bluuebunny/crossref_metadata_2025 huggingface dataset:
High Pressure Liquid Chromatographic Determination of Sodium Saccharin, Sodium Benzoate, and Caffeine in Soda Beverages: Collaborative Study
Authors: Woodward Betsy B , Heffelfinger Gordon P , Ruggles Dennis I
Published: February 2020

A collaborative study for the determination of sodium saccharin, sodium benzoate, and caffeine in 3 types of soda beverage, cola, grape, and lemon-lime, has been completed using reverse phase high pressure liquid chromatography with a μC18 column and acetic acid mobile phase. Recoveries for sodium saccharin were 98.6, 98.0, and 99.1%; for sodium benzoate, 100.6, 102.6, and 100.6%; and for caffeine, 100.8, 101.4, and 101.1%, respectively. The method has been adopted as official first action.
Semiautomated Method for Niacin and Niacinamide in Food Products: Collaborative Study
Authors: Egberg David C
Published: February 2020

collaborative study was conducted comparing a semiautomated colorimetric niacin method with a manual colorimetric and a microbiological method for 10 food products. Seven laboratories used the microbiological method, 7 laboratories used the manual colorimetric method, and 6 laboratories used the semiautomated method. The semiautomated method was more repeatable within a laboratory and more reproducible between laboratories than was either of the other methods. The semiautomated method results compared favorably with both the microbiological and manual colorimetric method results.
Analysis of Fat-Soluble Vitamins. XXII. High Performance Liquid Chromatographic Determination of Vitamin D in Concentrates. Collaborative Study1
Authors: Mulder Frits J , Vries Ellen J De , Borsje Ben
Published: February 2020

A collaborative study was carried out which compared the official chemical method (43.B14- 43.B24), the HPLC method according to Hofsass et al. including maleic anhydride treatment, and the HLPC procedure according to De Vries et al. for vitamin D concentrates. A total of 396 samples were distributed to 33 collaborators for analysis. Five laboratories performed both the chemical and the HPLC methods. Five laboratories performed the Hofsass method and 16 laboratories performed the De Vries method. The results for the chemical method agreed with the theoretical values for the samples, and the standard deviation was comparable to that obtained in previous AOAC collaborative studies. Collaborative results for the Hofsass method were low. In addition, incorrect use of a fixed conversion factor (1/0.586) and necessity of a double chromatographic system on a non-treated and a treated vitamin D sample reduce the effectiveness of the method. There were no adverse reactions to the De Vries HPLC method. It is recommended that the method be adopted official first action as an alternative procedure for determining vitamin D in concentrates, excluding powders containing irradiated 7-dehydrocholesterol.
Semiautomated Method for Riboflavin in Food Products: Collaborative Study
Authors: Egberg David C
Published: February 2020

A collaborative study was conducted comparing a semiautomated riboflavin method with a manual riboflavin method for 10 food products. Six laboratories provided results from the semiautomated method and 16 laboratories used the manual technique. The semiautomated method was more repeatable within a laboratory and more reproducible between laboratories than was the manual method. The semiautomated method results compared favorably with the manual method for all 10 products.
Atomic Absorption Determination of Tin in Foods: Collaborative Study
Authors: Elkins Edgar R , Sulek Arlene
Published: February 2020

Samples of green beans, applesauce, and a fruit juice were fortified with tin at 3 levels. Collaborators were asked to digest the samples, using HNO3-H2SO4, add methanol to enhance the absorption signal, and aspirate directly, using a nitrous oxide-acetylene flame. Results were received from 8 laboratories including 4 from Europe. However, only 6 laboratories used the prescribed methodology. All results were considered acceptable. The method has been adopted as interim official first action.
Lead, Fluoride, and Other Elements in Bonemeal Supplements
Authors: Capar Stephen G , Gould John H
Published: February 2020

The Pb, Cd, F, Al, Cr, Cu, Fe, Mn, Mo, Ni, Ti, and Zn content of 20 commercial bonemeal supplements was determined. Samples were mineralized with nitric and perchloric acids prior to determination of all elements except F, for which a diffusion method was used. Pb and Cd were determined by differential pulse anodic stripping voltammetry, F was measured using an ion selective electrode, and all other elements were determined by inductively coupled argon plasma spectroscopy. The mean recoveries of Pb and F were 97 and 99%, respectively. The concentration range of Pb was 1.5-8.7 μg/g. Cd was quantitated in only one sample at a level of 2.5 μg/g; all other samples were estimated to contain <0.05 μg Cd/g. The concentration of F ranged from 261 to 921 μg/g.
Microdiffusion and Fluoride-Specific Electrode Determination of Fluoride in Foods
Authors: Dabeka Robert W , Mckenzie Arthur D , Conacher Henry B S
Published: February 2020

A simple and accurate method was developed for routine determination of fluoride in foods. Hydrogen fluoride is diffused 20 hr at 50°C from fresh or freeze-dried samples (0.1 g dry wt) in polystyrene petri dishes containing 2 mL 40% HClO4 and 0.3 g Ag2SO4, and is absorbed on the lids, previously spotted with 0.1 mL 0.5M NaOH. The absorbent layer is dissolved in 2 mL buffer solution, and the fluoride is measured potentiometrically. The method was verified by analysis of NBS Standard Reference Materials; recovery from 28 spiked infant foods (average = 99%, range — 75-135%); and comparison of results with colorimetry results for the same diffusates, after modification to handle 1 g samples. Relative standard deviations varied from 4 to 20% day to day. Detection limits were below 0.05 μg/g dry weight.
Liquid Chromatographic Determination of Methscopolamine Bromide in Various Veterinary Formulations
Authors: Hartman Patrick A
Published: February 2020

A reverse phase paired ion liquid chromatographic procedure is described for determining methscopolamine bromide (Pamine) in the presence of neomycin sulfate in 5 veterinary formulations (Biosol M). Methscopolamine bromide is separated from neomycin sulfate and other formulation excipients by extraction into ethanol. The sample preparations are then concentrated and dissolved in water before chromatography. Recovery of methscopolamine bromide added to 5 placebo formulations ranged from 99.7 to 100.7%, with relative standard deviations of less than 2%. Specificity of the method with regard to potential degradation products is demonstrated.
Colorimetric Determination of Hydralazine with 9-Chloroacridine
Authors: Stewart James T , Chang Yu-Chu
Published: February 2020

A spectrophotometric assay for hydralazine hydrochloride based on the interaction of the drug with 9-chloroacridine has been developed. The interaction shows an absorption maximum at 460 nm and is affected by temperature, heating time, and quantity of acridine reagent used. Color development is maximum when the drug is heated in the presence of a 30-fold molar excess of the acridine in a 50±l°C water bath for 1 hr. The method detects hydralazine hydrochloride in the 10-5-10-6M range with sensitivity to 0.2 μ/mL and 3-4% accuracy. Typical calibration data obtained from linear regression analysis of absorbance at various drug concentrations show r = 0.9997 (n=6). Hydralazine can be determined in dosage forms that also contain varying quantities of reserpine and hydrochlorothiazide. The 9-chloroacridine method is as sensitive as other spectrophotometric procedures for hydralazine but also more accurate and precise, and involves fewer manipulative steps.
Determination of Edrophonium Chloride Injection USP in the Presence of Preservatives
Authors: Hamill Thomas W
Published: February 2020

The determination of Edrophonium Chloride Injection involves a modification of a procedure for phenylephrine and offers an alternative to the compendial assay. Edrophonium chloride forms an ion-pair with di-(2-ethylhexyl) phosphoric acid which can be extracted with an immiscible solvent such as ether. When this procedure is coupled with partition chromatography, the drug can be isolated from preservatives and quantitatively determined by its ultraviolet absorbance. Recovery data on synthetic mixtures ranged from 99.8 to 101.9% and were in good agreement with the compendial method.
Colorimetric and Spectrophotometric Determination of Total and Non-phenolic Alkaloids in Ipeca and Its Formulations
Authors: Saleh Mohamed R I , El-Masry Sawsan , El-Shaer Nagwa
Published: February 2020

A simple method, requiring no chromatographic separation, is presented for the determination of the total and non-phenolic alkaloids in ipeca and its preparations. The complex formed between the alkaloid and methyl orange at pH 5.0 is extracted with chloroform and treated with 0.1N NaOH. The liberated dye, determined at 460 nm, is a measure of the total alkaloids. The chloroform phase remaining is treated with 0.1N H2SO4, and the acid extract is measured at 283 nm for the non-phenolic alkaloids, calculated as emetine. The proposed method was successfully applied to samples of ipeca powder, ipeca tincture, and 3 British Pharmaceutical Codex mixtures containing ipeca tincture, namely, ipecacuanha mixture, pediatric; ipecacuanha and ammonia mixture, pediatric; and belladonna and ipecacuanha mixture, pediatric. The proposed method compares favorably with the Egyptian Pharmacopoeia, British Pharmacopoeia, and USP methods and has a relative standard deviation of 1.54%. The present procedure is less time-consuming and requires about 45 and 90 min for the assay of ipeca tincture and powder, respectively. Only a small sample (0.2 mL tincture or 1.0 g powder) is required.
Spectrophotometric Determination of Piperazine and Its Salts in Pharmaceuticals
Authors: Abou-Ouf Abdel M , Walash Mohamed I , Rizk Mohamed S , Ibrahim Fawzia A
Published: February 2020

A spectrophotometric determination of piperazine and some of its salts is described. The method depends on the UV measurement of the N-nitroso derivatives formed by the interaction of piperazine with nitrous acid. The chromophore is developed by heating the reaction mixture at 80°C for 15 min, at pH 2.3-2.6. Beer's law is obeyed in the range 1-15 μg/mL.
Cleanup of Biological Samples for Determining p,p’-DDT and Its Metabolites
Authors: Ahmad Nazir
Published: February 2020

A method is described for extracting tissue samples with hexane-acetone and hydrolyzing the fat and protein with aqueous sodium hydroxide. p,p’-DDT and its metabolites are measured on a gas chromatograph with an electron capture detector after cleanup on an alumina column. The new cleanup procedure gives 98% recoveries for p,p’-DDT and its metabolites added to fat in vitro, compared with 84% recovery by a modified commonly used method. Comparison by Student's f-test of the new method with the modified method on 32 cattle biopsy, 46 bird, and 20 fish samples for in vivo incurred p,p’-DDT residues showed that the results by the new method were significantly higher at the 95% confidence level. Alkali-hydrolyzed extract did not contaminate the detector. The new procedure avoids the use of dimethylformamide and shortens the time of analyses. A correlation (r=0.68) was observed between the fat-soluble protein concentration of the n-hexane extract and the p,p’-DDT residues.
Gas-Liquid Chromatographic Determination of Bromide Ion in Lettuce: Interlaboratory Studies
Authors: Greve Peter A , Grevenstuk Willem B F
Published: February 2020

The gas-liquid chromatographic method for the determination of bromide ion, as originally described for grain by Heuser and Scudamore, was adapted for use on lettuce, and later on products of other vegetable or of animal origin. After optimization of the ashing and derivatization conditions, 2 interlaboratory studies were carried out in The Netherlands. In the first, a preparatory study, 6 laboratories investigated freeze-dried lettuce; in the second definitive study, 8 laboratories investigated both freeze-dried and fresh lettuce. Four lots of lettuce with bromide contents ranging from about 5 to about 200 mg/kg were investigated. Average bromide contents (mg/kg) and between-laboratory coefficients of variation were 5.6 (11.0%), 13.3 (18.4%), 29.9 (8.3%), and 209 (12.8%). The results obtained are normal for the type of work and the conditions of the study. The method will be recommended for regulatory use in The Netherlands and in international organizations.
Long-Term Storage of Microorganisms Used in Antimicrobial Effectiveness Tests
Authors: Cosgrove Raymond F
Published: February 2020

Liquid nitrogen storage of organisms designated in the U.S. Pharmacopeia (XIX) for the assessment of antimicrobial effectiveness is described. By use of simple apparatus and procedures, 85-95% viabilities of pre-frozen cells are attained immediately upon freezing. Viability levels have remained constant over a 3-year period and the use of such inocula has considerably improved the reliability of the test. The superiority of liquid nitrogen storage for microbial test inocula over other types of storage is discussed.
Equivalence of Microbiological and Hydroxylamine Methods of Analysis for Ampicillin Dosage Forms
Authors: Lin Song-Ling , Sutton Vincent J , Quraishi Mateen
Published: February 2020

Ampicillin formulations were assayed by microbiological and hydroxylamine methods to determine whether the hydroxylamine analytical method is a suitable substitute for the microbiological method. Paired assay results by the 2 analytical methods were obtained on different strengths of tablet, capsule, and suspension formulations containing ampicillin and ampicillin degradation compounds. Several statistical tests were used to assess the equivalence of the paired assay results. The data analyses indicate that the hydroxylamine method is a suitable substitute for the microbiological method for potency assays and stability studies of ampicillin formulations. The hydroxylamine method yielded slightly higher assay results than the microbiological method for severely degraded formulations.
Spectrophotometric Difference Method for Determination of Capsaicin
Authors: Dicecco Joseph J
Published: February 2020

Capsaicin is extracted from capsicum spice with acetone. The extract is cleaned up on an activated alumina column and assayed by using a spectrophotometric difference method (SDM). The coefficient of variation of replicate samples for 2 pungency levels was 0.36%. The correlation coefficient between the organoleptic assay and SDM was 0.95.
Criteria of Purity for Zearalenone Standards
Authors: Pathre Sadanand V , Mirocha Chester J , Fenton Stuart W
Published: February 2020

cis-Zearalenone was identified as one of the impurities in commercial zearalenone used as a reference standard. Zearalenone purified chromatographically gave molar absorptivities of 29,512±376, 13,225±15, and 6,162±61 at the absorption maxima of 236, 274, and 316 nm, respectively, in methanol. The precision in the ratio of absorbances for the major spectral peaks for purified zearalenone preparations provided a useful criterion of purity for zearalenone. A comparison of the GLC measurements of various purified zearalenone preparations with the amount of zearalenone in each preparation as determined by absorbance measurements demonstrated the validity of using absorbance measurements for zearalenone quantitation. Results from a collaborative study demonstrated that the concentration of solutions of zearalenone standards can be determined by UV absorbance measurements.
Analytical Reference Materials. I. Preparation and Purification of Photomirex
Authors: Chau Alfred S Y , Thomson Rod
Published: February 2020

The preparation and purification of photomirex (1,2,3,4,5,5,6,7,9,10,10 - undecachloropentacyclo [5.3.0.02,6.03,9.04,8]decane) as an analytical reference standard is detailed. A previous synthetic procedure was modified and improved to reduce hazards and to increase yield. Briefly, Mirex is reduced by triphenylphosphine in the presence of propionic acid, and purified by alumina column chromatography to obtain 60-70% yield of the desired compound.
Switching Valve Designed For High Pressure Liquid Chromatographic Fraction Collection
Authors: Landen William O
Published: February 2020

The use of a collection valve specifically designed for high pressure liquid chromatography is described. Application of the valve to high pressure gel permeation chromatographic (GPC) separation of oil from the vitamin A active fraction of margarine resulted in efficient oil removal after one pass through 2 μStyragel (100A) columns connected in series. Using the normal collection mode of the high pressure liquid chromatograph, 2 passes through the GPC columns were required to adequately resolve the fractions.
Thin Layer Chromatographic Method for Analysis and Chemical Confirmation of Sterigmatocystin in Cheese
Authors: Van Egmond Hans P , Paulsch Walter E , Deijll Ellen , Schuller Pieter L
Published: February 2020

A semi-quantitative method is described for the analysis of sterigmatocystin in cheese. The method is based on extraction of cheese with MeOH-4% KC1 (9+1), followed by Florisil and polyamide column cleanup and 2-dimensionaI thin layer chromatography (TLC). Visualization of sterigmatocystin on the TLC plates is enhanced by an ALCL3 spray reagent. The identity of sterigmatocystin is confirmed by a 2-dimensional TLC test based on reaction with trifluoroacetic acid (TFA) on the plate after first development. The reaction product formed is visualized by spraying with ALCL3. The method allows detection and confirmation of sterigmatocystin in cheese at concentrations as low as 5 μg/kg. The method has been applied to cheese samples ripening in warehouses and naturally molded with Aspergillus versicolor
Gas-Liquid Chromatographic Determination of Sodium Fluoroacetate (Compound 1080)
Authors: Okuno Iwao , Meeker Dennis L
Published: February 2020

An analytical method is described for the determination of Compound 1080 (sodium fluoroacetate) residues in 1–10 g tissue. Sample extracts of tissues are cleaned up with silica gel, and Compound 1080 (as fluoroacetic acid) is separated by a micro-distillation procedure. The fluoroacetic acid in the distillate is derivatized with pentafluorobenzyl bromide to form pentafluorobenzyl fluoroacetate which is measured by electron capture gas-liquid chromatography. Recoveries of sodium fluoroacetate from fortified tissue samples averaged about 25%. Despite the limited recoveries, results were quite reproducible, and levels as low at 2 ppm were determined in fortified 1 g samples, and 0.2 ppm in 10 g samples. The method is relatively simple and has been used routinely in our laboratory for the analysis of various types of samples such as grain, and tissues from birds, rodents, and larger animals.
Some Factors Affecting Assay Variability in the Determination of Chlortetracydine in Premix Feeds
Authors: Ragheb Hussein S
Published: February 2020

There are many sources of error in the microbiological determination of high levels of chlortetracycline in premix. Among the critical factors that can be controlled by the analyst are careful weighing of the reference standard and careful dosing of cylinders. A spectrophotometric approach and automatic filling of cylinders are suggested to ensure proper monitoring of these operations. Among factors that cannot be controlled by the analyst is the assay design. A 3-point design which is a modified version of the (3+3) design is considered, and its advantages are illustrated.
Ion Exchange Method for Rapid Determination of Alkalinity of Water-Soluble Tea Ash Containing High Levels of Manganese
Authors: Qureshi Saidul Z , Najib Fadhil M , Mohammed Fahmi A
Published: February 2020

An ion exchange method to determine the alkalinity of water-soluble tea ash containing high levels of manganese is described. A chromatographic column containing a strong cation exchange resin (20–50 mesh) in Na+ form, with a bed volume of 5 mL is used. The present ion exchange method is compared to pH titrations and also to the official AOAC methods (31.012, 31.015, 31.016). Results with the new method are accurate and precise.
Separation and Detection of Arsenical Pesticide Residues and Some of Their Metabolites by High Pressure Liquid Chromatography-Graphite Furnace Atomic Absorption Spectrometry
Authors: Woolson Edwin A , Aharonson Nadav
Published: February 2020

A method was developed for the separation and quantitative determination of arsenite, methanearsonic acid (MAA), dimethylarsinic acid (cacodylic acid or CA), and arsenate by high pressure liquid chromatography (HPLC) coupled to a graphite furnace atomic absorption (GFAA) detector. The compounds are separated on a low capacity anion exchange column with gradient elution from 100+ water-methanol (80 + 20, v/v) to 100% 0.02M (NH4)2CO3-methanol (85 + IS, v/v) at 1.2 mL/min and a pressure of about 300 psi. The HPLC was coupled by an automatic sampling unit to the GFAA through an interface consisting of a Teflon flow-through sampling cup. Limit of detection for the arsenic compounds was about 5 ng As injected in aliquots of 20 μL (0.25 ppm As in solution). All 4 arsenical compounds gave similar calibration curves, which were linear from 0.1 to 2.0 ng for single atomizations in the GFAA and from 5 to 200 ng when multiple, sequential atomizations of HPLC eluant were used to quantitate HPLC peaks. Quenching by soil extracts as well as aqueous HPLC solvents was minimal.
Colorimetric Determination of Methyl Parathion and Oxygen Analog
Authors: Nanda Kumar Nanguneri V , Ramasundari Mattipalli
Published: February 2020

A simple, sensitive, and rapid colorimetric method is described (or determining methyl parathion (0,0-dimethyl-O-ρ-nitrophenyl phosphorothioate) and methyl paraoxon (O,O-dimethyl-O-ρ-nitrophenyl phosphate), using ρ-nitrobenzene diazonium fluoroborate as the chromogenic salt. This colorimetric method is more sensitive than are other colorimetric methods based on nonenzymatic reactions. Pig liver acetone powder cholinesterase was found to be sensitive to methyl parathion. Inhibition can be detected at picogram levels, and 50–80 ng methyl paraoxon and 1–9 μg methyl parathion can be estimated.
High Performance Liquid Chromatographic Determination of Carbaryl Insecticide in Formulations
Authors: Mcdermott William H
Published: February 2020

A high performance liquid chromatographic method for carbaryl in formulations has been developed and used to assay 3 formulations in a 10-day repeatability study. The method uses a cyano modified silica gel column packing and a mobile phase of heptane-methylene chloride-isopropanol-methanol (60+35+4.8+0.2). The coefficients of variation for 2 wettable powders and one aqueous flowable formulation were 0.61, 0.62, and 0.75%, respectively. It is recommended that a collaborative study be conducted on this method.
Enhanced Detectability and Chromatography of Some Amines by High Pressure Liquid Chromatography
Authors: Noggle F Taylor
Published: February 2020

The high pressure liquid chromatographic properties of 13 phenylisothiocyanate derivatives of primary and secondary amines were examined with ultraviolet detection at 254 nm. Urine extracts of subjects who were taking ephedrine, phenylpropanolamine, and phentermine were also examined. The method described improves the chromatographic properties of the amines and also enhances their detectability.
Performance Specifications for Measuring Milkfat by Turbidimetric Means
Authors: Shipe W Frank , Senyk Gary F
Published: February 2020

Precision between duplicates of ≤0.03% for 0–5% and ≤0.04% for 5–8% fat is recommended regardless of type of milk. Maximum mean differences of ≤0.04% and standard deviations of difference of 0.10% for individual cow milk and 0.06% for bulk milks between instrumental values and standard chemical reference methods are specified. These recommendations are based on 95% confidence limits for 20 samples analyzed in triplicate. Sections 16.063–16.068 are revised to apply to all turbidimetric instruments regardless of model or manufacturer. A precaution section is included in the specifications to assure accurate instrumental performance. The specifications have been adopted as official first action.
Total Nitrogen Analysis of Soil and Plant Tissues
Authors: Nelson Darrell W , Sommers Lee E
Published: February 2020

Progress of the Dumas and Kjeldahl procedures over the past century is reviewed. Many recent papers claim that various modifications of the standard Kjeldahl method enhance accuracy, precision, or speed, and reduce cost of analysis. Furthermore, several authors advocate use of Pyrex tubes heated in an aluminum block for digestion instead of traditional Kjeldahl flasks. A review of current semimicro-Kjeldahl methodology suggests that proceeding under the following conditions gives satisfactory results: sample size, 50–200 mg for plant material, 100–500 mg for soil; digestion acid, concentrated H2SO4; sample size ratio (mL/g) of 16:1 for soils and 22:1 for plant materials; digestion salt, minimum 0.33 g K2SO4 added/mL H2SO4; catalysts, add CuSO4 5H2O at rate of 10% (w/w) of K2SO4 added, HgO at 5% (w/w) of K2SO4, or add Se to K2SO4–CuSO4 5H2O mixtures at rate of 1% (w/w) K2SO4; digestion time, 1 and 3 h past clearing for plant materials and soils, respectively; pretreatments, use salicylic acid or reduced iron to recover nitrate from sample. Use of Pyrex tubes heated in an aluminum block appears suitable for digestions. Our results indicate that the 2 commercial tube digestion systems tested produce satisfactory recovery of total N from soils and plant materials. Ammonium in Kjeldahl digests may be quantitatively determined by distillationtitration, ammonia electrode, or colorimetric techniques.
NBS Plant Tissue Standard Reference Materials
Authors: Alvarez Robert
Published: February 2020

NBS issues 6 Standard Reference Materials for use in determining nutrient and contaminant elements in plant tissues and agricultural food products. They are SRM 1571, Orchard Leaves; SRM 1573, Tomato Leaves; SRM 1575, Pine Needles; SRM 1570, Spinach; SRM 1567, Wheat Flour; and SRM 1568, Rice Flour. These SRMs are used to calibrate instrumentation, to determine accuracy of existing analytical methods, and to develop more accurate methods. The Certificate of Analysis for each SRM details the homogeneity of the powdered material, the minimum sample size to be used, the certified values for the elements with their uncertainties, and the noncertified values. A certified value is based either on concordant results by independent analytical methods or on results by a definitive method, i.e., an accurate method having identified, systematic errors. These certified values can serve as common reference points for comparison of data acquired over a long period by various investigators using a variety of methods.
Trace Element Analysis of Bovine Liver: Interlaboratory Survey in Australia and New Zealand
Authors: Koh T S , Benson T H , Judson G J
Published: February 2020

An interlaboratory survey of the determination of trace elements in bovine liver was undertaken. Thirty-three laboratories from Australia and 15 from New Zealand returned results. Moisture determination results were variable despite the use of a recommended drying procedure. For the 10 trace elements determined, the mean values (μg/g) with their interlaboratory coefficients of variation (CV) were: cadmium, 1.2 (42.5%); cobalt, 0.21 (9.5%); copper, 110 (6.0%); iron, 276 (11.0%); lead, 0.6 (48.9%); manganese, 8.6 (13.9%); mercury, 0.03 (30.0%); molybdenum, 2.5 (45.6%); selenium, 1.0 (17.5%); zinc, 219 (8.2%). The intralaboratory CV for determining each of these elements was less than 9% except for the lead CV which was 20.2%. Results for the determination of sodium, potassium, calcium, and magnesium were also reported. The survey shows that while the use of a standard reference material can improve the performance of laboratories in trace element analysis, it may also introduce analytical bias.
Paper Chromatographic Determination of Phosphorus Species
Authors: Trimm Joe R , Stumpe Louis A , Lawrence Edward J , Duncan Russell D , Johnson Frank J
Published: February 2020

Ascending paper chromatographic methods are described to identify and quantify phosphorus species present in polyphosphates, metaphosphates, fluorophosphates, and phosphites. After interfering cations are removed or complexed, samples are chromatographed, and the individual species are leached from the paper, hydrolyzed to orthophosphate, and determined by the heteropoly blue method. Different solvents and techniques are used for the various phosphate compounds.
Thin Layer Chromatographic Detection and Fluorometric Determination of the Preservative cis-l-(3-Chloroallyl)-3,5,7-triaza-lazoniaadamantane Chloride (Quaternium-15) in Cosmetics
Authors: Wisneski Harris H
Published: February 2020

The preservative cis-l-(3-chloroallyl)-3,5,7- triaza-1-azoniaadamantane chloride (quaternium-15) was detected and differentiated from other formaldehyde-releasing preservatives such as 2-bromo-2-nitropropane-l,3-diol, l-hydroxymethyl-5,5-dimethylhydantoin, and imidazolidinyl urea in cosmetics by thin layer chromatography. A minimum of 0.1 μg quaternium-15 was detected by fluorescence of the lutidine derivative formed from a buffered 2,4-pentanedione indicator spray and formaldehyde liberated from this preservative. Another indicator spray, a modified Dragendorf reagent, provided additional confirmation at lower sensitivity. The fluorometric determination of quaternium-15 was based on its quantitative release of formaldehyde to form the fluorescent 3,5-diacetyl-1,4-dihydrolutidine. Close to the theoretical value of 6 moles of formaldehyde per mole of quaternium-15 was verified experimentally (5.8–6.3). Average recoveries of quaternium-15 from a bath oil and lotion ranged from 91.7 to 103%.
Infrared Spectrophotometric Determination of Encapsulated Methoprene in Poly (lactic Acid) Formulations
Authors: Giang Paul A , Jaffe Howard
Published: February 2020

A simple infrared spectrophotometric method is described for determination of the percentage methoprene (isopropyl (E,E)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate, Altosid, ZR-515) in a microcapsule sample of lactic acid polymer material. In the analysis, a weighed microcapsule sample was extracted with toluene–isopropanol in an Erlenmeyer flask, and the solvent mixture was evaporated in a rotary vacuum evaporator. For cleanup, the extract was dissolved in methanol and chromatographed through a column composed of sodium sulfate, silica gel, and aluminum oxide. The solvent was again completely evaporated, the dried eluate was dissolved in an appropriate volume of carbon tetrachloride, and the infrared absorption was scanned. The response can then be related by a standard curve to mg methoprene/mL.
High Performance Liquid Chromatographic Determination of α-Tocopherol in Fish Liver
Authors: Hung Silas S O , Cho Young C , Slinger Stanley J
Published: February 2020

A simple method is described for the determinatio n of α-tocopherol in fish liver by high performance liquid chromatography. This method does not involve saponification or thin layer chromatography and thus avoids the destruction of α-tocopherol during sample preparation. The homogenized liver sample is extracted twice with dioxane–isooctane (20+80, v/v), and the combined extracts are dried under vacuum. The residue is extracted 3 times with acetonitrile from which α-tocopherol is then extracted with isooctane. The residue from the dried isooctane solution is dissolved in methanol–water (90+10, v/v) which is injected directly onto a micro Bondapak C18 high performance liquid chromatograph. The detection response to α-tocopherol at 280 nm was measured by peak height which was linear from 1 to 10 μg/25 μL injection. The coefficients of variation for retention time and peak height for 5 replicate analyses of the standard during 2 weeks were 1.4 and 2.4%, respectively. Recovery of α-tocopherol added to the sample before homogenization was 80–92% with a mean of 86.2% and a coefficient of variation of 4.9%. The minimum amount of sample and the concentration of α-tocopherol that can be accurately determined by the method are 0.5 g liver and 1 μg α-tocopherol/g liver, respectively.
Survey for Zearalenone, Aflatoxin, and Ochratoxin in U.S. Grain Sorghum from 1975 and 1976 Crops
Authors: Shotwell Odette L , Bennett Glenn A , Goulden Marion L , Plattner Ronald D , Hesseltine Clifford W
Published: February 2020

Grain sorghum samples (197) from 10 States harvested in 1975 and 1976 were analyzed for zearalenone, aflatoxin, and ochratoxin by the Eppley procedure. Zearalenone was detected in 56 samples (28%) at levels of 200–6900 ng/g (the detection limit was 100–200 ng/g). Zearalenone identity was confirmed in representative samples by gas chromatography–mass spectroscopy of the trimethylsilyl derivatives. No ochratoxin was detected in any sample (the detection limit was about 50 ng/g). Aflatoxin was detected in 4 samples at levels of 54, 6, 10, and 7 ng total aflatoxin/g (the detection limit was ca 3 ng/g). The identity of aflatoxin B1 in the samples was confirmed by formation of the water adduct on thin layer chromatographic plates.
Gas Chromatographic and Mass Spectrometric Characterization of Impurities in Technical Methoxychlor
Authors: Lamoureux Carolejean H , Feil Vernon J
Published: February 2020

The impurities in technical methoxychlor were concentrated by removing most of the 1,1,1-trichloro-2,2-bis(4-methoxyphenyl)ethane by recrystallization. Analysis of the impurities by gas chromatography–mass spectrometry provided evidence for more than 50 compounds. Twenty-five of these were identified through interpretation of mass spectra and synthesis.
Rapid High Pressure Liquid Chromatography of Patulin in Apple Juice
Authors: Möller Tord E , Josefsson Egon
Published: February 2020

A rapid method has been developed for screening patulin in apple juice. The sample is extracted with ethyl acetate and the extract is cleaned up by extraction with a sodium carbonate solution. Patulin is determined after high pressure liquid chromatography on a Spherisorb 5 μm ODS column with an ultraviolet detector set at 276 nm. The detection limit of the method is 5 μg/L and recovery is 70–75%.
Gas-Liquid Chromatographic Determination of Pentachlorophenol in Mason Jar Lids and Home Canned Foods
Authors: Heikes David L , Griffitt Kenneth R
Published: February 2020

A method was developed for the determination of pentachlorophenol (PCP) in the seals and enamel of Mason lids. After extraction with acidic CH2Cl2 and methylation, the resulting pentachloroanisole was determined by gas-liquid chromatography (GLC) with electron capture detection (EC). Three of the 9 brands of lids examined contained PCP. Levels were as high as 198 μg/lid. Recoveries from fortified samples ranged from 92 to 103%. Six fruits and vegetables were canned by home canning techniques, using lids shown to contain PCP. PCP in these foods was determined by a procedure specifying extraction with acidic CH2Cl2 and gel permeation chromatography cleanup. Extracts were methylated and determined by GLC-EC. PCP was found in all the canned foods. Levels were as high as 16 μg/qt. Recoveries from foods fortified with PCP ranged from 85 to 94%. The presence of PCP was confirmed by GLC-mass spectrometric determination of the derivative, pentachloroanisole.
Rapid High Performance Liquid Chromatographic Method for Determination of Gelatin-Coated Supplemental Vitamin E in Feeds
Authors: Eriksen Svend
Published: February 2020

A rapid method is described for determining supplemental vitamin E in feeds by means of high performance liquid chromatography (HPLC) using isocratic elution with methanol-water. The sample is mixed with water and left on a water bath to dissolve the coating. The released vitamin E is extracted, the solvent is evaporated, and the sample is redissolved in methanol for injection. The method is applicable to gelatin-coated vitamin preparations. Standard deviations for 2 ranges of supplemented vitamin E, 10–50 ppm and 50–200 ppm, are 1.6 and 5.7, respectively.
Determination of Low Levels of Vitamin D3 in Animal Feeds, Using Sephadex LH-20 and Normal Phase High Pressure Liquid Chromatography
Authors: Cohen Huguette , Lapointe Michel
Published: February 2020

A procedure has been developed for the purification and quantification of vitamin D3 at levels of 4000 down to 500 IU/kg from a variety of animal feeds. The method involves initial extraction with dichloromethane followed by filtration through a Sep-Pak cartridge. The D3 fraction from the Sep-Pak is further purified by using a 45 × 1.6 cm Sephadex LH-20 column followed by a Partisil-10 PAC cleanup column. Final analysis is performed by high pressure liquid chromatography (HPLC) using a LiChrosorb NH2 10 μm column and a variable wavelength UV detector set at 264 nm. The detection response curve for a vitamin D3 standard was linear over the range 5 to 100 ng, using both peak area and peak height measurements; the minimum detectable amount was 5 ng. The average percent recovery of vitamin D3 in animal feeds was 94.16 ± 5.2%.
High Pressure Liquid Chromatographic Determination of Vitamin D3 in Instant Nonfat Dried Milk
Authors: Cohen Huguette , Wakeford Bryan
Published: February 2020

Vitamin D3 was determined in commercially fortified instant nonfat dried milk by using normal phase high pressure liquid chromatography (HPLC). The sample was extracted with dichloromethane with sodium phosphate tribasic solution added. The sample was cleaned up by using a Sep-Pak silica cartridge and then a microparticulate column containing 10 μm Partisil-10 PAC packing material. The final analysis was performed by using a normal phase HPLC system with a 10 μm LiChrosorb NH2 column. Recovery of vitamin D3 at levels as low as 1000 IU/kg was 97.7% with a standard deviation of 3.9%.
Analytical Reference Materials. III. Preparation and Homogeneity Test of Large Quantities of Wet and Dry Sediment Reference Materials for Long Term Polychlorinated Biphenyl Quality Control Studies
Authors: Chau Alfred S Y , Lee Hing-Biu
Published: February 2020

This paper describes the preparation of large quantities of wet and dried lake sediments to be used as analytical reference materials for long term polychlorinated biphenyl (FCB) quality control studies. Five hundred and forty subsamples (15–20 g each) of wet sediment spiked with PCBs and more than 4900 subsamples (25–30 g each) of naturally contaminated dried sediment were prepared. Evidence of homogeneity between subsamples in each group is presented.
Quantitative Determination of Individual Chlorinated Biphenyls in Milkfat by Splitless Glass Capillary Gas Chromatography
Authors: Tuinstra Louis G M T , Traag Wim A , Keukens Henk J
Published: February 2020

A method is described for determining individual polychlorinated biphenyls (PCBs) in milkfat at the ppb level. Extraction and major cleanup are done simultaneously by saponification of the milkfat. After final cleanup on basic alumina, the concentrated extract is injected under splitless conditions on a capillary column coated with CPSil 7 stationary phase. The recovery of several individual PCBs from milkfat at a level of 25 ppb is better than 80%. The reproducibility for duplicates analyzed on several days showed standard deviations from 0.2 to 0.9 ppb for 19 individual chlorinated biphenyls. Some preliminary results for 165 samples of milkfat are reported.
Simultaneous Spectrophotometric Determination of Nifuroxime and Furazolidone in Pharmaceutical Preparations
Authors: Elsayed Laila , Hassan Sayed M , Kelani Khadiga M , El-Fatatry Hamed M
Published: February 2020

Two spectrophotometric methods have been developed for the simultaneous determination of nifuroxime and furazolidone in their pharmaceutical preparations. No preliminary separation step is required in either method. The first, a modified Vierordt method, gives accurate and reproducible results for both drugs. Mean percent recoveries for nifuroxime and furazolidone were 99.50 ±1.59 and 100.20 ±1.16 (P = 0.05), respectively. This method also gives accurate and reproducible results for the determination of nifuroxime and furazolidone in their pharmaceutical preparations: Tricofuran vaginal suppositories and powder. The second method, which involves the use of the first-derivative curves, gives unreliable results; the reasons for these are discussed.
Quantitative Determination of Steroid Acetates in Pharmaceutical Preparations by High Performance Liquid Chromatography
Authors: Van Dame Halver C
Published: February 2020

A high performance liquid chromatographic method is described for the rapid, quantitative determination of corticosteroid acetates in a variety of pharmaceutical preparations. The method not only separates the steroids from other ingredients in tablets, creams, ointments, lotions, or suspensions, but also from their probable degradation products. The steroid acetate is extracted from a tablet matrix or from a suspension with water and acetonitrile (50+50), or from a hexane suspension of a cream, ointment, or lotion with acetonitrile. A liquid chromatogi aph equipped with an accurate flow controller, a variable wavelength detector capable of measurement at 240 nm, and a 10 μL loop injector was used. Components were separated on a μBondpak C18 column with acetonitrile-water as the mobile phase. K’ values of 10 commonly used steroid acetates are shown and compared with Rf values from thin layer chromatographic systems. Results were equivalent for cortisone acetate tablets assayed by both the proposed and the official USP methods. Other pharmaceutical preparations were assayed to test the method, with satisfactory results.
High Performance Liquid Chromatography of Furfural and Hydroxymethylfurfural in Spirits and Honey
Authors: Jeuring Hans J , Kuppers Frans J E M
Published: February 2020

Furfural (2-Jfuraldehyde) and hydroxymethylfurfural (S-hydroxy-2-furaIdehyde, HMF) are determined in brandy and honey by reverse phase high performance liquid chromatography. Brandies and other spirits are injected without sample preparation; honey is diluted with water and the solution is filtered before injection onto a reverse phase column with detection at 285 nm. The mobile phase is methanol–water (10+90) and the effluent flow rate is maintained at 1.0 mL/min. External standardization is used for quantitative determination. Recoveries from cognac and honey spiked at different levels ranged from 95 to 99% (furfural) and 95 to 100% (HMF). The furfural content of the brandies was also determined by the existing colorimetric method of the Bureau National Interprofessionel du Cognac. The HMF content of the honey was correlated to the results of the classic method of Winkler.
Isotachophoretic Determination of Ethylenediaminetetraacetate in Salad Dressing, Mayonnaise, and Margarine
Authors: Ito Yoshio , Toyoda Masatake , Suzuki Hideyo , Iwaida Masahiro
Published: February 2020

An isotachophoretic method was developed for the determination of EDTA in foods imported by Japan. Skimmed samples of dressings, mayonnaise, or margarine were chromatographed on an anion exchange column, and interfering organic acids were eluted with water and 0.01N HC1. EDTA was eluted with 0.2N HC1 and reacted with ferric chloride to form a stable EDTA-Fe complex. Electrophoresis was carried out with dilute HCl containing 0.05% Triton and β-alanine (pH 3.5) as the leading electrolyte and 0.01M caproic acid as terminating electrolyte. Since uncoupled EDTA showed more than one zone, it was reacted with ferric chloride to form EDTA-Fe complex which showed only a single zone on an isotachopherogram. More than 90% of EDTA spiked at 100 or 1000 ppm level as disodium salt was recovered from the above mentioned three types of food. Detection limit was 10 ppm as disodium EDTA.
Identification of Hazardous Organic Chemicals in Fish from the Ashtabula River, Ohio, and Wabash River, Indiana
Authors: Kuehl Douglas W , Leonard Edward N , Welch Kenneth J , Veith Gilman D
Published: February 2020

Composite fish samples from the Wabash River, IN, and the Ashtabula River, OH, were analyzed by conventional pesticide procedures for PCBs, DDTs, chlordane components, and hexachlorobenzene. Additional aliquots of each sample were processed by gel permeation chromatography and were analyzed with gas chromatography–mass spectrometry by using both electron impact and negative chemical ionization modes. These analyses resulted in the identification of a series of chlorinated alkanes, chlorinated alkenes, chlorinated alkylamines containing 2–5 carbons, and polychlorinated styrenes in the Ashtabula River sample, and a series of chlorinated norbornenes, pentachlorobenzyl alcohol, and pentachlorophenol in the Wabash River sample.
Laboratory Screening for Zearalenone Formation in Corn Hybrids and Inbreds
Authors: Shannon Gail M , Shotwell Odette L , Lyons Allister J , White Donald G , Garcia-Aguirre Genoveva
Published: February 2020

Grains from 14 corn inbreds and 4 single cross hybrids were inoculated with 3 isolates of Gibber ella zeae to determine their inhibition of zearalenone production. The corn hybrids: Pa762 × A632 (50 mg/kg zearalenone production), A619 × A632 (17 mg/kg zearalenone production), H95 × Mol7 (132 mg/kg zearalenone production), and B73 × Mol7 (33 mg/kg zearalenone production) appear to have less resistance than the inbreds to toxin formation. Inbred H95 (64 mg/kg zearalenone production) supported the highest toxin production of all inbreds. The remaining 13 inbreds did not exceed 15 mg/kg zearalenone production. The inbreds A632 (4 mg/kg zearalenone production) and Pa762 (2 mg/kg zearalenone production) demonstrated some resistance; the resulting cross, hybrid Pa762 × A632 (50 mg/kg zearalenone production), does have greater resistance than hybrid H95 × Mol7 (132 mg/kg zearalenone production). Analysis of variance indicated highly significant variation between corn varieties and fungal isolates. The coefficient of variation for 29 fermentations run in duplicate on inoculated control corn to produce zearalenone (212 mg/kg) was 37%, which would include variation in both the fermentation and analysis. Isolate and variety interaction is not significant.
GasChromatographic-Mass Spectrometric Analysis, Identification, and Detection of Adulteration of Perfumery Products from Bitter Orange Trees
Authors: Prager Manfred J , Miskiewicz Michael A
Published: February 2020

A gas chromatographic procedure was developed for identifying and detecting adulteration of several perfumery products from the bitter orange tree. Components present to the extent of about 1% or more were determined quantitatively in reference and commercial samples of petitgrain oil, petitgrain absolute from water, neroli oil, orange flower absolute from water, and orange flower absolute. About 20 major components were common to these materials. These compounds were identified by mass spectrometric analysis following chromatographic separation and included β-pinene, limonene, γ-terpinene, linalool oxide, linalool, linalylacetate, α-terpineol, neryl acetate, geranyl acetate, nerol, geraniol, phenethyl alcohol, benzyl cyanide, nerolidol, methyl anthranilate, farnesol, and indole.