bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphorylation of Alcohols/Phenols for Gas-Liquid Chromatographic Separation and Flame Photometric Detection
Authors: Deo Padmakar G , Howard Philip H
Published: February 2020

A new procedure is presented for the gas-liquid chromatographic separation of alcohols and phenols, using phosphorylation by diethyl chlorophosphate. Alcohols/phenols were phosphorylated by a base-catalyzed reaction with diethyl chlorophosphate, and the resulting alkyl/aryl diethyl phosphates were separated by gas-liquid chromatography and detected by a flame photometric detector supplied with a 526 nm filter. For seven alcohols/phenols tested, quantities as low as 10–25 ng were easily detected.
Microbiological Assay of Lincomycin in Swine and Broiler Feeds
Authors: Stahl Gerald L
Published: February 2020

The AOAC official first action method for lincomycin has been modified to include the broiler 2 g/ton level and the swine feed levels approved for use as high as 2600 g/ton. The procedures involve 3 different sample preparatory methods with progressive simplification as the concentration of the antibiotic is increased. A 7–8 ml agar monolayer is used with slightly lower standard concentrations which produce a more sensitive response by the organism and allows for a reduction in sample size for 2 g/ton feeds. Samples prepared by all 3 techniques are analyzed by this same bio-plate system. Recoveries of the feed concentrations analyzed ranged from 80.5 to 118.0% and averaged 96– 103% of theory. Standard deviations of 10% or less indicate the methods described are accurate and precise enough to be used with confidence. The use of these methods has resulted in more rapid assay turnover and cost savings.
Modified Gas Chromatographic Determination of Phosphine
Authors: Dumas Theodore
Published: February 2020

A method for determining residual phosphine (PH3) at the ppt level using 10 cm × 3 mm id stainless steel tubing containing absorbent and cooled with Dry Ice was used to trap PH3 from a stream of air. The trap which was adapted for use with a gas chromatographic (GC) system was then transferred to the gas chromatograph for direct analysis of the PH3. Samples of wheat treated with PH3 and exposed to air for several days were analyzed after 24-hr desorption and ppt quantities of PH3 were found even after 17 days’ aeration. Trapping PH3 and the GC determination took less than 30 min, and the time for inserting the trap in the gas chromatograph was about 10 sec.
Quantitative Determination of Chlorpromazine. HC1 in Tablets, Spansules, Injectables, and Bulk Chemical by Nuclear Magnetic Resonance Spectroscopy
Authors: Zarembo John E , Warren Richard J , Staiger David B
Published: February 2020

A nuclear magnetic resonance (NMR) procedure is described for the quantitative analysis of chlorpromazine. HC1 in bulk chemical as well as in final dosage forms—tablets, spansules, and injectables. The method is based on measurement of a characteristic signal of chlorpromazine relative to an internal standard. Three different internal standards are specified: Cyclohexane was selected because of the convenience and rapidity with which samples could be prepared for assay. Piperonal was used to verify the method and to show that precision and accuracy were not affected by the volatility of the cyclohexane. Tetramethylammonium bromide was used as an internal standard for Thorazine injectable. No interferences were found from stearates and other tablet excipients. The NMR procedure provides a simple, direct, and specific assay with a precision of ± 1–2%.
Gas-Liquid Chromatographic Determination of p-Chloroacetanilide in Acetaminophen
Authors: Wyatt Dorothy K , Grady Lee T
Published: February 2020

Gas-liquid chromatography (GLC) coupled with column chromatography was used to accurately determine as little as 25 ppm p-chloroacetanilide in acetaminophen. p-Chloroacetanilide was eluted from a pH 8 phosphate-buffered diatomite partition column by using purified tetrachloroethylene (acetaminophen was retained). This solution was concentrated, internal standard (docosane) was added, and p-chloroacetanilide was determined by using a 0.9 m × 2 mm glass column packed with 3% Poly A 103 on Supelcoport and a flame ionization detector with electronic integration. Standard curves were linear for 10–100 ppm p-chloroacetanilide. Various chromatographic materials were investigated for optimal retention characteristics. High pressure liquid chromatography (HPLC) was also evaluated as an alternative; however, lack of reproducibility of the HPLC column favored the GLC procedure.
Simplified Fat Extraction with Sulfuric Acid as Cleanup Procedure for Residue Determination of Chlorinated Hydrocarbons in Butter
Authors: Veierov Dan , Veierov Dan
Published: February 2020

A new cleanup procedure is described for chlorinated hydrocarbon residues in butterfat. The method is based on the dropwise addition of H2SO4 to a fat solution column and continuous removal of the lipids and the acid. The cleanup of 0.25-2.0 g fat requires only 10–40 ml sulfuric acid and 12–17 ml petroleum ether. There is no need for any further cleanup step, solvent evaporation, or centrifugation. The method is easy to standardize and is suitable for automation. At least 30 fat samples can be cleaned up manually by one analyst in one day. Recoveries were complete (>90%) for polychlorinated biphenyl compounds and for 13 chlorinated pesticides of 16 examined. The method was tested on chlorinated hydrocarbon residues in commercial butter and the results were compared with those obtained with the acetonitrile method. The versatility and limitations of the method were investigated by varying the sulfuric acid strength, initial fat solution concentration, and column dimensions.
Gas-Solid Chromatographic Determination of Vinylidene Chloride in Saran Film and Three Food-Simulating Solvents
Authors: Hollifield Henry C , McNeal Timothy
Published: February 2020

Gas-solid chromatographic (GSC) procedures are described for the analysis of Saran films for vinylidene chloride (VdC) and for determining the level of VdC migration from Saran film into 3 food-simulating solvents. The films are dissolved in tetrahydrofuran and analyzed for VdC by direct injection of the polymer solutions. VdC migration from Saran film to corn oil, heptane, and water is measured by headspace GSC. With electron capture detection and confirmation by GSC-mass spectrometry fragmentography, about 1 ppm VdC can be quantitated in the polymer and 5–10 ppb in the food simulants. Data for VdC migration from 2 commercial Saran films into the food simulants are presented to demonstrate the utility of the method.
Thin Layer Chromatographic Determination of Aflatoxin in Eggs: Collaborative Study
Authors: Nesheim Stanley , Trucksess Mary W
Published: February 2020

The thin layer chromatographic method of Trucksess et al. for aflatoxin Bx in eggs was collaboratively studied. Each collaborator analyzed 3 known practice samples and 9 unknown samples containing added aflatoxin Bx at 0, 0.05, 0.10, and 0.30 ng/g. For 9 collaborators, recoveries for the 3 positive levels were: 0–0.13 ng/g (average 98%, coefficient of variation (C.V.) 83%), 0.05-0.18 ng/g (average 102%, C.V. 36%), and 0.11-0.42 ng/g (average 93%, C.V. 31%), respectively. The method has been adopted as official first action.
Spectral Behavior of Ochratoxin A in Different Solvents
Authors: Goliński Piotr , Chetkowski Jerzy
Published: February 2020

The spectral behavior of ochratoxin A in solvents of different polarity was investigated. A red shift of absorption maximum to 375 nm in several solvents was observed as well as a red shift of fluorescence maxima. Molar extinction coefficients and efficiencies of fluorescence were dependent on solvent polarity.
High Pressure Liquid Chromatographic Determination of Strychnine, Using a Reverse Phase Solvent System
Authors: Crouch Michael D , Short Charles R
Published: February 2020

A simple, rapid extraction and subsequent determination for strychnine, using high pressure liquid chromatography (HPLC) with a reverse phase solvent system, is described. Stomach contents or grain bait containing strychnine were made alkaline with sodium hydroxide and extracted with chloroform. Extract filtrates were injected directly into a liquid chromatograph without further preparation except for dilution, if necessary. Peaks were resolved within 3.5 min and peak heights were used for quantitation. HPLC of strychnine was carried out on a 30 cm × 4 mm id stainless steel column packed with ≧Bondapak C18. The solvent program was 0.005M phosphate buffer-methanol (60+40) at a flow of 1.5 ml /min. Recovery from spiked stomach contents was 93.9±3.5%. The detection capability for strynchnine, using the 254 nm ultraviolet detector, was 5 ng. The strychnine peak was collected and subjected to thin layer chromatography with strychnine standards for confirmation.
Neutral Cleanup Procedure for 2,3,7,8-Tetrachlorodibenzo-p-dioxin Residues in Bovine Fat and Milk
Authors: O'Keefe Patrick W , Meselson Matthew S , Baughman Robert W
Published: February 2020

A neutral cleanup method for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in milk and animal tissue was developed involving solvent extraction and liquid adsorption chromatography on magnesia-Celite 545, alumina, and Florisil. Cleaned up extracts were subjected to dual-ion analysis in a direct probe high resolution mass spectrometer, interfaced to a multichannel analyzer for signal averaging. Calibration experiments were carried out with bovine milk and beef fat samples containing added TCDD. The 37C1 isotopic isomer of TCDD was added as an internal standard. The response was linear for concentrations in the ppt range, with recoveries about 80%. Milk from a cow fed TCDD was cleaned up by the neutral procedure or, alternatively, a base-acid extraction procedure. The TCDD recoveries for both procedures were essentially the same. Recoveries of TCDD from liver samples of a rat given 14C-TCDD intraperitoneally, subjected to neutral cleanup and radioactive counting, were about 70%.
Direct Analysis of Lead in Fruit Juice by Anodic Stripping Voltammetry With No Prior Sample Preparation
Authors: Zink Eric W , Matson Wayne R , Pfeiffer Sandra L , Pietrzyk Alexander F
Published: February 2020

A method is presented for determining lead in fruit juice in less than 3 min after instrument calibration. The range examined is 0.01 to 1.3 ppm lead. The method is compared with 3 other methods in general use. Standard error of estimates between the methods compared range from 0.023 to 0.051 ppm for a set of 50 samples and from 0.037 to 0.091 ppm for a set of 9 samples. Regression correlation coefficients between methods range from 0.968 to 0.995. Judged by the comparisons, the direct method is precise and accurate over greater than a 100-fold range of lead concentrations.
Automated Fluorometric Analysis of Calcium Pantothenate in Multivitamin Preparations
Authors: Roy Ram B , Buccafuri Anthony
Published: February 2020

An automated fluorometric procedure is described for assaying calcium pantothenate in multivitamin preparations. Sample extracts containing calcium pantothenate are treated on-line with a slurry of magnesium trisilicate which removes any interfering riboflavin that may be present. The nitrate is resampled, mixed online with a slurry of Dowex 50W-X4 (H+) which removes any interfering β-alanine that may be present, and dialyzed. Dialysates are hydrolyzed in an alkaline medium and reacted with a mixture of o-phthalaldehyde and 2-mercaptoethanoI in boric acid solution. The fluorescence intensity due to the formation of a fluorogenic compound is measured at 455 nm after excitation at 350 nm. The procedure developed is capable of analyzing 20 samples/hr. Analytical data indicate that calcium pantothenate is assayed reliably both from real and synthetic multivitamin preparations. The mean recovery of calcium pantothenate added to sample solutions of tablet composites was 95.4%.
Analysis of Fat-Soluble Vitamins. XX. Determination of Vitamin D in Multivitamin Preparations. Second Collaborative Study
Authors: De Vries Ellen J , Mulder Frits J , Borsje Ben
Published: February 2020

The official first action method for determining vitamin D in multivitamin preparations was modified. The method was collaboratively studied by 7 laboratories, using 6 preparations in oil. The preparations consisted of vitamin D at various levels and at various ratios (in w/w) to vitamin A. Three samples contained cholecalciferol and 3 samples contained vitamin D3 from vitamin D3 resin. After outliers were eliminated by the Dixon test, data were analyzed and averages were compared with amounts of vitamin D known to be in each sample. For samples with vitamin D: vitamin A ratios of 1:0.5, 1:5, and 1:10, the mean vitamin D recoveries were 98.8, 94.6, and 90.7%, respectively. The method has been adopted as official final action.
Mass Spectrometric Detection of High-Fructose Corn Sirup in Honey by Use of 13C/12C Ratio: Collaborative Study
Authors: White Jonathan W , Doner Landis W
Published: February 2020

Mass spectrometry is used to determine the 13C/12C/ratios in honey products. The 13C/12C ratios in domestic and imported honeys are sufficiently consistent and different from those of high-fructose corn sirups (HFCSs) so that the presence of added HFCS in honey can be demonstrated. Average values of δ13C of —25.4%0 (parts per thousand) for 119 honey samples and —9.7%0 for 4 HFCSs were found. δ13C values of mixtures are the weighted sum of the 813C values of the components. In a collaborative study, 4 honey-HFCS mixtures and 1 pure honey sample were correctly identified by 6 laboratories. The method has been adopted as official first action.
Rapid Spectrophotometric Method for Determination of 2-Aminobutane in Postharvest Dips
Authors: Baker Harvey J
Published: February 2020

A rapid method is described for measuring 2-aminobutane in postharvest dip fluids. Samples of the dip fluid are diluted to bring the 2-aminobutane content in the range 500—5000 μg and reacted with carbon disulfide and cupric ion to form a chloroform-extractable complex measured spectrophotometrically at 430 nm. The accuracy and reproducibility of the method are comparable with the more lengthy modified product and residue methods.
High Pressure Liquid Chromatographic Determination of Aflatoxins in Peanut Products
Authors: Pons Walter A , Franz Anthony O
Published: February 2020

A precise and sensitive high pressure liquid chromatographic method is proposed for determining aflatoxins B1, B2, G1, and G2 in all types of peanut products. The method is based on acidified aqueous methanol extraction, partition of aflatoxins into dichloromethane, and purification of the extract on a 2 g silica gel column. Aflatoxins in the purified extract are completely resolved on a microparticulate (10 μm) porous silica gel column in approximately 10 min with a water-saturated chloroform-cyclohexane-acetonitrile solvent. The preferred detection system, B1 and B2 by ultraviolet absorbance at 360— 365 nm and G1 and G2 by fluorescence, allows accurate and sensitive detection of all 4 aflatoxins at levels as low as 0.3—1.0 μg/kg. Repetitive assay of 3 samples of naturally contaminated peanut butters containing total aflatoxins (B1 + B2 + G1 + G2) at levels of 5, 10, and 15 μg/kg gave within-laboratory coefficients of variation of 11, 5, and 5%, respectively.
Headspace Sampling and Gas-Solid Chromatographic Determination and Confirmation of ≥ 1 ppb Vinyl Chloride Residues in Polyvinyl Chloride Food Packaging
Authors: Dennison J Lawrence , Breder Charles V , Mcneal Timothy , Snyder Roger C , Roach John A , Sphon James A
Published: February 2020

The determination and confirmation of residual vinyl chloride (VC) in polyvinyl chloride (PVC) food packaging materials are described. PVC packaging materials are dissolved in dimethylacetamide (DMAC). VC is sparged from solution with helium gas and collected in sealed vials of ethanol. VC is detected and quantitated by using a headspace sampling technique and standard gas-solid chromatography (GSC) with flame ionization detection. GSC peak heights of about 5% full scale deflection are obtained for samples of PVC containing 1 ppb VC. Polymer samples taken from tubing, blood bags, food packaging films, bottles, and unprocessed resin were analyzed. Residual VC levels ranged from 0.3 to 913 ppb. VC was confirmed by GSC-mass spectrometry, using selected ion recording of m/z 62 and 64 in conjunction with full mass scans to identify components eluting near VC.
Gas-Liquid Chromatography and Flame Photometric Detection of Phosphine in Wheat
Authors: Nowicki Thomas W
Published: February 2020

A screening method using gas-liquid chromatography with flame photometric detection has been developed for determining phosphine in wheat. Phosphine is measured as the sum of physically bound intact phosphine and that derived from residual aluminum phosphide. Wheat is extracted in a closed, partially evacuated glass system by refluxing with 10% sulfuric acid. Liberated gases are swept into a gas-collection flask fitted with rubber septa to permit gas sampling. Aliquots of collected gas are injected into a gas chromatograph. Phosphine is quantitated by peak area as determined by an electronic integrator. Recoveries varied with concentration: 67% was recovered at 0.10 ppm and 98% was recovered at 19 ppm. For concentrations less than 1.5 ppm, the coefficient of variation was 9.95%. Using flame photometric detection, phosphine concentrations as low as 0.04 ppm were easily determined in wheat.
Microcolorimetric Method for Determining Boron in Fertiliz
Authors: Thorpe Virginia A
Published: February 2020

A modification and evaluation of an unpublished azomethine H colorimetric method for determining boron in fertilizer are described By changing formulations of the color reagent and buffer-masking solution, interferences were eliminated and color development reached a maximum in 1 hr and remained stable for an additional hour. The method was simplified by combining the color reagent and buffer-masking solution; matrix and acid effects were controlled by adjusting sample and acid background in the solution, thus eliminating the need for standard addition techniques. Samples with boron contents from 0.03 to 3.0% were analyzed with the proposed method; the expected values were obtained with coefficients of variation of 3.19 and 1.27%, respectively, for the low and high levels of boron.
High Pressure Liquid and Thin Layer Chromatography of Synthetic Acid Fast Dyes in Alcoholic Products
Authors: Martin Glenn E , Tenenbaum Milton , Alfonso Felipe , Dyer Randolph H
Published: February 2020

High pressure liquid chromatography (HPLC) was used to resolve FD&C Blue No. 1 (Brilliant Blue), FD&C Blue No. 2 (Indigotine), Amaranth (formerly certified as FD&C Red No. 2 ) , FD&C Red No. 3 (Erythrosine), FD&C Red No. 4, FD&C Red No. 40, FD&C Yellow No. 5 (Tartrazine), FD&C Yellow No. 6 (Sunset Yellow FCF), and FD&C Green No. 3 (Fast Green FCF). These synthetic acid fast dyes as found in wine and flavor samples were extracted with wool yarn and analyzed by HPLC and thin layer chromatography. The 2 methods are compared for sensitivity and resolution. The HPLC procedure is a quicker way to screen a larger number of samples for artificial colors with better resolution than that obtained by thin layer chromatography. HPLC can separate FD&C Red No. 40 from FD&C Red No. 4 and this could not be achieved by using the described TLC solvent system. The FD&C dyes most commonly found in flavors and distilled spirits were FD&C Red No. 40, FD&C Yellow No. 5, and FD&C Yellow No. 6.
Fluorometric Determination of Metaraminol Bitartrate Injection
Authors: Weber John D
Published: February 2020

A fluorescence assay for metaraminol bitartrate injection has been developed which uses o-phthalaldehyde as a fluorogenic reagent, and does not require prior isolation of metaraminol. It is 50 times more sensitive than the USP assay. Six analyses of 2 vials of the same lot of metaraminol bitartrate injection gave 96.0± 0.4% of label declaration.
Use of the High-Speed Over-Head Mixer in Howard Mold Count Preparations
Authors: Cichowicz Stanley M
Published: February 2020

High-speed blenders are used in the preparation step for mold counting of ground capsicums, onion powder, garlic powder, and tomato powder. Waring-type blenders have several disadvantages: (1) accurate rpm measurement cannot be made under load conditions; (2) an external variable transformer must be used to regulate the speed; (3) different models can have varying top speeds. The over-head Sorvall-type mixer overcomes these disadvantages. It has a built-in speed control and can be calibrated under load conditions by direct access through the top of the motor. Test results show that there is no difference between mold counts of samples prepared by the 2 types of blenders. The high-speed over-head mixer has been adopted as an alternative to the high-speed blender now described in the official method.
Comparative Accuracy of Five Biochemical Systems for Identifying Salmonella and Related Foodborne Bacteria: Collaborative Study
Authors: Poelma Paul L , Romero Aida , Andrews Wallace H
Published: February 2020

The comparative accuracy of 4 biochemical diagnostic kits (API, Enterotube, Minitek, and Pathotec) and the conventional (AOAC) tube system for identifying primarily Salmonella and other enteric isolates was collaboratively studied. Each of 11 participating analysts received 40 foodborne isolates (25 Salmonella and 15 non-Salmonella cultures), representing a total of 440 cultures examined by each identification system. In decreasing order of accuracy, the overall number of correctly identified cultures with each of the systems was as follows: AOAC, 423 (96.1%), Minitek, 403 (91.6%), Enterotube, 395 (89.8%), API, 394 (89.5%), and Pathotec, 373 (84.8%). A cost analysis showed that all 4 diagnostic kit systems were less expensive than the conventional AOAC tube system for a single culture identification. Three of the diagnostic kits have been adopted as official first action as alternatives to the AOAC biochemical tube system for presumptive generic identification of foodborne Salmonella and for screening and eliminating non-Salmonella isolates. Routine incorporation of any one of the 3 diagnostic kits, however, should be preceded by the demonstration in the analyst's own laboratory of adequate correlation between the kit and the AOAC system.
Modified Method for Electron Capture Gas-Liquid Chromatographic Determination of Hexestrol Residues in Bovine Tissues
Authors: Tobioka Hisaya , Kawashima Ryoji
Published: February 2020

A gas-liquid chromatographic (GLC) method with electron capture detection was developed for determining hexestrol residues based on a GLC method for diethylstilbestrol residues. The extraction and purification procedures were based on a published procedure. Pentafluoropropionic (PFP) and heptafluorobutyric (HFB) anhydrides and other halogenated compounds were compared as acylation reagents. PFP anhydride was selected because it provided reproducible GLC responses. Of the 3 column packing materials tested, OV-17, OV-210, and QF-1, OV-17 was the most stable under the GLC conditions used. A pH 10.5—10.6 in the purification step gave higher recoveries than pH 10.3 or pH 10.8 and was selected for use. The method is suitable for determining residues of 0.5 ppb. The limit of sensitivity ranges from 0.1 to 0.2 ppb.
Fluorometric Determination of Histamine in Cheese
Authors: Chambers Theodore L , Staruszkiewicz Walter F
Published: February 2020

Thirty-one samples of cheese obtained from retail outlets were analyzed for histamine, using an official AOAC fluorometric method. The types of cheese analyzed and the ranges of histamine found were: colby, 0.3—2.8; camembert, 0 . 4 - 4 . 2 ; cheddar, 1.2-5.8; gouda, 1.3-2.4; provolone, 2.0-23.5; roquefort, 1.0-16.8; mozzarella 1.6-5.0; and Swiss, 0.4—250 mg histamine/ 100 g. Ten of the 12 samples of swiss cheese contained < 1 6 mg histamine/100 g. The remaining 2 samples which contained 116 and 250 mg histamine/lOO g were judged organoleptically to be of poor quality. An investigation of one processing facility showed that the production of histamine in swiss cheese may have been a result of a hydrogen peroxide/ low temperature treatment of the milk supply. Recovery of histamine added to methanol extracts of cheese ranged from 93 to 105%. Histamine content was confirmed by high pressure liquid chromatographic analysis of the methanol extracts.
Determination of Streptomycin Residues in Eggs and Stability of Residues After Cooking
Authors: Inglis Jean M , Katz Stanley E
Published: February 2020

An assay procedure for streptomycin was developed, using a surfactant-pH 8 buffer extraction, heating at 85°C to eliminate inhibition from lysozyme activity, and centrifuging to remove physical- barriers to diffusion. Recoveries of streptomycin from supplemented eggs averaged 42% over the range of 0.33—2.05 jug streptomycin/g egg. Eggs were supplemented at 3.0, 30.0, and 300 /tg streptomycin/g and subjected to various cooking procedures: frying, poaching, scrambling, and hard boiling. There was little or no loss of activity as a result of the various cooking procedures with the exception of one of the hard boiled varieties where there was a 40% loss only at the 3.0 /ig/g supplementation. Streptomycin residues were quite stable to normal egg preparation procedures.
Extraction of Benzene Hexachloride Isomers from Water Samples, Using a Macroreticular Resin
Authors: Yamato Yasuhiro , Suzuki Manabu , Watanabe Tadao
Published: February 2020

Four BHC isomers added to 3 L BHC-free distilled water at levels of 1.0, 0.1, and 0.01 ppb were quantitatively recovered (>94%), using an amberlite XAD-2 resin. Cas-liquid chromatography with electron capture detection and a column packed with 2 % Apiezon L on 100—120 mesh Gas-Chrom Q was used as a determinative step. This method was also used to detect BHC residues in tap water and river surface waters in the Kitakyushu District, Japan. The 4 BHC isomers were detected at levels below parts per trillion in almost all the samples analyzed: α-BHC > β-BHC > γ-BHC > δ-BHC. The maximum residue level of total BHC was 0.604 ppb and the minimum was 0.007 ppb. The minimum detectability for total BHC in a 3 L water sample was 0.001 ppb.
Pentafluorobenzyl Ester Derivatives of Nine Chlorophenoxy Acid Herbicides: Spectroscopic Properties and Utility for Identification Purposes
Authors: De Beer Jacques O , Van Peteghem Carlos H , Heyndrickx Aubin M
Published: February 2020

The pentafluorobenzyl esters of 9 chlorophenoxy acid herbicides were synthesized by the reaction of the acids with pentafluorobenzylbromide in alkaline acetone solution. Ultraviolet (UV), infrared (IR), proton magnetic resonance (PMR), and mass spectra (MS) were recorded. IR and mass spectra are shown and UV, PMR, and MS data are tabulated and discussed. A technique for extraction of the chlorophenoxy alkyl acid herbicides, followed by conversion to the corresponding pentafluorobenzyl esters, was developed for human urine samples. Applications in different concentration ranges (ppm, ppb) by different spectroscopic techniques (MS, IR) are demonstrated.
Analytical Methodology and the Interface with Animal Drug Approval
Authors: Perez Maryln K
Published: February 2020

FDA is engaged in a systematic review of approved animal drugs to determine whether upgrading of safety data is required to provide continuing assurance that the approved uses for these drugs are safe. These reviews will be undertaken on the basis of a priority of anticipated human health significance.
Drug Residues in Animal Tissues and Their Regulatory Significance—The Canadian Point of View
Authors: Campbell David J
Published: February 2020

Today it is almost impossible to produce food of animal origin which is free from traces of drugs or chemicals. In Canada the problem of drug residues is controlled by a method of assessment of human safety which involves many factors. The toxicity of the drug in laboratory animals or, if possible, in man, is established and a no-effect dose is then estimated. These studies require oral administration of the drug and include acute, subacute, and teratogenicity studies. Depending on these results, chronic reproductive or carcinogenicity studies may be required before a no-effect dose can be estimated. Residue studies must encompass data on metabolism, pharmacokinetics, and depletion studies in edible tissues and for products such as milk and eggs. For veterinary drug residues, we must consider the target food animal with its particular metabolism, tissue disposition, and excretion patterns. The analytical method for residue detection must be acceptable and its sensitivity limits suitable for the drug and its major metabolites.
Trends in the European Communities Toward Developing Analytical Methods for Regulating Animal Drugs and Feed Additives
Authors: Somogyi Arpad
Published: February 2020

The heterogeneity of the legal basis in the 9 member states of the European Communities (EC) regarding the tolerance of drug residues in edible animal products precluded, until now, the establishment of common principles governing the relationship between analytical requirements and the approval of animal drugs and feed additives. While feed additives are regulated on the EC level (Directive on Additives in Feedingstuffs of 1970), no binding and comprehensive measures are currently in force regarding animal drugs. A draft proposal, presently under review by the member states, covers the regulatory aspects of approval, use, and control of veterinary medicinal substances. Furthermore, it describes in detail the analytical, pharmacological, toxicological, and clinical requirements and standards a new drug must meet before application for approval within the EC can be considered. According to this document, the first of its kind in the EC, sufficiently sensitive analytical methods must be submitted to assure that, under conditions prevailing in a routine laboratory, drug residue levels which are not considered safe will be detected. A brief outline of current measures and draft proposals of future regulations is given from the viewpoint of analytical methods for residues of animal drugs and feed additives.
Antibiotic Residues: Regulations, Tolerances, and Detection in the European Economic Community
Authors: Van Schothorst Mike , Van Leusden Frans M , Nouws Jac F M
Published: February 2020

The use of antimicrobial agents for growth promotion and therapy in the European Economic Community and the resulting public health problems are discussed. Methods for detection of residues based on microbiological criteria for acceptance are presented and evaluated.
Method for Antibiotic Determination in Animal Tissue, As Applied to Lasalocid
Authors: Donald Alexander Mac
Published: February 2020

The development of a tissue residue method for an antibiotic is dependent on the history of the overall problem; the current requirements that must be met for regulatory approval; the chemistry of the compound; its physical/chemical parameters; and its microbiological spectrum for the best possible fit of all of these to ensure a procedure that will work reliably in the originator's laboratory and to the same degree of effectiveness in anyone's laboratory. A note is made of those factors that must be included as controls on the procedure and those experiments that must be included to differentiate matrix from method influences.
Detection, Identification, and Quantitation of Organic Compounds with Bioanalytical Systems Based on Mass Spectrometry
Authors: Horning Evan C , Carroll David I , Dzidic Ismet , Stillwell Richard N , Thenot Jean-Paul
Published: February 2020

Bioanalytical systems which include a gas chromatograph, a mass spectrometer, and a computer provide the most effective analytical methods for organic compounds other than macromolecules. The use of computer and microprocessor/computer instrumental combinations is increasing. Electron impact mass spectrometry is used for identification purposes; chemical ionization is best for quantitative work. Current studies indicate that negative ion mass spectrometry with non-filament sources will be useful in analyses for toxic agents (pesticides, fungicides, herbicides). Future analytical systems will have both positive and negative ion mass analyzer capabilities. Sample preparation methods depend on the type of analysis. Liquid chromatography is useful when the concentration is low. Open tubular glass capillary columns are coming into wider use, both in gas chromatography alone and in combined systems. The limits of detection are now in the subpicogram range, but the determining factor is usually the nature of the compounds under analysis and the extent of adsorption.
Endogenous Estradiol-17/β in Bovine Tissues
Authors: Henricks Donald M , Torrence Allan K
Published: February 2020

The development of an assay for the estrogen estradiol-17β in bovine muscle, kidney, liver, and uterine endometrium is described in this report. The tissue was homogenized, extracted, partitioned, and subjected to routine radioimmunoassay. Chromatography was not used. The first part of the report presents data on the accuracy, reproducibility, and sensitivity of the assay. The concentration of estradiol-17β in the tissues compared with muscle was ranked as follows: uterine endometrium (10-fold higher), liver (3-fold), and kidney (3-fold). The estrogen concentration was not significantly different in the muscle between heifers, but was significantly greater (P < 0.05) in the liver and kidney of heifers and steers. In heifers pre- and post-estrous phase endometrium (a target tissue of E2β) contained significantly greater concentrations of estradiol-17β than did luteal phase endometrium (P < 0.05), but mean levels in the edible tissues were not significantly different (P > 0.05) between these 2 of the 4 stages of the estrous cycle.
Atomic Absorption Spectrometric Determination of Arsenic and Selenium in Offal and Fish by Hydride Generation
Authors: Flanjak Johann
Published: February 2020

A method for determining As and Se in beef offal and fish was developed. The sample was digested by heating with a mixture of nitric, perchloric, and sulfuric acids. No pre-reduction of As and Se was necessary. Using a simplified generator, the metal hydrides were evolved by reduction with sodium borohydride pellets from sulfuric and hydrochloric acid media. The hydrides were swept by a flow of nitrogen into a nitrogen-hydrogen-entrained air flame. Absolute detection limit of the method was about 6 ng for As and 4 ng for Se, and absolute sensitivity for both metals was estimated to be 5 ng. Effects of the presence of several cations and anions in the matrix were investigated and some were found to have a suppressive effect on the atomic absorption signal. The analytical results obtained for samples of NBS No. 1571 Orchard Leaves and NBS No. 1577 Bovine Liver agreed well with certified values.
Mass Fragmentographic Determination of Pentachlorophenol in Rainbow Trout
Authors: Wu Anthony , Lech John J , Glickman Andrew , Lynn Pearson M
Published: February 2020

Pentachlorophenol (PCP) is extracted from selected tissues of rainbow trout and converted to pentachloroanisole (PCA) by means of alkylation in the presence of potassium carbonate as a condensing agent. Pentachlorophenetole (PPT) is used as an internal standard. The electron impact mass fragmentography is carried out by monitoring m/e 280 (PCA), 294 (PPT), and 237. A plot of peak height vs. concentration is linear from 0.03 to 4.0 ng. Accuracy and precision of the method is ± 2% (N = 36). The results are accurate enough to warrant the use of this method for determining PCP in fish, as well as for monitoring PCP from various environmental sources. In addition, this technique provides a simple and rapid method by which a mixture of PCA and PCP can be determined simultaneously.
Enumeration of Coliforms and Salmonella in Food Prepared by Blending and Stomaching
Authors: Andrews Wallace H , Wilson Clyde R , Poelma Paul L , Romero Aida , Mcclure Foster D , Gentile Dorothy E
Published: February 2020

The efficiencies of the Waring blender, the Stomacher 400, and the Stomacher 3500 were compared for preparing food samples for enumerating coliforms and Salmonella. Comparative most probable number (MPN) determinations were performed on 289 samples, representing 12 categories of nonfatty foods and 2 categories of fatty foods. Total coliforms were enumerated in 9 categories of nonfatty foods, and the geometric means of MPNs in samples prepared by the Stomacher 400 and the Stomacher 3500 were not statistically different from those means of MPNs of samples prepared by the blender in 100 and 89% of the categories, respectively. In the 3 categories of nonfatty foods in which fecal coliforms were enumerated, geometric means of the MPNs of samples prepared by the Stomacher 400 and the Stomacher 3500 were not statistically different from those means of MPNs of samples prepared by the blender in 3 and 2 of the food categories, respectively. Of the 3 categories of nonfatty foods in which Salmonella was enumerated, geometric means of the MPNs of samples prepared by the Stomacher 400 and the Stomacher 3500 were not statistically different from those means of MPNs of samples prepared by the blender in 3 and 2 of the categories, respectively. Adding Tween 80 to 2 categories of fatty foods at final concentrations of 0.5, 1.0, and 2.0% did not result in a consistent increase in coliform MPNs obtained after stomaching with either model.
Thin Layer Chromatographic Determination of Aflatoxin B1 in Corn Silage
Authors: Häggblom Per E , Casper Howard H
Published: February 2020

A procedure is described for the purification and quantitation of aflatoxin B1 in corn silage. The toxin is extracted and partially purified using parts of the AOAC minicolumn detection method. The extract is further cleaned up on a 2-step minicolumn and is then analyzed by using thin layer chromatography. Essentially all interferences are removed when the procedure is applied to moldy and non-moldy corn silage. The estimated limit of detection is 5 μg aflatoxin B1/kg corn silage, and 73±8% of the added aflatoxin B1 (20 and 85 μg/kg) was recovered. No aflatoxin B1 was detected in 270 samples collected from 19 silage piles in late fall 1976 and early spring 1977. This procedure also removes interferences associated with moldy corn and mixed feeds.
Automated Fluorometric Determination of Vitamin A in Milk
Authors: Thompson James N , Madère René
Published: February 2020

A previously published fluorometric method for vitamin A in milk, involving saponification in centrifuge tubes and extraction with hexane, was automated using conventional automated equipment including a filter fluorometer. The extraction and separation steps were affected by the presence of fat, so standards were prepared in milk. The peaks obtained with samples were 95% of steady state values. The coefficients of variation for 10 replicate analyses were 1.9% for unfortified milk and 1.3% for fortified milk. In tests on 19 different milk samples, the results of the automated and manual fluorometric methods differed by less than 10%; a colorimetric method using SbCl3 gave more erratic results and was more lengthy and laborious.
Survey of Cured Meat Products for Volatile N-Nitrosamines: Comparison of Two Analytical Methods
Authors: Havery Donald C , Fazio Thomas , Howard John W
Published: February 2020

A survey has been completed of 106 cured meat samples for 14 volatile N-nitrosamines. N-Nitrosopyrrolidine has been confirmed in fried bacon at levels ranging from 5 to 75 ppb. Unconfirmed trace levels of N-nitrosodimethylamine have been observed in a variety of cured meat products. The comparison of the multi-detection gas-liquid chromatographic (GLC)- mass spectrometric method with the mineral oil distillation-thermal energy analyzer (TEA) method for the determination of volatile N-nitrosamines in foods shows good agreement between the analytical methods, especially at the 10 ppb level, and excellent agreement between the GLC and TEA analyses of an identical sample extract.
High Pressure Liquid Chromatographic Determination of Imazalil Residues in Gtrus Fruit
Authors: Norman Shirley M , Fouse David C
Published: February 2020

A high pressure reverse phase liquid chromatographic method is described for determining the fungicide imazalil (1-[2,4-dichlorophenyl) -2- (2-propenyloxy)ethyl] -1H-imidazole) residues in whole citrus fruit, peel, and pulp. Imazalil is extracted from the fruit with ethyl acetate, partitioned into acid and back into ethyl acetate for cleanup, and detected by ultraviolet absorbance at 202 nm. Recovery from whole ground fruit of known amounts of imazalil applied to the surface of intact fruit averaged 84% 24 hr after application and 80% after the fruit had been stored 4 weeks at 15°C.
High Pressure Liquid Chromatographic Determination of Major Organic Acids in Cranberry Juice
Authors: Coppola Elia D , Conrad Edward C , Cotter Richard
Published: February 2020

A reverse phase high pressure liquid chromatographic method is presented for the simultaneous separation and determination of quinic, malic, and citric acids in single strength, undiluted cranberry juice. After a 1:10 dilution and cleanup through a disposable column, major organic acids in cranberry juice are separated on a Bondapak/C18 column and quantitated by using a differential refractometer. Twenty-seven samples of different single strength cranberry juice were analyzed using this method; the mean content of quinic, malic, and citric acids were 1.32 (std dev. 0.150), 0.92 (std dev. 0.079), and 1.08% (std dev. 0.111), respectively. Mean percent recoveries of each acid were quinic 95.4 (std dev. 6.8), malic 96.6 (std dev. 5.8), and citric 94.0% (std dev. 4.8).
Potentiometric Method for Determining Triphenyltin Compounds in Formulations: Collaborative Study
Authors: Litan René , Basters John , Martijn Albertus , Van Der Molen Thomas , Pasma Piet , Rabenort Barend , Smink Jaap
Published: February 2020

Five laboratories collaboratively studied 2 procedures for the quantitative determination of triphenyltin compounds in technical material and in formulations. Both procedures include an extraction step and a potentiometric titration but differ in how byproducts are removed. The first is based on cleanup with sodium tartrate and in the second one alkaline alumina is used for purification. The performance, however, is different. The reproducibility and the repeatability are significantly better with the alumina method than with the tartrate method. The average (systematic) difference between the 2 methods was —2.3%. The method based on alkaline alumina cleanup has been adopted as an interim CIPAC method.
Substitution of n-Heptane for Ethyl Ether in USP Assay for Chlorpromazine Hydrochloride in Tablets, Injections, and Sirups
Authors: Kirchhoefer Ross D , Myrick James W
Published: February 2020

Peroxide levels above 0.0001% in the ethyl ether used in the USP XIX assay for chlorpromazine hydrochloride in tablets, sirups, and injections produce a distorted spectrophotometric curve in the 350-220 nm region. The use of peroxide-free ethyl ether or n-heptane avoids this problem. Recoveries of 91–100% are obtained with either of these reagents.
Gas-Liquid Chromatographic Determination of Sodium Bisulfite in Complex Matrices
Authors: Czarnecki John J , Koehler Walter R , Cooper Aaron D
Published: February 2020

A gas-liquid chromatographic (GLC) headspace technique is described for determining sodium bisulfite in a dermatological cream. The sample is dispersed in an aqueous medium and acidified to convert sulfite to volatile sulfur dioxide which partitions into the headspace. An aliquot of the headspace vapor is analyzed by GLC using the sulfur-selective flame photometric detector. Advantages of the method include the facility of sample preparation, the specificity and sensitivity resulting from the combined use of the headspace technique and the flame photometric detector, and the applicability of the method to various types of sample matrices. Recoveries ranged from 95 to 102% for spiked samples containing 200—2000 ppm sodium bisulfite. For the sample size and experimental conditions used in this application, the detection limit is 0.02 mg sodium bisulfite.
Gas-Liquid Chromatographic Determination of Maleic Hydrazide in Tobacco and Tobacco Smoke
Authors: Haeberer Alfred F , Chortyk Orestes T
Published: February 2020

A method is presented for the determination of the plant growth regulator maleic hydrazide (MH; l,2-dihydro-3,6-pyridazinedione) in tobacco and tobacco smoke. Residues are converted to the bis(trimethylsilyl) derivative before analysis by gas-liquid chromatography. The method has been applied to cigarettes and condensed smoke and has been used to determine the per cent transfer of MH into cigarette smoke. Free MH residues could be determined directly on the tobacco samples, whereas total MH values were obtainable only after acid hydrolysis. In spite of large MH residues in tobacco, only 0.2% of the MH was transferred into smoke.
Gas-Solid Chromatographic-Mass Spectrometric Confirmation of Low Levels of Acrylonitrile After Distillation from Food-Simulating Solvents
Authors: McNeal Timothy , Brumley William C , Breder Charles , Sphon James A
Published: February 2020

Acrylonitrile (AN) in aqueous food-simulating solvents is concentrated by adding methanol and distilling the AN-methanol azeotrope. AN in heptane is partitioned into water and azeotropically distilled with methanol. This procedure concentrates approximately 30% of the An in 0.5 ml methanolic solution. The concentrate obtained is analyzed by gas-solid chromatography (GSC) and the presence of AN is confirmed by GSC-mass spectrometry, using multiple ion monitoring of ions at m/z 53, 52, 51, and 26. Levels as low as 0.01 ppm AN in the original food-simulating solvents can be confirmed. The migration of AN into 8% ethanol and 3% acetic acid contained in styrene-acrylonitrile bottles has been confirmed by using this method.
Gas-Solid Chromatographic Determination of Moisture in Lyophilized Pharmaceutical Products
Authors: Lyman Gary W , Johnson Raymond N
Published: February 2020

A gas-solid chromatographic procedure is described for the analysis of low levels of moisture in individual lyophilized vials of pharmaceutical products. Dry ethanol, which contains methanol as the internal standard, is injected through the septum of the vial to dissolve the lyophilized contents. An aliquot of this solution is then withdrawn and injected onto a Porapak QS column at 110°C where the components are separated and detected using thermal conductivity detection. A solvent blank correction allows quantitation of the water in the individual vial. The method is conveniently applied to samples containing as little as 50 μ g water/vial, and as many as 25 vials can be assayed/day. A simple technique is also described for removing water from the ethanol solvent to < 1 0 0 ppm, using a molecular sieve.
Rapid Florisil Cleanup Method for Analysis of Chlorinated Pesticide Residues
Authors: Stimac Robert M
Published: February 2020

A modification of the current Florisil chromatographic cleanup procedure for pesticide residue analysis is presented. By prewashing the Florisil column with a specified quantity of ethyl ether, many chlorinated pesticides, including dieldrin and endrin, can be eluted in one step. The demonstrated cleanup efficiency of the proposed method eliminates the need for further cleanup, since the concentrated eluate is suitable for gas chromatographic analysis. Recovery of 13 chlorinated pesticides in typical products of corn wet milling ranged from 85 to 115%.