bluuebunny/crossref_metadata_2025 huggingface dataset:
Mortality after drug-eluting stents vs. coronary artery bypass grafting for left main coronary artery disease: a meta-analysis of randomized controlled trials
Authors: Ahmad Yousif , Howard James P , Arnold Ahran D , Cook Christopher M , Prasad Megha , Ali Ziad A , Parikh Manish A , Kosmidou Ioanna , Francis Darrel P , Moses Jeffrey W , Leon Martin B , Kirtane Ajay J , Stone Gregg W , Karmpaliotis Dimitri
Published: February 2020

Aims 

The optimal method of revascularization for patients with left main coronary artery disease (LMCAD) is controversial. Coronary artery bypass graft surgery (CABG) has traditionally been considered the gold standard therapy, and recent randomized trials comparing CABG with percutaneous coronary intervention (PCI) with drug-eluting stents (DES) have reported conflicting outcomes. We, therefore, performed a systematic review and updated meta-analysis comparing CABG to PCI with DES for the treatment of LMCAD.

Methods and results 

We systematically identified all randomized trials comparing PCI with DES vs. CABG in patients with LMCAD. The primary efficacy endpoint was all-cause mortality. Secondary endpoints included cardiac death, myocardial infarction (MI), stroke, and unplanned revascularization. All analyses were by intention-to-treat. There were five eligible trials in which 4612 patients were randomized. The weighted mean follow-up duration was 67.1 months. There were no significant differences between PCI and CABG for the risk of all-cause mortality [relative risk (RR) 1.03, 95% confidence interval (CI) 0.81–1.32; P = 0.779] or cardiac death (RR 1.03, 95% CI 0.79–1.34; P = 0.817). There were also no significant differences in the risk of stroke (RR 0.74, 95% CI 0.35–1.50; P = 0.400) or MI (RR 1.22, 95% CI 0.96–1.56; P = 0.110). Percutaneous coronary intervention was associated with an increased risk of unplanned revascularization (RR 1.73, 95% CI 1.49–2.02; P < 0.001).

Conclusion 

The totality of randomized clinical trial evidence demonstrated similar long-term mortality after PCI with DES compared with CABG in patients with LMCAD. Nor were there significant differences in cardiac death, stroke, or MI between PCI and CABG. Unplanned revascularization procedures were less common after CABG compared with PCI. These findings may inform clinical decision-making between cardiologists, surgeons, and patients with LMCAD.
Association Between Erythrocyte Levels of n-3 Polyunsaturated Fatty Acids and Risk of Frailty in Community-Dwelling Older Adults: The Korean Frailty and Aging Cohort Study
Authors: Kim Doyeon , Won Chang Won , Park Yongsoon
Published: February 2020

Background

Inflammation is a major risk factor for frailty, but n-3 polyunsaturated fatty acids (PUFA) has been suggested as an anti-inflammatory agent. The present study aimed to investigate the hypothesis that the higher erythrocyte levels of long-chain n-3 PUFA were associated with lower odds of frailty and frailty criterion.

Methods

Cross-sectional analysis from the Korean Frailty and Aging Cohort Study, a total of 1,435 people aged 70–84 years were included. Sex- and age-stratified community residents, drawn in urban and rural regions nationwide, were eligible for participation in the study. All participants were categorized as frail and nonfrail according to the Cardiovascular Health Study index.

Results

The likelihood of frailty was inversely associated with the erythrocyte levels of eicosapentaenoic acid (EPA; odds ratio [OR] per unit 0.33; 95% confidence interval [CI] 0.14–0.77; p for trend = .002) and docosahexaenoic acid (DHA; OR per unit 0.42; 95% CI 0.20–0.87; p for trend = .018). Among each frailty criterion, the likelihood of slow walking speed was associated with erythrocyte levels of EPA and DHA, and the likelihood of exhaustion was inversely associated with the erythrocyte levels of DHA.

Conclusions

The present study showed that the frailty and frailty criterion were significantly associated with lower erythrocyte levels of long-chain n-3 PUFA, suggesting that lower n-3 PUFA could be a marker for the risk of frailty.
Rigorous analysis of free solution glycosaminoglycan dynamics using simple, new tools
Authors: Nagarajan Balaji , Sankaranarayanan Nehru Viji , Desai Umesh R
Published: February 2020

Heparin/heparan sulfates (H/HS) are ubiquitous biopolymers that interact with many proteins to induce a range of biological functions. Unfortunately, how these biopolymers recognize their preferred protein targets remain poorly understood. It is suggested that computational simulations offer attractive avenues but a number of challenges, e.g., difficulty of selecting a comprehensive force field, few simple tools to interpret data, among others, remain. This work addresses several such challenges so as to help ease the implementation and analysis of computational experiments. First, this work presents a rigorous comparison of two different recent force fields, CHARMM36 and GLYCAM06, for H/HS studies. Second, it introduces two new straightforward parameters, i.e., end-to-end distance and minimum volume enclosing ellipsoid, to understand the myriad conformational forms of oligosaccharides that evolve over time in water. Third, it presents an application to elucidate the number and nature of inter and intramolecular, nondirect bridging water molecules, which help stabilize unique forms of H/HS. The results show that nonspecialists can use either CHARMM36 or GLYCAM06 force fields because both gave comparable results, albeit with small differences. The comparative study shows that the HS hexasaccharide samples a range of conformations with nearly equivalent energies, which could be the reason for its recognition by different proteins. Finally, analysis of the nondirect water bridges across the dynamics trajectory shows their importance in stabilization of certain conformational forms, which may become important for protein recognition. Overall, the work aids nonspecialists employ computational studies for understanding the solution behavior of H/HS.
Ancient Caloric Functions on Graphs With Unbounded Laplacians
Authors: Hua Bobo
Published: February 2020

We study ancient solutions of polynomial growth to both continuous-time and discrete-time heat equations on graphs with unbounded Laplacians. We extend Colding and Minicozzi’s theorem [12] on manifolds and the result [22] on graphs with normalized Laplacians to the setting of graphs with unbounded Laplacians: for a graph admitting an intrinsic metric, which has polynomial volume growth, the dimension of the space of ancient solutions of polynomial growth is bounded by the dimension of harmonic functions with the same growth up to some factor.
Liquid Chromatographic Method for Determination of Cyhexatin in Technical and Formulated Products: Collaborative Study
Authors: Lupan Stephen
Published: February 2020

Cyhexatin technical (95%), 25 and 50% wettable powders, and a 600 g/L suspension concentrate were analyzed by liquid chromatography in a collaborative study of the method. Paired samples of cyhexatin technical and the 3 formulations were extracted with a mixture of methanol-water-acetic acid (950 + 49 + 1) containing n-decylbenzene as internal standard. Components were separated on a Lichrosorb RP-18 column using methanol-water-HCl-NaCl (93 + 7 + 0.001M + 0.005M) at 2.0 mL/min, and then detected at 214 nm. Results were received from 18 of the 20 laboratories who agreed to participate in the study; 14 sets of data were suitable for statistical evaluation. Repeatability coefficients of variation (CV0 ranged from 0.46% for the 50% wettable powder to 1.14% for the suspension concentrate. Reproducibility coefficients of variation (CVX) ranged from 0.70 to 1.85% for the 4 types of samples. The method has been adopted official first action as a CIPAC-AOAC method.
Liquid Chromatographic Method for Determination of Piperine in Piper nigrum (Black and White Pepper)
Authors: Weaver Kenneth M , Neale Michael E , Laneville Ann
Published: February 2020

A method was developed for the detection and quantitation of piperine in Piper nigrum. A reverse-phase liquid chromatographic system equipped with a C18 column with detection at 340 nm was used. A rapid 1 h acetone extraction followed by solvent dilution was used to avoid sample cleanup. The detection limit is 3 ng injected piperine, with 97.5-100.5% recovery of added piperine.
Statistical Sampling Approaches
Authors: Springer Janet A , Mcclure Foster D
Published: February 2020

This article describes basic sampling principles and the application of statistical sampling techniques to specific problems encountered in the Food and Drug Administration (FDA). Concepts are emphasized, and theory is minimized. The basic principles of sampling from a normal and binomial population, including confidence interval calculation and sample size determination, are briefly reviewed. Stratified, random, systematic, and judgment sampling are explained. Operating characteristic curves for attribute (and perhaps variable) sampling for acceptance of lots are derived and applied to specific FDA problems. The advantages and disadvantages of single and multiple sampling plans and plans which address multiple classes of criteria such as major and minor defects are discussed. Sampling schedules such as MIL-STD-105D and Canada's Government Specifications Board CGSB-105-GP-1 are reviewed to familiarize readers with the principles involved in these plans and to give them an idea of how they could be applied to FDA problems.
In Vitro Analytical System for Determining the Ability of Antibiotics at Residue Levels to
Select for Resistance in Bacteria
Authors: Suebrady Marietta , Strobel Robert J , Katz Stanley E
Published: February 2020

An analytical procedure, based on the concept that exposure of bacteria to antibiotics will result in the selection of a resistant population, was developed. Two strains of enteric bacteria, Escherichia coli CS-1 and Enterobacter cloacae B520, which are sensitive to a wide variety of antibiotics, were used as the test organisms. E. coli CS-1 were exposed to 1.00 μg antibiotic or antimicrobial/mL; E. cloacae B520 were exposed to 0.01, 0.10, 0.50,1.00, and 5.00 μg/mL. Both organisms developed increased resistance to other antibiotics after exposure to chlortetracycline and oxytetracycline, as measured by the minimum inhibitory concentration (MIC). E. cloacae B520 showed increased resistance to ampicillin, oxytetracycline, and chloramphenicol after exposure to levels as low as 0.10 μg/mL. Exposure to streptomycin, sulfamethazine, tylosin, bacitracin, flavomycin, virginiamycin, and monensin at levels of 1.00 μg/mL did not increase the MIC. Exposure to 5.00 *tg streptomycin, sulfamethazine, tylosin, and monensin/mL increased the MIC ofE. cloacae to one of the antibiotic markers. These increased MICs exceeded the 95% confidence limits of the MIC values of the unexposed organisms.
Liquid Chromatographic Determination of Phenolic Impurities in Technical MCPA Using
Electrochemical Detection (Coulometric Mode)
Authors: Wigfield Yuk Y , Lanouette Monique
Published: February 2020

Fifteen samples of technical 4-chloro-2-methylphenoxy acetic acid (MCPA) from 6 manufacturers were analyzed for the presence of 13 different phenolic impurities. Reverse-phase liquid chromatography with an electrochemical (coulometric mode) detector was used for qualitative and quantitative determinations. The phenols were separated using a 40-70% methanol and 60-30% 0.02M KH2P04 (pH 4.0) 35 min gradient system on a Spheri-5-RP-18 column. Confirmation of the phenols present was done by retention time comparison with the corresponding standards, using 2 other isocratic mobile phases, methanol-0.2M acetic acid (60 + 40) at a flow rate of 1.3 mL/min and acetonitrile-0.02M KH2P04 (45 + 55) (pH 3.0) at a flow rate of 0.90 mL/min. The similarity of results on 3 different solvent systems demonstrates the absence of any interfering responses. 2-Methyl-4-chlorophenol (average 0.168%) and 2-methyl- 4,6-dichlorophenol (average 0.004%) were detected in all 15 samples. 3-Methylphenol (0.002%) and 2,6-dimethyl-4-chlorophenol (0.002%) were detected in one sample only. The minimum detectable amount ranged from 0.1 to 0.6 ng, depending on the phenol. This corresponds to less than 0.002% when expressed relative to the weight of sample. The coefficient of variation for multiple analyses of the same sample (n = 6) is 1% for 2-methyl-4-chlorophenol and 3% for 2-methy 1-4,6- dichlorophenol.
Simple Determination of Ranitidine in Dosage Forms by In-Phase Selective AC Polarography
Authors: Squella Juan A , Zuñiga Luis A , Lemus Igor , Vergara Luis J. Nuñez
Published: February 2020

A new AC polarographic method for the determination of pharmaceutical forms of ranitidine is proposed, based on the electroactivity of the ranitidine nitro group. Individual and composite assays as well as recovery studies are described. Results show adequate precision and accuracy. Sample preparation is easy and no excipient separation is required.
Liquid Chromatographic Quantitation of Chicken and Turkey in Unheated Chicken-Turkey Mixtures
Authors: Ashoor Samy H , Osman Magdi A
Published: February 2020

A simple and rapid liquid chromatographic (LC) method has been used to quantitate chicken and turkey in unheated chicken-turkey mixtures. The LC method is sensitive and detects as little as 1% chicken or turkey. It reliably quantitates 5-100% chicken or turkey in unheated poultry mixtures. The method applies also to chicken or turkey which has been frozen, but does not apply to heat-treated poultry meats.
Liquid Chromatographic Determination of Tetracycline Residues in Animal Feeds
Authors: Martinez Elizabeth E , Shimoda Wilbert
Published: February 2020

A liquid chromatographic method for the multiresidue determination of tetracyclines (TCs) in feeds is described. The levels of quantitation were 10 ppm each for tetracycline-HCl (TC), oxytetracycline (OTC), and chlortetracycline-HCl (CTC); the detection limit was 40 ppb for each. The calibration curves were linear between 2.5 and 100 ppm. The procedure involved double extraction with pH 2.0 and pH 4.5 Mcllvain buffers, cleanup on a Sephadex LH-20 column, separation on a Nova-Pak C18 column, and detection at 370 nm. Recoveries of 10 μg/g of each TC in multiresidue feed samples ranged from 55.8 to 75.5% for OTC, 71.6 to 100% for TC, and 22.4 to 60.6% for CTC. The identities of the TCs were confirmed by thin layer chromatography.
Reverse-Phase Liquid Chromatographic Determination of Dexamethasone Acetate and
Cortisone Acetate in Bulk Drug Substance and Dosage Forms: Collaborative Study
Authors: Ng Linda L
Published: February 2020

A reverse-phase liquid chromatographic method for determination of dexamethasone acetate and of cortisone acetate was subjected to an interlaboratory study by 8 collaborators for each steroid acetate. Bulk drug substance, suspensions, and tablets were assayed. Bulk drug or dosage form is dissolved in an acetonitrile-buffer mixture and analyzed by an external standard method. The steroid acetate is resolved from extraneous components by reverse-phase chromatography and detected at 254 nm. The sample solutions are stable for at least 72 h. For dexamethasone acetate, coefficients of variation were 0.9 and <3.1% for the bulk drug substance and the suspensions, respectively. For cortisone acetate, coefficients of variation were 0.7% for bulk material, <2.0% for suspensions, and <2.5% for tablets. All dosage forms were commercial formulations. The 2 methods have been adopted official first action
Determination of Formaldehyde and Other Aldehydes in Industrial Surfactants hy Liquid
Chromatographic Separation of Their Respective 2,4-Dinitrophenylhydrazone Derivatives
Authors: Dahlgran James R , Jameson Melvin N
Published: February 2020

A rapid and simple method for the determination of formaldehyde, acetaldehyde, and propionaldehyde in surfactants by derivatization with 2,4-dinitrophenylhydrazine (DNPH) has been developed. Samples are prepared in small vials containing a solution of DNPH and acetonitrile. This procedure allows direct injection of an aliquot of the sample into a liquid chromatograph (LC) for analysis. Separation and quantitation of the derivatives can be performed using reversephase liquid chromatography. Detection limits for formaldehyde, acetaldehyde, and propionaldehyde are 0.1, 0.1, and 0.5 pg/g, respectively, for a 1 g sample of the surfactant. The technique has been applied to other ethoxylated and propoxylated polymeric materials with equal success
Enantiomer Resolution and Assay of Propionic Acid-Derived Herbicides in Formulations by
Using Chiral Liquid Chromatography and Achiral Gas Chromatography
Authors: MÜller Markus D , Bosshardt Hans-Paul
Published: February 2020

Enantiomers of 6 propionic acid-derived herbicides in the form of their esters were resolved using liquid chromatography with a chiral column. Free acids are converted to methyl esters by means of a BF3- catalyzed reaction. Chromatographic resolutions for 6 of 8 herbicides investigated were in the range of 2 to 4. The method was applied for the simultaneous determination of mecoprop and 2,4-D content and individual mecoprop enantiomers in 2 formulations containing racemic and R-mecoprop in mixture with 2,4-D. Precision and accuracy of content determination was comparable to standard methods, and enantiomer contents were in good agreement with declared values. The enantiomers of dichlorprop and mecoprop were also resolved as diastereomeric menthyl esters by achiral high resolution gas chromatography (HRGC). HRGC data on enantiomer composition were in good agreement with those from the LC method and other data
Cooperation, Collaboration, and Contracts Between Industry and University Analytical Facilities
Authors: Spittler Terry D
Published: February 2020

Ranging from service units to basic research facilities, analytical laboratories associated with universities have both unique capabilities and limitations. Method development and validation in cooperation with professional peers in government and industry is encouraged and straightforward to the extent that such efforts are within the laboratories' mandate(s). In certain situations, university laboratories are more flexible in their research objectives and are able to pursue interesting trails not specifically justified in project/profit schemes. University policies may, on the other hand, preclude specific areas of inquiry. Contract arrangements with universities can take several forms depending on the magnitude of intended support, the degree of confidence and confidentiality required, and the urgency of the project. Direct gifts, equipment grants, research contracts, consulting arrangements, competitive grants, memoranda of understanding, invoiced analyses, third party agreements—each of these has advantages and potential disadvantages for the participants. Universities represent tremendous pools of scientific talent and technical resources that may be enlisted for exploratory assaults on a problem before an industry makes inappropriate capital and organizational commitments
Gas Chromatographic/Mass Spectrometric Determination of Daminozide in High Protein Food Products
Authors: Conditt Margaret K , Baumgardner James R , Hellmann Lesle M
Published: February 2020

A gas chromatographic/mass spectrometric (GC/MS) method for determining daminozide in high protein products has been developed. Daminozide is hydrolyzed in the presence of a strong base to form unsymmetrical dimethylhydrazine (UDMH) which is then distilled from the food matrix. A stable derivative is formed by reacting UDMH with salicylaldehyde to form salicylaldehyde dimethylhydrazone. This derivative is separated and quantitated by GC/MS using selected ion monitoring (SIM) of key ions in the fragmentation pattern: m/z 164 (molecular ion of hydrazone) and m/z 120 (C7H6ON). An internal standard, 4-nitroanisole, is monitored at m/z 153 (molecular ion) and m/z 123 (C6H502N). The limit of detection is 0.01 ppm daminozide in a 50 g sample; however, because of variation at low levels, the limit of quantitation is 0.1 ppm. Recoveries are 90% or greater from peanuts and peanut butter spiked at the 0.1-2 ppm level. Reproducibility of the method depends on the food matrix and is 26% RSD in the worst case. Data are compared for the GC/MS method and the official EPA colorimetric procedure. Results showed a high bias in the colorimetric method, especially when roasted peanut products were analyzed.
Simple and Rapid Spectrophotometry Method for Determination of Adrenaline and Isoprenaline
Authors: El-Shabouri Salwa R , Hussein Samiha A , Abdel-Alim Abdel-Alim M
Published: February 2020

A simple, rapid, and specific method for determination of adrenaline bitartrate and isoprenaline sulfate was developed. The method is based on the oxidation reaction in aqueous solution of either adrenaline bitartrate or isoprenaline sulfate in the presence of silver oxide to give a red aminochrome measurable at 490 nm. The color is stable for 2 h. Beer's law is valid within a concentration range of 5-80 ng/ mL for each drug. All variables were studied to optimize the reaction conditions. The method is specific for catecholamine drugs having a secondary amine in the side chain. Other catecholamines such as orciprenaline and noradrenaline do not interfere, and no interference was observed in the presence of common pharmaceutical adjuvants. Interference due to sodium metabisulfite and sodium chloride was circumvented. The validity of the method was tested by analyzing adrenaline injections and isoprenaline tablets. Good recoveries were obtained for these preparations. The results were comparable to those obtained by official procedures. The proposed method is also recommended as a stability indicating assay for oxidative degradation of both drugs.
Ion-Pair Liquid Chromatographic Determination of Some Penicillins in Canine and Equine Sera
Authors: Tyczkowska Krystyna , Aronson Arthur L
Published: February 2020

A sensitive liquid chromatographic method was developed for determining oxacillin, cloxacillin, and dicloxacillin (simultaneously), and penicillin G, amoxicillin, carbenicillin, and ticarcillin in canine and/ or equine serum. The method involves filtering diluted serum through a 30 000 molecular weight cut-off filter and separating penicillins from other serum components by ion-pair liquid chromatography using a reverse-phase column eluted with acetonitrile-water solutions. The ultraviolet absorbance of the column effluent was monitored at 230 nm. Recoveries of oxacillin, cloxacillin, dicloxacillin, and penicillin G (spiked at 2.5 μg/mL), amoxicillin (spiked at 5 μg/ mL), and carbenicillin and ticarcillin (spiked at 10 μg/mL) from canine and equine serums ranged from 78.3 to 104.4% with coefficients of variation ranging from 3.35 to 5.95%. The limit of detection for these penicillins was 0.02-0.05 μg/mL
Liquid Chromatographic Separation and Fluorometric Determination of cw- and frans-Isoeugenol in Perfumes, Colognes, and Toilet Waters
Authors: Wisneski Harris H , Yates Ronald L , Wenninger John A
Published: February 2020

A liquid chromatographic (LC)-fluorometric method is described for the determination of cis- and frans-isoeugenol (2-methoxy-4-propenylphenol) in perfumes, colognes, and toilet waters. A test portion of the product is added to diethyl ether, and the isoeugenol isomers are extracted with sodium hydroxide solution. The basic extract is then acidified, and the isoeugenol isomers are extracted with isooctane. Aliquots of the isooctane extract are analyzed by using a silver ion cation exchange LC column interfaced to a spectrophotofluorometer. Each isomer in the product is determined by comparing its fluorescence emission intensity with that of an external standard consisting of a mixture of both isomers in which the relative concentration of each has been determined. Average recoveries from various commercial fragrances fortified with a mixture of cis- and trans-isoeugenol with total isoeugenol content of 0.1,0.5, and 4.0 mg/mL ranged from 87 to 105% for the taww-isomer (SD = 4.6%) and from 83 to 113% for the cw-isomer (SD = 6.7%). The limit of determination is approximately 0.002 mg/mL.
Evaluation of Amino Acid Analysis as Reference Method to Quantitate Highly Purified Proteins
Authors: Sittampalam G Sitta , Ellis Robert M , Miner David J , Rickard Eugene C , Clodfelter Dean K
Published: February 2020

The applicability of amino acid analysis for accurate quantitation of reference standard preparations of proteins has been evaluated. This approach is very useful since, in addition to absolute quantitative information, it also provides a measure of composition, partial identity, and purity in a single experiment. Comparisons with Kjeldahl nitrogen assay and/or UV measurements shows that amino acid analysis is reliable for the quantitation of small-to-medium size proteins in the molecular weight range of 6-22 kDa. For larger proteins such as immunoglobulins (150 kDa), amino acid analysis may "underestimate" the total protein concentration. These results also show the effect of recovery of individual residues on protein quantitation. As expected, the recovery of more than one stable residue could be used to calculate total protein content of samples, which is in good agreement with the results obtained by Kjeldahl nitrogen assay. However, the protein concentrations calculated from the total mass of the recovered residues appear to give relatively low estimates in almost all cases. Thus, it is concluded that amino acid analysis is an appropriate reference method only when stable residues are employed for quantitation, particularly for highly purified proteins of rDNA origin
Determination of Tartaric Acid and the Sum of Malic and Citric Acids in Grape Juices by
Potentiometric Titration
Authors: Godinho Oswaldo E S , Desouza Nilson E , Aleixo Luiz M , Ivaska Ari U
Published: February 2020

Application of a linear algebraic method to the potentiometric titration of a mixture of tartaric and malic acids makes it possible to determine the individual concentrations of both acids in the same sample. These 2 acids have also been determined in grape juice free of citric acid after their separation from the juice matrix by precipitation as barium salts, followed by selective solubilization. It is also possible to determine tartaric acid and the sum of malic acid and citric acid in grape juice when the latter is present.
Liquid Chromatographic Determination of Morphine Sulfate and Some Contaminants in
Injections and Bulk Drug Material: Collaborative Study
Authors: Bello Ada C , Jhangiani Rita K
Published: February 2020

A liquid chromatographic method for the assay of morphine sulfate and some preservatives and impurities in the bulk drug and in injections has been developed and collaboratively studied in 8 laboratories. Each collaborator analyzed 5 samples: 1 bulk drug, 3 different concentrations of injectable dosages, and 1 prepared mixture containing, in addition to morphine sulfate, phenol, 2-mercaptobenzothiazole, and pseudomorphine. The proposed method quantitates morphine sulfate and resolves the other components for identification using a Clg reverse-phase column with a mobile solvent containing 240 mL methanol, 720 mL 0.005M 1-heptanesulfonic acid Na salt, and 10 mL acetic acid. Samples are prepared by direct dilution with mobile solvent minus 1-heptanesulfonic acid. All collaborators met system suitability requirements and performed the analysis without difficulty. No outliers were found when data were analyzed by the Dixon, Grubbs, double Grubbs, and Cochran tests. Relative standard deviations between laboratories (RSDR) for duplicate determinations of morphine sulfate ranged from 1.4 to 2.1%. Mean morphine sulfate recoveries for the bulk drug and the prepared mixture were 100.8 and 100.4%, respectively. The method has been approved interim official first action.
Gas Chromatographic Determination with Electron Capture Detection of Residual Ethylene
Oxide in Intraocular Lenses
Authors: Kikuchi Hiroshi , Nakamura Akitada , Tsuji Kusuo
Published: February 2020

A sensitive method is described to determine trace quantities of ethylene oxide (EO) in EO-sterilized intraocular lenses (IOLs). An IOL is dipped in ethanol containing 0.25 ppm propylene oxide (PO) in a 4 mL vial, 2 drops of freshly distilled hydrobromic acid is added through a septum, and the mixture is warmed at 50°C for 24 h. It is then neutralized by vigorous shaking with sodium bicarbonate, dehydrated with anhydrous sodium sulfate, and filtered. The filtrate is injected into a gas chromatograph with electron-capture detection, and the peak height ratio of ethylene bromohydrin/propylene bromohydrin is measured. EO residue is calculated from the calibration curve obtained through a similar procedure with the standard EO/ PO solutions. The limit of determination is 0.04 fig/lens (ca 2.0 ppm). When EO residue levels were determined for IOLs sampled at 3 different aeration periods after sterilization, we found that 9 days of aeration was necessary to meet the U.S. Food and Drug Administration proposed limit for EO residue in IOLs.
Effect of Volume of Solution per Cylinder on Estimation of Antibiotic Potency in Diffusion
Assay
Authors: Ragheb Hussein S
Published: February 2020

The volume of antibiotic solutions in cylinders used for diffusion assays is assumed to have no significant effect on estimation of potency. The size of zones of inhibition from cylinders containing 0.10, 0.20, and 0.30 mL of sample solution was compared with zones of inhibition from cylinders containing 0.20 mL of standard solutions. For zinc bacitracin, chlortetracycline-HCl, oxytetracycline, lincomycin- HCl, monensin Na, neomycin sulfate, K penicillin, streptomycin sulfate, and tylosin, the percent recovery (95-102) was optimum when both standard and sample cylinders contained the same volume (0.20 mL/cylinder). At 0.30 mL/cylinder for sample and 0.20 mL for standard solutions, there was a positive bias in potency of about 50%. At 0.10 mL/cylinder, there was a negative bias of approximately 25% except for neomycin, monensin, and bacitracin. For these antibiotics, the bias was about -50%. For hygromycin B, variation in volume of solution per cylinder has little effect on assay results. Experiments on commercial feeds and premixes gave essentially the same results as for the standard solutions experiments.
Validation Study of Gas Chromatographic Determination of Pentachlorophenol in Animal Liver
Authors: Gillard Douglas , Epstein Robert L , Ashworth Raymond B , Curry Kevin , Nathan Quincy
Published: February 2020

A validation study was conducted of a gas chromatographic procedure for the determination of pentachlorophenol (PCP) in chicken, pork, and beef liver. Five analysts representing 5 laboratories analyzed randomly numbered blind duplicates at 3 fortified tissue concentrations and one incurred tissue on 2 consecutive days. The PCP concentrations ranged from approximately 40 to 400 parts per billion (ppb). All data were reported to 3 significant figures in ppb. The coefficients of variation for repeatability were between 2.8 and 8.5%, except for the beef liver, at a mean value of 80 ppb PCP, where the CV was 11.3%. The CVs for reproducibility were in the range of 9.7- 16.5% with little significant difference by species. The CV asymptotically approached 10% as the PCP level increased.
Enzyme-Linked Immunosorbent Assay for Deoxynivalenol in Corn and Wheat
Authors: XU Yi-Chun , Zhang Guang S , Chu Fun S
Published: February 2020

The availability of antibody against deoxynivalenol (DON) triacetate (Tri-Ac-DON) has enabled development of a direct enzyme-linked immunosorbent assay (ELISA) and an indirect ELISA for DON in corn and wheat. In both assays, DON is extracted from the sample with acetonitrile- water, reacted with acetic anhydride to form Tri- Ac-DON, and diluted in phosphate buffer for analysis. Direct ELISA was found to be the more sensitive procedure. Fewer interferences are evidenced, and the assay is less time consuming than is indirect ELISA. For direct ELISA, recovery of 10-1000 ppb DON added to corn and wheat was 100% (SD 15, CV 15%) and 102.1% (SD 12.2, CV 11.9%), respectively. For indirect ELISA, overall recovery of 10- 1000 ppb DON added to wheat was 121.5% (SD 39.5, CV 32.5%); in the higher concentration range (500-1000 ppb), recovery was 105% (SD 18, CV 17%). The minimal detection level for DON was around 10 ppb. Analysis of 7 naturally contaminated samples for DON showed that the ELISA results agreed well with those obtained by radioimmunoassay and thin-layer chromatography.
Determination of Ochratoxin A by Monoclonal Antibody-Based Enzyme Immunoassay
Authors: Candlish Alan A G , Stimson William H , Smith John E
Published: February 2020

A simple and rapid indirect enzyme-linked immunosorbent assay was developed for the quantitative determination of ochratoxin A in barley after the successful production of a high affinity, specific monoclonal antibody. A rapid sample cleanup was achieved by extracting ochratoxin A from barley with chloroform and partitioning the toxin into bicarbonate buffer; the buffer solution was then added directly to the assay plate and ochratoxin A content was assessed. Recoveries were greater than 85% and detection limits were 5 μg ochratoxin A/ kg barley.
Location Dependent Biases in Automatic 96-Well Microplate Readers
Authors: Harrison Robert O , Hammock Bruce D
Published: February 2020

Procedures performed in 96-well microplates and quantitated by automatic readers assume instruments to be precise, accurate, and free of well location dependent bias. Instrument specifications generally focus on precision and accuracy without specifically addressing biases which are dependent on well location. These biases appear to be meniscus dependent and can be demonstrated in varying degrees in automatic readers of many designs by using a reverse plate wet test, which compares repeated readings of a dye loaded plate in normal and reversed positions. This test analyzes differences between readings and is, therefore, independent of pipetting error or other experimental variables such as protein binding or immunoassay variability. Different plates increased or decreased the magnitude of observed errors but did not themselves cause the errors measured by the reverse plate wet test. Error patterns were consistent for each reader and varied widely among the 16 instruments tested. Only 4 of 16 instruments passed an existing manufacturer's specification for precision, and only one of the 16 readers tested passed a similar specification for accuracy. The severest location dependent bias was found in an instrument which exhibited excellent repeatability and consistently passed its built-in diagnostic tests. One reader with significant bias was returned to the manufacturer for routine service and calibration, but it was not demonstrably improved. The reverse plate wet test is an extremely useful diagnostic tool for quality control at all stages of instrument manufacture and use.
Determination of Trace Volatile Organic Compounds in Fish Tissues by Gas Chromatography
Authors: J Murray Derek A , Lockhart W Lyle
Published: February 2020

Several volatile organic compounds associated with petroleum fuels (mainly alkylated benzenes) were extracted from spiked fish tissue samples with a stream of air, trapped on charcoal, eluted with a solvent, and analyzed by gas chromatography. These volatile compounds are among the most water-soluble components of crude oils and petroleum products, and they have been associated with tainting in fish tissues. Recoveries for these compounds were about 90% when spiked directly either onto traps or into fish tissues although naphthalene desorbed poorly from the charcoal; recoveries of this compound were about 50%. Relative standard deviations (RSD) for most recoveries of spiked samples were in the 2-10% range based on 6 samples analyzed in duplicate. However, when live fish were contaminated experimentally by adding the aromatic compounds to the aquarium water, the RSDs were higher (10-30%)
Spectrophotometric Determination of Isocarboxazid Bulk Drug and Tablets by Reaction
with/7-Dimethylaminocinnamaldehyde
Authors: El-Kommos Michael E
Published: February 2020

A Spectrophotometric Method Is Described For The Determination Of Isocarboxazid. The Method Is Based On The Reaction Of The Drug With p-Dimethylaminocinnamaldehyde In The Presence Of Trichloroacetic Acid In A Methanolic Medium To Produce A Very Intense Red Chromophore (ℷmax = 500 Nm, Emax= 1.05 X 105). The Reaction Is Proposed To Proceed Via Electrophilic Attack At The C-4 Position Of The Isoxazole Nucleus. Job's Plot Indicated A 1:1 Drug-To-Reagent Ratio. Regression Analysis Of Beer's Plot Showed Excellent Correlation (R = 0.9996) In The Concentration Range 0.25-2.10 Fig Isocarboxazid/Ml. The Developed Color Is Stable For At Least 12 H. Results Of Analyses Of Bulk Drug And Tablets By The Proposed Method Are Comparable To Those For Usp Xxi Methods.
Gas Chromatographic Assay of Supplemental Vitamin E Acetate Concentrates:
Collaborative Study
Authors: Labadie Michael P , Boufford Charles E
Published: February 2020

A gas chromatographic (GC) method for determination of supplemental a-tocopheryl acetate in high potency vitamin £ powders and oils was collaboratively studied as an alternative to the AOAC colorimetric method (43.147-43.151, Emmerie-Engel), which requires saponification, extraction of the saponifiable fraction, and quantitation by colorimetry. The simpler GC procedure requires only extraction and/or enzymatic digestion and dilution before quantitation. Six blind duplicates were distributed to 10 laboratories; all 10 returned results. Repeatability (sr) and reproducibility (sR), % vitamin E/g, for the feed oil concentrates was 1.1 and 1.3, respectively; for the feed adsorbates 1.0 and 1.5; and for the spray-formulated powders 1.4 and 1.3. These results compare favorably with results obtained in a comparison study of the GC and Emmerie-Engel methods conducted by BASF in 1985. The method has been approved interim official first action for determination of a-tocopheryl acetate in vitamin E acetate concentrates as an alternative for those products only to AOAC colorimetric method 43.147-43.151
Survey of Aflatoxins, Ochratoxin A, Zearalenone, and Sterigmatocystin in Some Brazilian Foods by Using Multi-toxin Thin-Layer Chromatographic Method
Authors: Soares Lucia M Valente , Rodriguez-Amaya Delia B
Published: February 2020

A previously published method for ochratoxin A was evaluated and proved appropriate for simultaneous determination of aflatoxins, ochratoxin A, sterigmatocystin, and zearalenone, with considerable savings in time and reagent costs. The detection limits were 2, 5,15, and 55 μg/kg, respectively. The recoveries and coefficients of variation obtained with artificially contaminated samples were 91-101% and 0-16% for aflatoxin B1, 98-117% and 0-17% for sterigmatocystin, and 96-107% and 0-17% for zearalenone, respectively. The coefficients of variation for naturally contaminated samples (aflatoxins in rice and ochratoxin A in beans) ranged from 0 to 8%. The method was used to survey 296 samples that included 10 cultivars of dried beans, 8 types of corn products, 3 types of cassava flour, and both polished and parboiled rice between May 1985 and June 1986 in Campinas, Brazil. Only aflatoxin B, (9 samples, 20-52 μg/kg), aflatoxin G, (4 samples, 18-31 μg/kg), and ochratoxin A (5 samples, 32-160 μg/kg) were found. The average contamination percentage was 4.7%; beans showed the highest (6.6%) and rice showed the lowest (3.3%) incidence rates. Zearalenone and sterigmatocystin were not detected. Positive samples were confirmed by chemical derivatization, corroborated by development in 3 solvent systems.
Methods of Analysis for Toxic Elements in Food Products. 1. Mineralization Methods to Determine Heavy Metals and Arsenic According to the USSR Standard
Authors: Skurikhin Igor M
Published: February 2020

Results of the work of 22 laboratories in the USSR on optimizing methods for mineralizing foods to determine Pb, Cd, As, Zn, Cu, Sn, and Fe are summarized. Recommendations are given on dry and wet mineralization as related to the analyte and the kind of food product. Optimum amounts of test portions for 22 food groups are also recommended according to the element of interest.
Survey of Lead in Canned Evaporated Milk
Authors: Capar Stephen G , Rigsby Eddie J
Published: February 2020

A Food and Drug Administration survey of lead in canned evaporated milk conducted in fiscal year 1985/86 found a mean level of 0.006 μg Pb/g. This level is much lower than that found in previous surveys and is attributed to the use of nonlead-soldered cans for packaging evaporated milk.
Ion Chromatographic Determination of Lactose, Galactose, and Dextrose in Grated Cheese Using Pulsed Amperometric Detection
Authors: Pollman Roger M
Published: February 2020

A method is presented to determine lactose, galactose, and dextrose in grated cheese using ion chromatography with pulsed amperometric detection (IC/PAD). The method is specific, sensitive, rapid, and precise. Sugar levels as low as 0.01% are detectable, and recoveries ranged from 114% at the 0.1% level to 93.3% at the 2.0% level. The precision expressed as coefficient of variation (CV) was 2.3% for lactose, 2.1% for galactose, and 3.1% for dextrose. Lactose, galactose, and dextrose levels are given for 45 authentic hard cheeses and 26 authentic soft cheeses.
Codex Alimentarius Approach to Pesticide Residue Standards
Authors: Maybury Ronald B
Published: February 2020

To protect consumers' health, most countries have maximum legal limits for pesticide residues in foods. Trade difficulties can arise when limits differ between countries. The Codex Alimentarius Commission was established in 1962 to implement the Joint FAO/WHO Food Standards Programme, the purpose of which is to protect consumer health and ensure fair practices in international food trade. The Codex Committee on Pesticide Residues (CCPR), an intergovernmental body which advises the Commission on matters related to pesticide residues, is responsible for establishing maximum residue limits (MRLs) for pesticides in foods and feeds that move in international trade. Codex MRLs are based on residue data obtained mainly from supervised trials that reflect approved pesticide use in accordance with "good agricultural practice." MRLs must be toxicologically acceptable in terms of estimated pesticide intake by consumers. CCPR Working Groups examine problems related to establishing and implementing MRLs, including sampling and methods of analysis. Despite time and effort expended, acceptance and application of Codex MRLs face many problems in international trade.
Liquid Chromatographic Method for Determination of Vanillin and Related Flavor Compounds in Vanilla Extract: Collaborative Study
Authors: Kahan Sidney
Published: February 2020

A liquid chromatographic method for determination of vanillin, vanillic acid, p-hydroxybenzaldehyde, and p-hydroxybenzoic acid was collaboratively studied. The compounds are separated on a reversephase C-8 column using an acidic 10% methanol solvent and are detected at 254 nm. Recoveries for the 4 compounds present in vanilla extract ranged from 94 to 99%. Method performance as measured by repeatability and reproducibility standard deviations (sr and sR) and relative standard deviations (RSDr and RSDR), respectively, for determination of the 4 flavor compounds in authentic and adulterated vanilla extracts were as follows: p-hydroxybenzoic acid—sr 0.29, SR 0.39, RSDr 8.98%, RSDR 11.68%; p-hydroxybenzaldehyde—sr 0.92, sR 1.20, RSDr 6.16%, RSDR 6.95%; vanillic acid—sr 0.85, sR 1.12, RSDr 7.47%, RSDR 9.97%; vanillin—sr 7.45, sR 7.50, RSDr 3.43%, RSDR 3.48%. The method has been approved interim official first action.
Gas Chromatographic Determination of Poly chlorinated Biphenyls (as Aroclor 1254) in Serum: Collaborative Study
Authors: Burse Virlyn W , Korver Margaret P , Needham Larry L , Lapeza Chester R , Chester R Elizabeth L , Head Susan L , Liddle John A , Bayse David D
Published: February 2020

A gas chromatographic-electron capture detection method for determining the concentration of polychlorinated biphenyls (PCBs) as Aroclor 1254 (AR 1254) in serum was evaluated through a 2-phase collaborative study. In Phase I, each collaborator's lot of Woelm silica gel (70-150 mesh) was evaluated for elution and recovery of AR 1254, which had been added in vitro at 25 ng/mL to a serum extract. In Phase II, each collaborator analyzed a series of bovine serum samples that contained the following: (1) in vitro-spiked AR 1254; (2) in vivo AR 1254 and 8 in vitro-spiked chlorinated hydrocarbons; (3) in vivo AR 1254 only; (4) 8 in vitro-spiked chlorinated hydrocarbons only; and (5) neither AR 1254 nor chlorinated hydrocarbons above the detection limit of the method. In Phase I, the average recovery of AR 1254 from silica gel for the 6 collaborators was 87.9 ± 15.44% (mean ± 1 SD; N = 18; range = 52.3-105.8%). In Phase II, the analysis of in vitro spikes of AR 1254 in serum at 8.58,16.8, 41.8, and 84.3 ppb gave mean (X) interlaboratory recoveries of 89.0, 83.3, 79.4, and 76.9%, respectively, with within-laboratory (repeatability) relative standard deviations (RSDr) of 18.8, 20.5, 10.2, and 14.1%, respectively, and among-laboratory (reproducibility) relative standard deviations (RSDR) of 21.5, 21.1, 14.6, and 20.8%, respectively. The determination of in vivo AR 1254 in samples containing approximately 10, 25, 50, and 100 ng/mL of AR 1254 resulted in interlaboratory means of 10,22,39, and 79 ng/mL, respectively, with RSDr = 6.7,9.7,6.4, and 5.8%, respectively, and RSDR = 20.6,16.0, 10.9, and 10.3%, respectively. The precision of the method for incurred AR 1254 showed a maximum RSDr of less than 10% and a maximum RSDR of less than 21% for a concentration range of 10-100 ng/mL. The accuracy of the method as demonstrated by the mean recovery of in vitro-spiked AR 1254 over a concentration range of 8.58-84.3 ng/mL was 82.2%. The method has been approved interim official first action.
Thin-Layer Chromatography/Bioautography Method for Detection of Monensin in Poultry Tissues
Authors: Vanderkop Perry A , Macneil James D
Published: February 2020

Monensin is an effective anticoccidial agent widely used in the poultry industry. Because of concerns over its toxicity, a sensitive, reliable, fast, and simple method for residue detection in poultry tissues is desirable from both a diagnostic and a regulatory view. Many methods of detection are excluded due to this ionophore's complex chemical and biological nature. A common method used for its detection is thin-layer chromatography/bioautography (TLC/B), although this is usually only semiquantitative. A new TLC/B method for monensin detection in poultry tissues was developed and is reported here. Recovery from cardiac muscle, skeletal muscle, and liver and kidney tissues is in the range of 93-97%. A detection limit of 250 Mg/kg with 99% reliability was achieved with this method. Lower limits (to 10 Mg/kg) were detectable, but with lower reliability (60%). Quantitative analysis is not possible on samples from fatty tissue.
Isolation and Gas Chromatographic Determination of Chlorsulfuron in Milk
Authors: Long Austin R , Hsieh Lily C , Malbrough Marsha S , Short Charles R , Barker Steven A
Published: February 2020

A method for the isolation and gas chromatographic determination of chlorsulfuron in milk is presented. Blank or chlorsulfuron-spiked milk samples were blended into C-18 (octadecylsilyl derivatized silica, ODS) packing material. A column made from the C-18/milk matrix was washed with hexane after which chlorsulfuron was eluted with dichloromethane (DCM). The DCM eluate contained chlorsulfuron which was free from interfering co-extractants when analyzed by gas chromatography utilizing a nitrogen/phosphorus detector. Chlorsulfuron was found to undergo a thermally induced decomposition to give 2-amino-4-methoxy-6-methyl-l,3,5-triazine, which was detected and quantitated by this method. Standard curves for these analyses were linear (r = 0.992 ± 0.004, n = 5), with an average percentage recovery of 91.6 ± 10.8%, over the concentration range examined (62.5-2000 ng/mL). The inter- and intra-assay variabilities were 11.6 ± 7.5% and 6.2%, respectively.