bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Trif luralin, Diallate, Triallate, Atrazine, Barban, Diclofop-Methyl, and Benzoylprop-Ethyl in Natural Waters at Parts per Trillion Levels
Authors: Lee Hing-Biu , Chau Alfred S Y
Published: February 2020

A sensitive multiresidue method is presented for the determination of 7 neutral herbicides in natural waters, with practical detection limits between 5 and 100 ng/L(ppt). The extraction was carried out at pH ≼1, using dichloromethane, so that acid-type herbicides can also be incorporated in the future. The entire cleanup procedure involves base partitioning, preliminary cleanup and fractionation on a 10% deactivated Florisil column, and final cleanup of the fractions on an activated Florisil column. However, the cleanup procedure is flexible enough to permit the analyst to use some or all of the cleanup steps, depending on the herbicide levels of interest. Recoveries of the 7 herbicides from distilled and natural water samples were between 82 and 104% at 2 fortification levels. Furthermore, this basic analytical scheme has been demonstrated, separately, to be effective in the determination of other neutral compounds such as PCBs, 18 organochlorine pesticides, and chlorobenzenes and thus has a potential to be developed into a multiclass, multiresidue method.
Determination of 2-Chloroethanol in Honey, Beeswax, and Pollen
Authors: Bruns Gary W , Currie Robert A
Published: February 2020

Procedures were developed and tested for the determination of residues of 2-chloroethanol (ethylene chlorohydrin, ECH) in honey, beeswax, and pollen. Recoveries of ECH from fortified samples averaged 91,87, and 89%, respectively, for each substrate. The maximum amount of ECH found in substrate fumigated with ethylene oxide was 36 μg/g in honey, 124 μg/g in beeswax, and 132 μg/g in pollen. A tendency was noted for darker waxes, which contain larger amounts of naturally occurring chlorides than light-colored waxes, to contain the greater amounts of ECH. A gas-liquid chromatograph equipped with a Dohrmann halogen-specific detector was used for identification and quantitation.
Analysis of Fat-Soluble Vitamins. XXVIII. High Performance Liquid Chromatographic Determination of Vitamin D in Pet Foods and Feeds: Collaborative Study
Authors: Vries Ellen J De , Bemmel Pieter Van , Borsje Ben ,   Collaborators:, Adams M L , Baillies T , Berthels J , Rosario C M del , Egtberts W , Gillingham P J , Giuliany B , Hancock W , Haustraete K , Herforth S , Hsieh B , Jensen E Klint , Knapstein H , Mahn F P , Nabholz A , Nedelkovitch G , Nicolas E C , Nicolaux G , Oelrich E , Phillips G F , Phlix J , Richter E F , Schwarze P , Smallidge R L , Steuerle H , Thiele U , Tichelaar G R , Venteicher R , Westergaard S , Woo W O , Zygmunt L
Published: February 2020

A high performance liquid chromatographic (HPLC) method for vitamin D in pet foods and feeds at low concentrations (2-8 IU/g = 50-200 ppb) was studied collaboratively. The procedure consists of the following purification steps: saponification, extraction oMhe unsaponifiable fraction, chromatography on alumina, cleanup on reverse phase HPLC, and quantitation with straight phase HPLC. The original method, developed by Knapstein, was simplified by deleting the quantitative TLC step. Six coded samples were distributed to 31 laboratories, along with a known sample containing 15 IU/g to allow practice of the rather complicated procedure. Eighteen collaborators returned their results. Results for the spiked samples show good recovery. The estimates of repeatability and reproducibility are 0.96 and 2.2 IU/g for spiked samples and 1.5 and 3.1 IU/g for commercial samples, respectively, which are considered acceptable for these low concentrations. The method has been adopted official first action.
High Pressure Liquid Chromatographic Determination of Fensulfothion: Collaborative Study
Authors: Owen Margie E ,   Collaborators:, Bennett O O , Chenery L T , Cohen C J , Freedlander R S , Gentry G M , Grimes G S , Hodgins W E , Meinen V J , Skelly N E , Wright D
Published: February 2020

A method for analyzing fensulfothion was tested by 10 collaborators. Formulations were dissolved, or extracted from inerts, in methanol. Benzophenone was used as an internal standard. The solution was diromatographed on a Partisil-10 ODS-2, or equivalent, reverse phase column, and detected at 230 nm. A mobile phase of methanol-water-phosphoric acid was used. The ratio of fensulfothion peak height to benzophenone peak height was calculated from the UV response and compared to the standard material for quantitation. A 15% granular formulation was analyzed as a matched pair. The results of one collaborator were outliers by the Dixon test. The coefficient of variation for the granular formulation was 1.6%. A matched pair of 63% spray concentrate samples was analyzed by 10 collaborators. The difference in results was an outlier for one collaborator; the coefficient of variation for the other collaborators was 1.5%. The method has been adopted official first action.
Analytical Methodology for Determining Glucosinolate Composition and Content
Authors: Mcgregor Douglas I , Mullin William J , Fenwick Gruffydd R
Published: February 2020

New analytical techniques and instrumentation and increased knowledge of the diversity and distribution of glucosinolates, the diversity of their enzymatically released products, and factors influencing their release, have led to significant advances in methodology for analysis of glucosinolates over the past three decades. However, many of the methods have been developed for specific agricultural crops or commodities and their particular glucosinolate compositions. They can only be applied to certain types of plant material or can detect and quantitate only certain glucosinolates or their products. Other methods have been designed to meet specific research, regulatory, or quality control requirements. This had necessitated sacrifice of either speed, simplicity, accuracy, precision, or the ability to distinguish different glucosinolates or their products. This review examines the methods available for sample preparation, identification, and quantitation of glucosinolates in light of current knowledge of their diversity, distribution, and chemistry. Consideration is given to the suitability of methods for rapid screening or precise, discriminating measurement, and to the standardization of methodology and reporting of results.
Compositional Analysis of Nonfat Dry Milk by Using Near Infrared Diffuse Reflectance Spectroscopy
Authors: Baer Robert J , Frank Joseph F , Loewenstein Morrison
Published: February 2020

Proximate data from 82 nonfat dry milk (NFDM) samples were correlated with near infrared reflectance (NIR) measurements. The best wavelengths for determining constituent concentrations were chosen from 19 preselected filters by using linear regression analysis. The correlation coefficient (r) was 0.971 and the standard error of prediction (SEP) was 0.274 when the predicted values (from NIR measurements) using the 3 wavelengths selected for determining moisture content were compared with laboratory values; r and SEP were 0.961 and 0.099, respectively, when the predicted values using the 4 wavelengths selected for fat content were compared with laboratory results; 0.887 and 0.594, respectively, using the 4 wavelengths selected for lactose content; 0.905 and 0.438 using the 8 wavelengths selected for protein (micro-Kjeldahl) content; and 0.911 and 0.509 using the 7 wavelengths selected for protein (dye binding). These data indicate that NIR can be used to estimate moisture, fat, lactose, and protein content of NFDM.
High Pressure Liquid Chromatographic Determination of Nitrofurazone and Furazolidone in Chicken and Pork Tissues
Authors: Sugden Edward A , Macintosh Agnes I , Vilim Arnost B
Published: February 2020

A high pressure liquid chromatographic (HPLC) procedure is presented for the determination of nitrofurazone and furazolidone in chicken and pork tissues in the 2-40 ppb range. Muscle, liver, and kidney are homogenized with cold methanol and water (50 + 50). Following methanol evaporation, the nitrofurans are partitioned into ethyl acetate and cleaned up on an alumina column. After elution with 20% methanol in ethyl acetate and evaporation to dryness, residues are determined by HPLC, using a reverse phase analytical column. Overall average recoveries for nitrofurazone and furazolidone were 65.7 and 73.5%, respectively. Average relative standard deviations of 11.9% (nitrofurazone) and 9.5% (furazolidone) at the 2 ppb level were achieved.
Quantitative Thin Layer Chromatographic Multi-Sulf onamide Screening Procedure
Authors: Thomas Michael H , Soroka Karen E , Thomas Sharon H
Published: February 2020

In-situ optical scanning of f luorescamine derivatives on thin layer silica gel plates provides a rapid method for the determination of multiple sulfonamides at levels below 0.1 ppm. Sample preparation is minimal. Homogenized liver or muscle is extracted with ethyl acetate and then back-extracted into 0.2M glycine buffer. After pH adjustment, the extract is washed with hexane and extracted with methylene chloride. The organic phase is evaporated to dryness and reconstituted in methanol. Pre-adsorbent layer silica gel plates are used for chromatography. The method has been applied to residues of sulfamethazine, sulfadimethoxine, sulfathiazole, sulfaquinoxaline, and sulfabromomethazine in cattle, swine, turkey, and duck tissues.
Quantitative Thin Layer Chromatographic Multi-Sulfonamide Screening Procedure: Collaborative Study
Authors: Thomas Michael H , Epstein Robert L , Ashworth Raymond B , Marks Harry ,   Collaborators:, Gonzales L , Hunter T , Kao C , Leadbetter M , Mitchell F , Patterson J , Soroka K E , Thomas S H , Willis B D
Published: February 2020

A thin layer chromatographic procedure suitable for detection of multiple sulfonamides at 0.1 ppm was studied in an interlaboratory collaborative study. Sulfamethazine, sulfadimethoxine, and sulfaquinoxaline were variously analyzed in liver and muscle tissues from swine, turkey, and duck. The average recovery for all drugs across all tissues was 95%. The corresponding repeatability and reproducibility were 7.7% and 10.5%, respectively.
Atomic Absorption Spectroscopic Analysis of Aluminum Sulfate-Type Soil Acidifiers: Mini-Collaborative Study
Authors: Knutson Ann ,   Collaborators:, Crawford D , Erickson M , Ingebrigtsen E , Jones C , Lambert T , Melton J , Sensmeier R , Wheeler W
Published: February 2020

Commercial brand aluminum sulfate soil acidifiers were subjected to a simple water extraction and analyzed for aluminum content by applying the principles of AOAC method 8.023. The study was designed to follow Youden's procedure for closely matched pairs and yielded results in close agreement. Statistical analysis, using 98% confidence limits, showed no outliers among analyses or laboratories. The combined Sr value was 0.1702, indicating satisfactory within-laboratory precision. The method has been adopted official first action.
Atomic Absorption Spectrophotometric Determination of Chelated Iron in Iron Chelate Concentrates: Collaborative Study
Authors: Silkey James R ,   Collaborators:, Angell S G , Bartunek K , Clark L W , Crawford D , Engvall D , Erickson M , Gordon D L , Hasselberger M L , Helmer J W , Jurgens D , Lambert T W , Melton J R , Miller C , Minyard J P , Sensmeier R K , Shatz W E , Stouffer N J , Tannenbaum S , Thorpe V A , Warren J D
Published: February 2020

An atomic absorption Spectrophotometric (AAS) method for determining chelated iron in iron chelate concentrates was collaboratively studied by 13 laboratories. Nonchelated iron was selectively precipitated as ferric hydroxide from an aqueous solution of the sample by adjusting to pH 8.5 with sodium hydroxide. A filtered portion of the sample solution was diluted with 0.5N HC1, and the iron was determined by AAS using standards containing disodium EDTA. Six pairs of iron chelate materials (12 samples) were analyzed and the average coefficients of variation were iron EDTA 3.52%, iron HEDTA 4.16%, iron DTPA 3.55%, iron EDDHA 3.52%, iron citrate 2.86%, and iron DPS 8.47%. The method has been adopted official first action.
Rapid Screening Procedure for Pesticides and Polychlorinated Biphenyls in Fish: Collaborative Study
Authors: Erney D Ronald ,   Collaborators:, Bong R L , Bulmer W , Hansen L B , Hennessy M K , Merser V , Pardue J R , Saxton W L
Published: February 2020

A simplified rapid method is presented to determine organochlorine pesticides and polychlorinated biphenyls in fish. Samples are mixed with sodium sulfate and blended with petroleum ether. A portion of the blend is placed on a miniaturized Florisil column and compounds are eluted with mixtures containing 6 and 15% ethyl ether in petroleum ether. Gas-liquid chromatography with electron capture detection comparable to the official methods (29.018) is used for determination of residues. Each of 7 collaborators reported results in duplicate for 10 samples containing one or more of the following compounds: p,p’-DDD,p,p’-DDE, p,p’-DDT, dieldrin, heptachlor epoxide, Aroclor 1254, and Aroclor 1260. Recoveries ranged from 79.3 to 100.7%. The coefficients of variation between laboratories ranged from 6.3 to 20.6%. This method allows up to 80% reduction in reagents and up to 50% reduction in analytical time, and requires less laboratory space than current official methods. The method has been adopted official first action.
Gas-Liquid Chromatographic Determination of Endosulfan Technical and Formulations: Collaborative Study1
Authors: Asshauer Jürgen , Watson Robert , Launer James E
Published: February 2020

The gas-liquid chromatographic determination of endosulfan technical and formulations was collaboratively studied with 11 laboratories. Fifteen samples were dissolved in toluene with di-(2-ethyl-hexyl)phthalate as the internal standard, chromatographed on a column of 10% OV-210, and detected by thermal conductivity. The average coefficients of variation were 0.55% for the 5 technical samples, 0.60% for the 5 wettable powders, and 0.68% for the 5 emulsifiable concentrates. The method has been adopted official first action.
Release of Lead and Cadmium: Comparison of Two Hot Leach Methods with a Room Temperature Method, Using Specially Glazed Ceramic Ware
Authors: Gould John H , Butler Stephen W , Steele Edward A
Published: February 2020

Oven and hot plate leach methods were compared with the official AOAC room temperature method for leaching Pb and Cd from specially glazed ceramic cookware. The hot leach methods released from 7 to 11 times more Pb and from 6 to 10 times more Cd after 24 h than did the AOAC procedure. Both hot leach methods specify a 2 h treatment with boiling 4% acetic acid, followed by 22 h of cooling at room temperature. The results show that essentially all of the Pb and Cd are released within 2 h, suggesting that the total contact time can be limited to 2 h to save laboratory space and time. The hot plate method is less difficult to perform and results in a continuous refluxing action. For these reasons, it is proposed as the hot leach method of choice.
Electron Capture Gas-Liquid Chromatographic Determination of Methyl Mercury in Fish and Shellfish: Collaborative Study
Authors: Hight Susan C , Capar Stephen G ,   Collaborators:, Anderson J , Brzezinski J , Cappon C J , Carr R , Kim E S , McNerney F G , Mitchell L , Newton J , Panaro K
Published: February 2020

A method for determining methyl mercury in fish and shellfish was collaboratively studied in 8 laboratories. Methyl mercury is isolated from acetonewashed, homogenized tissue by adding hydrochloric acid and extracting into benzene the methyl mercuric chloride that is formed. The benzene extract is concentrated and analyzed for methyl mercuric chloride by electron capture gas-liquid chromatography on 5% DEGS-PS treated with inorganic mercuric chloride solution. The quantitation limit for the method is 0.05 μg Hg/g. Each collaborator determined methyl mercury at 2 levels in blind duplicate samples of swordfish, tuna, oyster, and shrimp tissues. Both fortified and unfortified samples were analyzed. Methyl-bound mercury in the samples ranged from 0.15 to 148 μg Hg/g. The reproducibility coefficients of variation for the 8 samples ranged from 3 to 13%. The accuracy, measured by comparison to reference values, ranged from 99 to 120%. Reference values were determined in the Associate Referee's laboratory by replicate analyses of the fortified and unfortified samples. The method has been adopted official first action.
Electrothermal Atomic Absorption Spectrometric Determination of Selenium in Foods and Diets
Authors: Kumpulainen Jorma , Raittila Anna-Maria , Lehto Jari , Koivistoinen Pekka
Published: February 2020

The validity of 2 electrothermal atomic absorption spectrometric methods for determination of selenium in foods and diets was tested. By using 0.5% Ni(II) as a matrix modifier to prevent selenium losses during the ashing step, it was shown that selenium can be determined in samples containing ≥1 μg Se/g dry wt without organic extraction. The mean recovery tested, using NBS Bovine Liver, was 98%; recovery of added inorganic selenium in Bovine Liver matrix was 100%. In addition, this method gave values closest to the median value of all participating laboratories using hydride generation AAS or the spectrof luorometric method in a collaborative study on high selenium wheat, flour, and toast samples. For samples with concentrations <1 μg Se/g dry wt, separation of selenium from interfering Fe and P ions by organic extraction was necessary. Using inorganic ,5 Se in meat and human milk matrixes, an ammonium pyrrolidine dithiocarbamate-methyl isobutyl ketone- extraction system with added Cu(II) as a matrix modifier yielded the best extraction recoveries, 97 and %%, respectively. Accuracy and precision of the method were tested using several official and unofficial biological standard materials. The mean accuracy was within 4% of the certified or best values of the standard materials and the day-to-day variation was 9%. The Se/Fe or Se/P interference limits proved to be low enough not to affect selenium determinations in practically all foods or diets. The practical detection limit of the method was 3 ng Se/g dry wt for 1.0 g dry wt samples. Approximately 20 duplicate determinations can be performed per day. In terms of sensitivity, accuracy, precision, and sample throughput, the tested method compares favorably with the best methods available.
Atomic Absorption Determination of Serum Copper: Collaborative Study
Authors: Osheim David L ,   Collaborators:, Casper H , Colvin W , Emerick R J , Everson R J , Hamar D , Hunter T , Jain A V , Reynolds J D , Roof J E , Rottinghaus G , Stahr H M , Torma L
Published: February 2020

Preliminary to conducting a collaborative study on a method for copper in serum, methods used by a selected group of laboratories were surveyed. The responding laboratories were supplied with a Youden pair of bovine serum samples and requested to use their current method for serum copper. Results of the analyses and the methods used were evaluated; hypotheses were developed in our laboratory to explain some of the interlaboratory variation. For the AAS method chosen, each of 12 collaborating laboratories analyzed one blind duplicate and 2 Youden pair of serum samples. A commercially available external control serum with a certified level of copper and a 1000 mg copper/L standard were also submitted. The method requires the serum to be diluted 1 + 1 with distilled water and the standards to be diluted with 10% glycerin to approximate the viscosity of the diluted serum. The intralaboratory coefficients of variation (CV) ranged from 2.24 to 4.40% and the interlaboratory CV ranged from 2.56% to 6.05%. The method has been adopted official first action.
Gas Chromatographic Determination of Ethanol in Wine: Collaborative Study
Authors: Caputi Arthur , Mooney Dennis P ,   Collaborators:, Cherolis J , Clements M , Crowell E A , Dowrie B , Fike S , Ho L , King J , Lerner M , Posey R , Ribeiro T , Rommel M , Scheidt R , Tolosa R , Vahl J
Published: February 2020

After a survey of laboratories using gas chromatographic procedures for wine alcohol analysis, 3 sets of columns and operating parameters were chosen on the basis of comparative reproducibility evaluations run in this laboratory. Fourteen collaborators participated in the study and were given their choice of any one of the 3 columns: (1) 1.8 m × 2 mm id glass, packed with 80-100 mesh Poropak QS; (2) 1.8 m × 2 mm id glass, packed with 0.2% Carbowax 1500 on 80-100 mesh Carbopack C; (3) 1.8 m × 6.35 mm copper, packed with 3% Carbowax 600 on 40-60 mesh Chromosorb T. Standards and samples were diluted 1:100 with 0.1% v/v n-butanol in water before analysis. Eight samples containing from 7.3 to 23.6% ethanol (v/v) were submitted as randomly coded duplicates along with a calibration standard and a practice sample. Two injections each of the diluted duplicates were made. On the basis of the reported results, 2 laboratories were rejected as outliers. The results of the remaining 12 collaborators showed an average reproducibility of 0.142 and a repeatability of 0.036. The method has been adopted official first action.
Gas Chromatographic Determination of Dimethylamine and Trimethylamine in Seafoods
Authors: Lundstrom Ronald C , Racicot Linda D
Published: February 2020

The volatile amines dimethylamine (DMA) and trimethylamine (TMA) are common degradation products of TMA-oxide in marine fish- Both compounds are used as important indicators of quality in seafoods. DMA is produced along with an equimolar quantity of formaldehyde by action of an endogenous enzyme found primarily in gadoid fish. TMA is produced in fresh, but not frozen seafoods by a bacterial enzyme. The current AOAC method for determination of TMA in fish is based on the colorimetric estimation of TMA as a picrate salt. This method is not specific for TMA; ammonia, monomethylamine, and DMA also form corresponding picrate salts. Gas chromatography provides a means of separating and quantitating the individual volatile amines. A simple perchloric acid extract of fish is neutralized with potassium hydroxide and extracted with benzene. The amines are then separated by gas chromatography on a porous polymer packed column and detected by using a nitrogen-phosphorus-specific flame ionization detector. The method provides simple, rapid simultaneous quantitation of DMA and TMA, and is applicable to a wide variety of seafoods.
Rapid High Pressure Liquid Chromatographic Determination of Amitriptyline Hydrochloride in Tablets and Injectables: Collaborative Study
Authors: Walker Samuel T ,   Collaborators:, Balbach R , Jefferson E , Jordan D , Lepore J , Lia U , Lookabaugh M , McCarthy J , Roberts S , Romano M , Uribe M
Published: February 2020

A previously reported high pressure liquid chromatographic method for the determination of amitriptyline hydrochloride in dosage forms was modified to permit its use as a stability-indicating method. The modified method, entailing a nitrile bonded microparticulate column, a methanol-0.005M ammonium acetate (90 + 10) mobile phase, and photometric detection at 239 nm, was collaboratively tested by 10 laboratories. Each collaborator received samples of synthetic and commercial tablets and injections. The recovery from a synthetic injection at the 10.06 mg/mL spiking level averaged 98.6%. The amount of declared found in commercial injections averaged 103.1%. The pooled reproducibility SD (CV%) and repeatability SD (CV%) were ± 2.12 (2.15) and ± 1.81 (1.84), respectively. The recovery from synthetic tablet composite at the 7.45% spiking level averaged 102.0%. The amount of declared found for commercial 25 mg and 100 mg tablets averaged 96.7 and 97.9%, respectively. The pooled reproducibility SD (CV%) and repeatability SD (CV%) for these 3 tablet samples were ± 1.89 (1.86) and ± 1.66 (1.64), respectively. Content uniformity analysis of commercial 25 mg and 100 mg tablets (n = 10) gave amounts of declared values averaging 100.5% (range 92.4-108.8%) and 99.3% (range 89.6-107.0%), respectively. The pooled reproducibility SD (CV%) and repeatability SD (CV%) were ± 3.23 (3.2) and ± 2.78 (2.8), respectively. A commercial injectable preparation spiked with dibenzosuberone was also collaboratively analyzed by a thin layer method. The method was adopted interim official first action.
Role of Anthranilic Acid in Background Levels of Sulfonamide in Porcine Livers when Determined by the Tishler Method
Authors: Parks Owen W
Published: February 2020

Anthranilic acid occurs in excised swine livers as a result of temperature abuse before and/or after freezing. The tryptophan metabolite is the major source of the variable non-sulf onamide background level frequently encountered in the Tishler method for determining sulfonamide residues in swine livers. Diazotized anthranilic acid reacts slowly with N-( naphthyl)ethylenediamine [k(s-1) = 5.79 (±0.07) × 10-5] and the final background level depends on the time elapsed between addition of the coupling agent and spectrophotometric determination. Kynurenine was tentatively identified as a minor source of the non-sulfonamide background level.
Modified Method for Electron Capture Gas-Liquid Chromatographic Determination of Diethylstilbestrol Residues in Urine of Fattened Bulls
Authors: Tirpenou Athanasios E , Kilikidis Stylianos D , Kamarianos Athanasios P
Published: February 2020

A gas-liquid chromatographic (GLC) method with electron capture (EC) detection was developed fof determining diethylstilbestrol residues in the urine of fattened bulls. Diethylstilbestrol (DES) is extracted into benzene, and then into IN sodium hydroxide. The pH of the phenolic fraction (alkaline phase) is adjusted to 10.2 and DES is extracted again into benzene. Sample extracts are cleaned up on silica gel. Trifluoroacetic anhydride (TFAA) is used as acylation reagent, and the derivatized sample is chromatographed on a 3% OV-17 column and measured with a 63Ni EC detector. The method is suitable for determining residues at levels as low as 2 ppb.
Flame Photometric Determination of K2O in Fertilizers: Collaborative Study
Authors: Kane Peter F , Stringham Rodger W ,   Collaborators:, Coggin D , Grigor S , Holmes J H , Johnson F J , Kirk L A , Lee C , Lehe C M , Neuman J F , Proska P , Ptak F L , Shideler R , Wall L L , Wheeler W L , Woodis T C
Published: February 2020

A collaborative study of the flame photometric determination of K2O in fertilizers has been conducted. The proposed method is intended to replace both the official manual flame method, 2.091, and the official automated method, 2.097. This is possible because the method is written in a general fashion in terms of instrument performance, rather than specifically for a particular instrument configuration. An example automated instrumental system in specific detail, which meets the general method requirements, is also included. Results for 20 samples from 11 laboratories were compared with results by the official STPB method, 2.102. Means and standard deviations of results are comparable between methods. Analysis of variance does not show any difference in methods. The method has been adopted official first action.
Gas Chromatographic Determination of Trifluralin, Diallate, Triallate, Atrazine, Barban, Diclofop-Methyl, and Benzoylprop-Ethyl in Sediments at Parts Per Billion Levels
Authors: Lee Hing-Biu , Chau Alfred S Y
Published: February 2020

A sensitive gas chromatographic method was developed for the multiresidue determination of 7 neutral herbicides in sediment. The sediment sample was ultrasonically extracted 3 times with acetone. The extract was concentrated to about 50 mL and then partitioned with 2% KHCO3 and CH2C12. The organic phase was dried over anhydrous Na2So4. The concentrated extract was then cleaned up on a 10% deactivated Florisil column, and the herbicides were separated into 2 fractions. Further cleanup of these fractions was performed on activated Florisil columns. Electron capture detection was used for analysis except for atrazine which was analyzed by nitrogen-phosphorus detection. Recoveries of the herbicides from fortified sediment samples at 3 levels were generally better than 80%. The practical detection limit of this method was 1 ppb or 1 ng/g based on a 50 g sediment sample.
Evaluation of Nielsen-Kryger Steam Distillation Technique for Recovery of Phenols from Soil
Authors: Narang Amarjit S , Vernoy Charles A , Eadon George A
Published: February 2020

The Nielsen-Kryger steam distillation technique has been evaluated for recovery of phenols from soil. Soils are acidified to pH <1 and steam-distilled, and chlorinated phenols are extracted with toluene-methylene chloride (95 + 5). Mean recoveries from 4 samples spiked at 1 μg/50 g clay soil ranged from 67 to 78%. The method has limited utility for the recovery of other substituted phenols on the Environmental Protection Agency priority pollutant list.
Semiautomated Fluorometric Method for Determination of Vitamin C in Foods: Collaborative Study
Authors: DeVries Jonathan W ,   Collaborators:, Defibaugh P W , Dunmire D , Ebert F , Ge H , Oman G , Lim N , Moffitt R A , Muelle E E , Schnitzer R , Shaffer S
Published: February 2020

Continuous flow automation of the microfluorometric procedure compares favorably with the manual method in sensitivity, specificity, and generality, and reduces the cost of routine vitamin C assay. Fifteen samples of 12 different products of ready-to-eat cereals, fruit juices, and infant formula were sent to 6 collaborators; one sample in each category was sent as blind duplicates. The within-laboratory standard deviations for 5 collaborators on the 3 sets of blind duplicates were 1.23, 0.87, and 3.64 mg/100 g, respectively. Overall, the average relative standard deviation between laboratories was 11.1% (range 4.5-16.6%) for the manual method and 4.99% (range 1.5-12.6%) for the semiautomated method. The method has been adopted official first action.
Titratable Acidity in Corn Syrup: Collaborative Study
Authors: Bernetti Raffaele , Owen Roger ,   Collaborators:, Harness J , Holme R A , Hovden R , Owen R L , Schopmeyer H H , Steele E M , Wolff P
Published: February 2020

Six sets of blind duplicate samples of commercial corn syrups, including high fructose corn syrups, were distributed to 9 collaborating laboratories. Samples were titrated with alkali, according to the AOAC method, to a phenolphthalein "faint pink" end point as well as being assayed by a modified method specifying a larger sample, more dilute alkali, and electrometric end points at pH 6.0,7.0, and 8.3. Repeatabilities and reproducibilities were about as poor in the AOAC method as in the modified method at pH 8.3, but improved considerably when the modified electrometric end point method was carried out to pH 6.0. The method calling for electrometric titratable acidity at pH 6.0 end point was adopted official first action, and the present method, 31.217, was deleted.
Direct Determination of Lead in Evaporated Milk and Apple Juice by Anodic Stripping Voltammetry: Collaborative Study
Authors: Zink Eric W , Davis Phillip H , Griffin Reginald M , Matson Wayne R , Moffitt Robert A , Sakai David T ,   Collaborators:, Abbe S , Booth H , Brumley J , Chamberlain N , Chisolm J J , Green R , Harrison H , Hudak J W , Neuman T R , Phillips R N , Rieders F , Shelhorse N A , Sideman L , Spratt E , Sulek A M , Walkowiak W
Published: February 2020

A method for the direct determination of lead in evaporated milk and in fruit juice with no prior sample digestion was successfully collaborated by 13 laboratories. The anodic stripping voltammetric (ASV) method studied consisted of adding 0.2 mL aliquots of evaporated milk or 0.3 mL aliquots of fruit juice to 2.9 mL of a dechelating reagent, Metexchange. The reagent-sample mixture is then analyzed for lead by ASV with no further sample preparation. Each collaborator received 24 samples, 2 each at 5 different levels (0.07-0.70 ppm for spiked evaporated milk and 0.09-0.87 ppm for spiked apple juice) along with duplicate practice samples of labeled lead content at each of 2 levels for each sample type. All unknowns were coded with random numbers. Approximately 69% of the reporting laboratories had never analyzed either evaporated milk or fruit juice for lead. Average time between receipt of samples and reporting of results was 1.6 days for all laboratories. The pooled variations between duplicate determinations for apple juice and evaporated milk were 0.00059 and 0.00043, respectively. The method was adopted official first action for both fruit juice and evaporated milk.
Separation and Characterization of Amine Drugs and Their Enantiomers by Capillary Column Gas Chromatography-Mass Spectrometry
Authors: Liu Ray H , Ku Warren W , Fitzgerald Mary P
Published: February 2020

A gas chromatograph-mass spectrometer-data system equipped with a capillary column is used to analyze commonly abused amine drug mixtures. Enantiomeric amines are analyzed as N-trifluoroacetyl- I-prolyl chloride derivatives. The 10 compounds included in this study are amphetamine, methamphetamine, norephedrine, ephedrine, 3,-4-methylenedioxyamphetamine, N,N-dimethyltryptamine, N,N-diethyltryptamine, N,N-dimethyl-5-methoxytryptamine, mescaline, and caffeine. All compounds, including possible enantiomers, are resolved and identified by the described method.
Analysis for Fusarium Toxins in Various Samples Implicated in Biological Warfare in Southeast Asia
Authors: Mirocha Chester J , Pawlosky Robert A , Chatterjee Kajal , Watson Sharon , Hayes Wallace
Published: February 2020

Samples of leaves, water, cereal grains, soil, and yellow powder as well as blood, urine, and body tissues from chemical warfare victims were analyzed for Fusarium toxins by using gas chromatography and mass spectrometry. The leaves, water, and yellow powder samples contained various combinations of T-2 toxin, diacetoxyscirpenol, deoxynivalenol, nivalenol, and zearalenone in concentrations ranging from trace (1.0 ppb) amounts to 143 ppm. These trichothecenes do not occur naturally on the substrates described and were correlated with the so-called "yellow rain" chemical attacks against Hmong people in Southeast Asia. Analysis of leaves, soil, water, and cereals collected in areas adjacent to but apart from the area where chemical attacks had been staged did not contain any Fusarium toxins. Moreover, T-2 and HT-2 toxins were found in human blood, urine, and body tissues (heart, esophagus, kidney, lung, and large intestine) of alleged victims. In addition, diacetoxyscirpenol was found in the kidney of one person who had died
Potentiometric Determination of Chlorine in Microliter Water Samples
Authors: Paterson A H J , Kerekes R J
Published: February 2020

A novel method has been developed to measure low concentrations (about 100 ppm) of chlorine in very small (1–5 μL) samples of water. The method uses a specially cast silicone rubber cap fitted over the tip of a combination electrode probe. The fabrication, calibration, and use of this modified commercial probe is described in detail.
Histologic Detection of Cardiac Musculature, Soy Flour, and Partially Defatted Tissue in Ground Beef: Interlaboratory Study
Authors: Carey Albert M , Archer Jean N , Priore Joseph D , Kotula Anthony W ,   Collaborators:, Cannon L D , Carey A M , Deshmukh D R , Dyer J E , Glenn M W , Langheinrich K A
Published: February 2020

A collaborative study was designed and conducted to evaluate the accuracy of a procedure for the histologic detection of cardiac muscle, soy flour, and partially defatted tissue that may occur as adulterants in ground beef. Ground beef samples were prepared containing 0, 3, 5, 10, and 15% of each of the 3 adulterants. Five samples of each composition at each of the 5 dilutions, for a total of 75 unknown samples, were analyzed at each of 5 participating laboratories. The study revealed that this technique is reliable for the detection of these adulterants in ground beef.
Pesticide, Heavy Metal, and Other Chemical Residues in Infant and Toddler Total Diet Samples. (IV). October 1977–September 1978
Authors: Podrebarac David S
Published: February 2020

The Food and Drug Administration has conducted the Total Diet Study since 1964. The program originally focused on the average total diet of the young adult male but was eventually expanded to include the average total diets of infants and toddlers. This report is the fourth in the infant and toddler series and represents residues found in market basket samples, i.e., items comprising the average 2-week diet of infants and toddlers, collected in 10 different cities throughout 4 geographic areas of the United States from October 1977 through September 1978. The results are based on analyses of food composites representing 11 food classes into which all the food items were separated. Averages and ranges are reported for residues of pesticides, herbicides, fungicides, and selected metals and industrial chemicals. Recovery results are also included for various representative compounds added to a variety of food classes. The results for the adult market basket samples for the same reporting period are presented in a separate report.
Pesticide, Metal, and Other Chemical Residues in Adult Total Diet Samples. (XIV). October 1977–September 1978
Authors: Podrebarac David S
Published: February 2020

Residues of pesticides, herbicides, fungicides, and selected industrial chemicals and metals have been reported since 1964 through the Total Diet Study conducted by the Food and Drug Administration. This report, which is the fourteenth in the series, includes data for the adult diet market basket samples collected from October 1977 through September 1978 in 20 cities throughout 4 geographical areas. All items from each market basket were separated into 12 food classes for analysis, and the averages and ranges of the residues found are presented in various formats. In addition to the 240 composites analyzed, the individual items making up the dairy composites and the meat-fishpoultry composites were analyzed separately for 4 market baskets. The results of a recovery study in which composites were fortified with the more commonly reported residue compounds are also presented as a part of this report. Results for the infant and toddler Total Diet market baskets for the same period are published in a separate report.
Mass Spectrometric Determination of Cane Sugar and Corn Syrup in Maple Syrup by Use of 13C/12C Ratio: Collaborative Study
Authors: Morselli Maria Franca , Baggett Kelly L ,   Collaborators:, Bender M , Cairo O , Fontes J C , Fritz P , Gagnon M , Gearing P , Hillaire-Marcel C , Knyf M , Krouse H R , Schwarcz H P
Published: February 2020

Use of C3 carbon dioxide (CO2) fixation cycle by the sugar maple (Acer saccharum Marsh.), a dicotyledenous plant, and C4 carbon fixation cycle by 2 monocotyledenous plants, corn and cane, results in a physiological discrimination between 13C and 12C isotopes. Therefore, determination of 13C/12C ratio of maple syrup by mass spectrometry can be used to detect adulteration with cane and corn sugars. Four samples of pure maple syrup and 3 adulterated maple syrup samples were analyzed in a collaborative study. Results indicate that stable carbon isotope analysis can determine authenticity of maple products. Samples with δ13C values less negative than – 23.49%c (parts per thousand) can, with a high degree of confidence (95%), be classified as adulterated. The method has been adopted official first action.
Effects of Methanol Concentration and Solvent:Peanut Ratio on Extraction of Aflatoxin from Raw Peanuts
Authors: Whitaker Thomas B , Whitaker Thomas B , Dickens James W , Giesbrecht F G
Published: February 2020

Aflatoxin Bi was extracted by a water slurry process using methanol concentrations of 55, 60, 65, and 70% in water and solvent:peanut ratios of 3, 4, 5, and 6 mL/g. Results failed to show that methanol concentration had an effect on amount of B1 extracted; however, the amount of B1 extracted increased with an increase in solvent:peanut ratio. Aflatoxin Bt was also extracted by the official AOAC method II, using methanol concentrations of 55, 60, 65, and 70% in water and solvent:peanut ratios of 2, 3, 4, and 5 mL/g. Results showed that the amount of B1 extracted increased with percent methanol at low solvent: peanut ratios but not at high ratios. Also, the amount of B1 extracted increased with solvent:peanut ratios at all methanol concentrations.
Fluorometric Screening Method for Citrinin in Corn, Barley, and Peanuts
Authors: Trantham Allen L , Wilson David M
Published: February 2020

A fluorometric method is described for rapid screening of citrinin in corn, barley, and peanuts. The initial extraction uses an aqueous acidified acetonitrile solution, and the resulting extract is partially purified by several acid–base partition steps. Citrinin is determined by using a fluorometer. Mean recoveries of added citrinin from corn, barley, and peanuts were 56.4,66.6, and 40.0 %, respectively, at levels of 100–8000 ng/g.
Simple Colorimetric Estimation of Cyclopiazonic Acid in Contaminated Food and Feeds
Authors: Rathinavelu A , Shanmugasundaram Edayathimangalam Rajabhavani B
Published: February 2020

A method has been developed for quantitative determination of cyclopiazonic acid, a mycotoxin produced by a common food contaminant, Penicillium cyclopium. The organism was grown successively in synthetic minimal medium, rice, corn, and wheat for 15 days. The toxin was extracted with chloroform followed by separation by thin layer chromatography. A colorimetric assay procedure has been successfully developed for the analysis of cyclopiazonic acid present in infected rice, corn, and wheat. The sensitivity of the method was tested by using recovery experiments.
Deoxynivalenol in Winter Wheat: Thin Layer Chromatographic Method and Survey
Authors: Eppley Robert M , Trucksess Stanley Nesheim Mary W , Thorpe Charles W , Wood Garnett E , Pohland Albert E
Published: February 2020

A rapid method for the determination of deoxynivalenol (DON) in wheat was used to analyze 57 wheat samples collected from 4 midwestern states where the winter wheat crop was contaminated with Fusaria. The method involves sample extraction with acetonitrilewater (84 + 16), cleanup by charcoal-alumina column chromatography, and determination by thin layer chromatography (TLC), using an AlClj solution spray and heat to form a fluorescent derivative. Recoveries of DON added to wheat at levels as low as 0.2 μg/g averaged >80%. DON was detected at an average level of 3.6 μg/g; the levels ranged from 0.2 to 9.0 μg/g in 54 of 57 of the wheat samples. The quantity of DON was, in general, proportional to the percentage of total damaged kernels (grade). The chemical identity of DON was confirmed by mass spectrometry after isolation with preparative TLC.
Enzyme-Linked Immunosorbent Assay of Ochratoxin A in Wheat
Authors: Lee Sungsoo C , Chu Fun S
Published: February 2020

An enzyme-linked immunosorbent assay (ELISA) was developed for the quantitation of ochratoxin A amended to wheat. Ochratoxin A conjugated to horseradish peroxidase (HRP) was used as an enzyme marker in the assay. At toxin levels below 30 ppb, a cleanup treatment was necessary for ELISA. Among 3 cleanup methods tested (solvent partition, Sep-Pak cartridge treatment, solvent partition and cartridge treatment), reverse phase cartridge treatment was the most simple and effective. In the analysis, ochratoxin A was extracted from wheat with methanol. The methanolic extract was diluted with water to a final 10–15% methanol content, and then passed through a cartridge. Ochratoxin A was eluted from the cartridge with 85% methanol which was then concentrated. The final solution, in 0.1M, pH 7.5 sodium phosphate–Tween 20 buffer and 5% methanol, was then subjected to ELISA. ELISA allowed minimal detection of the toxin in wheat at the 1–2 ppb level after cleanup. Recoveries of toxin added to wheat samples in the 1.0–30 ppb range were 85–90% with standard deviations of 10–15%.
Rapid Determination of Deoxynivalenol (Vomitoxin) by Liquid Chromatography Using Modified Romer Column Cleanup
Authors: Chang Henry L , Devries Jonathan W , Larson Paul A , Patel Hasmukh H
Published: February 2020

A modification of the Romer method for determining deoxynivalenol (DON) provides rapid sample cleanup and includes liquid chromatographic (LC) quantitation. The method was evaluated using wheat, wheat flour, and other wheat products. The sample is extracted with acetonitrile–water (84 + 16), and an aliquot of the extract is subjected to activated charcoal–alumina column chromatography. The extract is then evaporated and diluted to volume with mobile phase, and DON is quantitated using liquid chromatography. The relative standard deviation based on duplicate samples is 6.07%. The detection limit is 30 ppb based on 2 x signal/noise ratio. Results by this method compared with the results obtained by the Scott GC method showed a correlation coefficient of 0.992 with a mean vomitoxin content of 779 ppb by this method and 716 ppb by the Scott method for 14 samples.
Determination of N-Nitrosodimethylamine in Nonfat Dry Milk: Collaborative Study
Authors: Sen Nrisinha P , Seaman Stephen , Karpinsky K ,   Collaborators:, Castegnaro M , Ellen G , Fiddler W , Lamontagne J C , Houlahan B J , Issenberg P , Klein D , Scanlan R , Thomas G , Thomsen J
Published: February 2020

Ten laboratories participated in a collaborative study of a method for the determination of JV-nitrosodimethylamine (NDMA) in nonfat dry milk. NDMA is eluted with dichloromethane from a mixture of Celite, acidic sulfamic acid, and nonfat dry milk (all packed in a chromatography column), concentrated in a Kuderna-Danish concentrator, and finally analyzed by a GC-thermal energy analyzer technique. Ten samples were studied: 6 were naturally contaminated (NDMA levels 0.38- 3.56 ppb) and 4 were spiked with known levels (0.96 and 3.2 ppb) of NDMA. The coefficients of variation (CV) of the complete data for the naturally contaminated samples (excluding the 2 samples containing the lowest levels) were 8.5% and 22.5% for repeatability and reproducibility, respectively. The corresponding CVs for the spiked samples were 14.4% and 20.4%, respectively. The percent recoveries of the added NDMA in the spiked samples (at the 2 levels indicated above) were 101.6 ± 3.2 (omitting 1 outlier) and 95 ∓ 2.1, respectively. The method has been adopted official first action.
Liquid Chromatographic Determination of Intermediates, Subsidiary Colors, and Two Reaction By-Products in FD&C Yellow No. 6: Reverse Phase Method
Authors: Cox Elizabeth A , Richfield-Fratz Naomi , Bailey Catherine J , Albert Richard H
Published: February 2020

A reverse phase liquid chromatographic (LC) method is presented for determining intermediates, subsidiary colors, and 2 reaction by-products in FD&C Yellow No. 6. Gradient elution from 0.02M ammonium acetate to 60% methanol in 0.02M ammonium acetate is performed on a C-8 column. Recoveries of the analytes from samples of FD&C Yellow No. 6 were as follows: 82 to 129% for the intermediate sulfanilic acid added at levels ranging from 0.04 to 0.2%; 85 to 107% for the intermediate Schaeffer's salt added at levels ranging from 0.03 to 0.3%; 91 to 107% for the reaction by-product 4,4'-(diazoamino)-dibenzenesulfonic acid added at levels ranging from 0.01 to 0.1%; 67 to 108% for the reaction by-product 6,6'-oxybis(2-naphthalenesulfonic acid) added at levels ranging from 0.1 to 1%; 88 to 100% for the subsidiary color 3-hydroxy-4-[(4-sulfophenyl)azo]-2,7-naphthaIenedisulfonic acid added at levels ranging from 0.7 to 5%; and 43 to 106% for the subsidiary color 6-hydroxy-5-(phenyIazo)-2-naphthalenesulfonic acid added at levels ranging from 0.1 to 1 %. To further demonstrate the capabilities of the method, results of multiple analyses of several FD&C Yellow No. 6 samples are presented, and results from corresponding analyses by an AOAC ion exchange LC method and by a thin layer chromatographic method are compared with results found with the new reverse phase LC method.