bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas-Liquid Chromatographic Determination of Pyrethrins and Piperonyl Butoxide: Collaborative Study
Authors: Meinen Vernon J , Kassera Dean C ,   Collaborators:, Anderson P , Audino J B , Bennett B R , Carlson D J , Chang W L , Conigliaro P J , Earls P , Garbrecht T P , Gentry G M , Guzman B , Hayes E H , Hodgins W E , Jorengby D , Korger P D , Launer J E , Martin R , Nielson P , Tannahill G O , Torma L , Vaught C , Vonnahme T
Published: February 2020

A gas-liquid chromatographic method is described for the quantitative determination of pyrethrins and piperonyl butoxide in various formulations. The samples are diluted in acetone and analyzed by gas chromatography, with a flame ionization detector and a column packed with OV-101 or OV-1 on Chromosorb W (HP). The method was collaboratively studied with technical piperonyl butoxide and 3 pyrethrin-piperonyl butoxide formulations. The coefficients of variation for piperonyl butoxide ranged from 1.36 to 3.41% for the 5 samples. For pyrethrins in 3 formulations, the coefficients of variation were 2.20, 4.73, and 2.22%. An examination of the t-values indicated little or no contribution to systematic error, with the exception of one formulation. The method has been adopted official first action.
Ceramic Fiber for Replacement of Asbestos as Filter Aid in Crude Fiber Determination: Collaborative Study
Authors: Holst David O ,   Collaborators:, Cashman C J , DeCann J , Komenda L , Lewis S , Psotka J J , Rigler J R , Salah D M , Smallidge R L , Tinsley G , Vick R
Published: February 2020

A commercially available ceramic fiber has been tested collaboratively for replacement of asbestos as a filter aid. Eleven laboratories participated, using 10 samples with crude fiber content from 1 to 40%, one sample high in starch, and 2 samples high in protein. The following data were obtained for asbestos and the proposed ceramic fiber, respectively, in AOAC method 7.061-7.065: sd = 0.52 and 0.62; sr = 0.22 and 0.28; sb = 0.47 and 0.55; average range be- tween independent analyses = 0.18 and 0.24% crude fiber; and average maximum spread among laboratories = 1.65 and 2.42% crude fiber. The blank value for ceramic fiber varied considerably among laboratories, necessitating more precise control over size or weight of ceramic filter pad. A ceramic filter pad or-material of 1.5-2.0 g dry weight will give a uniform blank of approximately 2 mg. Ceramic fiber is suit- able for replacing asbestos and is not known to be carcinogenic. Replacement of asbestos in 7.061-7.065 with ceramic fiber has been adopted official first action.
Screening Procedure for Uric Acid as Indicator of Infestation in Spices
Authors: Brown Susan M , Abbott Susan , Guarino Philip A
Published: February 2020

Uric acid levels in selected spice products were determined by using a glucose analyzer, modified and calibrated for uric acid. In the method, uricase is used to decompose the uric acid; the reaction is monitored with an oxygen-sensitive electrode. Uric acid levels correlated with infestation as determined by AOAC methods.
Time Required to Achieve Homogeneity in Swine Feed Mixtures
Authors: Ikeda George J , Miller Eugene , King Mark T , Perfetti Gracia A , Warner Charles R , Adamo Nicholas C , Sporn Eugene M
Published: February 2020

FD&C Red No. 3 was mixed with 20 kg pig feed to give a concentration of 0.1%. A mixing time of 30 min was sufficient to achieve homogeneity for this mixture. For larger amounts or more flocculent types of additives, a longer time may be required. Ammoniated glycyrrhizin was mixed with 8 separate batches of pig feed at a concentration of 1%; 1 h was sufficient mixing time.
Analytical Methods for Foods in the Next Decade
Authors: Tanner James T
Published: February 2020

With each passing decade new problems arise for the regulatory analytical chemist. The push for low detection limits from percent to parts per million to parts per billion brought the need for new and improved analytical instrumentation followed by questions of reliability at such low values. Each question has been met by new instruments or techniques and critical studies. The question for the 1980s is not how to achieve low detection limits but how to reliably and rapidly perform analyses at low values. During the 1960s the emphasis was on the single component/element techniques. We seem now to be entering the computer-controlled era. In each analytical specialty, computer-controlled instruments are offered which greatly aid the analyst in producing an accurate, reliable analysis in a shorter time. The advantage of larger numbers of analyses per unit of time with, in some cases, reduced personnel are not to be overlooked in this age of economy. To the AOAC collaborative study this means a reduction in the number of laboratories who can participate. It also means greater standardization of methodology, and the chemist’s laboratory ability becomes less of a factor in producing reliable analyses. Specific analytical examples are discussed to illustrate the trend for the 1980s.
Malt Beverages and Brewing Materials: Screening and Confirmatory Methods for Nitrosamines in Beer
Authors: Cutaia Anthony J
Published: February 2020

Screening methods for nitrosamines in beer were studied by 15 collaborators. Collaborators studied 4 extraction techniques and 2 calculation procedures. All methods showed acceptable recoveries and no significant differences between methods. Based on accuracy, simplicity and speed, the Celite extraction with internal standard calculation is recommended. Fifteen collaborators also studied a distillation confirmatory method compared with a direct extraction with dichloromethane. Because the former gives an extract more suitable for mass spectrometric confirmation of nitrosamines, it is the recommended reference method. The screening and confirmatory methods have been adopted official first action.
Procedures for Measuring Accuracy and Sensitivity of Immunochemical Pregnancy Test Kits
Authors: Gill Lillian J
Published: February 2020

Analytical procedures were used to measure the accuracy and sensitivity of immunochemical pregnancy test kits. Performances of all currently marketed hemagglutination inhibition, latex agglutination inhibition, and direct latex agglutination pregnancy kits were evaluated.
Mass Spectrometric 13C/12C Determinations to Detect High Fructose Corn Syrup in Orange Juice: Collaborative Study
Authors: Doner Landis W , Bills Donald D ,   Collaborators:, Carro O , Drimmie R , Fritz P , Gearing J N , Marcel C Hillaire , Parker P L , Reeseman R M , Smith B N , Ziegler H
Published: February 2020

The 13C/12C ratios in orange juice are sufficiently uniform and different from those in high fructose corn syrup (HFCS) so that the addition of HFCS to orange juice can be detected. HFCS averages –9.7‰ (parts per thousand) δ13C, orange juice averages —24.5‰, and mixtures of HFCS and orange juice possess intermediate values. One pure orange juice and 4 orange juice-HFCS mixtures containing from 25 to 70% orange juice were properly classified by 7 collaborators. Samples with δ13C values less negative than — 22.1‰, 4 standard deviations from the mean of pure juices, can, with a high degree of confidence, be classified as adulterated. Samples with values more negative than —22.1‰ must be considered unadulterated with HFCS, because pure orange juices possess a range of δ13C values. The 13C/12C mass spectrometric method was adopted official first action for detecting HFCS in orange juice.
Graphite Furnace Atomic Absorption Spectrophotometric Determination of 4-Hydroxy-3-Nitrobenzenearsonic Acid, Other Organic Arsenicals, and Inorganic Arsenic in Finished Animal Feed
Authors: George Glenn M , Frahm Larry J , McDonnell J Patrick
Published: February 2020

4-Hydroxy-3-nitrobenzenearsonic acid (roxarsone) is administered in animal feed as a growth stimulant over a concentration range of 25-50 ppm. The drug is extracted from 5 g feed with 200 mL aqueous 1.0% ammonium carbonate solution and 5 min of mechanical shaking. Undissolved feed particles are allowed to settle and 1.0 mL aliquot of extract is diluted with 9.0 mL 15% methanol solution. This solution is subjected to sample atomization by a graphite furnace and arsenic detection by atomic absorption spectrophotometry (AAS). Roxarsone recovery from nonmedicated commercial feed fortified at 25 ppm was 103.6% with a relative standard deviation (RSD) of 4.0%. Recovery for 50 ppm fortification was 104.5% (RSD 4.3%). Roxarsone assay results by furnace AAS were compared with results by the current AOAC spectrophotometric method and the AOAC total arsenic method. Results by the 3 methods compare well. The procedure was also used to determine other organic arsenicals and inorganic arsenic in laboratory-fortified feed samples; these recoveries were essentially theoretical.
Liquid Chromatographic Identification of cis- and trans- Cinnamoylcocaine in Illicit Cocaine
Authors: Noggle F Taylor , Clark C Randall
Published: February 2020

A liquid chromatographic procedure is described for the analysis of illicit cocaine samples. The isomeric cis- and trans-cinnamoylcocaines are separated from cocaine, benzoylecgonine, and benzoic acid in a reverse phase isocratic system with dual wavelength detection at 254 and 280 nm. Specific identification of cocaine and the cinnamoylcocaines is accomplished by ultraviolet spectrophotometry and mass spectrometry of the chromatographic effluent.
Analytical Methods Used by Industry for Lead in Infant Formula
Authors: Miles J Preston
Published: February 2020

The lead content of liquid infant products has been a prime focus of regulatory, industrial, and private analysts for some time. The principal source of Pb in these products is the solder used in 3-piece can manufacture. Voluntary surveys by the Infant Formula Council member companies from 1978 to present show that even low 1978 levels have been significantly reduced. Two procedures, anodic stripping voltammetry and electrothermal atomization (graphite furnace and carbon rod) atomic absorption spectrophotometry, are currently used by industry analysts. The results of 2 comparison studies provide a means of estimating the reliability of the procedures. Results of thousands of trace Pb determinations have demonstrated that steps to ensure the validity of results must be integrated into the entire analytical scheme. Quality control practices are described. Control of the laboratory environment is essential for ultimate sensitivity, and the design and performance of a trace metals analysis facility are discussed.
Induction of Aryl Hydrocarbon Hydroxylase Activity in Cell Cultures by Aroclors, Residues from Yusho Oil Samples, and Polychlorinated Biphenyl Residues from Fish Samples
Authors: Trotter William J , Young Susan J V , Casterline James L , Bradlaw June A , Kamps Laverne R
Published: February 2020

Four Aroclor reference materials, cleaned-up extracts of 2 Yusho rice oil samples, and cleaned-up extracts of 3 fish samples containing polychlorinated biphenyl (PCB) residues were tested for their ability to induce aryl hydrocarbon hydroxylase (AHH) activity in a rat hepatoma cell line. Before the AHH bioassay, the samples were fractionated by a Florisil column chromatographic method. All samples contained about 1000 fig PCBs before Florisil column chromatography. The first Florisil eluate contains about 95% of the PCBs in a typical Aroclor, and the second contains the more polar or adsorbent PCB congeners. In this study, the first eluate for all samples produced no quantifiable AHH activity. The second Florisil eluates of both Aroclors 1242 and 1248 induced AHH activity, whereas these eluates of both Aroclors 1254 and 1260 did not. This difference may be due to the presence in Aroclors 1242 and 1248 of 3,3',4,4'-tetrachlorobiphenyl, which has not been detected in Aroclors 1254 and 1260. The second Florisil eluates of the fish samples induced somewhat less AHH activity than did Aroclor 1242 or 1248. The second Florisil eluates of the PCB residues from Yusho rice oil samples induced significantly greater AHH activity than these eluates of either Aroclor 1242 or 1248, perhaps because Yusho rice oil contains a greater amount of polychlorinated dibenzofurans than PCB commercial mixtures on a PCB equivalent basis.
Spectrophotometric Determination of Ephedrine Hydrochloride and Phenylephrine Hydrochloride
Authors: Amer Mohamed M , Taha Aly M , El-Shabouri Salwa R , Khashaba Pakinaz Y
Published: February 2020

A method is described for quantitative determination of the sympathomimetic amines ephedrine HCl and phenylephrine HCl. The method is based on the interaction of N-alkylvinylamine formed from the condensation of the free secondary amine group and acetaldehyde with chloranil to give a vinylaminosubstituted quinone. The colored product for ephedrine HCl and phenylephrine HCl exhibits 2 maximas at about 320 and 680 nm. All variables were studied to optimize reaction conditions. The relationship between absorbance and concentration was linear within 1-25 μg/mL under the conditions studied for both drugs at both wavelengths. The method has been applied to the analysis of some pharmaceutical formulations including tablets and eye drops with good recoveries (98.75-100.4%).
Stability of Individual Natural Pyrethrins in Solution after Separation by Preparative High Performance Liquid Chromatography
Authors: Dickinson Charlotte M
Published: February 2020

The 6 components of natural pyrethrum (jasmolins I and II, cinerins I and II, and pyrethrins I and II) were separated by preparative high performance liquid chromatography (HPLC) from a standard pyrethrum extract. Each component was then isolated and weighed, and its identity was established by mass spectrometry. Dilute solutions of each compound were prepared incorporating an internal standard and stored under the test conditions: Solutions were placed in clear-glass vials covered with aluminum foil to protect the contents from light, and one vial of each compound was stored at —18, —5,23, and 37°C. One set of vials not covered with foil was stored at room temperature under a fluorescent desk lamp burning continuously for the 2 month test. The solutions were analyzed periodically by gas chromatography, and all 6 compounds were stable during the test period if protected from light. Temperatures up to 37°C had no effect on stability. It was concluded that standard solutions of individual pyrethrum compounds could be prepared and stored for use in the quantitative analysis of pyrethrum formulations. During studies of the effect of light on the solutions, photoproducts of all 6 compounds were formed. The photoproducts of pyrethrins I and II were isolated and identified, in each case, as the (E)-isomer of the parent compound. Nuclear magnetic resonance spectra (300 MHz) of these new compounds are presented.
Determination of Lead and Cadmium in Foods by Anodic Stripping Voltammetry: II. Collaborative Study
Authors: Capar Stephen G , Gajan Raymond J , Madzsar Elizabeth , Albert Richard H , Sanders Marion , Zyren John ,   Collaborators:, Baetz R , Beavin P , Davis P H , Faul K , Gardner W T , Hansen C , Hopefl R , Hostetter J O , Klopp T , Loges M D , Moffitt R , Newton C B , Newton R T , Paillard G , Panaro K , Satzger R D , Schwartz D , Snider P , Suddendorf R F , Tepedino N , Williams J
Published: February 2020

A dry ash anodic stripping voltammetric method for determining lead and cadmium in foods was collaboratively studied by 20 laboratories. The food commodities studied were strained green beans, beef (baby food), fish (mackerel), infant formula (milk base), apple juice, and cereal (wheat farina). Each collaborator analyzed 3 commodities, each consisting of 2 duplicate lead and cadmium fortification levels, for a total of 4 samples for each commodity. The low fortification levels ranged from 0.03 to 0.08 ppm for cadmium and from 0.05 to 0.15 ppm for lead. The high fortification levels ranged from 0.12 to 0.28 ppm for cadmium and from 0.24 to 0.45 ppm for lead. Each commodity was analyzed by 10 collaborators. The average overall reproducibilities of the low level fortifications were 247c for lead and 21% for cadmium; for the high level fortifications, average overall reproducibilities were 18% for lead and 16% for cadmium. The average accuracies of the collaborative results as measured by comparison to reference values were 96 and 97% for cadmium and lead, respectively. This method has been adopted official first action.
Precautions in Ashing Techniques for Lead Determination in Food
Authors: Thornburg Wayne
Published: February 2020

In determining lead in food, the matrix must be destroyed before quantitation by atomic absorption spectrophotometry. Wet or dry ashing techniques are generally used. Dry ashing assisted by ultrapure H2SO4 or K2SO4 has the advantages of safety, low reagent blanks, rapidity, and good recoveries of added lead. These techniques are also less laborintensive than wet ashing.
High Performance Liquid Chromatographic Determination of Subsidiary Colors in FD&C Red No. 3
Authors: Calvey Robert J , Goldberg Allen L
Published: February 2020

Two rapid, sensitive, reproducible methods that use a Zorbax C-8 reverse phase column and high performance liquid chromatography are described for the determination of the subsidiary colors in FD&C Red No. 3. With the first method, 8 subsidiary colors (fluorescein, 2'-iodofluorescein, 4'-iodofluorescein, 2',5'-diiodofluorescein, 2',7'-diiodofluorescein, 4',- 5'-diiodofluorescein, 2',4',7'-triiodofluorescein, and 2',4',5'-triiodofluorescein) are eluted in a reproducible pattern by increasing the organic nature of a buffered mobile phase. Method 1 is capable of quantitating all the subsidiary colors except 4'-iodofluorescein and 4',5'-diiodofluorescein. If these 2 subsidiary colors are seen, the sample must be run again by method 2, which uses a different program and solvent system to quantitate them. The average recoveries for the 6 subsidiary colors quantitatively determined in FD&C Red No. 3 by method 1 ranged from 96 to 98%. The average recoveries for 4'-iodofluorescein and 4',5'-diiodofluorescein, quantitatively determined in FD&C Red No. 3 by method 2, were 101 and 103%, respectively. The amounts of the 6 subsidiary colors recovered by method 1 were 0.04-7.4% by weight of the total sample. The amounts of the 2 subsidiary colors recovered by method 2 were 0.13-2.6% by weight of the total sample.
Extraction of Light Filth from Rice Flours, Extruded Rice Products, and Rice Paper: Collaborative Study
Authors: Dent Russell G ,   Collaborators:, Bryce J R , Cox B C , Hughes D D , Karpus J T , Nagy J , Vail D J
Published: February 2020

Two new methods were developed for the extraction of rodent hairs and insect fragments from rice products: one for rice flour and one for extruded rice products and rice paper. A 100 g sample of rice flour was extracted with mineral oil-40% isopropanol, followed by a water phase as needed for additional cycles. For extruded rice products and rice paper, a 225 g sample of each was initially extracted as above, followed by a single extraction with mineral oil-20% isopropanol. Both methods used an acid hydrolysis pretreatment followed by wet sieving and a percolator extraction. Average rodent hair recoveries were 77.8% for rice flour and 82.2% for extruded rice products and rice paper. Average insect fragment recoveries were 89.6% for rice flour and 91.9% for extruded rice products and rice paper. Both methods were adopted official first action.
Howard Mold Count of Fruit Nectars, Purees, and Pastes: Collaborative Study
Authors: Cichowicz Stanley M , Bandler Ruth ,   Collaborators:, Bandler R , Dzidowski G , Floyd D , Galacci R , Kaminski J , McNerney F
Published: February 2020

The various mold count methods for nectars, purees, and pastes make no adjustment for concentration of the pulped liquid. Thus, mold counts of different forms of the same product (e.g., guava nectar, puree, or paste) or of the same product from different manufacturers cannot be compared. A method was developed in which the product is centrifuged under standardized conditions, then diluted to a standard pellet-to-final-volume ratio. Because variations in the concentration of fruit or vegetable tissue are corrected, comparisons of mold counts are possible. The method was adopted official first action.
Modified Gas-Liquid Chromatographic Method for Determination of Compound 1080 (Sodium Fluoroacetate)
Authors: Okuno Iwao , Meeker Dennis L , Felton Robert R
Published: February 2020

A method capable of determining 0.1 ppm 1080 (sodium fluoroacetate) in 1 g animal tissue was developed. It involves extraction of 1080 from the sample with acetone-water, and then evaporation of the acetone followed by extraction of 1080 as fluoroacetic acid from water with ethyl acetate. Ethyl acetate is removed by volatilization from fluoroacetic acid which is retained as the triethanolammonium fluoroacetate salt. Fluoroacetic acid is subsequently derivatized with α-bromo-2,3,4,5,6-pentafluorotoluene and quantitated by gas-liquid chromatography with an electron capture detector. The method is rapid and requires no special apparatus or equipment and no more than 12 ml of any one solvent. Recoveries of 1080 from tissue samples fortified with 0.1-100 ppm averaged about 85%.
Cylinder Plate Assay for Determining Bacitracin in Premix Feeds and Finished Feeds: Collaborative Study
Authors: Gallagher John B , Knotts Linda L ,   Collaborators:, Brennecke D , Bryant H H , Carter G G , Harpster C , Hasselberger M L , Jones K D , Knotts L L , Martin J , Olsen J I , Ragheb H S , Stouffer N , Winely C
Published: February 2020

A cylinder plate assay procedure was studied by 10 laboratories. For premix feeds, 3 samples of bacitracin methylene disalicylic acid and 3 samples of bacitracin zinc premixes covering the range of 10 to 50 g/lb were used. The repeatability standard deviation was 2.11, and the reproducibility standard deviation was 2.13. The average recovery of bacitracin was 101.5%. The method has been adopted official first action. For finished feeds, 6 samples of bacitracin methylene disalicylic acid and 6 samples of bacitracin zinc covering the range of 10 to 800 g/ton were used in the study. The procedure included a sample cleanup step using disposable reverse phase columns. This step appears to be the cause of the poor results reported by most collaborators. Continued study is needed to develop an acceptable method for finished feeds.
High Pressure Liquid Chromatographic Determination of Bacitracin in Premix Feeds and Finished Feeds: Collaborative Study
Authors: Gallagher John B , Love Paul W , Knotts Linda L ,   Collaborators:, Allred M , Hasselberger M L , Johnson A , Louie D , Love P W , Quick F , Sharley D , Smallidge R L , Thorpe V A , Williams W H
Published: February 2020

A liquid chromatographic technique for the determination of bacitracin in finished feeds and premix feeds consists of an isocratic reverse phase, ion-suppressed technique. The chromatography can be completed in less than 25 min. In a collaborative study involving 9 laboratories and 3 samples of bacitracin methylene disalicylic acid and 3 samples of bacitracin zinc premixes covering the range of 10-50 g/lb, the repeatability standard deviation was 0.55, and the reproducibility standard deviation was 1.35. The average recovery of the bacitracin was 102.0%. The method has been adopted official first action for bacitracin in premix feeds.
Rapid Screening Assay for Beta-Lactam Antibiotics in Milk: Collaborative Study
Authors: Charm Stanley E , Chi Ruey K ,   Collaborators:, Bryant H , Carson M , Chu W S , Fraser A , Gruetmacher C F , Hostetler O , Jones K , Kenell L , McQuattie R , O’Neill C , Richwine D , Salimbene J , Smith S , Wallace C , Yokote R
Published: February 2020

A 15 min assay for beta-lactam antibiotics has been used by dairies for several years as a screening procedure for testing milk tankers before they unload. The test is based on a competition between 14C-penicillin and beta-lactam antibiotics in the milk samples for sites on a microbial cell wall that specifically binds beta-lactam. In a collaborative study, 11 laboratories correctly distinguished 10 coded zero penicillin G samples and 10 coded 0.01 IU/mL samples. The proposed test is qualitative, positive or negative, and can detect the presence of beta-lactam antibiotics at the 0.01 IU/mL level. The control point for determining positive or negative samples is more than 3 standard deviations from the mean of 0.01 IU/mL. The method has been adopted official first action.
Qualitative Ampule and Multitest for Beta-Lactam Residues in Fluid Milk Products: Collaborative Study
Authors: Kelley Wesley N ,   Collaborators:, Andrews J , Appelt A W , Barber R , Barnett J , Barta L , Bass B , Bone E , Breske L , Bryant H H , Case R A , Coleman K , Cyr R , Dewald S K , Dombroski P , Dubs E L , Feldstein F F , Gay B E , Ginn R E , Gottomoller C , Grant H , Heady J , Hills D G , Jerrod L , Jones K , Kaus C , Lane A L , Leslie J E , Marchette D , Misup M , Morris L , Mullen R N , Payton C , Schmidt J , Schneider D , Share R , Sierck M , Wehr H M , Williams R
Published: February 2020

A collaborative study was performed on a rapid Bacillus stearothermophilus agar diffusion ampule method to detect low levels of penicillin G in 7 types of fluid milk products. A multitest technique for processing a large number of samples simultaneously was also studied. Slight modifications were made in the original method to establish more uniformity and to eliminate doubtful responses by specifying a confirmation procedure. Twenty samples spiked with penicillin G (0.000 to 0.008 IU/mL) and tetracycline hydrochloride were frozen and sent to 20 laboratories in the ampule test, and 16 laboratories in the multitest. Each analyst was asked to do a screening run and a confirmation run. Results were reported by color reaction and also as positive or negative for β-lactam inhibitors. The concentrations (penicillin G) where percent positive results equal 100 or not significantly less than 100 (α = 0.05) ranged from 0.005 to 0.007 IU/mi in the ampule test and from 0.004 to 0.007 IU/mL in the multitest. Both techniques have been adopted official first action.
Analysis of Fat-Soluble Vitamins. XXVII. High Performance Liquid Chromatographic arid Gas-Liquid Chromatographic Determination of Vitamin D in Fortified Milk and Milkpowder: Collaborative Study
Authors: De Vries Ellen J , Borsje Ben ,   Collaborators:, Ameika L , Baillies N T , Delano N , de Vries E J , Egtberts W , Fischer G A , George E , Gillingham P J , Hancock W , Knapstein H , Monard A , Muniz J F , Nedelkovitch G , Nicolaux G , Oelrich E , Phillips G F , Pollman R , Richter E F , Scholz H , Schwarze P , Steuerle H , Thiele U , Thorpe V A , Weaver C , Wehr H M
Published: February 2020

A collaborative study of the high performance liquid chromatographic (HPLC) method for vitamin D in fortified milkpowder (skimmed and whole milk) and a milkpowder preparation was carried out on 182 samples distributed to 26 laboratories. Thirteen laboratories submitted results. The level of vitamin D was 2-7IU vitamin D3/g milkpowder. All samples also contained vitamin A. Three laboratories were excluded from the statistical evaluation because of incomplete results or deviation from the analytical procedure. Other laboratories reported acceptable results. At the same time, 63 samples were distributed to 9 laboratories which used a gas-liquid chromatographic method for determining vitamin D in milkpowder. Only one laboratory reported results. The HPLC method has been adopted official first action.
SIREN: Data Base Approach to Scientific Information Handling in the Bureau of Foods, Food and Drug Administration
Authors: Brindza George A , Mccann Adriana
Published: February 2020

The Bureau of Foods has developed the Scientific Information Retrieval and Exchange Network (SIREN) to provide a modern method of records management and an automated cross-referenced subject index for accurate and comprehensive information retrieval. Authorized Bureau personnel may access SIREN's 200 000 references directly on distributed, interactive on-line terminals or indirectly through searches conducted by the SIREN Document Control Center.
Comparison of Three Methods for Determination of Crude Protein in Meat: Collaborative Study
Authors: Suhre Francis B , Corrao Paul A , Glover Angeline , Malanoski Anthony J ,   Collaborators:, Cannon L D , Dummett T , Funk R , Glover A , Heavner G , Hoover R L , Latham M , Long F L , Martini J H , McGee K , Morris W C , Oberste W , Okamoto M , Pakrasi B , Pasquarella P J , Reiser J , Sorensen L , Lovestrand J , Taylor M , Trombella B , Warden S R , Wayo C , Wiebke R , Woods W
Published: February 2020

A study was designed to compare the Kjel-Foss automated macro-Kjeldahl method and a block digestion- steam distillation method. The official AOAC Kjeldahl method was used as a reference procedure. Six products with a crude protein range of 10-30% were analyzed by 23 laboratories. Five laboratories analyzed the samples by the official AOAC method, 8 laboratories used the automated Kjel-Foss method, and 11 laboratories used the block digestion with steam distillation method. Standard deviations for each product and each method for both repeatability and reproducibility are given. The block digestion- steam distillation method has been adopted official first action.
Determination of Chloride Concentration in Cheese: Collaborative Study
Authors: Poortvliet L J , Horwitz William
Published: February 2020

Three samples of ground Gouda cheese containing 1-2% chloride were analyzed by 7 laboratories by 3 methods: oxidation with KMnO4 and HNO3 followed by a Volhard titration; the same but with filtering off the precipitated AgCl before back-titration; and the general potentiometric method without ashing or oxidation. The data were analyzed by ISO statistics (ISO-R 5725) and by AOAC statistics (Youden), the major differences being the rejection of different values as outliers and in the statement of the precision parameters. The within-laboratory variability (repeatability) is comparable for all 3 methods; the between-laboratory variability (reproducibility) is comparable for the Volhard method with filtration and the potentiometric methods, but the direct Volhard method is inferior. Because of its generality and simplicity, the potentiometric method has been adopted official first action; the Volhard method with filtration has been reinstated official final action as an alternative.
Determination and Thin Layer Chromatographic Confirmation of Identity of Aflatoxins B1 and M1 in Artificially Contaminated Beef Livers: Collaborative Study
Authors: Stubblefield Robert D , Kwolek William F , Stoloff Leonard ,   Collaborators:, Fremy J M , Greer J I , Juszkiewicz T , Kronert W , Meyer C J , Patterson D S P , Pulzhofer K , Richard J L , Saito Y , Schuller P L , Sizoo E A , Trucksess M W , Tuinstra L G M Th , van Egmond H P , Wilson D
Published: February 2020

An international collaborative study involving 13 laboratories was conducted to test methods for the determination and thin layer chromatographic (TLC) confirmation of identity of aflatoxins B1 and M1 in beef liver. For the determination, each collaborator furnished fresh or frozen beef liver. Samples were artificially contaminated by adding solutions containing various concentrations of aflatoxins B1 and M1 (0.032-0.69 ng/g). Two TLC confirmation methods were tested with extracts obtained from the determination. Two measurement methods using 2-dimensional TLC were evaluated. In the first, sample extracts were compared directly with B1 and M1 standards on TLC plates; in the second, internal standards plus sample extracts were compared with Bi and M1 standards on the plates. Average within-laboratory coefficients of variation (CV) for the direct method were 26% for B1 and 26% for M1 compared with 24 and 26%, respectively, for the internal standard method. The average between-laboratory CV values were 39% for Bi and 41% for M1 by the direct method and 36% for B1 and 39% for M1 by the internal standard method. Recoveries ranged from 64 to 90% for Bi and from 72 to 86% for M1. These data indicate that the more convenient direct method was sufficient, and internal standards were unnecessary. An analysis of variance was calculated from combined sample data to determine components of variance. The within-laboratory CV values were 27.0 and 32.3% for B1 and M1, respectively, and the between-laboratory CV values were 47.1 and 53.2%, respectively. Both TLC confirmation methods gave satisfactory results and have been adopted official first action, along with the determination method.
Spectrophotometric and Titrimetric Determination of Certain Adrenergic Drugs, Using Organic Brominating Agents
Authors: Walash Mohamed I , Ouf A Abou , Salem Fatma B
Published: February 2020

New oxidimetric titrants, bromamine T, dibromohydantoin, N-bromophthalimide, and N-bromosuccinimide, were applied to the determination of ephedrine.HCl, norephedrine.HCl, and methyldopa. Direct potentiometric and visual indicator titration methods as well as back-titration procedures have been developed for their determination. Oxidation of ephedrine and norephedrine produces benzaldehyde, which is extracted from pH 11.0 phosphate buffer with ether or hexane and determined spectrophotometrically at 242 nm. Beer’s law is obeyed in the concentration range from 0.2 to 2 mg ephedrine.HCl and from 0.15 to 1.9 mg norephedrine. HCl. Methyldopa is determined titrimetrically and spectrophotometrically. In addition, this drug acts as a self-indicator: Solutions change from colorless to red, which gradually disappears with continuous addition of brominating agent and shaking. Phosphate buffer is used to produce adrenochrome, characterized by its pink color which can be measured at 485 nm in a working range from 40 to 650 μg.
High Performance Liquid Chromatographic Analysis of Impurities and Degradation Products of Methoxychlor
Authors: West Paul R , Chaudhary Sunil K , Branton Graham R , Mitchell Reginald H
Published: February 2020

Both reverse and normal phase high performance liquid chromatographic techniques have been applied to the analysis of technical methoxychlor. Facile detection of high molecular weight components yields information that is complementary to the gas chromatographic analysis of the technical pesticide and environmentally altered samples.
The Infant Formula Industry, the Infant Formula Act of 1980, and Quality Control
Authors: Gelardi Robert C
Published: February 2020

Throughout the months following the discovery of the low-chloride problem in infant formula, the industry undertook independent and voluntary measures to ensure the compositional quality of formulas. Members of the Infant Formula Council reviewed industry procedures, practices, and policies, and submitted a detailed description of its quality control and clinical testing procedures to the Food and Drug Administration. New product concepts and product reformulation proposals are based on medical and nutritional findings, on changes in medical concepts for nutritional support, on availability of improved nutrient sources, or on improved ingredients or processing technologies. Quality control is maintained throughout the manufacturing process through inspection of raw materials, analysis of major and minor constituents, equipment and process controls, and continuous product monitoring. However, despite cooperation of the infant formula industry with FDA and Congress during the development of the infant formula bills, the proposed document was too rigid and did not take into account that manufacturing methods of a given manufacturer often vary for the same product, for different products, and on different production equipment. The statistical criteria established uneven and inconsistent requirements for various manufacturers. Congress did not forsee that the proposed regulatory procedures would significantly affect industry.
Limitations in Protection Afforded by Gloves in Laboratory Handling of Aflatoxins
Authors: Castegnaro Marcel , Van Egmond Hans P , Paulsch Walter E , Michelon Jocelyne
Published: February 2020

The permeability of latex and vinyl laboratory gloves by aflatoxins in chloroform or dimethyl sulfoxide (DMSO) has been investigated. Latex gloves provide good protection against permeation by aflatoxins in DMSO, but aflatoxins in chloroform permeate all types of laboratory gloves. If gloves are contaminated when aflatoxins in chloroform are handled, an immediate change of gloves is recommended.
Identification of Frozen, Cooked Shellfish Species by Agarose Isoelectric Focusing
Authors: Wiggin Kate , Krzynowek Judith
Published: February 2020

A modification of the AOAC official method for generic identification of cooked and frozen crabmeat was investigated in an experiment in which the cooked meats of a variety of shellfish were identified. The modification, substituting agarose for polyacrylamide as the gel medium, has many advantages over the official method, including ease of gel preparation, nontoxic reagents, and rapid focusing. Results indicate that the modified method is easier to use and that identifications of cooked shellfish species can be made as readily as with the current AOAC method.
Liquid Chromatographic Analysis of Samples Containing Cocaine, Local Anesthetics, and Other Amines
Authors: Noggle F Taylor , Clark C Randall
Published: February 2020

A liquid chromatographic procedure is described the for separation of cocaine, local anesthetics, and other amines often encountered in cocaine look-alike preparations. Amines such as ephedrine, pseudoephedrine, and phenylpropanolamine are identified following derivatization with phenylisothiocyanate. The isocratic, reverse phase method uses dual wavelength detection at 254 and 280 nm.
Gas-Liquid Chromatographic Method for Determining 1,4-Dioxane in Cosmetics
Authors: Black Donald B , Lawrence Robert C , Lovering Edward G , Watson James R
Published: February 2020

A gas-liquid chromatographic procedure has been developed for the quantitation of 1,4-dioxane in various cosmetic products including lotions, cleansers, skin creams, make-ups, and shampoos. The impurity is extracted into an aqueous phase followed by column cleanup to remove nonpolar interferents. 1,4-Dioxane is partitioned into toluene, passed through an extraction tube to remove water and other polar compounds including organic dyes, concentrated by adsorption onto silica, further purified by washing with dichloromethane, and eluted with acetonitrile for injection into the gas chromatograph. The mean recovery of 1,4-dioxane from 51 cosmetic products, determined by spiking, was 63%. The limit of detectability is about 0.5 ppm and the minimum quantifiable level is about 2 ppm. The identity of 1,4-dioxane is confirmed by mass spectrometry.
Elimination of Sodium Chloride Interference During High Pressure Liquid Chromatographic Determination of Sugars
Authors: Devries Jonathan W , Chang Henry L , Heroff John C , Johnson Kevin D
Published: February 2020

A method is described to eliminate the potential interference of sodium chloride found in some food samples, which occurs during high pressure liquid chromatographic (HPLC) analysis of sugars, using certain bonded aminopropyl columns. The column is tested, and if an interference is present, it is removed by washing the column with a solution of tetraethylenepentamine in mobile phase. HPLC separation and quantitation of the sugars are essentially the same as before washing; however, sodium chloride no longer interferes with any of the sugars being analyzed.
Problems in Collection of Representative Samples for Determination of Tributoxyethyl Phosphate in Potable Water
Authors: Lebel Guy L , Williams David T
Published: February 2020

Results of a brief investigation on tributoxyethyl phosphate in tap water are presented to illustrate the difficulties in obtaining representative samples and to alert analysts to the importance of designing suitable sampling protocols.
Presumptive Screening Test for Seminal Acid Phosphatase Using Sodium Thymolphthalein Monophosphate
Authors: Seiden Howard , Duncan George T
Published: February 2020

The use of sodium thymolphthalein monophosphate for presumptive seminal acid phosphatase testing is discussed. Recent evidence reveals that the dye (o-dianisidine) used in conjunction with α-naphthyl phosphate for seminal acid phosphatase testing is a carcinogenic hazard. Numerous tests for seminal acid phosphatase were conducted with swabs from sexual assault kits to compare both substrates. Results of tests using sodium thymolphthalein or α-naphthyl phosphate correlated exactly. Sodium thymolphthalein is an effective alternative for preliminary seminal fluid analysis because of its high degree of selectivity and stability, and because it eliminates the potential health hazard.
Reliability of Analyses for Indigenous Insect Fragments in Ground Paprika
Authors: Woodbury James E
Published: February 2020

Variation in cleanliness (light filth) determinations within and between laboratories for paprikas with indigenous insect fragments was significantly greater than previously reported for paprika with spiked insect fragments.
High Performance Liquid Chromatographic Determination of Selected Gas Phase Carbonyls in Tobacco Smoke
Authors: Manning Delmar L , Maskarinec Michael P , Jenkins Roger A , Marshall Amos H
Published: February 2020

Low molecular weight gas phase carbonyls in tobacco smoke are separated as 2,4-dinitrophenylhydrazones and determined by reverse phase high performance liquid chromatography. A trapping procedure is used whereby the gas phase carbonyls are reacted with the derivatizing reagent in a closed system. The deliveries of acetaldehyde and acrolein are compared with published data. In addition, propionaldehyde and acetone deliveries of selected cigarettes are reported.
Preparation and Characterization of Acid Dehydration Products of Aflatoxicol
Authors: Lau Hon P , Chu Fun S
Published: February 2020

Treatment of aflatoxicol with acid resulted in the formation of dehydrated derivatives with the 2,3 double bond either hydrated or unaffected. Chromatographic and physicochemical analyses of the purified derivatives revealed that hydration of the 2,3 double bond of aflatoxicol with simultaneous dehydration occurred when sulfuric acid was used. When a weaker acid such as chloroacetic acid was used, no hydration occurred, and 2 isomeric forms of the dehydrated aflatoxicol were obtained. Chicken embryo assay and the Ames test revealed that dehydrated aflatoxicols were much less toxic and mutagenic than aflatoxicol. A mechanism for the dehydration of aflatoxicol is proposed.
Rapid Thin Layer Chromatographic Determination of Zearalenone in Corn, Sorghum, and Wheat
Authors: Gimeno Alberto
Published: February 2020

Arapid method is described for determining zearalenone in corn, sorghum, and wheat. The myco-toxin is extracted with a mixture of acetonitrile and 4% KC1 in HC1. The extract is cleaned up with iso- octane, evaporated, and redissolved in chloroform. Zearalenone is separated by thin layer chromatography; identity is confirmed with various developing solvents and spray reagents. Zearalenone is then quantitated by the limit detection method. The minimum detectable concentration is 140-160 μg/kg when aluminum chloride solution is used as spray reagent, and 85-110 μg/kg when Fast Violet B salt is used as spray reagent
Extraction and Thin Layer Chromatography of Aflatoxin Bi in Mixed Feeds
Authors: Shannon Gail M , Shotwell Odette L , Kwolek William F
Published: February 2020

A method was developed for the determination of aflatoxin B1 in commercially prepared feeds. The method incorporates methylene chloride and citric acid solution extraction, cleanup on a small silica gel column, and thin layer chromatography for quantitation. Commercial turkey starter, catfish chow, medicated pig starter, broiler finisher, rabbit chow, horse feed, rat chow, and dog chow were investigated. The feeds were spiked with naturally contaminated corn at 4 different levels of aflatoxin B1 (16-130 μg/kg). Three assays were run on each of the 32 combinations of feed and levels of aflatoxin. Mean recoveries were 85.9-92.8% at levels of 16.5,32.9,65.8, and 131.6 μg/kg. The relative standard deviation per assay was 18.6%. This method is more rapid and less involved than most previously published methods for mixed feeds.
Derivation of Fluorometric Chlorophyll and Pheophytin Equations
Authors: Kollig Heinz P
Published: February 2020

Equations for calculation of chlorophyll a and pheophytin a by fluorometry have been cited in a number of publications. None of them, however, includes the derivation of the equations to substantiate their validity. The derivation is given here to let the user apply the equations with confidence.
High Pressure Liquid Chromatographic Determination of Carbadox and Pyrantel Tartrate in Swine Feed and Supplements
Authors: Lowie Dwight M , Teague Robert T , Quick Floyd E , Foster Clarence L
Published: February 2020

A rapid yet reliable procedure for the simultaneous extraction and assay of carbadox and pyrantel tartrate is described. The feed is extracted with water-acetonitrile-methanol and cleaned up on a short alumina column. The eluant is separated by high pressure liquid chromatography and the compounds are detected at different wavelengths. The drugs of interest are well resolved in all feeds studied. The procedure has also been applied to a wide range of feeds which contained either one of the drugs or both in combination. No significant interferences were observed. Spiked sample recoveries were 97% for carbadox and 101% for pyrantel tartrate. Ruggedness test coefficients of variation were 2.0% for carbadox and 2.1% for pyrantel tartrate.
Microbiological Assay for Antibiotics in Surface Waters
Authors: Katz Jack M , Katz Stanley E
Published: February 2020

Assay procedures were developed for determining bacitracin, chlortetracycline, erythromycin, oxytetracycline, penicillin, streptomycin, and tylosin residues in surface waters. Direct addition of solid potassium phosphate buffering salts to water samples enabled suitable pH adjustments for optimum assay conditions. Recoveries from 2 surface waters averaged 97.9 and 102.7% for chlortetracycline, 101.0 and 101.5% for bacitracin, 94.5 and 95.3% for erythromycin, 84.2 and 89.8% for oxy tetracycline, 82.3 and 97.5% for penicillin, 97.4 and 99.2% for streptomycin, 87.4 and 94.2% for tylosin.
Determination of Xanthates, Dithiocarbamates, and Some Fungicides by Titration with Electrogenerated Iodine in Anhydrous Acetonitrile
Authors: Clyde Dale D
Published: February 2020

Xanthates, dithiocarbamates, and the fungicides maneb and zineb were determined by titration with electrogenerated iodine in anhydrous acetonitrile. The electrolyte was potassium iodide. The generating electrode was a platinum spiral (2.5 cm diameter, 2 mm cross section). The enclosed cell compartment was continuously flushed with dry nitrogen, and sample solutions (0.20-0.40 mL) were introduced by syringe. With the aid of 2 platinum electrodes, the end point was indicated amperometrically. Ten minutes was required for each determination. The compounds were determined at ≥5 μequiv. with relative errors of 0.21-9%. Precision is 0.60-5.7%. Thiourea, sulfur, and urea did not interfere, but thioacetamide did. Solutions of maneb and zineb in dimethyl sulfoxide are stable enough that μequiv. amounts of each compound can be determined with a relative error of 7% or less.