bluuebunny/crossref_metadata_2025 huggingface dataset:
High Pressure Liquid Chromatography of Captan in Formulations: Collaborative Study
Authors: Carlstrom A Aner ,   Collaborators:, Bryant M Akerblom , Allochuku G C , Audino J B , Coppi E L , Day E W , Grorud R B , Haye E H , Jenning F A , Kawan Y , Eachern G Mac , Martijn A , McDermott W H , Meier J , Meinen V J , Minyard J P , Pavel K , Povlsen H H , Skelly N E , Suter R
Published: February 2020

A simple method for measuring captan was tested by 18 collaborators. Formulations are extracted with methylene chloride which contains diethyl phthalate as an internal standard, and detected at 254 nm after high pressure liquid chromatographic separation in a 25 cm × 4 mm column packed with 10 µm silica gel. After inert materials are removed, the supernate is added directly to the column with methylene chloride as the mobile phase; peak height ratios are used for quantitation. Most pesticides commonly formulated with captan do not interfere. Retention times and UV response factors relative to captan are listed for 34 pesticides formulated with captan. The collaborators made single determinations on 6 samples (3 pairs of duplicates). The coefficients of variation were 0.67% for the technical, 1.16% for the 50% wettable powder, and 1.71% for the 5% dust. Several collaborators were unable to separate carbaryl and diethyl phthalate on a combination dust containing captan, dicofol and carbaryl; therefore, the method has been adopted as official first action only for captan formulations containing no other active ingredients.
Chemical Test for Mammalian Feces: Collaborative Study
Authors: Thrasher Joel J , Gecan John S ,   Collaborators:, Bradicich R , Chaput M , Grimmet J , Jessop J , Kaminski J , Loges M , Palmer W , Schaefer P
Published: February 2020

A chemical method was developed to determine the presence of mammalian feces in food. The method consisted of the colorimetric determination of alkaline phosphatase and involved the splitting of the phosphate radical from phenolphthalein diphosphate and the resultant color development of phenolphthalein in a basic medium. A collaborative study testing the feces of 22 animals resulted in a 95% correct identification of samples as mammalian feces. The method has been adopted official first action.
Analysis of Fat-Soluble Vitamins. XXV. High Performance Liquid Chromatographic Determination of Vitamin D in Multivitamin Preparations: Collaborative Study1
Authors: Vries Ellen J De , Mulder Frits J , Borsje Ben ,   Collaborators:, Ameika L , Anderssen E , Bagnall K W , Baillies T , Bjorholm H , Boufford C E , Bruno J V , Chadde F , Delano N , Vries E J De , Egtberts W , Fine B G , Gillingham P J , Grady L T , Jekabsons E , Johansson S , Jordi H C , Knapstein H , Kobayashi T , Kring P , Kurtz G W , Lotfy P A , Mahn F P , May E M , Monard A , Minister J V , Nedelkovitch G , Nicolaux G , Oelrich E , Öhrner B , Okano T , Phillips G F , Richter E F , Schwarze P , Steuerle H , Thakker K D , Theivagt J , Townley E , Antwerp J Van , Riper E S Van , Vuht G , Whall P J , Woodby J A , Zygmunt L
Published: February 2020

The HPLC method for determining vitamin D in multivitamin preparations was studied collaboratively. Samples were distributed to 43 laboratories in 10 countries. Twenty-four laboratories gave their results. The method specifies a reverse phase system for the cleanup and a straight phase system for the determination. Difficulties arise when laboratories are equipped with HPLC apparatus with a single column. Laboratories experienced in vitamin D analysis reported good results, even if they were equipped with a single column HPLC apparatus. Eleven of the 24 laboratories reported satisfactory results. For this rather complicated method, the coefficient of variation for a single assay is acceptable. The method has been adopted official first action as an alternative procedure to the chemical method for determining vitamin D in multivitamins.
Novel Cleanup Method for Quantitative Gas Chromatographic Determination of Trace Amounts of Di-2-Ethylhexyl Phthalate in Fish Lipid
Authors: Burns B Garth , Musial Charles J , Uthe John F
Published: February 2020

A new, simple, and rapid cleanup procedure is described for di-2-ethylhexyl phthalate (DEHP) residues in fish lipids. Extracts are chromatographed on small alumina:sulfuric acid-impregnated alumina (layered) columns after gel permeation chromatography of the fish lipid extracts on BioBeads SX-3. Quantitative analyses were carried out by electron capture gas chromatography using 2 columns. Spiked DEHP recoveries varied from 79.3% in mackerel to 86.1% in herring. DEHP concentrations were determined in plaice, eel, redfish, herring, cod, and mackerel tissues and ranged from trace (<0.001 µ/g) to approximately 10 µ/g (wet wt basis). Ethanolic KOH saponification of the purified DEHP fraction, resulting in the disappearance of the DEHP peak, was used as a confirmatory test. Limited studies with dibutyl, di-n-heptyl, and diethyl phthalates suggest that the method can be made more versatile.
Colorimetric Determination of Disulfiram in Tablets: Collaborative Study
Authors: Wojtowicz Edward J ,   Collaborators:, Harms J P , Johnson R H , Lazar A , Olsen R E , Newton J M , Petzinger G , Ristich R , Robinette M L
Published: February 2020

The colorimetric reaction of cuprous iodide and disulfiram has been collaboratively studied in 8 laboratories to determine the drug in tablet form at 2 dosage levels. The disulfiram was extracted from the tablet matrix with methylene chloride. After a basic wash with 1 M NaOH, an aliquot of the methylene chloride solution was reacted with solid cuprous iodide, and the absorbance of the resulting color was measured. Single assays on 2 synthetic preparations of known disulfiram content were performed with average recoveries of 98.4 and 99.2% for 93.3 and 105.3mg, respectively. Duplicate determinations on 2 commercial tablet preparations declared at 250 and 500 mg gave mean and standard deviation values of 246.6 ± 6.40 and 493.6 ± 12.0 mg, respectively. The results agreed closely with those obtained by the author using the NF iodometric titration procedure. The method has been adopted official first action.
High Pressure Liquid Chromatographic Analysis of Chlorpyrifos Containing Insecticidal Formulations: Collaborative Study
Authors: Skelly Norman E , Jackson David J , Anderson Phyllis K ,   Collaborators:, Audino J B , Bushway R J , Chang W , Hageman L , Hanks A R , Hodgins W E , Kawano Y , Magnenant R , Mcdaniels S , Rivera L , Rowe N W , Turley R
Published: February 2020

A high pressure liquid chromatographic method for determining chlorpyrifos was collaboratively studied. Three liquid and 2 solid formulations were analyzed by 12 collaborators. Samples were weighed and diluted with acetonitrile containing the internal standard, 1,4-dibromonaphthalene. Chlorpyriphos is separated on a Zorbax ODS column with acetonitrile- water-acetic acid (82 ± 17.5 ± 0.5) at 2 mL/min and monitored at 300 nm. Clay samples are extracted with the internal standard solution by agitation for 5 min. Coefficients of variation ranged from 1.28 to 2.40%. Results of all 12 collaborators fell within the 5% two-tail limits. The method has been adopted official first action.
Liquid Chromatographic Determination of Residual Styrene in Polystyrene Food Packaging
Authors: Varner Sandra L , Breder Charles V
Published: February 2020

The determination of residual styrene in polystyrene food packaging polymers by a reverse phase liquid chromatographic method is described. The polymer is dissolved in tetrahydrofuran and then reprecipitated with methanol. The filtered solution is chromatographed by using an aqueous tetrahydrofuran mobile phase, and the styrene is detected and quantitated by ultraviolet at 254 nm. The detection limit for the method is about 0.5 ppm styrene on a solution basis and 20 ppm in the polymer. The average recovery of styrene from spiked polymer (about 50–3700 ppm) is 88%. Apparent residual styrene was determined in several commercial products, including rigid polystyrene cups, flexible plastic containers, and several foam products. The monomer levels ranged from about 60 to 2250 ppm.
Lead in Preserved Duck Eggs: Field Screening Test and Confirmation and Quantitation by Atomic Absorption Spectrophotometry and Anodic Stripping Voltammetry
Authors: Krinitz Benjamin , Tepedino Nivia
Published: February 2020

Analysis of preserved duck eggs in this laboratory by acid digestion and atomic absorption spectrophotometry has shown that addition of lead salts to the egg coating to speed the preservation process results in lead in the egg albumen and yolk. The lead levels decrease as the lead passes through successive membranes, i.e., the lead level in the yolk is lower than that in the albumen. A method has been developed for the field screening of preserved duck eggs for the presence of lead in which a portion of the egg coating is shaken with 4% acetic acid, and the resulting solution is tested by a modification of the AOAC dithizone method. A quantitative method for laboratory confirmation of lead in egg albumen and/or yolk has also been developed in which lead is determined by atomic absorption spectrophotometry or anodic stripping voltammetry after closed-system Tefloncup digestion with nitric acid.
Mass Spectral Quantitation of Cocaine HCl in Powders
Authors: Clark Charles C
Published: February 2020

Gas-liquid chromatography (GLC) using a mass spectrometer (MS) as a detector is used for the quantitative determination of cocaine HCl in powders. After the sample is dissolved in methanol containing deuterated cocaine HCl internal standard, an aliquot is injected into the GLC-MS system with the mass spectrometer operating in the scan mode. The cocaine HCl concentration is calculated from the 303/308 m/e ratio. The procedure has a relative deviation of approximately 2.3% and is applicable to samples containing a wide variety of diluents and adulterants.
Pre-enrichment Broths for Recovery of Salmonella from Milk Chocolate and Edible Casein: Collaborative Study
Authors: Poelma Paul L , Andrews Wallace H , Wilson Clyde R ,   Collaborators:, Coles C M , Edwards A W , Hayden M A , Haymond R E , Heagy J , Kallander K , Lappin D , Latt T G , McDonald R L , McKee C R , Mihm J , Palmieri M J , Quinones L , Richter S G , Roderick C N , Sado P N , Sellers R L , Singleton E , Smith M , Tardio J L , Wagner D E , White C H , Williams M P
Published: February 2020

A collaborative study was conducted to compare the relative efficiency of nonfat dry milk with brilliant green dye (NFDM-BG) and buffered peptone water (BPVV) as pre-enrichment broths for recovery of Salmonella from milk chocolate. Lactose broth and modified lactose broth with added 1% NaHCO3 and brilliant green dye were compared as pre-enrichment broths for recovery of Salmonella from edible casein. Two sets of 8 samples each of milk chocolate, containing initial levels of Salmonella ranging from <0.03 to 43 organisms/g, were examined by 13 collaborators. Of 104 determinations, 102 (98.1%) and 100(96.2%) using NFDM-BG and BPW, respectively, were in agreement with sample results of the control laboratory. Two sets of 7 samples each of edible casein, containing initial levels of Salmonella ranging from <0.03 to 93 organisms/g, were also examined by the 13 collaborators. Of 91 determinations, 87 (95.6%) and 88 (96.7%) using lactose broth and modified lactose broth, respectively, were in agreement with sample results of the control laboratory. For recovery of Salmonella, therefore, NFDM-BG pre-enrichment is recommended for milk chocolate, and lactose broth is recommended for casein. The proposed revision of official final action method 46.054-46.067 has been adopted official first action
Simplified Apparatus for Determination of Mercury by Atomic Absorption and Inductively Coupled Plasma Emission Spectroscopy
Authors: Suddendorf Ronald F , Watts James O , Boyer Kenneth
Published: February 2020

A simplified apparatus has been applied to the determination of mercury by cold vapor generation. The equipment consists of a reaction flask incorporating a side arm in which a rubber septum is mounted. A sample solution is injected from a syringe through the rubber septum into the reaction flask, where it is mixed with a stannous chloride reducing solution. The elemental mercury generated is then swept with a carrier gas to the inductively coupled plasma (ICP), an absorption cell of an atomic absorption spectrometer, or a nondispersive UV monitor for determination. Detection limits were 0.00.9 and 0.005 μg with atomic absorption and the UV monitor, respectively, and 0.09 μg with the ICP. Repeatability of the procedure was 1.4% at 0.66 μg injected mercury with the ICP and 5.2% at 0.45 μg injected with atomic absorption. Tuna and halibut samples fortified with from 0.09 to 1.31 μg mercury/g were analyzed by the AOAC official method and the procedure described here. The average mercury recovery was 103% with the ICP, and 99% with the UV monitor and with atomic absorption. The procedure is free from interference by elements commonly present in biological material.
Analysis and Evaluation of Barley Used in the Malt Beverage Industry
Authors: West Dwight B
Published: February 2020

The American Society of Brewing Chemists methods for barley moisture, extract, and potential diastatic power are presented. These methods were reviewed by a Barley Analysis Subcommittee during 1975–1980 and published as recommended procedures. The moisture determination has been adopted as an official first action ASBC-AOAC method.
Colorimetric Alpha-Amylase, Falling Number, and Amylograph Assays of Sprouted Wheat: Collaborative Study
Authors: Mathewson Paul R , Fahrenholz Charles H , Booth Gordon D , Miller Byron S , Pomeranz Yeshajahu ,   Collaborators:, Ahmed S R , Axford D W , Bass E J , Boiling H , Chapman D W , Dot J W , Dur R H , Egber D C , Hempleman E W , Marchyl B , Meredit P , Naga S , Perten H , Perten P , Prasad K , Rubenthaler G L , Sawabe T , Sog L , Spillan P , Sundberg D F , Udy D C , Wyant R N
Published: February 2020

Results are reported of a collaborative study on the determination of sprout damage in wheat. Methods of analysis included falling number, amylograph, and a colorimetric α-amylase assay. Data for the 3 methods were linearly interrelated. Primary source of error for each method was lack of agreement among collaborators. The 3 tests adequately differentiated among sprout damage levels within a single laboratory. The colorimetric test was the most sensitive to change in α-amylase content and appeared to have greater potential for standardization than the other 2 methods
High Pressure Liquid Chromatographic Determination of Aflatoxins in Spices
Authors: Awe Michael J , Schranz John L
Published: February 2020

High pressure liquid chromatography with fluorescence detection is used to determine aflatoxin in 5 common spices. A 10 µm microparticulate silica gel column is used with a dichloromethane-cyclohexane-acetonitrile solvent system to resolve aflatoxins B1, G1, B2, and G1. The fluorescence detector contained a silica gel-packed f lowcell. Samples of black, white, and red pepper, ginger, and nutmeg were extracted according to a previously published method. Recoveries from aflatoxin-free samples of white pepper, ginger, and red pepper spiked with 1-50 µg aflatoxin/kg ranged from 64 to 92%.
Oscillating U-Tube Density Meter Determination of Alcoholic Strength: Analysis of Parameter Errors
Authors: Kovář Jan
Published: February 2020

Determination of density by using the density meter was superior to pycnometry and hydrometry in precision, accuracy, insensitivity to operator, temperature control, speed, and adaptability to automation. The linearity between oscillation period and density in the range of ethanol-water solutions is more than adequate. The method is practically insensitive to changes in air pressure; the single most important influence on the error in results is temperature reading errors. It is recommended that the Organisation Internationale de Métrologie Légale General Formula be used to correlate densities with alcoholic strength.
High Performance Liquid Chromatographic Determination and Clearance Time of Aflatoxin Residues in Swine Tissues
Authors: Miller Doris M , Wilson David M , Wyatt Roger D , Mckinney Jerry K , Crowell Wayne A , Stuart Barry P
Published: February 2020

Liver, kidney, and muscle tissues from swine given a single oral dose of 1.2 mg aflatoxins/kg body weight and from young pigs fed an aflatoxin-contaminated diet (0,400, or 800 ng/g feed) for 10 weeks were analyzed for aflatoxin residues. Extraction was performed according to the method of Stubblef ield and Shotwell. Aflatoxin residues were detected by high performance liquid chromatography (HPLC), and residue levels were correlated with withdrawal times. Residues were present in liver and kidney but not muscle by 12 h post-dosing; residues were detected in muscle after 24 h. Residue levels decreased over the 72 h period in all tissues. No aflatoxin residues were detected in the muscle from any pig 72 h postdosing or in those pigs fed the 400 ng/g diet, but were present in the muscle of pigs fed the 800 ng/g diet.
High Pressure Liquid Chromatographic Determination of Physostigmine Salicylate and Physostigmine Sulfate in Liquids and Ointments: Collaborative Study
Authors: Tymes Norlin W ,   Collaborators:, Briguglio G , Corcoran C , Everett R , Feyns L V , Fisher E , Gray V , Hughes D , Lazar A , Marks A , Radin J , Thompson R
Published: February 2020

Results of 11 laboratories are presented for the collaborative study of a proposed method for the quantitative reverse phase high pressure liquid chromatographic (HPLC) determination of physostigmine salicylate and physostigmine sulfate in pharmaceutical formulations. The samples consisted of commercial solution, injection, and ointment preparations, each containing one of the physostigmine salts. The physostigmine salt is extracted from ointments with acetonitrile after the ointment is dissolved in hexane. Liquid preparations are diluted directly. Physostigmine is determined at 254 nm on a C18 column by comparison with a physostigmine standard. Flurazepam hydrochloride is the internal standard. The method has been adopted official first action for the solution dosage form.
Evaluation of Analytical Methods Used for Regulation
Authors: Horwitz William
Published: February 2020

Regulatory analysis requires methods for analysis for 3purposes: surveillance, to detect problems; monitoring, to follow trends; and compliance, to enforce specifications (standards, action levels, tolerances). Each purpose requires a different weight to be assigned to the relative importance of the scientific characteristics of methods of analysis: systematic error, repeatability, reproducibility, limit of determination, and specificity. Evaluation consists of balancing the level of scientific requirements against the practical considerations of cost, time, and level of (raining required. In trace analysis, FDA utilizes recovery limits of 80-110% at ≥0.1 ppm and 60-100% below. The criterion for acceptable reproducibility (total of between- and within-laboratories) of methods of analysis can be represented by a relationship between coefficient of variation and concentration. The results of collaborative studies show that 10% outliers must be tolerated, but above 20% is excessive. Other new, important criteria for evaluation of methods at trace levels are % false positives, false negatives, and the magnitude of the blank.
Dry Ashing, Hydride Generation Atomic Absorption Spectrometric Determination of Arsenic and Selenium in Foods
Authors: Tam Gerard K H , Lacroix Gladys
Published: February 2020

A dry ashing, flameless atomic absorption spectrometric method was evaluated to determine arsenic and selenium in foods. Samples were dry-ashed with Mg(N03)2-MgO and dissolved in HC1. Selenate was reduced to selenite by boiling in 4N HC1, and arsenate to arsenite by treatment with KI. Hydrides of arsenic and selenium were generated by the addition of NaBH4 and were swept by nitrogen and hydrogen into a thermally heated silicate tube furnace. The detection limit was about 5 ppb for each element based on a 10 g sample. Analytical results obtained for several samples of NBS reference materials agreed with the certified values. The procedure was evaluated by another laboratory and results were satisfactory.
Evaluation of Thin Layer, Paper, and High Performance Liquid Chromatography for Identification of Dyes Extracted as Ion-Pairs with Tri-n-octylamine
Authors: Puttemans Marc L , Dryon Louis , Massart Désiré L
Published: February 2020

Food dyes, extracted into chloroform as ion-pairs with tri-n-octylamine, are chromatographed directly in various liquid chromatographic systems. Dyes can be identified by comparison of the chromatographic behavior of ion-pairs with behavior of reference dyes dissolved in water. In thin layer and paper chromatography, the ion-pairs dissociate when polar eluants are used; thin layer chromatography is preferred because of less tailing. In high performance liquid chromatography, a reverse phase ion-pair system is used with tetrabutylammonium as the counter ion; chloroform-extracted dyes show retention times similar to reference dyes dissolved in water.
Modification of the AOAC Gas-Liquid Chromatographic Method for Indole in Shrimp: Collaborative Study
Authors: Chambers Theodore L ,   Collaborators:, Netz E C , Ogger K
Published: February 2020

Several changes were suggested for standardization of the AOAC official final action gas chromatographic method for the determination of indole in shrimp. In a collaborative study, 3 FDA laboratories compared the modified method with the current method. At a 95% confidence level, the same results were obtained for each respective sample by the AOAC or the modified method, which had the following changes. The cleanup column was standardized by drying the silica gel for 2 h at 125°C and equilibrating with 3 g of water/25 g of silica gel. Concentrated ethyl acetate shrimp extracts were treated with anhydrous sodium sulfate before column cleanup and indole was eluted from the column with 15% ethyl ether/hexane. A reduced amount of the internal standard, 2-methylindole, was used to improve peak height measurements at the 25 μg% indole level. The modified method has been adopted official first action to replace method 18.075.
Determination of Background Levels of Lead and Cadmium in Raw Agricultural Crops by Using Differential Pulse Anodic Stripping Voltammetry
Authors: Satzger R Duane , Clow Charles S , Bonnin Evelyn , Fricke Fred L
Published: February 2020

A method is described for the simultaneous determination of ultratrace levels of lead and cadmium in selected agricultural crop samples by differential pulse anodic stripping voltammetry. Samples are dry ashed at high temperature with H2SO4 as an ashing aid. Techniques are described to control the lead and cadmium blank levels of 2 ng and 0.4 ng, respectively. Typical relative standard deviations for the crop analyses are 13% at 100 ng/g and 25% at 10 ng/g for lead, and 5% at 100 ng/g and 10% at 10 ng/g for cadmium. The lowest quantifiable level, based on 3 g dry sample, is 2 ng/g for lead and 1 ng/g for cadmium. Recovery studies, precision studies, and analyses of NBS Standard Reference Materials demonstrate the accuracy and reproducibility of this technique. A summary of results for over 1700 crop samples is reported.
High Performance Liquid Chromatographic Determination of Difenzoquat Residues in Water
Authors: Ahmad Ijaz
Published: February 2020

A simple analytical method is described for the quantitative determination of difenzoquat (1,2- dimethyl-3,5-diphenyl-lH-pyrazolium methyl sulfate) residues in water. The method involves high performance liquid chromatography with ultraviolet detection at 255 nm. The procedure is used to determine 2 ppb to 1 ppm levels of difenzoquat in pure and tap water. Samples which contain ≥50 ppb difenzoquat are injected directly into the liquid chromatograph without prior separation, concentration, or purification. Samples containing ≤50 ppb difenzoquat are first enriched on C18 Sep-Pak reverse phase cartridges and then injected into the liquid chromatograph. Average recoveries of difenzoquat were greater than 92% with a coefficient of variation less than 4.5%. The method can be used for water samples with difenzoquat concentrations as low as 2 ppb.
High Performance Liquid Chromatographic Determination of Caffeine in Decaffeinated Coffee, Tea, and Beverage Products
Authors: Ashoor Samy H , Seperich George J , Monte Woodrow C , Welty Jim
Published: February 2020

A method was developed for determining caffeine in decaffeinated coffee, tea, and beverage products by high performance liquid chromatography (HPLC). The HPLC system consisted of a Bio-Sil ODS-5S C18 column, methanol-water (25 + 75) mobile phase at 1 mL/min, and a UV detector. The method is simple and specific. Caffeine recoveries were 93.8-98.3% and coefficients of variation were 0.90-2.25%.
High Performance Liquid Chromatographic Determination of Seven Antioxidants in Oil and Lard: Collaborative Study
Authors: Page B Denis ,   Collaborators:, Bigornia R , Blanc M , Charbonneau C , Lamontagne J-C , Minnee J S , Perfetti G , Wong L , Zorniak D
Published: February 2020

A high performance liquid chromatographic procedure for the determination of propyl gallate (PG), 2,4,5-trihydroxybutyrophenone (THBP), tert-butylhydroquinone (TBHQ), nordihydroguaiaretic acid (NDGA), 2- and 3-tert-buty1-4-hydroxyanisole (BHA), 2,6-di-tert-buty1-4-hydroxymethylphenol (Ionox-100), and 3,5-di-tert-buty1-4-hydroxytoluene (BHT) was collaboratively studied by 8 laboratories. The 14 samples analyzed consisted of 10 vegetable oil samples spiked in matched pairs at about 200,100, and 20ppm and 4 lard samples spiked in matched pairs at about 100 and 40 ppm for each antioxidant except NDGA which was spiked only at the 2 lower levels in oil. In the method studied, the samples were dissolved in hexane and the antioxidants were partitioned into acetonitrile. The acetonitrile was concentrated and diluted with isopropanol to give isopropanol-acetonitrile (1 + 1). The antioxidants were separated by reverse phase gradient elution and detected at 280 nm. The results from one laboratory were rejected as outlying and were not considered in any calculations. For the remaining 7 laboratories, the overall mean recoveries for PG, THBP, TBHQ, NDGA, BHA, Ionox-100, and BHT were 93.2, 95.1,95.6,95.5,98.3,95.8, and 84.8%, respectively, and the overall mean coefficients of variation were 5.02,7.74, 19.3,4.36,3.75,6.33, and 3.45%, respectively.
High Pressure Liquid Chromatographic Determination of Nitrogen Derived from Urea and Water-Soluble Methylene Ureas in Urea Formaldehyde Fertilizers: Collaborative Study
Authors: Davidson Allan D ,   Collaborators:, Austin E R , Christensen B M , Coggin D , Diuguid J , Francis H K , Johnson F J , Porterfield D G , Proksa P , Quick F E , Reese B , Teague R T
Published: February 2020

A melhod for measuring nitrogen derived from urea, melhylenediurea (MDU), and dimethylenetriurea (DMTU) was tested by 9 collaborators. Collaborators made single determinations on 2 separate days on 5 sets of paired samples. Samples were extracted with water, filtered, and analyzed after high pressure liquid chromatographic separation on a C-8 or C-18 bonded silica column, using a refractive index detector. Peak heights compared to external standard of each component were used for quantitation. Mean coefficients of variation for the completed study were 3.24% for urea, 3.48% for MDU, and 6.56% for DMTU. The method has been adopted official first action.
High Pressure Liquid Chromatographic Determination of Oxazepam Dosage Forms: Collaborative Study
Authors: Bargo Eileen S ,   Collaborators:, Aranda E , Bonnin C , Hauser S , Henry K , Murphy C , Newman A , Perry J , Reed G , Rutgers J , Williams P
Published: February 2020

A reverse phase high pressure liquid chromatographic method for the determination of oxazepam in tablets and capsules was collaboratively studied by 9 laboratories. Collaborators were supplied with 6 samples that included synthetic and commercial formulations. Tablet and capsule composites are diluted with methanol and filtered. Oxazepam is determined at 254 nm by using a C18 column. Mean recoveries of oxazepam from synthetic tablet and capsule formulations were 97.2 and 99.0%, respectively. Mean coefficients of variation for tablets and capsules ranged from 1.85 to 2.86%. The method has been adopted official first action.
Enumeration of Coliforms in Nonfat Dry Milk and Canned Custard by Hydrophobic Grid Membrane Filter Method: Collaborative Study
Authors: Entis Phyllis ,   Collaborators:, Ciebin B W , Gipson V , Grahn M , Hunt S , Idziak E , Kalinowski R J , Kreiger F , Lachapelle G , Lancette G A , Lanier J M , Lister M M , Martin A , Maserang D L , Nath E J , Oji R T , Plank W M , Ponycharierks D , Smith A M , Varney G W , Wong P , Zapatka F A
Published: February 2020

A collaborative study was conducted in 14 laboratories to evaluate the performance of the hydrophobic grid membrane filter method against the official final action method, 46.016, for enumeration of colif orms in foods. Twelve artificially contaminated samples of nonfat dry milk and canned custard were analyzed by each laboratory. The random errors (Sr2) associated with the hydrophobic grid membrane filter method were significantly lower than those of the official method, and the counts obtained by the new method fell within the 95% confidence interval of the reference method. The colif orm counts obtained by tiie hydrophobic grid membrane filter method did not differ significantly from those obtained by the reference method as measured by a 3-way analysis of variance. The new method has been adopted official first action.
Chloroform-Methanol Extraction Method for Determination of Fat in Foods: Collaborative Study
Authors: Daugherty Chester E , Lento Harry G ,   Collaborators:, Adams M L , Beckert E W , Bender M L , Berman S , Chow L , Davis C , Gedang D , Howe K , Murphy M J , Porcuna M , Sabolish G , Shen C-S J , Smith N M , Tessaro A
Published: February 2020

Achloroform-methanol extraction method (complete extraction of fat in 3 min) for determining fat in processed and prepared foods has been studied collaboratively. Fourteen collaborators reported single replicate fat results on 7 samples representative of various food types and 2 spiked samples by the proposed method. Each sample was accompanied by a blind duplicate. For statistical purposes, the blind duplicates were treated as paired observations, and there were 2 laboratory outliers. There was a 97.9% agreement among the results from the remaining 12 collaborators and the Associate Referee for the unfortified samples. Recoveries of 93.8 and 98.3% were obtained on fortified samples, based on results obtained from 11 collaborators. The statistical analysis of the results indicate (ranges for standard deviations were Sr = 0.083-0.528, Sb = 0.101-0.379, Sd = 8.130-0.631, for fat values ranging from 1.58 to 26.91%) that this method is adequate for quantitating the fat content in a wide variety of processed foods for nutritional labeling. The method has been adopted official first action.
Separation and Identification of Phencyclidine and Some of Its Analogs
Authors: Rao K Gurudath , Soni Shiv K
Published: February 2020

l-(l-Phenylcyclohexyl)piperidine (PCP) and 9 of its analogs have been separated and identified by using thin layer chromatography, high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and infrared spectroscopy (IR). Spectral and chromatographic characteristics are discussed in terms of the structural variations observed in these compounds. Some compounds decomposed on the GC column; the HPLC procedure is a helpful substitute. A tentative scheme is proposed for the fragmentation of the major ions observed in the mass spectra. The effect of substitution on the IR spectra of the analogs was investigated.
Atomic Absorption Spectrophotometric Determination of Mercury in Mercury≃Containing Drugs: Collaborative Study
Authors: Holak Walter ,   Collaborators:, Baltz R , Elliott L , McGary E , McNerney E , Midwood R , Rupf J , Tepedino N
Published: February 2020

An atomic absorption spectrophotometric (AAS) method applicable to a wide variety of mercurycontaining drugs has been developed and subjected to a collaborative study. Samples were digested with a water-HCl-HN03 (4 + 3 + 1) mixture, and the mercury was determined in solution by AAS. High levels of mercury were measured with a conventional air-acetylene flame, whereas low levels were measured by the flameless technique. Each of 7 collaborators received duplicate synthetic samples of a tincture, an ophthalmic solution, and an antiseptic solution, and duplicate commercial samples of an ointment and an injectable. The overall mean value found by collaborators for mercury in these samples was 100.13%. The corresponding overall repeatability SD (CV, %) and reproducibility SD (CV, %) values were 2.18 (2.18) and 3.38 (3.38), respectively. The proposed AAS method has been adopted official first action.
Liquid Chromatographic Determination of Methyldopa and Methyldopa-Thiazide Combinations in Dosage Forms
Authors: Ting Susan
Published: February 2020

A liquid chromatographic (LC) method, using a reverse phase C18 column, an acetic acid-methanol-water mobile phase, and detection at 280 nm, was developed for the determination of methyldopa in tablets and oral suspensions and combinations of methyldopa with hydrochlorothiazide or chlorothiazide in tablets. A mixture of these 3 drugs was resolved in <8 min. Detector responses were linear for the following amounts (mg/mL) of drug injected: methyldopa 0.031-0.393, chlorothiazide 0.019-0.114, and hydrochlorothiazide 0.004-0.083. Recoveries from commercial dosage forms ranged from 99.1 to 100.9% for methyldopa, 99.2-100.4% for chlorothiazide, and 100.0-101.2% for hydrochlorothiazide. Replicate injections of methyldopa, chlorothiazide, and hydrochlorothiazide standard preparations alone or in combination gave overall relative standard deviations of <1.6% (n = 10). The results for methyldopa tablets by the proposed method were in agreement with those obtained by the USP XX method. The LC method detected as little as 0.6 μg 3-O-methylmethyldopa/mL and 0.5 μg 4-amino-6- chloro-l,3-benzenedisulfonamide/mL, which are sometimes found as contaminants of methyldopa and thiazides, respectively, and resolved methyldopa from its methyldopa glucose adduct, a substance found in methyldopa oral suspensions.
Pesticide, Metal, and Other Chemical Residues in Adult Total Diet Samples. (XIII). August 1976–September 1977
Authors: Johnson Roger D , Manske Dennis D , New Dallas H , 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.
Malt Beverages and Brewing Materials: Gas Chromatographic Determination of Ethanol in Beer
Authors: Cutaia Anthony J
Published: February 2020

The American Society of Brewing Chemists collaboratively tested a gas chromatographic method for determination of ethanol in beer. Ten laboratories collaborated in a comparison of the ASBC reference method for alcohol by distillation with the GC method. The latter was shown to be at least as precise as the former, it is more rapid, and it can be used for in-line or process monitoring. The method has been adopted official first action.
Liquid Chromatographic Determination of Ascorbic Acid in Foods
Authors: Ashoor Samy H , Monte Woodrow C , Welty Jim
Published: February 2020

Ascorbic acid has been determined quantitatively in a variety of fresh and frozen fruits and vegetables, fresh and fortified canned juices, and powdered drinks by liquid chromatography (LC). The method consists of blending the sample in a solution of 0.05% EDTA in 0.2N H2S04, centrifuging or filtering the mixture, then injecting a portion into the LC system. An Aminex HPX-87 LC column was used with 0.009N H2S04 as solvent with a flow rate of 0.5 mL/min. Detection was at 245 nm. The method is simple and sensitive, and yields a high recovery. It compares favorably with the AOAC method, and has the advantage of being more accurate for samples with interfering pigments.
Liquid Chromatographic Determination of Methocarbamol in Injection and Tablet Dosage Forms: Collaborative Study
Authors: Everett Richard L ,   Collaborators:, Allgire L , Ballbach R J , Booth J , Johnson D , Lookabaugh M , Tyson B C
Published: February 2020

A reverse phase liquid chromatographic method was developed for determining methocarbamol in injection and tablet dosage forms. The injections require dilution only; the tablets require a nitration step before introduction into the chromatograph. Response for methocarbamol was linear over the range 0-18 μg, using an ultraviolet detector at 274 nm. Recoveries by the author ranged from 96.1 to 101.9% for authentic injection formulations and 98.0 to 101.0% for authentic tablet formulations. A collaborative study of the method by 6 laboratories resulted in standard deviations of 1.70 and 2.22 for injection and tablet dosage forms, respectively. The method has been adopted official first action.
Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Poultry Fat: Collaborative Study
Authors: Ault James A , Spurgeon Tim E ,   Collaborators:, Anderson M M , Bowers R , Brunton E , Gillard D F , Johnson F , Johnson R W , McDaniel C A , Meyer K A , Miller B W , Mitchell J , Osheim D J , Patel V , Richardson H , Roof J , Stogsdill C
Published: February 2020

A gas chromatographic electron capture detector method is described for the quantitative determination of organochlorine pesticide residues in poultry fat. The samples are rendered and cleaned up using automated gel permeation chromatography. The collaborative samples consisted of 10 fortified samples and one incurred residue sample, all in duplicate. Fortification levels ranged from 0.15 to 1.0 ppm for a-BHC, lindane, cis- and frans-chlordane, octachlor epoxide, o,p' and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 91.9% with a range of 81-102%. The ranges of coefficients of variation were: CVo = 3.39-14.79%; CVL = 0-16.6%; and CVx = 5.82-19.0%. The results indicate accuracy and precision comparable to other official methodology. The method has been adopted official first action.
Liquid Chromatographic Determination of Methiocarb in Technical and Formulated Products: Collaborative Study
Authors: Slahck Stephen C ,   Collaborators:, Carlstrom A A , Chenery L T , Ellis N D , Folsom B D , Forrette J E , Gentry G M , Jensen T , Jurgens D , Korger P D , Laster W G , Mummah L , Pearson P M L , Stroh S , Wong D L
Published: February 2020

An LC method for the determination of methiocarb in methiocarb technical and formulated products has been subjected to a collaborative study with 9 participating collaborators. Formulations are extracted with acetonitrile and analyzed by reverse phase chromatography, with acetophenone as an internal standard. Collaborators were furnished samples of technical, 75% wettable powder, 75% seed treater, 75% concentrate, and 50% hopper box treater. Coefficient of variation values obtained on the 5 samples were 0.71, 0.83, 0.62, 1.57, and 0.82%, respectively. The method has been adopted official first action.
High Performance Thin Layer Chromatographic Identification of Synthetic Food Dyes in Alcoholic Products
Authors: Steele John A
Published: February 2020

High performance thin layer chromatography systems using 2 multicomponent solvent systems are described for the separation and identification of FD&C permitted dyes Yellow No. 5, Yellow No. 6, Red No. 40, Red No. 3, Blue No. 1, Blue No. 2, Green No. 3; FD&C delisted dyes for foods: Amaranth, formerly certified as FD&C Red No. 2, Red No. 1, Red No. 4 (delisted for foods, permitted for external drugs and cosmetics); D&C dyes Yellow No. 10, Green No. 5, and Red No. 4. The method is suitable for the rapid monitoring of synthetic food dyes in alcoholic beverage products. Also, the method offers the means of qualitative and quantitative spectrodensitometry of synthetic food dyes found in alcoholic beverage products.
Confirmation of Pesticide Residue Identity. XI. Organophosphorus Pesticides
Authors: Lee Hing-Biu , Weng Li-Da , Chau Alfred S Y
Published: February 2020

Modification of a method previously published by us generates a wider scope and more rugged procedure for the confirmation of 9 organophosphorus pesticides (OPs). This method involves the hydrolysis of OPs to the corresponding phenols which are then derivatized to their pentafluorobenzyl (PFB) ethers. The ethers are subsequently cleaned up and fractionated on a 5 % deactivated silica gel column and analyzed by electron capture gas chromatography. This procedure enables the confirmation of levels of 10–0.01 ppb OPs from 1 L of water.
Gas Chromatographic Determination of Metribuzin in Formulations: Collaborative Study
Authors: Betker William R ,   Collaborators:, Anderson D , Bajovich J M , Bennett O O , Carlstrom A A , Chenery L T , Chiang T C H , Doherty P J , Forrette J E , Grypa R , Hageman L , Hodgins E , Karr J J , Koenig D K , Korger P D , Launer J E , McDaniel S , Meinen V J , Minyard J P , Owen M E , Polli R L , Sabbann M , Teubert W E , Torma L , Victoria V C
Published: February 2020

A collaborative study was conducted on a gas chromatographic method for determining metribuzin. Two 75% dry flow able and two 42% liquid flowable formulations were analyzed by 18 laboratories. Formulations were extracted by shaking or ultrasonic mixing for 1-5 min with methylene chloride which contained di-n-butyl phthalate as an internal standard. The extracts were injected into a gas chromatograph equipped with an OV-225 column. Peak area ratios and peak height ratios showed no significant difference. The reproducibility coefficient of variation was 0.75% for the 75% formulation and 1.41% for the 42% formulation. This GC method has been adopted official first action.
Liquid Chromatographic Determination of Lactose Purity: Collaborative Study
Authors: Saucerman Janice R , Winstead Charles E ,   Collaborators:, Casaletto P J , DeAngelis N J , Foglia T A , Greene G W , Helbig T , Hugunin A G , Mills R S , Nupson H , West L G , West L G , Zimmermann A F
Published: February 2020

Results from 8 laboratories are presented for the collaborative study of a proposed method for quantitative liquid chromatographic (LC) determination of lactose purity. Each laboratory was provided with 10 blind duplicate, edible-grade lactose samples plus a lactose reference standard and a fructose internal standard. Testing required the comparison of aqueous 2% lactose sample solution against a reference standard of equal concentration and quantitation by using a fructose internal standard. The LC system specified an isocratic acetonitrilewater (80 + 20) mobile phase, flow rate 2.0 mL/min, and chromatographic separation on a carbohydrate column. Compounds were detected by using refractive index. Statistical analysis for all study data indicates excellent between-laboratory precision with a coefficient of variation (CV) range of 0.53-1.37% and an overall average of 0.977%. Statistical analysis after excluding outliers showed equally good repeatability and reproducibility of less than 1 % and 1.5% CV, respectively. The method has been adopted official first action.
Comparison of Helium Leak Test and Vacuum Leak Test Using Canned Foods: Collaborative Study
Authors: Rhea Ulysses S , Gilchrist James E , Peeler James T , Shah Dhirendra B ,   Collaborators:, Allen B , Hoffman D , Landry W , Radle C D , Shields S , Tepidino A , Varney G
Published: February 2020

Two can leak tests were compared by 7 collaborators. In the helium leak test, pressurized helium is applied to the outside of the container, and a headspace gas sample from the can is then analyzed for the presence of helium. The vacuum test is described in the Bacteriological Analytical Manual. Ninety No. 303 cans of creamed-style corn, green beans, carrots, fruit cocktail, and whole-kernel corn were shipped in 3 groups. Two groups of 30 cans had 10 dented flat cans, 5 flat controls (nondented), 10 dented swollen cans, and 5 swollen control cans (nondented). The third group had 10 dented swollen cans and 5 swollen control cans. Of 600 cans analyzed, 37 (6.2%) were deleted from the analysis because results were not available for both tests. One laboratory was constrained by scheduling to analyze 15 of 45 swollen cans. The helium leak test found 12 (13%) positives of 92 nondented swollen cans. One pressurization test yielded 7 of those 12 positives. Of the 400 dented cans sent as possible leakers, the helium test found 267 positives, and the vacuum test found 181. Five of the 7 analysts had significantly (α = 0.05) higher percent positive helium results. One analyst found more leakers by the vacuum leak test. Both tests found fewer positives in the swollen dented cans than in the flat dented cans. After exposure to pressurized helium, all cans with greater than 8 psi headspace pressure were positive helium leakers. The method was adopted official first action.
Development of an Overnight Rapid Bovine Identification Test (ORBIT) for Field Use
Authors: Mageau Richard P , Cutrufelli Mark E , Schwab Bernard , Johnston Ralph W
Published: February 2020

An Overnight Rapid Bovine Identification Test (ORBIT) has been developed as a serological screen test for species verification of raw, whole tissue, bovine meat products. The test, an agar-gel immunodiffusion technique, uses stabilized reagent paper discs and prepared agar plates that have a printed template for correct placement of test components. This test is reliable, practical, economical, and easily performed in the field, such as at a meat import inspection station. The only nonbovine species found to react in the test are the bovine-related species of American bison (buffalo) and water buffalo (from Australia); however, these rare-occurring species do not present a problem for the intended application of the test. Stability of all test components, when stored in a refrigerator, is excellent for at least 1 year. The nature and stability of the test make it suitable for commercial development into test kits which should be highly practical and economical for wide availability and application of this procedure to meat inspection programs concerned with species verification.