bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integration of Immunochemical Methods with Other Analytical Techniques for Pesticide Residue Determination
Authors: Lucas Anne D , Gee Shirley J , Hammock Bruce D , Seiber James N 
Published: February 2020

Abstract
The growing volume of literature concerning immunoassay analysis for trace levels of agrochemicals and other low molecular weight contaminants in various matrixes is indicative of the tremendous interest in and utility of this analytical technique. Most immunoassay methods described in the literature analyze compounds directly, for example, a herbicide in water, or involve solvent exchange of an organic sample extract or dilution of an aqueous-based sample to minimize the matrix effect. As immunoassay for small molecules becomes widely accepted and applied, new challenges involving more complex chemicals in more difficult matrixes arise. The integration of “classical” analytical chemistry with immunochemistry can provide new techniques and approaches useful in discovering the movement, mode of action, and ultimate impact of certain chemicals on humans and the environment.
Agarose Gel Electrophoretic Detection of Six β-Lactam Antibiotic Residues in Milk
Authors: Cutting Jeffrey H , Kiessling William M , Bond Fred L , Mccarron James E , Kreuzer Karen S , Hurlbut Jeffrey A , Sofos John N 
Published: February 2020

Abstract
An electrophoretic method coupled with bioautography was developed for detection and identification of penicillin G, ampicillin, amoxicillin, cloxacillin, cephapirin, and ceftiofur residues in milk. The method uses a 2% agarose gel for electrophoresis, an overlay of PM indicator agar seeded with Bacillus stearothermophilus var. calidolactis, and incubation at 55°C for 16–18 h. The new method separated and detected residues in milk at the levels of concern for the Food and Drug Administration (FDA) for penicillin G (5 ppb), cephapirin (20 ppb), and ceftiofur (50 ppb). The method also detected ampicillin, amoxicillin, and cloxacillin at 20,30, and 30 ppb, respectively, but these levels are above those of concern for FDA (10 ppb).
Determination of Monensin in Edible Bovine Tissues and Milk by Liquid Chromatography
Authors: Moran John W , Turner James M , Coleman Mark R 
Published: February 2020

Abstract
A method is described for detection and quantitation of monensin in bovine tissues by liquid chromatography (LC) with postcolumn derivatization (PCD) with vanillin. Monensin is extracted from the tissues by homogenization with methanol–water and is isolated and concentrated by liquid–liquid partition and sorbent extraction with silica gel. Monensin is mixed postcolumn with vanillin under acidic conditions and heated, and the resulting products are measured by a variable-wavelength detector at 520 nm. The method has a limit of quantitation of 5 ppb monensin in milk and 25 ppb monensin in bovine muscle, liver, kidney, and fat. Standard recovery over the levels and matrixes tested ranged from 80 to 88%. The method is an improvement in specificity, accuracy, and analysis time over existing monensin residue methods for bovine tissues.
Evaluation of a Postcolumn Electrochemical Reactor for Oxidation of Paralytic Shellfish Poison Toxins
Authors: Lawrence James F , Wong Barbara 
Published: February 2020

Abstract
A liquid chromatographic method using a postcolumn electrochemical reactor that oxidizes paralytic shellfish poison toxins to fluorescent derivatives has been developed. Several experimental parameters, including pH and oxidation potential, were investigated. For nonhydroxylated toxins, the sensitivity improved with increasing pH and voltage. At optimum operating conditions, the sensitivity for saxitoxin and gonyautoxins 2 and 3 was an order of magnitude greater than that for neosaxitoxin and B1 and 2 orders of magnitude greater than that for B2. The limit of detection for saxitoxin was 0.10 ng (signal-to-noise ratio, 3:1). Electrochemical oxidation products were similar to those formed in the prechromatographic periodate oxidation method. Shellfish and plankton extracts were analyzed with the electrochemical system, and results agreed well with those obtained with established methods. Shellfish samples contaminated at the regulatory limit of 0.8 μ/g were readily analyzed by the method.
Immunoaffinity Column Coupled with Liquid Chromatography for Determination of Fumonisin B1 in Canned and Frozen Sweet Corn
Authors: Trucksess Mary W , Stack Michael E , Allen Shantae , Barrion Noel 
Published: February 2020

Abstract
A modified liquid chromatographic (LC) method for determining fumonisin B1 (FB1) in corn was applied to canned and frozen sweet corn. The corn is extracted with methanol–water (8 + 2), and the extract is filtered. The filtrate is diluted with water and passed through an immunoaffinity column. After the column is washed with water, FBi is eluted with methanol–water (8 + 2). The eluate is evaporated to dryness by using a vacuum concentrator, and the residue is dissolved in acetonitrile–water (1 +1). FB1 is derivatized with o-phthaldialdehyde. The derivative is separated on a reversed-phase C18 LC column using acetonitrile–water–acetic acid (50 + 50 + 1) and quantitated with a fluorescence detector. Recoveries of FB1 from canned and frozen corn spiked over the range of 50–200 ng/g were 76–88%. The limit of determination was about 25 ng/g, and the limit of detection was about 4 ng/g. The method was applied to 97 commercial canned and frozen sweet corn samples collected from different areas of the United States. Sixty samples contained no FB1. Low levels (trace–82 ng FB1/g corn) were found in 35 samples; 235 ng FB1/g was found in 1 canned corn sample, and 350 ng FB1/g was found in 1 frozen corn sample.
Liquid Chromatographic Method for Determination of Biogenic Amines in Fish and Fish Products
Authors: Veciana-Nogues María Teresa , Hernandez-Jover Teresa , Marine-Font Abel , Vedal-Carou María Del Carmen 
Published: February 2020

Abstract
A liquid chromatographic method with postcolumn derivatization is described for determination of biogenic amines in fish and fish products. Histamine, tyramine, serotonin, β-phenylethylamine, tryptamine, putrescine, cadaverine, agmatine, spermine, and spermidine can be determined in less than 60 min. Routine sample preinjection treatment implies only 2 extractions with 0.6N perchloric acid and filtration through a 0.45 μm filter. Lack of interferences from volatile amines, amino acids, and dipeptides was verified. Results of reliability study were satisfactory. The proposed method was linear for each amine between 0.25 and 8.00 mg/L. Average recoveries ranged from 92 to 103%. Precisions (coefficients of variation) ranged from 0.70 to 9.75%. Determination limits were ≤1 mg/kg. A modification in LC conditions was necessary to apply the method to ripened fish products to avoid interferences from food matrixes. In addition, stability of biogenic amines in fresh anchovies and hake during short-term frozen storage was studied. Results showed that, except for agmatine, frozen storage is suitable for keeping samples before analysis.
Quality Assurance in Weighing
Authors: Kenyon Allen S , Black J C , Layloff Thomas P 
Published: February 2020

Abstract
Weighing is the most used step in any analytical procedure, and the balance is the one essential piece of laboratory equipment in all analyses. Yet weighing is a common source of error in final analytical results and can be difficult to detect. Analysts may become complacent and expect all weighings to be accurate. Our laboratory experienced a problem in weighing and found that the principal error was due to drift. The ensuing investigation into the cause led to a procedure for reducing drift, which, in turn, ensured accurate weighings that have improved quality assurance in our total operations.
Liquid Chromatographic Determination of Sulfadiazine in Salmon by Postcolumn Derivatization and Fluorescence Detection
Authors: Gehring Theresa A , Rushing Larry G , Thompson Harold C 
Published: February 2020

Abstract
A reversed-phase (ODS-2) liquid chromatographic method was developed to determine low nanogramper-gram levels of sulfadiazine (SDZ) in salmon muscle tissue. SDZ was extracted with acetonitrile-aqueous 2% acetic acid (pH 3.0), partitioned into methylene chloride, and cleaned up by using a strong-cation-exchange, solid-phase extraction cartridge. SDZ was derivatized postcolumn with fluo-rescamine and detected by fluorescence. The limit of detection was 0.2 ng SDZ/g tissue. Recoveries from coho salmon tissue fortified with 1,5,10, and 20 ng SDZ/g tissue averaged 84.5,85.0,83.6, and 83.9%, respectively; recoveries from Atlantic salmon tissue fortified with 10 ng SDZ/g tissue averaged 82.6%.
Gas Chromatographic Determination of Yohimbine in Commercial Yohimbe Products
Authors: Betz Joseph M , White Kevin D , Marderosian Ara H Der 
Published: February 2020

Abstract
The bark of Pausinystalia yohimbe [K. Schumann] Pierre (Rubiaceae), long valued as an aphrodisiac in West Africa, recently has been promoted in the United States as a dietary supplement alternative to anabolic steroids for enhancement of athletic performance. As the number of yohimbe products on the retail market increases, concerns about their safety are raised because of the reported toxicity of yohimbine (the major alkaloid of the plant). Although plant materials are usually identified microscopically, we were unable to identify them in many of the products, because as their labels indicated, the products were mixtures of various bo-tanicals or were bark extracts and contained little or no plant material. A method for extraction and capillary gas chromatographic (GC) separation of the alkaloids of P. yohimbe was, therefore, developed and used to analyze a number of commercial yohimbe products. The method involved solvent extraction and partitioning in chloroform–water followed by separation on a methyl silicone capillary GC column (N–P detection). Comparisons of chromatograms of extracts of authentic bark with those of commercial products indicated that, although many products contained measurable quantities of the alkaloid yohimbine, they were largely devoid of the other alkaloids previously reported in this species. Concentrations of yohimbine in the commercial products ranged from &lt;0.1 to 489 ppm, compared with 7089 ppm in the authentic material. Authentic bark has been reported to contain up to 6% total alkaloids, 10–15% of which are yohimbine. The possible presence of undeclared diluents in the products was indicated by peaks in product chromatograms but not in those of authentic bark.
Infrared Analysis of Milk: Effect of Homogenizer and Optical Filter Selection on Apparent Homogenization Efficiency and Repeatability
Authors: Smith Erka B , Barbano David M , Lynch Joanna M , Fleming J Richard 
Published: February 2020

Abstract
The apparent homogenization efficiency (AHE) and repeatability of one instrument was measured with 5 instrument homogenizers that differ in true homogenization efficiency (THE) to determine if instrument characteristics change when different fat A and B optical filters are used in the same machine. Inefficient homogenizers demonstrated both poor repeatability and poor AHE with both sets of fat B filters. One set of fat A filters produced infrared readings that were influenced less by differences in homogenization efficiencies than the other set. The most inefficient homogenizer demonstrated poor repeatability and failed AHE evaluation with both pairs of fat B filters and one pair of fat A filters. Differences in the transmission characteristics of the 2 sets of fat A filters influenced results of AHE evaluation for the most inefficient homogenizers. However, a very efficient homogenizer passed evaluation of AHE and demonstrated good repeatability on both unhomogenized and homogenized milks regardless of differences in the spectral characteristics of filters. A second objective was to determine if AHE test values are correlated with true differences in milk fat globule (MFG) size distribution. A good correlation was found between AHE and THE data for a group of homogenizers for one reference milk. A weakness of the AHE tesl is that the MFG size distribution of the externally homogenized reference milk may vary from one evaluation to another, resulting in an inconsistent reference point for AHE values. The preferred method of evaluating homogenization efficiency of infrared milk analyzers is analysis of the MFG size distribution resulting from instrument homogenization of unhomogenized milk.
Determination of Phenol Sulfone, Phenol Sulfoxide, and Phenol Sulfonic Acid Metabolites of Fenamiphos in Soil by Liquid Chromatography
Authors: Mattern Gregory C , Parker Gilbert D , Green Debra L , Yeutter Gregory L 
Published: February 2020

Abstract
An analytical method has been developed to quantitate fenamiphos phenol sulfone, phenol sulfoxide, and phenol sulfonic acid in soil. Both control and analyte-fortified soil samples from Fresno, CA, were extracted with methanol–water (2 + 1) and partitioned with ethyl acetate. Fenamiphos phenol sulfone and phenol sulfoxide were determined by re-versed-phase liquid chromatography (LC) with UV detection at 240 nm after cleanup by silica solid-phase extraction. Fenamiphos phenol sulfonic acid was determined by reversed-phase ion-pairing LC with UV detection at 240 nm after cleanup by amino solid-phase extraction. Recoveries of fenamiphos phenol sulfoxide ranged from 88.2 to 111.0%, with an average of 97.4%. Recoveries of fenamiphos phenol sulfone ranged from 101.6 to 107.0%, with an average of 104.6%. Recoveries of fenamiphos phenol sulfonic acid ranged from 76.0 to 99.9%, with an average of 86.0%. Responses for analysis of analytes in both solvent and soil matrix were linear over the tested range of 10 to 500 ppb. Limits of determination of each analyte in soil were less than 10 ppb.
Comparison of Recoveries of Selected Organochlorine Pesticides, Related Compounds, and Polychlormated Biphenyls 1254 and 1260 from Fat after Kuderna-Danish and TurboVap Concentration
Authors: McCarthy Helen T , Sullivan Anna R 
Published: February 2020

Abstract
A 2-part study was performed to compare tho Tur-boVap evaporator v/ith the traditional Kuderna-Darv-Ish concentrator for analysis of selected pesticides and related compounds (study 1) and polychlorinated biphenyls (PCBs) (study 2) In fat samples. To compare results, bias and precision data were evaluated for pesticides and related compounds and bias v/as evaluated for PCBs. For study 1, 20 samples of poultry fat were spiked with known amounts of 13 pesticides and related compounds. Samples were extracted v/ith petroleum ether, cleaned up with Florisil, and evaporated in either a Kudorna-Danlsh concentrator or a TurboVap evaporator. The pesticides and related compounds were identified and quantitated by gas chromatography v/ith electron capture detection. Biases, as indicated by average recoveries of pesticides and related compounds, were 63 and 73%, respectively, for the TurboVap and Kudema-Danlsh procedures. Recoveries of pesticides and related compounds, except methoxychlor, by tho TurboVap evaporator were significantly lower (p ≤ 0.05) than recoveries by Kudema-Danish concentration. Average recoveries with the TurboVap procedure were 10% lower than recoveries with the Kudema-Danlsh procedure. Precisions for both procedures were determined by testing for equality of variances with the F-test. A significant difference (p ≤ 0.05) for precision between the 2 procedures was found only for endrin. Study 2 was conducted on 14 accreditation PCB samples from the U.S. Department of Agriculture’s Food Safety and Inspection Service. PCB recoveries were 70–125% with the Kuderna-Danish apparatus and 69–106% with the TurboVap evaporator. No significant difference (p &gt; 0.05) was found between the 2 procedures for PCB analysis. The TurboVap ovaporator gave consistently lower results for pesticides and related compounds compared with the traditional Kuderna-Danish concentrator; precisions for both procedures were similar. Results for PCBs analyzed by both procedures v/cre not significantly different. Lower recoveries for pcstlcidos and rotated compounds notwithstanding. tho TurboVap concentrator offers advantages over tho older Kudorna-Danlsh ovaporator In terms of turnaround time and efficient use of laboratory space.
Comparison of On-Column and Precolumn Derivatization for Liquid Chromatographic Determination of Molybdenum in Seawater and Bovine Liver
Authors: Nagaosa Yukio , Kobayashu Tetsuya 
Published: February 2020

Abstract
A rapid, accurate, and sensitive method was developed for the determination of molybdenum in seawater and bovine liver samples by reversed-phase liquid chromatography (LC) using a Cia column. The method was based on chelation of the metal with 8-hydroxyquinoline by on-column or precolumn derivatization followed by LC elution with acetonitrile-0.02M acetate buffer (3 + 2; pH 4.1) and 1 × 103M of the ligand as the mobile phase. The spectrophotometric detection was made at 390 nm. Data obtained from the 2 derivatizations (on- and precolumn chelation) were compared in terms of detection limit, precision, accuracy, and ease of LC determination of molybdenum. No significant difference exists in the detection limit and the sensitivity of the 2 methods. However, the on-column chelation method, that is, the direct injection of aqueous samples onto the column, showed relatively less interference from manganese and greater simplicity in operation compared with precolumn chelation; therefore, on-column chelation is preferable for routine analyses. The on-column method produced mean levels of 9.6 ± 0.4 μg/L for the seawater sample and 3.6 ± 0.2 μg/g (certified value, 3.5 ± 0.5 μg/g) for bovine liver.
Diarrhetic Shellfish Poisoning: Evaluation of Enzyme-Linked Immunosorbent Assay Methods for Determination of Dinophyslstoxin-2
Authors: Carmody Eoin P , James Kevin J , Kelly Seán S 
Published: February 2020

Abstract
Dinophysistoxin-2 (DTX-2), an isomer of okadaic acid (OA), recently has been found in Irish waters. DTX-2 was the predominant toxin during prolonged infestations in cultivated mussels along the southwest coast of Ireland. Substantial variations in toxin levels may exist both horizontally and vertically in the water column. The need to take multiple samples and the ethical concern about the use of mammals for routine quality control of shellfish prompted examination of 2 commercially available enzyme-linked immunosorbent assay (ELISA) methods, designed to detect OA, for determination of both OA and DTX-2. One ELISA method (DSPCheck, Sceti Co. Ltd., (Tokyo, Japan) showed good cross-reactivity (40 ± 5%) with standard DTX-2. This study showed that both ELISA methods show good correlation with the liquid chromatographic analysis of 9-anthryldiazomethane derivatives when OA is the predominant toxin present. The sensitivity was also good for OA determination using both methods, which allowed toxin measurement at 10 ng/mL (0.5 ng/well). This level is equivalent to 0.03 μg/g mussel meat. Blank mussel samples spiked with DTX-2 standards gave a good linear correlation (r = 0.997) with this ELISA method when toxin levels were 0.03-0.3 μg/g mussel meat. This range is appropriate for regulatory control of diarrhetic shellfish poisoning.
New Approach to Processing of Gas Chromatographic/Mass Spectrometric Data for Detection of Off Flavors in Complex Mixtures
Authors: Fay Laurent B , Staempfli Andreas A 
Published: February 2020

Abstract
Chemical compounds responsible for off flavors in foodstuffs are often difficult to identify because of their low levels in complex matrixes. A simple method is described to detect and identify off flavor compounds by gas chromatographic/mass spectrometric (GC/MS) analysis and data processing for sorting the GC/MS files in 14-ion series. The 14 homologous-ion series correspond to the sum of the intensities of the ions, x + (CH2)n, where x varies from 1 to 14 and n varies from 1 to ∞, allowing to cover the whole acquired mass range. Processing of the ion series allows automatic screening of all acquired masses. We use this method routinely in our laboratory to find compounds responsible for a contamination. It is a powerful tool for off flavor identification by comparison between a reference and a contaminated sample. The method can be used with any type of data system and any chromatographic instrument coupled to a mass spectrometer.
Incomplete Data Sets: Coping with Inadequate Databases
Authors: Albert Richard H , Horwttz William 
Published: February 2020

Abstract
Three problems arise in handling numerical values in databases: bad data, missing data, and sloppy data. The effects of bad data are mitigated by using statistical subterfuges such as robust statistics or outlier removal. Missing data are replaced by creating a substitute through interpolation or by using statistics appropriate to unbalanced designs. Sloppy, semiquantitative data are relegated to innocuous positions by using nonparametric, rank, or attribute statistics. These techniques are illustrated by the telephone directory, a database of carcinogenicity test results, and a database of precision parameters derived from method performance (collaborative) studies.
Monitoring of Pesticide Residues in Human Milk, Soil, Water, and Food Samples Collectedfrom Kafr El-Zayat Governorate
Authors: Dogheim Salwa M , Mohamed El-Zarka , Gad Alla Sohair A , El-Saied Samia , Salama Emel Y , Mohsen Ayoub M , Fahmy Safaa M 
Published: February 2020

Abstract
Pesticide residues in human milk and environmental samples from Kafr El-Zayat Governorate in Egypt were analyzed. This governorate is located near one of the biggest pesticide factories in Egypt. Organochlorine and organophosphorus pesticides were monitored, including those that have been prohibited from use in Egypt. Human milk samples (31 samples) from Kafr El-Zayat were compared with 11 samples collected from Cairo. Data were compared with results from studies performed in 1987 and 1990. The present study showed that aldrin and dieldrin, heptachlor and heptachlor epoxide, and endrin residues have been eliminated from human milk. Estimated daily intakes (EDIs) of DDT complex and γ-HCH by breast fed infants in Kafr El-Zayat were 85.96 and 3.1% of the respective acceptable daily intakes (ADIs). β- HCH residues showed an increasing pattern, especially in human milk samples from Cairo. DDT complex and HCH isomers in orange, spinach, lettuce, potatoes, and clover samples ranged from undetectable to very low concentrations. Higher levels of DDT and HCH were detected, but aldrin, dieldrin, endrin, and the heptachlors were not detected in food of animal origin. Residues in fish samples were below maximum residue limits established by some developed countries. Those in animal milk samples approached the extraneous residue limits of the Codex Committee on Pesticide Residues. HCH residues in soil were negligible, but DDT resi dues in soil were some what higher. Among watersamples, groundwater samples had the highest residues of HCHs and DDTs, followed by Nile River water and then tap water. However, the organo chlorine pesticide residues were found at concen trations below the maximum allowable limits set by the World Health Organization for drinking water. Among 12 organophosphorus pesticides moni toredas parent compounds, dimethoate,malathion, methamidophos, and chlorpyrifos residues were detected in low concentrations in soil samples from a pesticide factory. No organophosphorus pesticide residues were found in plant samples, except for very low residues of dimethoatein anorange sample. Water samples were devoid of organophosphorus residues as parent compounds.