bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Diclazuril in Avian Feed and Premixes with Gas Chromatography/Mass Spectrometry
Authors: Blanchflower W John , Hughes Peter J , Cannavan Andrew , Kennedy D Glenn 
Published: February 2020

Abstract
A method is presented for the determination of the relatively new anticoccidial drug diclazuril in avian feed and premixes. The drug was extracted from feed with acidified methanol-water, and the extracts were cleaned up by simple liquid-liquid extraction. These were then derivatized with ethereal diazomethane, and the methyl derivatives were analyzed by gas chromatography/mass spectrometry on a bench-top instrument An internal standard was used to enhance the reproducibility and ruggedness of the assay. The coefficients of variation for a finished feed and premix assayed 5 times each on 3 occasions were 6.6 and 6.0%, respectively. The detection limit of the assay is about 0.02 mg/kg, which is adequate for measuring the normal inclusion rate of 1 mg/kg in finished feed.
Determination of Reserpine, Hydralazine HCl, and Hydrochlorothiazide in Tablets by Liquid Chromatography on a Short, Normal-Phase Column
Authors: Cieri Ugo R 
Published: February 2020

Abstract
A procedure is presented for the determination of reserpine, hydralazine HCI, and hydrochlorothiazide in tablets by liquid chromatography. The sample is extracted with methanol, and the extract is filtered through paper. Chromatography is performed in 2 stages, each using a 7.5 cm-long normal-phase column but different mobile phases. In the first stage, intended exclusively for reserpine, the mobile phase consists of methanol containing 2% aqueous 1-pentanesulfonic acid sodium salt at 4 parts/1000. Detection and quantitation of reserpine was by fluorescence at 280 nm (excitation) and 360 nm (emission). In the second stage, the amount of the salt solution in the mobile phase was increased to 5%. Detection and quantitation of hydrochlorothiazide and hydralazine HCI was by UV absorbance at 260 nm. One commercial sample of tablets was analyzed by the proposed method. Two determination of each ingredient were made on a ground composite. Ten individual tablets also were examined.
Determination of Thiabendazole in Fruits and Vegetables by Competitive-Inhibition Enzyme Immunoassay
Authors: Bushway Rodney J , Young Barbara E S , Paradis Lance R , Perkins Lewis B 
Published: February 2020

Abstract
An enzyme immunoassay (EIA) was developed for analysis of thiabendazole (TBZ) in fruits and vegetables. A commercial kit using a polyclonal antibody for benomyl-carbendazim was used. Total analysis time, including sample preparation, was 35 min. As many as 8 samples can be analyzed simultaneously, with a limit of quantitation of 9 ppb. The assay's dynamic range ran from 9 to 304 ppb TBZ. Intra-as-say coefficients of variation (CVs) ranged from 5.0 to 9.6% for standards and 11 to 30% for samples. In-terassay CVs varied from 4.4 to 15% for standards and from 10 to 24% for samples. Average recovery from 29 samples spiked at 50-50 000 ppb was 116%. A total of 107 food products comprising 12 different fruits and vegetables and their processed products were analyzed for their TBZ content by EIA and liquid chromatography (LC). Of these samples, 84 were positive for TBZ by both methods, with a correlation coefficient (r) of 0.989. Eight samples had none detected by either technique, and 15 were positive for carbendazim. Concentrations of TBZ ranged from 11 to 94 000 ppb. The immunoassay with methanol sonication shows promise as a rapid screening method for TBZ in foods.
Analysis of Methyl Isothiocyanate in Wine by Gas Chromatography with Dual Detection
Authors: Satto Isao , Yamada Sadaji , Oshtma Harumi , Ikai Yoshttomo , Oka Hisao , Hayakawa Junko 
Published: February 2020

Abstract
Methyl isothiocyanate (MITC) was extracted from a 5 mL wine sample with 2 mL dichloromethane, and the extract was washed with 5% sodium chloride solution. MITC was determined by gas chromatography with a dual nitrogen-phosphorus detector (NPD) and a flame photometric detector (FPD, S mode) (DB-210 column, 30 m × 0.53 mm id, column temperature, 70°C). The limit of detection and quantitation of MITC with NPD–GC were 0.003 and 0.01 ppm, respectively. Average recoveries of MITC added to wine at 1 and 0.1 ppm were over 95%. This method is simple and rapid for routine analysis of MITC in wine.
Validation of Computerized Liquid Chromatographic Systems
Authors: Furman William B , Layloff Thomas P , Tetzlaff Ronald F 
Published: February 2020

Abstract
Almost all vendors of liquid chromatographs offer dedicated computer-based controller/data-processing systems. These systems are integrated into the operation of the equipment and frequently use pro-prietary software systems for which complete documentation and program listings are not available to the user. In some instances, data in magnetic media are considered to be “raw data” for regulatory retention requirements. In addition, printed copies of final data used to make decisions and the procedures used to generate these data from raw data must be prepared and retained. In all cases, the systems must be validated to demonstrate that they are suitable for their intended uses. Approaches to validation of these systems are described and discussed.
Display Methods for Visual Comparison of the Results of Two Measurement Methods
Authors: Hartmann Christa , Massart Desiré L 
Published: February 2020

Abstract
The use of a plot originally proposed by Bland and Altman (1986, Lancet 8,307-310) for the comparison of 2 clinical measurement methods was investigated and compared with a new visual display based on principal component analysis. The characteristics of both methods are demonstrated for several computer-simulated situations. For visual comparison of 2 methods, it is recommended to use the 2 methods simultaneously, together with a plot of the results of method 2 against method 1.
Identification of Vibrio vulnificus by Cellular Fatty Acid Composition Using the Hewlett-Packard 5898A Microbial Identification System: Collaborative Study
Authors: Landry Warren L 
Published: February 2020

Abstract
A gas chromatographic method using a capillary column for rapid identification of Vibrio vulnificus was examined in a collaborative study. Identifications were performed by analysis of cellular fatty acid profiles which were automatically searched against reference profiles stored in a computer-generated library. Each of the 13 collaborators was sent 15 unknown isolates, which included 10 V. vulnificus isolates and 5 negative control isolates. Each collaborator was furnished with a computergenerated library, developed by the Dallas U.S. Food and Drug Administration laboratory, which contained entries for V. vulnificus, V. cholerae, V. fluvialis, V. parahaemolyticus, V. mimicus, and Aeromonas hydrophila. Of the 195 isolates sent to the collaborators, results for 190 isolates were received. The other 5 isolates were nonviable before analyses began. Of the 126 V. vulnificus isolates analyzed, 118 (93.7%) were correctly identified. Of the 65 negative control isolates sent, one was nonviable, one was misidentified as V. vulnificus, and 2 were misidentified as V. parahaemolyticus. Of the 64 negative controls analyzed, 95.3% were correctly identified. Statistical analysis shows a sensitivity rate of 0.872, specificity rate of 0.982, false positive rate of 0.010, and false negative rate of 0.206. The gas chromatographic method for identification of Vibrio vulnificus by microbial fatty acid profile has been adopted first action by AOAC INTERNATIONAL.
Dibenzoyl Methane—A New Coupling Agent for Nitrite Determination
Authors: Shanthi K , Balasubramanian N 
Published: February 2020

Abstract
Dibenzoyl methane is introduced as a new coupling agent for the determination of nitrogen dioxide in air and for nitrite in water and soil samples. Nitrogen dioxide is fixed as nitrite in NaOH–sodium arsenite trapping solution and also in triethanoamine trapping solution. The method is based on the diazo coupling reaction of p-nitro aniline with a new coupling agent, dibenzoyl methane. The azo dye formed under aqueous alkaline condition has an absorption maximum at 520 nm and obeys Beer’s law over a range of 0–20 μg nitrite per 10 ml analyte. The dye formed is stable for 40 h. The relative standard deviation is 2.8% for 10 determinations at 10 μg nitrite per 10 ml analyte. The color system upon extraction with isobutyl methyl ketone–amyl alcohol (1+1) shows a λ max at 520 nm and a Beer’s law range of 0–4 μg nitrite. The developed color is stable for 7 h in the organic phase. The relative standard deviation is 3.0% for 10 determinations at 2 μg nitrite. The molar extinction coefficient of the color system is 3.6 × 104 L/(mol·cm). The effect of interfering gases and ions on the determination is described. The method was applied to the determination of residual amounts of nitrogen dioxide present in the laboratory fume cupboard and in automobile exhaust gas. The method was also applied to the determination of nitrite and nitrate in water and soil samples. The results obtained were compared with the standard sulfanilamide–NEDA (N-1 naphthyl ethylene diamine dihydrochloride) method. The method can be used to determine levels as low as 0.5 μg nitrite in aqueous medium and 0.1 μg nitrite upon extraction.
Determination of Thiabendazole Residues in Pears by Solid-Phase Spectrofluorimetry
Authors: Cápitan-Vallvey Luis Fermin , Avidad Ramiro , Vilchez Jose Luis 
Published: February 2020

Abstract
An analytical procedure for determination of thiabendazole (TBZ) residues in pears is described. The method involves extracting the chemical from the chopped fruit with buffer solution (acetic acid–acetate, pH 4.6), use of Sephadex G-15 dextrantype gel as a solid support, and determination of TBZ by solid-phase spectrof luorimetry (SPF). The relative fluorescence intensity of the Sephadex G- 15 gel–TBZ system, packed in a 1 mm-thickness silica cell, was measured directly at λex = 303 nm and λem = 350 nm with a solid-phase attachment. The applicable concentration range was 5.0–20.0 ppb with a detection limit of 0.5 ppb. Recoveries were from 98.7 to 102.0% when 15.0 ppb of TBZ was added to the fruit.
Effectiveness of a One-Day Procedure for Recovery of Salmonella from Milk Powders
Authors: Hammack Thomas S , Andrews Wallace H , Amaguana R Miguel , June Geraldine A , Sherrod Patricia S 
Published: February 2020

Abstract
A rapid procedure for enumerating Salmonella in milk powders was evaluated. Dry whole milk and instant nonfat dry milk were rehydrated, artificially inoculated with various numbers of Salmonella cells, and stomached. Test portions were then treated with Tween 80 and pancreatic trypsin, and incubated for 1 h at 30°C. The incubated test portions were centrifuged at 10 000 × g for 15 min at 5°C, and the resuspended pellets were plated on xylose lysine desoxycholate agar. The effectiveness of the procedure was expressed in terms of percentage recovery of the inoculum. The procedure, which was evaluated in 76 trials using 7 Salmonella serovars, recovered ≤73% of the inoculum for half of the trials conducted. Its effectiveness was dependent on the serovar, level of inoculation, and type of milk powder used.
Cholesterol Analysis in Foods by Direct Saponification—Gas Chromatographic Method: Collaborative Study
Authors: Klatt Low V , Mitchell Barbara A , Smith Randall L 
Published: February 2020

Abstract
A collaborative study was conducted on a method for determination of cholesterol in various foods and food products using a direct saponification technique and capillary column gas chromatography. The method is a modification of AOAC Official Method 976.26 for the determination of cholesterol in multicomponent foods. The major modifications include the use of direct hot alkaline saponification and capillary column gas chromatograph to quantitate the cholesterol. Blind duplicate samples of butter cookies, hot dog buns (made with eggs), bread crumbs, vegetable-bacon baby food dinner, NIST (SRM No. 1845) egg powder, skinless wieners, commercial egg powder, vegetable-chicken baby food dinner, and Cheez Whiz were analyzed by 14 collaborators. The mean cholesterol values of these products ranged from less than 1.0 to 1965 mg/100 g. The average repeatability (RSDr) for all samples was 4.81%. The average reproducibility (RSDR) was 8.58% with only 2 products having RSDR values above 10%. These 2 products were the baby food dinner complex matrices with cholesterol values below 5 mg/100 g. The fact that the cholesterol levels for these dinner products are close to the level of quantitation is one explanation for the elevated RSDR values. The direct saponification—gas chromatographic method for determination of cholesterol in foods has been adopted first action by AOAC INTERNATIONAL.
Liquid Chromatographic Determination of Thiamine in Rodent Feed by Postcolumn Derivatization and Fluorescence Detection
Authors: Gehring Theresa A , Cooper Willie M , Holder Claude L , Thompson Harold C 
Published: February 2020

Abstract
A liquid chromatographic method was developed for determination of the essential nutrient thiamine (vitamin Bi) in rodent feed. Thiamine was extracted with hydrochloric acid, separated by reversed-phase liquid chromatography, derivatized postcolumn to thiochrome with potassium hydroxide and potassium ferricyanide, and detected by fluorescence. Excitation and emission wavelengths were 370 and 430 nm, respectively. Detector response was linear in the range of 2.58 to 15.5 ng of thiamine injected. Instrument detection limit was 5 pg of thiamine injected.
Determination of Sulfadimethoxine Withdrawal Time from Milk. Part II: Statistical Assessment
Authors: Lentz Ellen L , Chung Jain 
Published: February 2020

Abstract
A statistical method is proposed to establish milk discard time for the data set described in Part I (preceding paper). Results are compared with those from the Food and Drug Administration (FDA)-recommended method. The milk discard time is established on the basis of a calculated tolerance limit. This limit provides 95% confidence that 99% of the population residue would assay below the permitted concentration (10 ppb for SDM). Unlike the FDA method, the proposed method allows easy calculation and requires no assumptions in drug depletion rate over time. For a permitted concentration of 10 ppb, both methods confirm the present 60-h discard time for SDM when it is assumed that no more than ⅓ of the milk came from treated cows.
Modified Immunoassays for Polyether Toxins: Implications of Biological Matrixes, Metabolic States, and Epitope Recognition
Authors: Baden Daniel G , Melinek Rosemary , Sechet Veronique , Trainer Vera L , Schultz Duane R , Rein Kathleen S , Tomas Carmelo R , Delgado Jesus , Hale Lauren 
Published: February 2020

Abstract
Polyether marine toxins are responsible for the seafood intoxication phenomena known as neurotoxic shellfish poisoning (due to brevetoxins), ciguatera (due to ciguatoxin), and diarrheic shellfish poisoning (due to okadaic acid). Using traditional techniques of hapten (pure toxin) conjugation to protein to create complete antigen, animal immunization and antibody isolation, and specific antibody subpopulation purification, discriminating antibodies have been isolated that detect brevetoxins and ciguatoxin, but not okadaic acid, in a dose-dependent fashion. Using microorganic chemistry and purified toxins, a unique set of tools has been created for the study of polyether ladder toxin accumulation; depuration; and specific site localization in tissues, food sources, and clinical samples. Developed test protocols can detect toxin in dinoflagellate cells, in extracts from food sources, in seawater and culture media, and in human serum samples. Enzyme-linked immunosorbent assay protocols developed for eventual collaborative testing have been successful in limited applications within the laboratory (correlation coefficient of 0.92 excluding 2 outliers), and alternative formats are being developed to optimize the basic test for use in research laboratories, regulatory laboratories, and field inspections.
Rapid Spectrophotometric Method for Analyzing Natamycin in Cheese and Cheese Rind
Authors: Fletouris Dbvutrios J , Botsoglou Nickos A , Mantis Antonios J 
Published: February 2020

Abstract
A rapid spectrophotometric method for determining natamycin in cheese and cheese rind has been developed. Samples are homogenized with acidified aqueous acetonitrile and homogenates are filtered. Natamycin is directly quantitated in filtered extracts on the basis of the characteristic thirdderivative trough at 322.6 nm. Additional cleanup of extracts is not required because derivative transformation of the conventional analytical band at around 319 nm eliminates spectral interferences from other compounds. The analysis is simple and can be completed in 6 min. The equipment is easily accessible because most modern spectrophotometers allow instant generation of derivative spectra. The method needs small amounts of solvents and has good analytical characteristics. Overall recovery was 98.4 ± 0.7%, and linearity was excellent (r= 0.9998) in the range examined (0.5–20 mg/kg). Quantitation and detection limits were estimated at 0.5 and 0.25 mg/kg, respectively. Precision statistics based on within-day and between-days variations suggest an overall relative standard deviation of 1.4%.
Determination of Methylmercury After Supercritical Fluid Extraction
Authors: Holak Walter 
Published: February 2020

Abstract
A method, using supercritical fluid extraction, for determining methylmercury in seafood has been developed to eliminate use of toxic organic solvents. Seafood samples were treated with 1N NaOH and then acidified with HCI to release CH3HgCI. After mixing the sample with cellulose powder (40 mesh) containing stearic acid modifier at 5 mg/g, the extraction was performed with supercritical CO2 under the following conditions: pressure, 200 atm; temperature, 50°C; time, 20 min; and trap, 0.01N Na2S2O3 in a conical tube immersed in a flask of warm water to prevent freezing. The extract was then analyzed by a suitable method, such as cold-vapor atomic absorption spectrophotometry. The accuracy of the procedure was verified by analyzing biological standard reference materials. Several commercial seafood samples and spikes have been analyzed.
Determination of Ajmalicine in Reserpine Raw Materials by Liquid Chromatography with Fluorescence Detection
Authors: Cieri Ugo R 
Published: February 2020

Abstract
A method is presented for determination of ajmalicine in reserpine raw materials by liquid chromatography (LC) with fluorescence detection. The sample is dissolved in a very small volume of chloroform, and the resulting solution is diluted with methanol. The reference solution of ajmalicine is prepared directly in methanol. For LC, a 30 cm long normal-phase column is used. The mobile phase is methanol containing a small volume of an aqueous solution of 1-pentanesulfonic acid, sodium salt. Detection is by fluorescence with excitation at 280 nm and emission at 360 nm. In 3 samples, the ajmalicine contents ranged from 1.2 to 1.9%.
Isolation, Purification, and Liquid Chromatographic Determination of Stilbene Phytoalexins in Peanuts
Authors: Sobolev Victor S , Cole Richard J , Dorner Joe W , Yagen Boris 
Published: February 2020

Abstract
A liquid chromatographic (LC) method for determination of stilbene phytoalexins (SPs) in peanuts has been developed. SPs were extracted with acetonitrile–water (90 + 10, v/v) by high-speed blending. An aliquot of extract was applied to a minicolumn packed with AI2O3–ODS (C18) mixture and eluted with acetonitrile-water (90 + 10, v/v). Eluate was evaporated under nitrogen, and residue was dissolved in LC mobile phase. SPs in an aliquot of purified extract were quantitated by normal-phase partition LC on silica gel with n-heptane–2-propanol–water–acetonitrile–acetic acid (1050 + 270 + 17 + 5 + 1, v/v) as mobile phase. Recoveries of SPs [frans-4-(3-methyl-but-1-enyl)-3,5,4′-trihy-droxystilbene (trans-arachidin-3; t-Ar-3), trans-3-isopentadienyl-4,3′,5′-trihydroxystilbene (t-IPD), and trans-3,5,4′-trihydroxystilbene (trans-resveratrol; t-Res)] from peanuts spiked at 300 ppb were 96.05 ± 2.8%. Limits of quantitation for t-Ar-3 and t-IPD were about 100 ppb. t-Ar-3, t-IPD, and t-Res were found in all parts of the peanut plant as major SPs produced in response to fungal invasion.
Determination of Honey Authenticity by Capillary Gas Chromatography
Authors: Low Nicholas H , South Wendy 
Published: February 2020

Abstract
Methodology using capillary gas chromatography was developed to determine addition of invert syrups (beet or cane) to honey. Fingerprint oligosaccharides, which were either not detectable or present in low concentrations in pure honey, were found in these inexpensive sweeteners. Oligosaccharides were analyzed as their trimethylsilyl ethers. Sixty-eight pure honey samples produced in continental North America, Hawaii, China, and Australia were analyzed. The detection limit for invert sugar addition was 5%.
Determination of Dithiocarbamate and Its Breakdown Product Ethylenethiourea in Fruits and Vegetables
Authors: Ahmad Nazir , Guo Lin , Mandarakas Peter , Appleby Sevieone 
Published: February 2020

Abstract
Improved methods for determination in fruits and vegetables of ethylene bisdithiocarbamate (EBDC) residues as carbon disulfide by gas–liquid chromatographic headspace analysis and of othylenethio-urea (ETU) residues by liquid chromatography (LC) are described. Improvements to the EBDC procedure include increased sensitivity by use of 140 mL crimp seal samples bottles fitted with silicone seals, which are leak-proof and reduce headspace volume; use of a Porapak column, which allows use of higher column temperature for better residue separation; and inclusion of thiopheno as an internal standard for bettor quality control. The relationship between the logarithm of the response of carbon disulfide divided by the thiophene response versus concentration of carbon disulfide is expressed by the regression equation Y = 1.011 X + 0.008, with a correlation coefficient r2 = 0.993. Mean recoveries from 8 commodities spiked with mancozcb at 1 and 3 mg/kg, equivalent to 0.473 and 1.419 mg/kg carbon disulfide, are 94.2 ±10 and 98.3 ± 13%, respectively. The Improved LC procedure for ETU residue analysis requires minimal cleanup of sample extract, no derivatization prior to injection, and no specialized LC detectors for quantitation. The UV detector response at 240 nm Is linearly related to ETU concentration [Y = (3.18X – 0.778) × 1000. r2 = 0.997]. Moan ETU recovery from 5 commodities spiked at 0.2 to 5 mg/kg is 93.9 ± 6%. ETU residues of 0.02 to 0.25 μg/g were detected in macerated samples of fruits and vegetables spiked with man-cozeb at 5 μg/g and incubated at room temperature for 3 days. The improved procedures were used to analyze EBDC and ETU residues in fruits and vegetables sampled at a wholesale Sydney produce market. Approximately 30% of samples tested contained EBDC residues, whereas ETU residues in the same samples were below the detection limit of the analytical method (&lt;0.02 mg/kg).