bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Fat in Dairy Products Using Pressurized Solvent Extraction
Authors: Richardson Russell K 
Published: February 2020

Abstract
Gravimetric fat data were obtained for a wide range of dairy products with fat contents ranging from 0.5 to 83% using pressurized solvent extraction at elevated temperatures and pressure (80–120°C; 10.3 MPa). Extraction performance was sensitive to solvent composition, temperature, and sample matrix. By optimizing solvent mixtures, sample–solvent contact times of 8–10 min were sufficient for high recoveries from all products tested. The most successful solvents with regard to speed of extraction, selectivity, and recovery (average recovery, %) were various mixtures of hexane (or petroleum ether)–dichloromethane–methanol for dried cream (99.8%), dried whole milk (99.6%), dried buttermilk (98.2%), dried skim milk (97.0%), dried whey protein concentrate (97.5%), casein (95.0%), and caseinate (102.1%); petroleum ether–acetone–ethanol or petroleum ether–acetone–isopropanol for cheddar-type cheese (99.4%); petroleum ether–acetone for butter (99.9%); petroleum ether–acetone–isopropanol for cream (100.3%); and petroleum ether–isopropanol for liquid milks (99.0%). Relative standard deviations for repeatability were obtained for dried whole milk (0.2%), dried whey protein concentrate (0.7%), cheese (0.3%), butter (0.1%), and ultraheat treated (UHT) milk (0.7%). Solvent removal and drying of extracts with a heated block evaporator saved time compared with conventional drying ovens. Estimated savings in labor (50–75%) and solvents (80%) were substantial compared with the manual Mojonnier methods.
Application of a Mixed-Mode Solid-Phase Extraction and Cleanup Procedure for LC/MS Determination of Thiabendazole and Carbendazim in Apple Juice
Authors: Young Michael S , Early Michael F , Mallet Claude R , Krol Jim 
Published: February 2020

Abstract
Recently, a mixed-mode solid-phase extraction (SPE) procedure was developed for rapid extraction and cleanup for determination of the fungicides thiabendazole and carbendazim in various fruit juices. This paper reports the application of that sample preparation procedure to the liquid chromatographic/mass spectrometric determination of these fungicides in apple juice with detection by positive electrospray ionization mass spectrometry (ESI/MS). Response was linear for sample concentrations from 2 to 500 μg/L (ppb). Recoveries averaged 74% (9% RSD) for carbendazim and 93% (9% RSD) for thiabendazole. After SPE cleanup, no matrix supression was observed for the ESI+ response for either compound studied. The method was applied to the analysis of incurred residues in 4 store-bought apple juices; carbendazim levels ranged from 10 to 70 μg/L and thiabendazole levels ranged from less than 2 to 130 μg/L.
Review and Assessment of In Vitro Detection Methods for Algal Toxins
Authors: Dolah Frances M van , Ramsdell John S 
Published: February 2020

Abstract
Algal toxins produced by marine and freshwater microalgae present a significant analytical challenge because of their complex structures and frequent occurrence as mixtures of structural congeners, which differ in toxic potencies and are present at varying proportions in contaminated samples. Rapid, sensitive in vitro detection methods specific for each class of algal toxins have been developed over the past decade, including immunoassays, enzyme inhibition assays, receptor assays, and cell assays. This review discusses the conceptual approaches to assay development and provides a detailed assessment of the use of in vitro detection methods for marine and freshwater algal toxins.
Novel Approach to the Study of the Chiral Discrimination Mechanism in a Series of Dansyl Amino Acids
Authors: Guillaume Yves-Claude , Guinchard Christiane , Tong Truong Thanh , Thomassin Mireille 
Published: February 2020

Abstract
With poly(octadecylsiloxane) as the liquid chromatographic stationary phase, phosphate buffer as the mobile phase, a series of D- and L-dansyl amino acids as solutes, and β-cyclodextrin as the chiral selector, a study was conducted of the hydrophobic effect on both the solute complexation with the chiral selector and chiral discrimination mechanisms by varying the sucrose concentration in the mobile phase and the column temperature. The number of sucrose molecules excluded during the solute complexation with the chiral selector proved to be a good marker of the solute inclusion in the cavity. Gibbs Helmotz parameters Δ(ΔH) and Δ(ΔS) between D- and L-enantiomers were determined from plots of the logarithm of the intrinsic selectivity versus the reciprocal of the temperature. The results obtained predicted that the enantioselectivity was related to the bulkiness of the solute. This numerical approach is a valuable tool in the exploration of the steric effects implied in the formation of the host-guest complex.
Simultaneous Determination of Binary Mixtures of Sulfonylurea Herbicides in Water by First-Derivative Photochemically Induced Spectrofluorimetry
Authors: Coly Atanasse , Aaron Jean-Jacques 
Published: February 2020

Abstract
First-derivative photochemically induced spectrofluorimetry (PIF-1D) is applied to the simultaneous determination of binary mixtures of 4 sulfonylurea herbicides in aqueous micellar samples. Synthetic binary mixtures of sulfometuronmethyl with chlorsulfuron, metsulfuron-methyl, and 3-rimsulfuron, respectively, are well resolved by using the zero-crossing point procedure. PIF-1D allows the determination of binary mixtures of these herbicides with linear dynamic ranges over about 2 orders of magnitude, limits of detection between 0.5 and 52 ng/mL, and relative standard deviations within 0.3–2.9%. Application to the determination of binary mixtures of these herbicides in spiked tap water samples yielded satisfactory recoveries (90–117%).
Speciation Analysis of Heavy Metals in Natural Waters: A Review
Authors: Fytianos Konstantinos 
Published: February 2020

Abstract
Metal speciation in natural waters is of increasing interest and importance because toxicity, bioavailability, environmental mobility, biogeochemical behavior, and potential risk in general are strongly dependent on the chemical species of metals. This paper provides an overview of the need for speciation of heavy metals in natural waters, the chemical and toxicological aspects of speciation, and the analytical procedures for separation and the different techniques for final determination that are used today. The trends and developments of speciation are also discussed. Finally, the case of chromium (Cr) was selected for a detailed presentation because the speciation of this metal has attracted a great deal of interest in view of the toxic properties of Cr(VI).
Application of Membrane Filters for Spectrophotometric Determination of Cationic Surfactants in River Water and Sediment
Authors: Hui-Feng Sun , Takamori Miwa , Hata Noriko , Kasahara Issei , Taguchi Shigeru 
Published: February 2020

Abstract
Cationic surfactant (CS+) in urban river water and sediment was extracted and determined spectrophotometrically with 2 membrane filters. The CS+ in the water samples, mostly in the form of an ion associate with the coexisting anionic surfactant (AS−), was collected on a polytetrafluoroethylene (PTFE) membrane filter and eluted with methanol. Bromphenol blue (BPB), hydrochloric acid, and water were added to the methanol solution successively, and the mixed solution was filtered through a mixed cellulose ester membrane filter. The CS+-BPB− ion associate, formed by a counter ion exchange, was collected on the filter and dissolved into N,N-dimethylformamide (DMF) together with the mixed cellulose ester membrane filter. After addition of 2 drops of triethanolamine, the absorbance of the DMF solution was measured. The CS+ in sediment samples was extracted with methanol by ultrasonic irradiation; the methanol solution was then passed through a PTFE membrane filter and evaporated to dryness. The CS+ was redissolved in a small amount of methanol. For water samples, recoveries and relative standard deviations for 0.30 μM benzyldimethyltetradecylammonium ion, a standard material, were ≥93 and ≤5%, with a detection limit of 0.02 μM. Concentrations of CS+ in sediments were much higher than those in water samples, indicating that CS+ is adsorbed on the surface of the sediment.
Determination of Fumonisins B1 and B2 in Corn and Corn Flakes by Liquid Chromatography with Immunoaffinity Column Cleanup: Collaborative Study
Authors: Visconti Angelo , Solfrizzo Michele , Girolamo Annalisa De ,   Collaborators:, Bresch H , Burdaspal P , Castegnaro M , Felgueiras I , Gardikis J , Jørgensen K , Kakouri; E , Kretschmer H , Lew H , Meyer K , Miller J , Møller T , Nuotio K , Patel S , Pietri A , Pittet A , Sizoo E , Spanjer; M C , Steiner W , Tiebach R , Usleber E , von Holst C , Wilson P 
Published: February 2020

Abstract
A liquid chromatographic (LC) method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn and corn flakes was collaboratively studied by 23 laboratories, which analyzed 5 blind duplicate pairs of each matrix to establish the accuracy, repeatability, and reproducibility characteristics of the method. Fumonisin levels in the corn ranged from &lt;0.05 (blank) to 1.41 μg/g for FB1 and from &lt;0.05 to 0.56 μg/g for FB2, whereas in the corn flakes they ranged from &lt;0.05 to 1.05 μg/g for FB1 and from &lt;0.05 to 0.46 μg/g for FB2. The method involved double extraction with acetonitrile–methanol–water (25 + 25 + 50), cleanup through an immunoaffinity column, and LC determination of the fumonisins after derivatization with o-phthaldialdehyde. Relative standard deviations for the within-laboratory repeatability (RSDr) of the corn analyses ranged from 19 to 24% for FB1 and from 19 to 27% for FB2; for the corn flakes analyses, RSDr ranged from 9 to 21% for FB1 and from 8 to 22% for FB2. Relative standard deviations for the between-laboratories reproducibility (RSDR) of the corn analyses ranged from 22 to 28% for FB1 and from 22 to 30% for the FB2; for corn flakes analyses, RSDR ranged from 27 to 32% for FB1 and from 26 to 35% for FB2. Mean recoveries of FB1 and FB2 from corn spiked with FB1 at 0.80 μg/g and with FB2 at 0.40 μg/g were 76 and 72%, respectively; for corn flakes spiked at the same levels recoveries were 110 and 97% for FB1 and FB2, respectively. HORRAT ratios for the analyses of corn ranged from 1.44 to 1.53 for FB1 and from 0.96 to 1.48 for FB2, whereas for corn flakes they ranged from 1.60 to 1.82 for FB1 and from 1.39 to 1.68 for FB2.
Semiautomatic Flow-Injection Method for Determination of Volatile Acidity in Wines
Authors: González-Rodríguez José , Pérez-Juan Pedro , Castro Maria Dolores Luque de 
Published: February 2020

Abstract
A flow-injection (FI) method based on analytical pervaporation was assessed for its routine use in the determination of volatile acidity in winery laboratories. The new method was compared with both the official method and the Mathieu method, which is most often used in Spanish wineries, by testing 30 different wines, including young and aged, and sweet and dry wines from Montilla-Moriles appellation d'origine. The robustness of the new method was established, and then all 3 methods were studied in terms of range of linearity and regression of the calibration curve, repeatability, reproducibility, sensitivity, detection and quantitation limits (LOD and LOQ, respectively), and time of analysis. The FI method surpassed the Mathieu method in reproducibility and both the Mathieu and official methods in LOD and LOQ and sensitivity; it also required less personnel involvement and shorter analysis time. The statistical criteria established by the Office International de la Vigne et du Vin were applied to the data and the results obtained indicated that the differences between the analytical parameters of the 3 methods are not significant and can be applied indistinctly. The correlation of the methods was studied by taking them 2 by 2, and the corresponding equations, coefficients, and deviations confirmed the statistical results. Thus, the new method can be used in winery laboratories with clear advantages over its 2 counterparts (the routine and official methods).
Honey as a Candidate Reference Material for Trace Elements
Authors: Forte Giovanni , D’Ilio Sonia , Caroli Sergio 
Published: February 2020

Abstract
The feasibility of producing and certifying new certified reference materials (CRMs) for trace elements in honey was investigated. Preliminary steps for preparation of candidate materials are performed at the Institute for Reference Materials and Measurements, Joint Research Centre of the European Commission (EC-JRC-IRMM). Two different types of honey, Acacia and Eucalyptus, were tested for determination of 10 trace elements. To each type of honey was added a given amount of high purity deionized water to obtain aqueous solutions with an acceptable degree of homogeneity which would require only minimal manipulation before analysis. Average values obtained for the trace elements by means of inductively coupled plasma-based techniques were as follows (in μg/kg ± SD): Acacia honey, As, 1.10 ± 0.20; Cd, 0.328 ± 0.035; Cr, 1.90 ± 0.22; Cu, 67.0 ± 5; Fe, 215 ± 30; Hg, &lt; 0.75; Mn, 82.1 ± 6.2; Ni, 21.0 ± 3.0; Pb, 2.30 ± 0.25; Se, 9.10 ± 1.2; Zn, 167 ± 22; Eucalyptus honey, As, 5.99 ± 0.10; Cd, 0.592 ± 0.074; Cr, 1.50 ± 0.07; Cu, 219 ± 24; Fe, 1008 ± 114; Hg, &lt;0.75; Mn, 1009 ± 51; Ni, 11.3 ± 1.5; Pb, 5.00 ± 0.40; Se, 5.60 ± 0.91; Zn, 791 ± 91. When these 2 pilot materials are ready, the certification project will be launched in full compliance with current rules set by EC-JRC-IRMM. If the project is successful, the new CRMs will be put primarily at the disposal of the National Reference Laboratories for trace elements.
Determination of Dissolved Naphthenic Acids in Natural Waters by Using Negative-Ion Electrospray Mass Spectrometry
Authors: Headley John V , Peru Kerry M , Mcmartin Dena W , Winkler Marcus 
Published: February 2020

Abstract
Naphthenic acids (NAs) have been implicated as some of the most toxic substances in oil sands leachates and identified as priority substances impacting on aquatic environments. As a group of compounds, NAs are not well characterized and comprise a large group of saturated aliphatic and alicyclic carboxylic acids found in hydrocarbon deposits (petroleum, oil sands bitumen, and crude oils). Described is an analytical method using negative-ion electrospray ionization mass spectrometry (ES/MS) of extracts. Preconcentration was achieved by using a solid-phase extraction procedure utilizing a crosslinked polystyrene-based polymer with acetonitrile elution. Recovery of the Fluka Chemicals NA mixture was highly pH-dependent, with 100% recovery at pH 3.0, but only 66 and 51% recoveries at pHs 7 and 9, respectively. The dissolved phase of the NA was very dependent on sample pH. It is thus critical to measure the pH and determine the appropriate mass profiles to identify NAs in natural waters. The ES/MS analytical procedure proved to be a fast and sensitive method for the recovery and detection of NAs in natural waters, with a detection limit of 0.01 mg/L.
Gas Chromatographic and Mass Spectrometric Analysis of Nitrilotriacetic Acid in Environmental Aqueous Samples
Authors: Raksit Asit 
Published: February 2020

Abstract
This study describes a fast and accurate method for the sample preparation, identification, and quantitation of nitrilotriacetic (NTA) acid in environmental aqueous samples at a concentration of ppb level. The method is sensitive, specific, and free from the interferences of fatty and amino acids. The tri-n-propyl- and tri-n-butyl-NTA acid esters were prepared by the reaction of n-propyl-HCl and n-butyl-HCl solutions and NTA acid, respectively. The derivatives were analyzed by a gas chromatograph equipped with a mass spectrometric detector. The method detection limit, 0.006 mg/L of each NTA ester, was determined and validated by an analysis of a fortified water sample. The overall recoveries were 103–115%, n = 8. The method was applied to a real sample and a 0.90 mg/L concentration of NTA acid was found. Mass fragmentation patterns of the derivatives are also reported.
Determination of Low-Level Glucose and Fructose in Raw and Refined Crystalline Sugar by High-Performance Anion-Exchange Chromatography: Collaborative Study
Authors: Schäffler Kevin ,   Collaborators:, Bourlet P , Hanko V , Henderson D , Hoebregs H , Maarten de Bruijin J , Morel du Boil P , Nguyen N , Pereira M , Ramphal E , Rearick E , Sural D , van der Waal W , Walford S , Wong L 
Published: February 2020

Abstract
A method was developed and a collaborative study was performed under the auspices of the International Commission of Uniform Methods for Sugar Analysis. The collaborators used high-performance anion-exchange chromatography (HPAEC) to determine trace amounts of glucose and fructose in 3 raw and 3 refined sugar samples provided as blind duplicates. Fourteen laboratories participated in the study. Although difficulties were experienced by a few analysts, 10 laboratories reported positive results. Average repeatabilities and reproducibilities for glucose and fructose in raw sugar were slightly above 5 and 10%, respectively, and the average Horwitz ratios were well under 2. Average repeatabilities and reproducibilities for glucose and fructose in refined sugar were 10 and 22%, respectively; although the Horwitz ratios were &gt;2, they were marginal (2.8). The HPAEC results agreed with results obtained by gas chromatography in an independent laboratory. Because the method was collaboratively studied according to the protocol of the International Union of Pure and Applied Chemistry for collaborative studies, and the results meet its criteria, it is recommended that the method be adopted Official First Action by AOAC INTERNATIONAL.
Determination of Crude Protein in Animal Feed, Forage, Grain, and Oilseeds by Using Block Digestion with a Copper Catalyst and Steam Distillation into Boric Acid: Collaborative Study
Authors: Thiex Nancy J , Manson Harold , Anderson Shirley , Persson Jan-Åke ,   Collaborators:, Anderson S , Bogren E , Bolek G , Budde D , Ellis C , Eriksson S , Field G , Frankenius E , Henderson C , Henry C , Kapphahn M , Lundberg L , Manson H , Moller J , Russell M , Sefert-Schwind J , Spann M 
Published: February 2020

Abstract
A collaborative study was conducted to evaluate the repeatability and reproducibility of an extension of AOAC Official Method 991.20, Nitrogen (Crude) in Milk, to animal feed, forage (plant tissue), grain, and oilseed materials. Test portions are digested in an aluminum block at 420°C in sulfuric acid with potassium sulfate and a copper catalyst. Digests are cooled and diluted, and concentrated sodium hydroxide is added to neutralize the acid and make the digest basic; the liberated ammonia is distilled by using steam distillation. The liberated ammonia is trapped in a weak boric acid solution and titrated with a stronger standardized acid, hydrochloric acid; colorimetric endpoint detection is used. Fourteen blind samples were sent to 13 collaborators in the United States, Denmark, Sweden, Germany, and the United Kingdom. Recoveries of nitrogen from lysine, tryptophan, and acetanilide were 86.8, 98.8, and 100.1%, respectively. The within-laboratory relative standard deviation (RSDr, repeatability) ranged from 0.40 to 2.38% for crude protein. The among-laboratories (including within-) relative standard deviation (RSDR, reproducibility) ranged from 0.44 to 2.38%. It is recommended that the method be adopted First Action by AOAC INTERNATIONAL. A lower concentration (1% H3BO3) of trapping solution was compared with the concentration specified in the original protocol (4% H3BO3) and was found comparable for use in an automatic titration system in which titration begins automatically as soon as distillation starts. The Study Directors recommend that 1% H3BO3 as an optional alternative to 4% boric acid trapping solution be allowed for automatic titrators that titrate throughout the distillation.
Parallux™ β-Lactam: A Capillary-Based Fluorescent Immunoassay for the Determination of Penicillin-G, Ampicillin, Amoxicillin, Cloxacillin, Cephapirin, and Ceftiofur in Bovine Milk
Authors: Huth Stacey P , Warholic Polly S , Devou Jane M , Chaney Larry K , Clark Genevieve H 
Published: February 2020

Abstract
An analytical system was developed for detection of antibiotic residues in bovine milk. The method is based on competitive fluorescent immunoassays in glass capillary tubes (U.S. Patent No. 5,624,850). The system consists of an assay cartridge containing 4 glass capillaries, a reagent tray with 4 wells of dried reagents, and a Parallux™ processor, which processes the assay, reads fluorescent output, and reports test results. Minimum sensitivity for detection of 6 β-lactam antibiotics in bovine milk was determined to be penicillin-G, 3.2 ppb; ampicillin, 2.9 ppb; amoxicillin, 3.6 ppb; cloxacillin, 7.4 ppb; cephapirin, 16.3 ppb; and ceftiofur, 33.7 ppb. The assay system was also specific and sensitive for detection of incurred residues at U.S. Food and Drug Administration tolerance levels: penicillin-G, 5 ppb; ampicillin, 10 ppb; amoxicillin, 10 ppb; cloxacillin, 10 ppb; cephapirin, 20 ppb; and ceftiofur, 50 ppb. There was no interference in detection of minimum sensitivity levels of antibiotic by the presence of somatic cells at approximately 1 × 106 cells/mL. Milk containing 3 × 106 cells/mL bacteria commonly found in mastitic milk also showed no interference when tolerance levels of antibiotic were present. There was no detectable interference on results by a wide variety of non-β-lactam drugs.
Validation of the Hygicult® E Dipslides Method in Surface Hygiene Control: A Nordic Collaborative Study
Authors: Salo Satu , Alanko Timo , Sjöberg Anna-Maija , Wirtanen Gun ,   Collaborators:, Guðbjörnsdóttir B , Jessen B , Langsrud S , Lindquist K , Lundén J , Mäki M , Nerbrink E , Niclasen; Ó , Tuominen P , Tuompo H , Vatunen E , Woivalin A 
Published: February 2020

Abstract
A collaborative study with Enterobacteriaceae was conducted to validate Hygicult® E dipslides by comparison with violet red bile glucose agar (VRBGA) contact plates and swabbing, using stainless steel surfaces artificially contaminated with microbes at various levels. Twelve laboratories participated in the validation procedure. The total number of collaborative samples was 108. The microbial level in each sample was assessed in triplicate by using the 3 above-mentioned methods. No Enterobacteriaceae were used at the low inoculation level. At the middle inoculation level, the percentages detached from the test surfaces were 16.6 with the Hygicult E method, 15.3 with the contact plate method, and 14.6 with swabbing; at the high innoculation level, the percentages were 14.5, 15.8, and 9.8, respectively. The percentage of acceptable results after the removal of outliers was 97.2. Repeatability relative standard deviations ranged from 33.4 to 44.9%; reproducibility relative standard deviations ranged from 45.2 to 77.1%. The Hygicult E dipslide, VRBGA contact plate, and swabbing methods gave similar results at all 3 microbial levels tested: &lt;1.0 colony-forming units (CFU)/cm2 at the low level, 1.2–1.3 CFU/cm2 at the middle level (theoretical yield 8.0 CFU/cm2), and 1.2–2.0 CFU/cm2 at the high level (theoretical yield 12.5 CFU/cm2).
Determination of Nitrite in Foods by Single-Sweep Polarography
Authors: Qiong Li , Tong Zhan , Yong Luo , Dandan Song , Guanghan Lu 
Published: February 2020

Abstract
In an acid medium, nitrite diazotized with p-rosaniline and then coupled with 8-hydroxyquinoline in a weak alkaline medium produces azo compounds. The azo compounds produce a very sensitive polarographic wave at −0.70 V (versus the saturated calomel electrode). The height of the peak is linear with the concentration of nitrite in the range of 5 × 10−9 to 5 × 10−7 g/mL. The detection limit is 3 × 10−9 g/mL. The electrochemical characteristics of the polarographic wave are also discussed. The method was used to determine nitrite in sausage. The results agree well with those obtained by spectrophotometry.