bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid Chromatographic Determination of 2-Chloro-4-nitroaniline, 2-Naphthol, and 2,4-Dinitroaniline in D&C Red No. 36
Authors: Scher Alan L , Adamo Nicholas C 
Published: February 2020

Abstract
A method is described for the determination of the intermediates and a related impurity in D&C Red No. 36 by reversed-phase liquid chromatography. This method may be used to ensure that limits set forth in the Code of Federal Regulations on the amounts of these 3 impurities in the color are not exceeded. The pigment is dissolved in boiling dioxane and then precipitated. The filtrate is chromatographed by isocratic elution, and then the column is washed and reequilibrated. Impurities were identified as 2-chloro-4-nitroaniline (2-CI-4-NA), 2-naphthol, and 2,4-dinitroaniline (2,4-DNA) by comparison of their retention times and spectra with those of standards. Peak area calibrations were linear to at least 0.375% 2-CI-4-NA, 1.25% 2-naphthol, and 0.025% 2,4-DNA, all with zero intercepts. At the specification levels, 99% confidence limits were 0.30 ± 0.006% for 2-CI-4-NA, 1.0 ± 0.03% for 2-naphthol, and 0.020 ± 0.0004% for 2,4-DNA. The limits of determination calculated from calibration data were 0.019% for 2-CI-4-NA, 0.10% for 2-naphthol, and 0.0014% for 2,4-DNA at the 99% confidence level. Recoveries were 100-104% for 2-CI-4-NA added to purified D&C Red No. 36,100% for 2-naphthol, and 100-110% for 2,4-DNA; relative standard deviations were 0.8-3.4%. A survey of certified D&C Red No. 36 samples showed that the batches contained higher levels of intermediates than were determined previously by a cellulose column method in which the pigment was not dissolved.
Determination of Residual Ethylene Oxide in Spectinomycin Hydrochloride Bulk Drug by Dynamic Headspace Gas Chromatography
Authors: Ramstad Tore , Miller Lisa S , Thomas Virginia N 
Published: February 2020

Abstract
A dynamic headspace gas chromatographic method was developed for the determination of residual ethylene oxide (EtO) in a pharmaceutical bulk drug, spectinomycin hydrochloride. The recommended column is PoraPLOT Q; PoraPLOT U was demonstrated to be equivalent. A detection limit of 2 ppb was achieved, and linearity was established to the highest value tested (5 ppm). The detection limit was 2-3 orders of magnitude lower than that achieved in previously published methods for EtO in pharmaceutical bulk drugs. Precision studies yielded relative standard deviations ranging from 2 to 10% over the 10-575 ppb concentration range. The method was applied to support EtO sterilization studies conducted at The Upjohn Company and was implemented for routine use. The sterilization studies demonstrated that residual levels of EtO &lt;10 ppb are achievable.
Assay of Oxytetracycline Residues in Salmon Muscle by Liquid Chromatography with Ultraviolet Detection
Authors: Carignan Germain , Carrier Karen , Sved Stephen 
Published: February 2020

Abstract
A novel method for the assay of oxytetracycline residues in salmon muscle is described. Tissue is homogenized with 4 volumes of 1 % metaphosphoric acid in the presence of a small amount of dichloromethane (0.4 volume), shaken, and centrifuged. The residue is washed twice (4 and 2 volumes, respectively) with 1 % metaphosphoric acid, and the combined aqueous supernatants are concentrated to about 2 mL by flash evaporation and then diluted to 5 mL. Filtered aliquots of the extract are subjected to liquid chromatography using a C18 column with a mobile phase of acetonitrile-tetrahydrofuran- 0.025M aqueous oxalic acid (9 + 1 + 30) containing octanesulfonic acid at a final concentration of 10mM. Eluted peaks are monitored at 355 nm. Calibration and standard curves were linear from 0.01 to 0.5 μg on-column, with a limit of quantitation better than 0.05 μg/g. Recoveries from spiked blanks varied from 85.8 to 90.3% (relative standard deviation, 13.1-2.4%) in the 0.05-1.00 μg/g concentration range and were 21.1% at 0.02 μg/g.
Evaluation of Microbial Loads of Bacillus subtilis Spores on Penicylinders
Authors: Danielson James W 
Published: February 2020

Abstract
Three types of penicylinders were compared for their retention of spores of Bacillus subtilis testing for sporicidal activity of disinfectants. Glass, porcelain, and stainless steel penicylinders are inoculated with a water suspension of B. subtilis var. niger (ATCC 9372) spores and dried. One set of each type of penicylinder is submerged 1 h in 0.9% saline. One set of porcelain penicylinders is submerged 15 h in a neutralized chemical germicide, and one set is also inoculated with a culture filtrate of B. subtilis (ATCC 19659), dried according to the AOAC method, and submerged 1 h in 0.9% saline. Microbial loads simulate those held on carriers used to test sporicidal activity of disinfectants. Carriers are immersed in chemical germicide, transferred to a neutralizer, and placed in a culture medium. Average percentages of B. subtilis var. niger spores retained on 10 carriers after 1 h submersion in saline and in water were as follows: glass, 93.6%; porcelain, 99.9%; and stainless steel, 99.5%. Retention of spores after 15 h submersion in a neutralized chemical germicide and in water was 98.9%. Porcelain penicylinders inoculated from a culture filtrate of B. subtilis (ATCC 19659) retained 26% of the spores after being submerged 1 h in saline and placed in water. Glass penicylinders, which retained the lowest and most variable number of spores, were the least suitable for sporicidal activity testing. B. subtilis (ATCC 19659) spores tested on porcelain penicylinders met only the minimum HCI resistance requirements of ≥2 min. On porcelain penicylinders, the resistance of B. subtilis var. niger spores to 2.5N HCI was relative to the number of spores inoculated.
Reliability of Mycotoxin Assays — An Update
Authors: Horwitz William , Albert Richard , Nesheim Stanley 
Published: February 2020

Abstract
The precision parameters of the method-performance (collaborative) studies for mycotoxins published in the literature through 1991 have been recalculated on a uniform basis by following the International Union of Pure and Applied Chemistry protocol. About 80% of the 793 accepted assays for mycotoxins, almost all of which have been conducted by thin-layer chromatography (TLC), liquid chromatography (LC), and enzyme-linked immunosorbent assays (ELISA), exhibit relative standard deviations among laboratories (RSDR) that are less than 2 times the values predicted from the Horwitz equation:
RSDR,% = 2(1 - 0.5log10C)
where C is the concentration expressed as a decimal fraction. The precision of TLC and LC methods is about the same, but that of ELISA is somewhat poorer. For those commodities for which sufficient data exist to provide a meaningful comparison, the methods applied to cottonseed products have the best precision and corn the worst, with peanuts intermediate. Overall, however, the primary factor affecting RSDR is concentration, more or less independent of analyte, method, matrix, and age of the study. If it is assumed that the test results are normally distributed and that an RSDR of 50% is the point where effective control of the results begins to be lost (a value equivalent to the production of 2% false-negative values), then relying on the Horwitz curve, the limit of quantitative measurement is the single digit, i.e., 5,µg/kg (10-9; ppb) concentration for solid food commodities. Such a value must be considered as a limit applicable to a single analyte, aflatoxin B1, and not as a mean, and not applicable to the sum of the individual components, each of whose associated standard deviation would lie in the unacceptable region. Enforcement of a 5 µg aflatoxin B1/kg limit, under the assumptions made, requires that a responsible manufacturer and a prudent regulator operate at opposite extremes of tolerance limits: e.g., the producer at 2 µg/kg and the consumer at 10. A proposed Codex “maximum level” of 0.05 µg aflatoxin M1/kg milk cannot be supported by the available data applied in an interlaboratory enforcement environment. These conclusions are also supported by an examination of the reported data from the ongoing, large-scale proficiency studies routinely performed by the American Oil Chemists’ Society and the International Agency for Research on Cancer.
Solid-Phase Extraction and Liquid Chromatographic Determination of Monophthalates and Phthalide ExtractedFrom Solution Administration Sets
Authors: Snell Robert P 
Published: February 2020

Abstract
A liquid chromatographic procedure is described for the determination of phthalide, monobutyl phthalate, and mono-2-ethylhexyl phthalate leached by water from solution administration sets. Recoveries varied from 88.8% for phthalide at 1 (μg/50 mL to 113% for monobutyl phthalate at 6 μg/50 mL. Relative standard deviations at 1 μg/50 mL were 2.59% for phthalide, 3.54% for monobutyl phthalate, and 11.6% for mono-2- ethylhexyl phthalate. At 6 μg/50 mL, the relative standard deviation for mono-2-ethylhexyl phthalate decreased to 3.88%. Reproducibilities for 5 standard injections were 1.40% for phthalide, 1.84% for monobutyl phthalate, and 1.95% for mono-2- ethylhexyl phthalate. Correlation coefficients were 1.00 for the 3 compounds. Five sets from 2 manufacturers were examined. No phthalide or monobutyl phthalate was found. One manufacturer’s sets contained 37.6-44.4 μg/L mono-2- ethylhexyl phthalate. The sample matrix had some interference if phthalide or monobutyl phthalate was present.
Liquid Chromatographic Determination of Biogenic Amines in Dry Sausages
Authors: Eerola Susanna , Hinkkanen Riitta , Lindfors Erja , Hirvi Timo 
Published: February 2020

Abstract
National Veterinary Institute, Department of Chemistry, SF-00101, Helsinki, Finland A liquid chromatographic method is described for the determination of biogenic amines found in dry sausages: tryptamine, phenylethylamine, putrescine, cadaverine, histamine, serotonin, tyramine, spermidine, and spermine. Amines were extracted with perchloric acid solution and derivatized with dansyl chloride. After derivatization, ammonia was added to remove an interfering peak near cadaverine. Liquid chromatographic separations were performed by using a Spherisorb ODS2 column and an ammonium acetate-acetonitrile gradient elution program. The limits of determination of the individual amines were 1-5 mg/kg. This method is also applicable to detection of amines in other food samples.
Reporting Ongoing Results of Interlaboratory Comparison Programs
Authors: Viggers Elizabeth A , Atkinson June , Purcell Steve 
Published: February 2020

Abstract
International standards have been established for reporting individual ring trials, but no established general method has been developed! for reporting ongoing Interlaboratory Comparison Programs (ILCPs) to participants, although some attempts have been made to address the problem. The present paper describes a system that has been developed, tested, and used in New Zealand and which has improvements over many current schemes. It is consistent with international standards and meets the needs of laboratory analysts and managers. It emphasizes graphic output, and essential statistics are given but not emphasized. Feedback is produced within a week of the analysts’ reporting deadline. The system is based on principles agreed to among analysts, the statistician, the systems analyst, and the scheme manager, and it embraces a wide variety of chemical and microbiological tests. The present paper covers only the statistical and reporting aspects of the system.
Gas Chromatographic Determination of Benalaxyl Residues in Different Crops and Water
Authors: Crisippi Teodoro , Zini Guido , Fabbrini Riccardo 
Published: February 2020

Abstract
A gas chromatographic method is described that is suitable for the determination of benalaxyl residues ranging from 10 to 0.1 μg/kg in several crops, must, wine, and water. The compound is extracted with acetone and purified either by partitioning between water and n-hexane or by passing the extract through an Extrelut column with n-hexane. Further purification is achieved by column chromatography on alumina. The active ingredient is finally determined by gas chromatography with nitrogenphosphorus detection. Mean recoveries were ≥95% in the various crops tested and in the 0.01-1.05 mg/kg fortification range. Standard deviations for each crop were ≤6.5%.
Potential Application of LASER/Microbe Bioassay Technology for Determining Water-Soluble Vitamins in Foods
Authors: Anderson Ellen M , Angyal Gerald N , Weaver Carol M , Felkner I Cecil , Wolf Wayne R , Worthy Brenda E 
Published: February 2020

Abstract
A microbiological technique was developed for quantitating niacin by determining microbial growth rates in response to the amount of vitamin available. Unlike the current official AOAC method, the new procedure for niacin measured the growth rates during the early exponential growth phase rather than during the stationary phase. Lactobacillus plantarum was used to determine niacin to a lower limit of 100 pg/mL. The assay time was approximately 6 h, compared with 16-24 h for the current AOAC method. The extent of microbial growth was determined by differential light scattering of a LASER beam. Multiple photodetectors were integrated with a computer system to collect and analyze the data. The use of differential light scattering to determine 8 water-soluble vitamins under stationary phase conditions demonstrated the potential application of the new technology for microorganisms and foods.
Liquid Chromatographic Method for Determination of Iodine in Milk: Collaborative Study
Authors: Sertl David , Malone William ,   Collaborators:, Beljaars P , Blake C , Byerly C , Chadha R K , Daniels T , Duda C , Liu J , McShane B , Parns N , Pollman R , Ponto K , Sertl D , Soloman B , Stemp A , Vaessen H 
Published: February 2020

Abstract
Nine laboratories participated in an AOAC International/ International Dairy Federation collaborative study on a liquid chromatographic (LC) method for determination of iodine in milk. Liquid milk is passed through a 25 000 MW membrane filter to remove protein and insoluble material. Iodine (in the form of iodide) in the clear filtrate is separated by reversed-phase ion-pair LC and is detected electrochemically. Participants analyzed 2 commercial pasteurized whole milks and 5 nonfat dry milk powders in blind duplicate. Each sample was tested in duplicate on 2 days. Repeatability and reproducibility standard deviations (sr and SR, respectively) and repeatability and reproducibility relative standard deviations (RSDr and RSDR, respectively) for determinations of iodine in whole milk (mean recovery, 86.7%) were as follows: sr, 22 μg/L; SR, 22 μg/L; RSDr, 8.2%; and RSDR, 8.3%. For powdered milk (mean recovery, 91 %), the values were as follows: sr, 0.14 μg/g; SR, 0.22 μg/g; RSDr, 9.0%; and RSDR, 12.7%. The method was adopted first action by AOAC International.
Liquid Chromatographic Method for Determination of Sulfamethazine Residues in Milk: Collaborative Study
Authors: Weber John D , Smedley Michael D ,   Collaborators:, Bradley B , Carignan G , McGary E D , Rowe W D , Schenck F J , Thompson R D , Thorpe C W 
Published: February 2020

Abstract
Seven laboratories participated in a collaborative study of a liquid chromatographic (LC) method for determination of sulfamethazine (SMZ) residues in raw milk that were previously frozen. The milk is extracted with chloroform, the chloroform is evaporated, and the residue is suspended in hexane and extracted with 0.1 M KH2P04 (PDP) solution. The PDP extract is analyzed by LC on a C18 column with methanol–0.1M PDP (30 + 70) as mobile phase. Individual laboratories were instructed to analyze 5 replicates each of control milk, fortified control milk at 2 levels, and 3 blind samples. Blind samples included raw milk fortified with SMZ at 10 and 20 ppb and 1 sample containing SMZ residue from a dosed cow. For blind fortified samples containing 10 ppb SMZ, average recovery and relative standard deviations for repeatability and reproducibility (RSDr and RSRR) based on the results from 6 of the 7 participating laboratories were 8.21 ppb, 7.16%, and 23.16%, respectively. Similar data, including results from a seventh participant who reported instrumental problems but was not eliminated by the Dixon outlier test, were 9.13 ppb, 8.38%, and 31.94%, respectively. These results demonstrate that the method is suitable for the determination of SMZ residues in milk at 10 ppb and above. The method was adopted first action by AOAC International.
Rapid Determination of Supplemental Vitamin E Acetate in Feed Premixes by Capillary Gas Chromatography
Authors: Kmostak Svatomir , Kurtz David A 
Published: February 2020

Abstract
A rapid capillary gas chromatographic method was developed for determination of supplemental cc-tocopherol acetate (containing and verified at 50–5000 mg/kg feed) in various kinds of feed premixes. The method is based on simple n-hexane extraction of feed samples pretreated with a solution of acetic acid in ether for matrix breakdown followed by column cleanup on deactivated alumina to eliminate background interference. Fused silica chromatography is completed in 3 min. The withinday precision expressed as the relative standard deviation for recovery examples was 3.4,2.9, and 4.0% for high, medium, and low concentrated feed premixes, respectively; extraction recovery was 99–110%. The storage stabilities of standards and feed premix preparations were found to be excellent up to 3 months and up to 60° C.
Liquid Chromatographic Method for the Determination of Nine Phenolic Antioxidants in Butter Oil: Collaborative Study
Authors: Denis Page B ,   Collaborators:, Carl M , Daniels D , Dominguez F , Essers M L , Hollman P C H , Rico I Ibanez , Ito Y , Kaiser R , Kempf U , Kittle C , Lacroix G , Lombaert G , Miyata M , Pettipas R , Pocifia R , Willis C , Wong L 
Published: February 2020

Abstract
Ten laboratories collaboratively studied a liquid chromatographic (LC) method for the determination of propyl, octyl, and dodecyl gallate (PG, OG, and DG, respectively), 2,4,5-trihydroxybutyrophenone (THBP), ferf-butylhydroquinone (TBHQ), nordihydroguaiaretic acid (NDGA), 2- and 3-tert-butyl-4- hydroxyanisole (BHA), 2,6-di-ferf-butyl-4-hydroxymethylphenol (lonox-100), and 3,5-di-terf-butyl-4- hydroxytoluene (BHT) in butter oil. The 10 samples analyzed were spiked in matched pairs at about 100,50, and 10 μg/g. In the method studied, antioxidants are extracted as in AOAC LC method 983.15, but different LC eluants are used to separate the 9 antioxidants. Results from 1 laboratory were rejected as not valid and were not included in any calculations. For the remaining 9 laboratories, the overall mean recoveries for PG, THBP, TBHQ, NDGA, BHA, OG, lonox, BHT, and DG were 100.9, 97.8,103.4,95.4, 97.4,93.6,95.5,79.0, and 96.2%, respectively. The overall reproducibility relative standard deviations were 8.55,17.4,25.6,14.5,6.60, 9.64,10.8,11.4, and 7.35%, respectively. The method was adopted first action by AOAC International as a modification of AOAC method 983.15.
Comparison of Kjeldahl Method for Determination of Crude Protein in Cereal Grains and Oilseeds with Generic Combustion Method: Collaborative Study
Authors: Bicsak Ronald C ,   Collaborators:, Boles R , Cathey R , Collins V , Hannasious K , Haselhorst J , Henderson L , Jann L , Meschi L , Molloy R , Stillions M , Swanson K , Tate D , Webb J , Wilkins G 
Published: February 2020

Abstract
Seven laboratories participated in a collaborative study to extend the applicability of the AOAC generic combustion method for determination of crude protein in animal feed (990.03) to include determination in cereal grains and oilseeds. In the study, method 990.03 was compared with the AOAC mercury catalyst Kjeldahl method for determination of protein in grains (979.09) and crude protein in animal feed (954.01). The study also evaluated the effect on the results of fineness of grind. For determination of crude protein in grains and oilseeds by the combustion method, standard deviations for repeatability and reproducibility ranged from 0.10 to 0.37 and from 0.25 to 0.54, respectively, and relative standard deviations for repeatability and reproducibility ranged from 0.77 to 2.57% and from 1.24 to 3.15%, respectively. The combustion method was adopted first action by AOAC International for determination of crude protein in cereal grains and oilseeds containing 0.2- 20% nitrogen.
Total Bacterial Count in Raw Milk Using the BactoScan 8000
Authors: Rodrίguez-Otero J L , Hermtoa M , Cepeda A , Franco C 
Published: February 2020

Abstract
The BactoScan 8000 (Foss Electric) automatically performs a total count of bacteria in raw milk. It was designed for fast, repeatable counting. The apparatus counts the individual bacteria (IBC) instead of colony forming units (CFU). IBC provides more information on the state of milk hygiene than the CFU count. The repeatability, sr, was 0.033 log (IBC/μL), which is equivalent to a coefficient of variation of 7.9% (IBC/μL). The carryover, which is the contamination one sample imposes on the next, was 0.19%. The BactoScan 8000 was calibrated against the reference method of counting colonies on a Petri dish. The correlation coefficient for 429 milk samples was r= 0.88, and the standard deviation of the residuals, syx, was 0.259. The detection limit was 15 CFU/μL. We recommend establishing a system of payment to farmers based on the bacteriological quality of their milk as determined by the BactoScan 8000. Because results are obtained in IBC/μL, analytical differences resulting from conversion to CFU/|iL are eliminated.
Evaluation and Application of a Bioluminescent Bacterial Genotoxicity Test
Authors: Sun Thomas S C , Stahr Henry M 
Published: February 2020

Abstract
The Mutatox® test (commercial name for the bioluminescent bacterial genotoxicity test) has been shown to be a good alternative to the Ames test. The test uses dark mutants of luminous bacteria (Vibrio fischeri) and determines the ability of various genotoxic agents to restore the luminescence by inducing mutation. It provides a rapid screening test which can be used to assay the genotoxicity of large numbers of pure and complex compounds. The test is completed in 1 day, and by serially diluting the compound, dose response data plus toxicity data can be generated for a number of samples simultaneously. For the direct assay (without exogenous metabolic activation), the positive controls selected were 3,6-diaminoacridine (proflavine) and N-methyl-N-nitro-nitrosoguanidine. For the S-9 assay, which incorporated the microsome fraction (S-9) from rat liver as an exogenous metabolic activation system, the positive controls selected were aflatoxin B1 and benzo(a)pyrene. This study also indicated that methyl-imidazo-quinoline and tryptophan pyrolysates were genotoxic in the presence of S-9 activation, aflatoxin B1 epoxide and fumonisin B1 showed direct genotoxic activity, and aflatoxin B2 and ochratoxin A were not genotoxic.
Determination of Selenium in Feeds, Premixes, Supplements, and Injectable Solutions by Hydride-Generated Inductively Coupled Plasma Atomic Emission Spectrometry
Authors: Anderson Kim A , Isaacs Brandon 
Published: February 2020

Abstract
A simple method is described for the determination of 0.01-30 000 μg selenium/g sample. Selenium is present in feed supplements, premixes, mineral mixes, and injectable solution as either selenite or selenate. High concentrations of other common minerals present in these supplements are tolerated by the method. The samples are initially digested by heating with nitric acid and then boiled in a mixture of sulfuric and perchloric acids to convert all selenium species to selenate. The selenate is reduced to selenite, Se (IV), with hydrochloric acid at 95°C. The selenite in turn is then reduced by acidic sodium borohydride to hydrogen selenide, which is measured by hydride-generated inductively coupled plasma atomic emission spectrometry at 196.026 nm. The instrument detection limit for this method is 0.0005 μg Se/g sample.