bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Chlorophenols in air at the Nanogram-per-Cubic-Meter-Level
Authors: Swami Kamal , Narang Rajinder S 
Published: February 2020

Abstract
A gas chromatographic (GC) method for the analysis of chlorophenols in air at the nanogram-per-cubic-meter level was developed. Chlorophenols were trapped on Porapak-N, eluted with methanol, and then derivatized before GC analysis.
Enzyme-Linked Immunosorbent Assay for Detection of Zearalenone in Corn, Wheat, and Pig Feed: Collaborative Study
Authors: Bennett Glenn A , Nelsen Terry C , Miller Brjnton M 
Published: February 2020

Abstract
A direct competitive enzyme-linked immunosorbent assay (ELISA) screening method for zearalenone in corn, wheat, and feed at 500 ng/g was evaluated by 23 collaborators (22 laboratories) in an international collaborative study. Eighteen samples of spiked or naturally contaminated corn, wheat, and pig feed were prepared by the sponsoring laboratory and sent for testing with complete test kits to participating collaborators in Canada, Italy, Sweden, The Netherlands, and the United States. Test samples were extracted with methanolwater solution (70 + 30) by shaking on a wrist-action shaker for 3 min. A portion of the extract was mixed with an equal volume of zearalenone-enzyme conjugate, and the mixture was incubated with zearalenone-specific monoclonal antibodies coated onto microtiter wells. All test samples were assayed in duplicate. One of 52 (2%) blanks was reported positive. Thirty-nine of the 52 (75%) samples that were spiked at 500 ng/g were reported as positive. Forty-nine of the 51 (96%) samples with concentrations at or above 1000 ng/g were reported as positive. The overall incidence of false negatives was 6.0% and the incidence of false positives was 22.7% by the ELISA method. Only one (3.4%) false negative was reported for samples containing ≥800 ng/g. In the spectrophotometric method, 8 collaborators determined approximate levels of zearalenone in test samples from standard curves constructed from spiked extracts (0–3000 ng/g of each commodity tested). This method gave and overall incidence of false negatives of 5.7% and false positives of 17.8%. Average relative standard deviations, RSDr (repeatability) and RSDR (reproducibility), were 11.6 and 25.1% for spiked samples and 11.7 and 33.1% for naturally contaminated samples, respectively. Standard curves were constructed with each set of samples assayed. Comparison of absorbance values from these standard curves indicate the performance of reagents and antibody used in the assay. The ELISA method has been adopted first action by AOAC INTERNATIONAL as a screening method for zearalenone at ≥800 ng/g in corn, wheat, and pig feed.
Development of a New Series of Agricultural/Food Reference Materials for Analytical Quality Control of Elemental Determinations
Authors: Ihnat Milan 
Published: February 2020

Abstract
Ten new Agricultural/Food Reference Materials — Bovine Muscle Powder (National Institute of Standards and Technology [NIST], code NIST RM 8414), Whole Egg Powder (NIST RM 8415), Microcrystalline Cellulose (NIST RM 8416), Wheat Gluten (NIST RM 8418), Corn Starch (NIST RM 8432), Corn Bran (NIST RM 8433), Whole Milk Powder (NIST RM 8435), Durum Wheat Flour (NIST RM 8436), Hard Red Spring Wheat Flour (NIST RM 8437) and Soft Winter Wheat Flour (NIST RM 8438) — were prepared by application of milling, irradiation, sieving, blending, and packaging procedures. Excellent material homogeneity was found for virtually all major, minor, and trace elements of interest. The reference materials were characterized with respect to elemental composition via an extensive international, interlaboratory characterization (certification) campaign. Chemical analyses conducted in 73 cooperating laboratories applying 13 major classes of independently different analytical methods led to 278 concentration values for 34 nutritionally, toxicologically, and environmentally pertinent elements. A total of 213 best-estimate and 65 informational concentration values are available for Al, As, B, Ba, Br, Ca, Cd, CI, Co, Cr, Cs, Cu, F, Fe, Hg, I, K, Mg, Mn, Mo, N, Na, Ni, P, Pb, Rb, S, Sb, Se, Sr, Ti, V, W, and Zn. These products make a substantial contribution to the existing world repertoire of biological reference materials with respect to natural matrix and elemental composition. They are expected to be useful to analysts for quality control of analytical data. Applications include evaluations of analytical methods and instruments used in nutritional, toxicological, monitory, regulatory, environmental, agricultural, and other investigations. These products are available to the analytical community from the Standard Reference Materials Program, NIST, Gaithersburg, MD.
Effect of Milling Procedure on the Measurement of Dietary Fiber by a Gravimetric Method
Authors: Mullin W John , Wolynetz Mark S 
Published: February 2020

Abstract
Samples of white potato, sweet potato, hard red spring wheat, soft white winter wheat, and soft wheat bran were ground in a Wiley mill or a Cyclotec mill. A significantly (p &lt; 0.0001) larger proportion of coarse material (&gt;75μ) resulted from the Wiley mill, and a significantly (p &lt; 0.0001) larger proportion of fine material (&lt;45μ) was produced by the Cyclotec mill. The effect of particle size on the determination of soluble, insoluble, and total dietary fiber was less well defined. In 4 of 5 commodities tested, samples from the Cyclotec mill showed a greater amount of soluble fiber, while the reverse was true for insoluble and total fiber. The difference in total dietary fiber, with respect to the mill used in sample preparation, varied from 0.24% on a total 9.10% for potatoes to 1.00% on a total of 14.05% for hard red spring wheat.
Liquid Chromatographic Assay of Diatrizoic Acid and Its Diiodo Degradation Products in Radio-Opaque Solutions
Authors: Farag Shawky A 
Published: February 2020

Abstract
A liquid chromatographic method is described for the analysis of diatrizoic acid (2,4,6-triiodo-3,5-diacetamidobenzoic acid) and its 2,4- and 2,6-diiodo degradation products in radio-opaque injection solutions. The method is accurate, precise, and linear at a concentration range of 5–50 ppm.
Spectrophotometric Method To Determine Ternary Mixtures of Atrazine, Diuron, and Chlorpyrifos in Water and Soil by a Ratio Spectrum-Zero Crossing Method
Authors: Galera M Martínez , Vidal J L Martínez , Frenich A Garrido , Vázquez P Parrilla 
Published: February 2020

Abstract
A spectrophotometric method based on simultaneous use of first derivative of ratio spectra and measurement of zero-crossing wavelengths resolves ternary mixtures of atrazine, diuron, and chlorpyrifos. Calibration graphs were linear for atrazine between 1 and 15 μg/mL and for diuron and chlorpyrifos between 1 and 10 μg/mL. The pesticides in groundwater and soil were determined by the method, at part-per-billion levels, after solidphase extraction, with good results. Interferences caused by other pesticides were studied.
Multicolumn Solid-Phase Extraction Cleanup of Organophosphorus and Organochlorine Pesticide Residues in Vegetable Oils and Butterfat
Authors: Gillespie Allesia M , Daly Sean L , Gilvydis Dalia M , Schneider Felix , Walters Stephen M 
Published: February 2020

Abstract
Diatomaceous earth columns used with reversed and normal solid phase extraction (SPE) cartridges were evaluated for the quantitative determination of a number of organophosphorus (OP) and organochlorine (OC) pesticide residues in edible vegetable oils and butterfat. An oil or fat sample (about 2 g) in hexane was passed through a diatomaceous earth (Extrelut QE) column and a Cis bonded silica (ODS) SPE cartridge, resulting in the separation of the pesticides from about 98% of the lipids. The eluate was split in half, with the first portion concentrated into acetone for the determination of OP pesticides by gas chromatography with flame photometric detection (GC–FPD). The other half was passed through an Alumina-N SPE cartridge for additional cleanup of lipid matrix to determine OC pesticides by GC with electron-capture detection (GC–ECD). Average recoveries from fortified samples were greater than 89% for the pesticides studied.
Determination of Six Common Phthalate Plasticizers in Grain Neutral Spirits and Vodka
Authors: Leebowitz Jeffrey N , Sarmiento Rafael , Dugar Sumer M , Ethridge Michael W 
Published: February 2020

Abstract
Two direct sample injection methods using liquid chromatography (LC) and gas chromatography coupled with mass spectrometry (GC/MS) were used to determine phthalate residues in grain neutral spirits and vodka. Six reported phthalates were quantitated at concentrations as low as 20 μg/L (20 ppb) with no sample preparation or sample enrichment.
Evaluation of a Liquid Chromatographic Method for the Determination of Fumonisins in Corn, Poultry Feed, and Fusarium Culture Material
Authors: Rice Larry G , Ross P Frank , Dejong Jan , Plattner Ronald D , Coats Joel R 
Published: February 2020

Abstract
The performance of a liquid chromatographic method for determining fumonisins in corn, animal feeds, and culture material was evaluated. Efficiencies of extractions with the following solvent systems were determined: acetonitrile–water (50 + 50, v/v), methanol–water (75 + 25, v/v), and 100% water. The acetonitrile solvent gave both higher extraction efficiencies and faster extraction times than the other 2 solvents. Extraction was followed by C18 solid-phase extraction column cleanup. Fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3) were measured by precolumn derivatization with ophthalaldehyde followed by isocratic separation on a C18 reversed-phase column with a moB1le phase of 50 mM potassium dihydrogen phosphate (pH 3.3)–acetonitrile (60 + 40). Commercially prepared poultry feed, corn, and Fusarium spp. corn cultures were analyzed at the following levels: FB1, 1.5 to 15 000 jig/g; FB2, 0.5 to 4000 μg/g; FB3, and 0.17 to 1 500 μg/g. Recoveries were 91–94%, 90–100%, and 81–93% for FB1, FB2, and FB3, respectively. Precision (coefficient of variation) was determined with pooled field samples and ranged from 2% at 19 μg/g for FB1 to 9% at 0.17 μg/g for FB3. Time and pH studies of the formation of the fluorescent derivative and its stability were conducted. Complete reaction occurred at pHs above 7.9, with optimal pH for chromatography between 8.0 and 8.5. No statistically significant response differences were detected for reaction times ranging from 4 to 40 min; however, the detector signal was significantly reduced when reaction times were shorter than 4 min. Chromatograms of samples were free of interferences for all feeds, corn, and culture material tested. Quantitation limits for the 3 fumonisins were of the same magnitude and were estimated to be 0.1 μg/g for FB1 and 0.2 μg/g for FB2 and FB3.
Analysis of Polychlonnated Biphenyls in Fatty Biological Matrixes by On-Line Supercritical Fluid Extraction and Supercritical Fluid Cleanup
Authors: Alley Earl G , Lu Guozhen 
Published: February 2020

Abstract
We present a method that combines the extraction of polychlonnated biphenyls (PCBs) and their separation from relatively large quantities of fat in biological matrixes by combined supercritical fluid extraction and separation. Cyano-functionalized silica gel, silica gel, aluminum oxide, Florisil, 3-aminopropyl- functionalized silica gel, and octadecyl-functionalized silica gel were tested for suitability as chromatographic media for separation of PCBs from lipids. Silica gel, 3-aminopropyl-functionalized silica gel, and Florisil adequately separated PCBs from lipids when eluted with supercritical CO2. Florisil allowed both the extraction of PCBs and their separation from lipids in PCB-spiked chicken egg and fish. Two grams of sample containing PCBs at 0.125 μg/g was sufficient for subsequent separations and the low-level analysis required for the more toxic PCB components.
Electrothermal Atomic Absorption Spectrometric Determination of Cadmium, Copper, Iron, Lead, and Selenium in Fruit Slurry: Analytical Application to Nutritional and Toxicological Quality Control
Authors: Cabrera Carmen , Lorenzo Maria Luisa , Lopez Maria Carmen 
Published: February 2020

Abstract
A method is described for direct determination of cadmium, copper, iron, lead, and selenium in slurried fruit samples by electrothermal atomic absorption spectrometry. The fresh samples were suspended in Triton X-100 and shaken with 10 g zirconia spheres until a slurry was formed. The graphite furnace conditions were optimized for each element. The detection limits were 0.3,3.5, 15.0,0.5, and 10.0 ng/g for Cd, Cu, Fe, Pb, and Se, respectively. Accuracy and precision were checked against sample mineralization in a microwave aciddigestion bomb. Results for analyses of National Institute of Standards and Technology standard reference materials agreed closely with certified values. Analytical application of this method was tested with 40 samples of 8 widely consumed fruit species. The mean values (referred to fresh weight of edible fraction) for each fruit species had ranges of 0.0003–0.050 μg/g for Cd, 0.316–1.094 μg/g for Cu, 2.00–5.50 μg/g for Fe, 0.050–0.396 μg/g for Pb, and 0.010–0.020 μg/g for Se. The proposed method is useful for routine multielemental analysis in nutritional and toxicological quality control of fruits and similar foodstuffs.
Enhancement of Ethylenethiourea Recoveries in Food Analyses by Addition of Cysteine Hydrochloride
Authors: Sack Chris A 
Published: February 2020

Abstract
The effectiveness of cysteine hydrochloride (Cys–HCI) as a preservative of ethylenethiourea (ETU) in product matrixes and during analysis was studied. ETU recoveries were adversely affected by certain product matrixes when fortified directly into the product. Recoveries in 8 selected food items were 0–92% when analyzed 30 min after fortification and 0–51% when analyzed after 24 h. When Cys–HCI was added to product prior to fortification, recoveries increased to 71–95% even after frozen storage for 2–4 weeks. Cys–HCI was added during analysis of 53 untreated items. Recoveries improved an average of 15% with Cys–HCI. Without Cys–HCI, recoveries were erratic (20–98%), but with Cys–HCI, recoveries were 68–113%. Other antioxidants (sodium sulfite, butylated hydroxyanisole, butylated hydroxytoluene, and vitamins A and C) also were evaluated as ETU preservatives. When lettuce was treated first with sodium sulfite and then fortified with ETU, recoveries averaged 86%; without sodium sulfite, they averaged 1%. The other antioxidants were less effective for preserving ETU in lettuce, giving only 8–46% recoveries. The effect of oxidizers (potassium bromate, sodium hypochlorite, and hydrogen peroxide) on ETU recovery was also determined. Recovery of ETU from a baby food product (pears and pineapple) was 82%; with oxidizers, recoveries were 0–8%.
Hard Surface Carrier Test as a Quantitative Test of Disinfection: A Collaborative Study
Authors: Hamilton Martin A , Devries Todd A , Rubino Joseph R 
Published: February 2020

Abstract
The hard surface carrier test (HSCT) recently was proposed as a qualitative test for disinfectant efficacy. A collaborative study of HSCT led to a suggested performance standard of ≤2 or 3 positive carriers out of 60 tested. Subsequently, it was discovered that HSCT can be used as a quantitative test, because the HSCT protocol requires measurement of inoculum level on some carriers. The data allow estimation of the log10 reduction in number of active bacteria. Producers, consumers, and policymakers will be better able to discuss merits of alternative performance standards if the focus is on log reduction of organisms rather than on number of positive carriers. Data from the collaborative study were reanalyzed from this quantitative viewpoint. If the point estimate of log reduction is LR and the 99% lower confidence limit estimate is LLR, the LR values ranged from 7.0 to 9.0 and the LLR values were greater than 6.0 for all disinfectants except the negative control formulation. The total variance for estimated LR is the sum of inter laboratory and intralaboratory variances. The total variance for LR was 0.095 for Pseudomonas aeruginosa, 0.251 for Staphylococcus aureus, and 0.118 for Salmonella choleraesuis. Percentages of the variance due to interlaboratory variability were 11% for P. aeruginosa, 52% for S. aureus, and 25% for S. choleraesuis. Chances of making false-effective and false-ineffective decisions can be calculated for the quantitative HSCT. The performance standard can be based on LLR.
Gas Chromatographic/Mass Spectrometric Confirmation of Leucomalachite Green in Catfish (Ictalurus punctatus) Tissue
Authors: Turnipseed Sherri B , Roybal José E , Hurlbut Jeffrey A , Long Austin R 
Published: February 2020

Abstract
A gas chromatographic/mass spectrometric (GC/MS) method was developed to confirm the presence of leucomalachite green (LMG), a metabolite of the triphenylmethane dye malachite green (MG), in catfish tissue. Residues were isolated according to a previously described liquid chromatographic (LC)A/IS spectrometric analysis of MG and LMG in fish. In our isolation procedure, analytes are extracted from tissue with acetonitrile–buffer, partitioned into CH2CI2, and applied to neutral alumina and propylsulfonic acid solid-phase extraction cartridges. Before GC/MS analysis, extracts prepared for the LC determinative method are eluted from a cyano solid-phase extraction cartridge, extracted into organic solvent, and concentrated for GC/MS analysis. Selected ion monitoring was performed by using 5 diagnostic ions (m/z 330,329,253,210, and 165) of LMG. The method was validated by confirming LMG in tissue fortified with mixtures of MG and LMG (5 and 10 ng/g each) and in tissue from fish that had been exposed to low levels of MG.
Identification and Measurement of β-Lactam Antibiotic Residues in Milk: Integration of Screening Kits with Liquid Chromatography
Authors: Hark-Khan Raida , Moats William A 
Published: February 2020

Abstract
A procedure for identifying and quantitating violative β-lactams in milk is described. This procedure integrates β-lactam residue detection kits with the multiresidue automated liquid chromatographic (LC) cleanup method developed in our laboratory. Spiked milk was deproteinized, extracted, and subjected to reversed-phase LC using a gradient program that concentrated the β-lactams. Amoxicillin, ampicillin, cephapirin, ceftiofur, cloxacillin, and penicillin G were, thus, separated into 5 fractions that were subsequently tested for activity by using 4 kits. (3-lactams in the positive fractions were quantitated by analytical LC methods developed in our laboratory. The LC cleanup method separated β-lactam antibiotics from each other and from interferences in the matrix and also concentrated the antibiotics, thus increasing the sensitivity of the kits to the β-lactam antibiotics. The procedure facilitated the task of identifying and measuring the β-lactam antibiotics that may be present in milk samples.
Improved Microbiological Assay for Folic Acid Based on Microtiter Plating with Streptococcus faecalis
Authors: Sarma Jayasri Das , Duttagupta Chandralekha , Ali Esahak , Dhar Tarun K 
Published: February 2020

Abstract
We have developed an improved method, using 96-well microtiter plates, for the microbiological assay of folic acid. With this method, the tedium of conventional microbiological analysis is substantially decreased. Culture volumes have been reduced 33-fold, and pipetting procedures have been simplified. Assay time has been reduced to 14 h, and sensitivity has increased 10-fold (0.1 ng/mL). Analytical recoveries range from 98 to 104%. Intra-assay and interassay variabilities are less than 11%. The assay does not require extensive manipulation of inoculum. Day-to-day variability has been minimized by using saline aliquots of the bacterial suspension stored at 4°C. The procedure is accurate, selective, and useful for direct measurement of folic acid in multivitamin formulations.
Evaluation of Commercially Available Milk Powders for Calibration of Mid-Infrared Analyzers
Authors: Lynch Joanna M , Barbano David M , Fleming J Richard 
Published: February 2020

Abstract
The performance of commercially available shelf-stable milk powders that upon reconstitution can be used as calibration samples for mid-infrared (IR) analyzers was evaluated. Twelve reconstituted powders and 7 raw milk samples were sent to each of 7 laboratories. Each laboratory analyzed the reconstituted powders and milk samples by IR and obtained both corrected and uncorrected data. The corrected data reflected the current calibrations (based on calibration with fresh, raw milk) of each instrument. The uncorrected data from the reconstituted powders were used to derive separate calibration equations for each instrument. Two of the 12 reconstituted powers were discarded from the analysis because of poor quality. The abilities of the powder-based and current calibrations to predict accurately the total protein and fat contents of the 7 raw milk samples were compared. For the current and powder-based calibrations, respectively, the mean differences from chemical analysis for total protein were −0.006 and 0.031%, and the standard deviations of the differences (SDD) were 0.029 and 0.029%. For fat, the mean difference for the current calibration was −0.001%, and the SDD was 0.034%. For the powder-based fat calibration, the mean differences were 0.034% (fat A only), −0.047% (fat B only), and −0.061% (fat A and fat B), and SDDs were 0.046% (fat A only), 0.036% (fat B only), and 0.056% (fat A and fat B). The reconstituted powders did not provide as accurate an IR fat calibration for testing raw milk samples as can be obtained with raw milk calibration samples. This is attributed primarily to differences in the characteristics of the fat in the reconstituted powders and in raw milk. For protein, analytical precisions for both types of calibrations were comparable, and the positive bias for the powder-based calibration is relatively easy to correct by basing calibration on true protein nitrogen instead of total nitrogen.
Optimization of a Liquid Chromatographic Method for Determination of Malachite Green and Its Metabolites in Fish Tissues
Authors: Plakas Steven M , El Said Kathleen R , Stehly Guy R , José E Roybal 
Published: February 2020

Abstract
A liquid chromatographic (LC) method was adapted and optimized for the determination of malachite green and its metabolites in fish plasma and muscle. Residues in plasma were extracted with acetonitrile, the extract was evaporated to dryness, and residues were resolubilized for LC analysis. Residues in muscle were extracted with an acetonitrile- acetate buffer mixture, reextracted with acetonitrile, and partitioned into methylene chloride with final cleanup on alumina and propylsulfonic acid solid-phase extraction columns. Residue levels were determined by using an LC cyano column with a Pb02 postcolumn and visible detection (618 nm). Overall mean recoveries of parent malachite green (MG-C) and its major metabolite, leucomalachite green (MG-L), from plasma were 93 and 87%, respectively, at fortification levels ranging from 25 to 250 ppb. Overall mean recoveries of MG-C and MG-L from muscle were 85 and 95%, respectively, at fortification levels ranging from 5 to 100 ppb. Relative standard deviations (RSDs) of recoveries at all fortification levels ranged from 3.9 to 7.0% for plasma and from 2.1 to 5.2% for muscle. The method was applied to incurred residues in tissues sampled from catfish after waterborne exposure to [14C]MG-C. Mean recoveries of total radioactive residues in plasma and muscle throughout the extraction and cleanup process were 88 and 87%, respectively, and corresponding RSDs for MG-C and MG-L were in the same range as those for fortified tissues. MG-L was confirmed as the major metabolite of MG-C in catfish.