feed or forage material into methanol–formamide (1 + 1) directly in the Karl Fischer titration vessel by high-speed homogenization. The water was titrated at 50°C with one-component Karl Fischer reagent based on imidazole. Ten blind samples were sent to 9 collaborators in the United States, Canada, and Germany. The within-laboratory relative standard deviation (repeatability) ranged from 1.14 to 6.99% for water or from 0.09 to 0.56% for dry matter. Among-laboratory (including within-) relative standard deviation (reproducibility) ranged from 5.35 to 10.73%, or from 0.44 to 0.77% for dry matter. The authors recommend that the method be adopted as Official First Action by AOAC INTERNATIONAL. A comparable alternative extraction procedure using boiling methanol is also recommended for Official First Action.
Measurement of Resistant Starch
Authors: McCleary Barry V , Monaghan Dympna A 
Published: February 2020

Abstract
A robust and reliable method was developed to measure resistant starch (RS), i.e., starch that enters the large intestine. In vivo conditions were reflected as much as possible while a user-friendly format was maintained. Parameters investigated included α-amylase concentration, pH of incubation, maltose inhibition of α-amylase, the need for amyloglucosidase inclusion, the effect of shaking and stirring on determined values, and problems in recovering and analyzing the RS-containing pellet. The RS values obtained were in good agreement with published in vivo data. An interlaboratory evaluation of the method has been completed (First Action Method 2002.02).
Detection of Genetically Modified Crops and Their Derivatives: Critical Steps in Sample Preparation and Extraction
Authors: Terry Catherine F , Harris Neil , Parkes Helen C 
Published: February 2020

Abstract
The detection of genetically modified crops in foodstuff relies on detection of transgenic DNA or protein material in the sample matrix. Purified DNA or proteins are used as analytical material for polymerase chain reaction technologies and immunodiagnostics. Successful sample preparation is critical to the validity of subsequent analysis. For routine analysis, a good sample preparation technique should be simple, safe, and inexpensive while reproducibly generating DNA/protein of sufficient quality and yield. The suitability of isolated DNA or protein as an analyte for a detection or characterization technique depends on amount or concentration, purity, and integrity, each of which may be influenced by sample matrix and the extraction technique, and, in turn, may impact the validity of analytical techniques. The key sample preparation steps of homogenization, pretreatment, extraction, and purification are discussed as well as typical analytical methods. Consideration is given to application of these steps for particular sample matrixes to maximize yield, reduce inhibition effects, and minimize contamination. The choice of the most appropriate and valid methods for sample preparation from particular foods is discussed with respect to DNA analysis. Attention is also given to ease of use, cost, and generic applicability of the procedures.
Characterization of Copolymer Hydroxybutyrate/Hydroxyvalerate from Saponified Vernonia, Soybean, and “Spent” Frying Oils
Authors: Saeed Kamal A , Eribo Broderick E , Ayorinde Folahan O , Collier Ledelle 
Published: February 2020

Abstract
Poly(β-hydroxyalkanoate)s (PHAs) were biosynthesized by Ralstonia eutropha (formerly known as Alcaligenes eutrophus) by using saponified soybean, vernonia, and “spent” frying oils. These PHAs were isolated and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–TOFMS), gas chromatography/mass spectrometry (GC/MS), proton nuclear magnetic resonance spectrometry (1H NMR), and 2-dimensional homonuclear (1H–1H) correlation spectroscopy (COSY). The analytical results revealed that the PHAs produced from saponified vernonia and soybean oils were copolymers of hydroxybutyrate (HB) and hydroxyvalerate (HV), that is, P(HB/HV)s, whereas the saponified “spent” frying oil produced only poly(β- hydroxybutyrate) (PHB) homopolymer. MALDI–MS, GC/MS, and NMR independently confirmed the composition of the PHAs. Saponified soybean oil and vernonia oil PHAs contained approximately 4 and 1% HV units, respectively. For comparison, commercial PHB and P(HB/HV), produced by R. eutropha by using glucose and a cosubstrate of glucose and propionic acid, respectively, as carbon sources, were similarly characterized.