bluuebunny/crossref_metadata_2025 huggingface dataset:
Assay of Tinidazole in Human Serum by High-Performance Thin-Layer Chromatography—Comparison with High-Performance Liquid Chromatography
Authors: Guermouche M H , Habel D , Guermouche S
Published: February 2020

Determination of tinidazole in human serum by high-performance thin-layer chromatography (HPTLC) is presented. It includes use of 10 × 10 cm plates coated with silica gel 60 and chloroform-acetonitrile-acetic acid (60 + 40 + 2) as mobile phase. Quantitation was performed by densitometry at 320 nm. The linearity (1-10 ng), precision (6%), reproducibility (5%), recovery (96%), and detection limit (1 mg/L) of tinidazole determination by HPTLC were comparable with corresponding method parameters by reversed-phase HPLC. A satisfactory correlation was found between the 2 analytical methods. The procedure was used to quantitate tinidazole in patient sera.
Analysis of All-Rac-α-Tocopheryl Acetate and Retinyl Palmitate in Medical Foods Using a Zero Control Reference Material (ZRM) as a Method Development Tool
Authors: William Chase G , Eitenmiller Ronald R , Long Austin R
Published: February 2020

A liquid chromatographic method is described for analysis of all-rac-α-tocopheryl acetate and retinyl palmitate in medical food. The vitamins are extracted in isopropyl alcohol and hexane-ethyl acetate without saponification and quantitated by normal-phase chromatography with fluorescence detection. All-rac-α-tocopheryl acetate and retinyl palmitate are chromatographed isocratically with a mobile phase of 0.5% (v/v) and 0.125% (v/v) isopropyl alcohol in hexane, respectively. Recovery studies performed on a medical food zero control reference material (ZRM) fortified with the analytes averaged 99.7% (n = 25) for retinyl palmitate and 101% (n = 25) for all-rac-α-tocopheryl acetate. Coefficients of variation were 0.87-2.63% for retinyl palmitate and 1.42-3.20% for all-rac-α-tocopheryl acetate. The method provides a rapid, specific, and easily controlled assay for analysis of vitamin A and vitamin E in medical foods. Use of chlorinated solvents is avoided.
Preparation of Standard Reference Material 2383 (Baby Food Composite) and Use of an Interlaboratory Comparison Exercise for Value Assignment of Its Nutrient Concentrations
Authors: Sharpless Katherine E , Gill Lisa M , Margolis Sam A , Wise Stephen A , Elkins Edgar
Published: February 2020

The preparation of the recently released Standard Reference Material (SRM) 2383 Baby Food Composite and the process used for value assignment of nutrient concentrations are reported. SRM 2383 can be used as a control material when assigning values to in-house control materials and when validating analytical methods for measuring proximates, vitamins, and minerals in baby food and similar matrixes. The SRM was prepared as a commercial baby food would be prepared, with the same ingredients. The Certificate of Analysis for SRM 2383 provides assigned values for concentrations of proximates, vitamins, and minerals for which product labeling is required by the Nutrition Labeling and Education Act of 1990. These assigned values were based on measurements by the National Institute of Standards and Technology (NIST) and/or collaborating laboratories. Assignment of analyte concentrations based solely on analyses by collaborating laboratories is described in this paper. Certified values are provided for retinol, tocopherols, and several carotenoids including total β-carotene; the certification of and methodology used for measurement of these analytes is discussed in a companion paper (this issue, page 288). Reference values are provided for solids, ash, fat, nitrogen, protein, carbohydrate, calories, vitamin B1, vitamin B2, vitamin B6, niacin, biotin, calcium, phosphorus, magnesium, manganese, iron, zinc, copper, sodium, potassium, and chloride. Reference values for additional carotenoids are reported in the companion paper (this issue, page 288). Information values are provided for iodine, selenium, molybdenum, vitamin D, vitamin B12, folic acid, pantothenic acid, choline, inositol, sugars, total dietary fiber, and 3 classes of fats.
Raman Spectroscopic Characterization of RP-18-Type Chemically Bonded Stationary Phases for Liquid Chromatography
Authors: Kowalik Gabriela , Rogosz Krystyna , Kowalska Teresa
Published: February 2020

This study is the first Raman spectroscopic characterization of conventional chemically bonded liquid chromatographic (LC) stationary phases of the RP-18 type using the high-power Nd:WV04 neodymium laser. Raman spectra were obtained for octadecyl (C18) chemically bonded silica-based stationary phases, as well as for silica, aminopropyl (NH2), cyanopropyl (CN), diol (OH), octyl (C8), and methyl (C1) phases for comparison. This study demonstrates that Raman spectroscopy using the high-power neodymium laser can be used to study RP-18-type LC stationary phases and to quantitate the density of coverage of the silica matrix with octadecyl ligands. The paper presents the experimental setup and conditions usedto obtain Raman spectra of commercial RP-18-type chemically bonded stationary phases and examines the spectroscopic similarities and differences observed for different bonded ligands typically used in reversed-phase and normal-phase LC separations.
Personal Overpressured-Layer Chromatography (OPLC) Basic System 50, Flexible Tool in Analytical and Semipreparative Work
Authors: Mincsovics Emil , Garami Márta , Kecskés László , Tapa Barnabás , Végh Zoltán , Kátay György , Tyihák Ernó
Published: February 2020

A new automated overpressured-layer chromatographic (OPLC) system called the Personal OPLC Basic System 50 is suitable for analytical and semi preparative separations. The automatic microprocessor-controlled system ensures rapid and reproducible off-line isocratic and stepwise gradientseparations. High external pressure (5 MPa) makes the sorbent layer more homogeneous, yielding more efficient off-line separation compared with those by early Chrompres chambers. A theoretical plate height of 10–30 μm can be achieved on an analytical high-performance thin-layer chromatographic (HPTLC) layer made of irregular silica gel with an average particle size of 5 μm if an optimal linear velocity (20–40 mm/min) and a nonviscous solvent system are used. On an analytical layer of 3 μm spherical silica gel, a theoretical plate height of 6–15 μm can be reached. Rapid analytical separations of resveratrol (1555 s) and xanthine by one-(498s) and two-directional (274 s) off-line developments were accomplished. On-line separation and detection combined with off-line sample application and fully on-line processing (including on-line sample application, separation, and detection) were fulfilled with a TLC plate for xanthine separation. Semi preparative isolation of xanthines was achieved through a fully on-line OPLC operating mode and scaled-up chromatography.
Stability-Indicating Methods for Determining Omeprazole and Octylonium Bromide in the Presence of Their Degradation Products
Authors: EL-Kousy Naglaa M , Bebawy Lories I
Published: February 2020

Four stability-indicating assays were developed for determining omeprazole and octylonium bromide. Omeprazole is photodegraded and estimated in the presence of its degradation products sul-phenamide (I) and benzimidazole sulphide (II) by 2 methods. The first method depends on use of first-, second-, and third-derivative spectrophotometry at 290.4,320.6, and 311.6 nm, respectively. The second method is based on applying the charge-transfer technique with chloranil as π acceptor to form a complex with omeprazole, the absorbance of which is measured at 377 nm. These methods determine omeprazole in concentration ranges of 5–20 μg/mL by first-, second-, and third-derivative spectrophotometry and 10–50 μg/mL by charge-transfer complexation with mean accuracies of 99.92 ± 0.73, 99.71 ±1.02, 99.64 ± 0.66, and 100.24± 0.81%, respectively. Octylonium bromide is determined by a densitometric method using thin-layer chromatography in the presence of its degradation products p-[2-(n-octyoxy)benzoyl]-aminobenzoic acid(III) and diethyl-(2-hydroxyethyl)methyl ammonium bromide (IV) without any interferences. Alternatively, octylonium bromide is evaluated by a colorimetric method using the acid dye rose bengal. The ion pair formed is extracted in chloroform at pH 4, and its absorbance is measured at 562 nm. These methods determine octylonium bromide in the presence of its degradation products in concentration ranges of 0.1–0.5 μg/μL by densitometry and 4.5–22.5 μg/mL by colorimetry, with mean accuracies of 100.21 ± 0.93 and 99.73 ±0.89%, respectively. The suggested methods were used to determine drugsin bulk powder, laboratory-prepared mixtures,and pharmaceutical dosage forms. Results werecompared statistically with those obtained with reference methods.
Determination of Flumequine in Channel Catfish by Liquid Chromatography with Fluorescence Detection
Authors: Plakas Steven M , El Said Kathleen R , Bencsath F Aladar , Musser Steven M , Walker Calvin C
Published: February 2020

Rapid methods are described for determination of flumequine (FLU) residues in muscle and plasma of farm-raised channel catfish (Ictalurus punctatus). FLU residues were extracted from tissues with an acidified methanol solution, and extracts were cleaned up on C18 solid-phase extraction cartridges. FLU concentrations were determined by liquid chromatography (LC)using a C18 analytical column and fluorescence detection (excitation, 325 nm; emission, 360 nm). Mean recoveries of FLU from fortified muscle were 87–94% at 5 levels ranging from 10 to 160 ppb (5 replicates per level). FLU recoveries from fortified plasma were 92–97% at 5 levels ranging from 20 to 320 ppb. Limits of detection (signal-to-noise ratio, 3:1)for the method as described were 3 and 6 ppb for muscle and plasma, respectively. Relative standard deviations (RSDs) for recoveries were ≤12%. Live catfish were dosed with 14C-labeled or unlabeled FLU to generate incurred residues. Recoveries of 14C residues throughout extraction and cleanup were 90 and 94% for muscle and plasma, respectively. RSDs for incurred FLU at 2 levels in muscle and plasma ranged from 2 to 6%. The identity of FLU in incurred tissues was confirmed by LC/mass spectrometry.
Reveal for Salmonella Test System
Authors: Bird Charles B , Miller Raymond L , Miller Brinton M
Published: February 2020

The Reveal for Salmonella(RSS) test system is a presumptive qualitative test that detects the presence of Salmonella organisms in foods within 21 h total testing time, allowing the user to release negative products 24 h earlier than when using other rapid test kits. Foods are enriched with a proprietary resuscitation medium called Revive and then selectively enriched with either Selenite Cystine or Rappaport-Vassiliadis selective media. The enriched culture is used to inoculate the RSS detection device, which initiates a lateral flow through areagent zone containing anti-Salmonella antibodies conjugated to colloidal gold particles that capture antigens present in the culture. The antigen–antibody complex migrates farther and is captured by an additional anti-Salmonella antibody, causing the colloidal gold to precipitate and form a visual line, indicating a positive result. A procedural control line also will form regardless of the presence of Salmonella organisms to indicate the test is working properly. Existing AO AC Official Methods for Salmonella organisms require a 48 h enrichment before testing. Hence, a food product has to be held before release, adding extra cost to the company and the consumer. The RSS test system was evaluated by quantitative spiking studies. Although AOAC encourages inclusion of naturally contaminated foods, almost all microbiological AOAC validation studies have been performed with artificially contaminated foods for absolute control over the study. The RSS test system is designed to test many food types for Salmonella organisms and has a limit of detection of 5–10 colony-forming units (cfu)/25 g with a false-negative rate of <1 % and a false-positive rate of <5.0%. It showed an 81 % overall agreement with the traditional procedure of the U.S. Department of Agriculture’s Food Safety Inspection Service.
The Impact of Household Preparations on the Residues of Pesticides in Selected Agricultural Food Commodities Available in India
Authors: Ramesh Atmakuru , Balasubramanian Muthukrishnan
Published: February 2020

Gas chromatographic multiresidue methods for simultaneous determination of organophosphorus, organochlorine, and organonitrogen pesticides were used to study the exposure of the Indian population to pesticide contamination at their actual dietary intakes. Selected agricultural commodities—5 kinds of vegetables (tomato, potato, okra, cabbage, and green beans), 6 kinds of cereals and pulses (rice, maize, wheat, red gram, black gram, and green gram), and 6 kinds of fruits (mango, orange, guava, banana, apple, and grapes)—readily available in Chennai City local markets—were studied for this purpose. Samples were fortified with known concentrations of various pesticides and subjected to household preparation methods commonly used in India. The impact of household preparation is very high, resulting in 65–95% decontamination of pesticides at different stages. Of 512 raw market samples analyzed, the organo chlorine and organophosphorus pesticides present in 12 samples were removed during household preparations, resulting in residues well below the toxicologically acceptable limits.
Measurement of Sugars and Starches in Foods by a Modification of the AOAC Total Dietary Fiber Method
Authors: Casterline James L , Oles Carolyn J , Ku Yuoh
Published: February 2020

A separation scheme for the determination of sugars and starch in processed food was developed. It is based on AOAC Method 985.29 for total dietary fiber with these modifications: carbohydrate starches are separated into soluble and insoluble fractions before they are hydrolyzed; acetonitrile is used instead of ethanol to separate sugars from enzyme-resistant carbohydrates, proteins, and other macromolecules; and a solid-phase extraction filter is included to remove substances that interfere with high-performance liquid chromatography (HPLC). Recovery studies indicate a >97% sugar recovery. Twenty foods were analyzed. After enzymatic hydrolysis, fructose, glucose, sucrose, maltose, and lactose were extracted and determined by HPLC using a refractive index detector. Starch content was calculated from the increase in the amount of glucose. The results were compared with values listed on the “Nutrition Facts” panel for that food. The analyzed amounts of sugars and starches were 73–96% of declared values.
An Improved Method for Analysis of Cholecalciferol-Treated Baits
Authors: Mauldin Richard E , Johnston John J , Riekena Craig A
Published: February 2020

A liquid extraction method is described that permits rapid determination of cholecalciferol (D3) in rodenticidal grain baits. Purified D3 was incubated for various time periods to produce pre-D3. Response ratios (concentration/detector response) for various concentrations of pre-D3 and D3 in solutions permitted generation of a correction factor for direct quantitation of pre-D3 in solutions with a pure D3 standard. The method has equal precision and accuracy, yet is simpler and less time consuming and requires less solvents than widely accepted methods for extracting D3 from grain baits. Recoveries from control oat baits fortified at 0.05 and 0.75 wt% were 100.9 and 98%, respectively. A standard curve for concentrations ranging from 6.4 to 204 μg/mL had an r2 of 0.9999 and an intercept of zero and was linear and proportional. The method limit of detection was 2.0 × 10−4 wt % D3.
Comparisons of Karl Fischer Method with Oven Methods for Determination of Water in Forages and Animal Feeds
Authors: Thiex Nancy , Van Erem Terri
Published: February 2020

In a comparative study of the Karl Fischer method with oven methods for determination of water in forages and animal feeds, oven methods yielded the following relative recoveries (expressed as a percentage of the recovery obtained by the Karl Fischer method) for hay, haylage, and corn silage, respectively: (1) drying at 135°C for 2 h (AOAC 930.15), 113,162, and 133%; (2) drying at 104°C for 3 h (AOAC 935.29), 96,122, and 113%; and (3) drying at 104°C for 6 h, 97, 129, and 117%. Relative recoveries for nonurea-containing and urea-containing feed, respectively, were as fol lows: (1) drying at 135°C for 2 h (AOAC 930.15), 116 and 2746% (2) drying at 104°C for 3 h (AOAC 935.29), 88 and 239%; (3) drying at 95°C for 5 h under vacuum (AOAC 934.01), 83 and 727% (4) drying at 104°C for 6 h, 90 and 427%; and (5) drying at 110°C for 3 h, 94 and 425%. Preliminary near-infrared reflectance calibrations for water (moisture) based on the Karl Fischer method were promising (r2 = 0.98; standard error of calibration = 0.20).
Validation Study for the Determination of Tetracycline Residues in Animal Tissues
Authors: Posyniak Andrzej , Zmudzki Jan , Ellis Richard L , Semeniuk Stanislaw , Niedzielska Jolanta ,   Collaborators:, Andrzejak R , Cabon J , Jaromin E , Milian A , Rodziewicz L , Zuczek G
Published: February 2020

An interlaboratory study of the liquid chromatographic (LC) determination of tetracyclines—oxytetracycline (OTC), tetracycline (TTC), and chlortetracycline (CTC)—in animal tissues was conducted. Isolation was performed with oxalic buffer followed by dechelation and deproteination with oxalic acid–acetonitrile. The extract was cleaned with a styrene–divinylbenzene cartridge. LC analysis was performed with a PLRP-S column and 0.01 M oxalic acid–acetonitrile (75 + 25, v/v) as mobile phase. Participants analyzed 2 control and 10 fortified porcine muscle and kidney samples. Additionally, porcine muscle samples containing incurred residues of tetracyclines were analyzed. Mean recoveries of fortified residues from porcine tissue ranged from 76.00 to 86.89%. Repeatabilities varied from 2.05% for OTC to 3.61 % for TTC for muscle samples and from 6.75% for CTC to 8.74% for OTC for kidney samples. Reproducibilities ranged from 2.05 to 4.30% for muscle samples and from 15.77 to 18.81 % for kidney samples.
Surveillance and Control of Aflatoxins B1, B2, G1, G2, and M1 in Foodstuffs in the Republic of Cyprus: 1992–1996
Authors: Ioannou-Kakouri Eleni , Aletrari Maria , Christou Eftychia , Hadjioannou-Ralli Artemisia , Koliou Athena , Akkelidou Dina
Published: February 2020

Aflatoxins (AFs) B1, B2, G1, and G2 in locally produced and imported foodstuffs (nuts, cereals, oily seeds, pulses, etc.) were monitored and controlled systematically and effectively from 1992–1996. Samples (peanuts, pistachios, etc.) with total AFs above the Cyprus maximum level (ML) of 10 μg/kg fluctuated between 0.7 and 6.9%. The results indicate the effectiveness of monitoring, as well as the need for constant surveillance and control, especially at critical control points (sites of import, primary storage, etc.), to prevent unfit products from entering the Cyprus market. The control included sampling, retainment, analysis, and destruction of foodstuff lots with AF levels above MLs. The highest incidence of aflatoxin contamination was observed in peanut butter (56.7%) and the highest level of AF B1 was found in peanuts (700 μg/kg). Levels of AF M1 in raw and pasteurized milk analyzed in 1993,1995, and 1996 were within both the Cyprus ML (0.5 μg/L) and the lower ML (0.05 μg/L) of some European countries. Only 12% of samples had detectable levels of AF M1. Analyses were performed by immunochemical methods. When recoveries were lower than 80%, the AF levels were corrected for recovery.
Flow-Injection Spectrophotometric Determination of Phenolic Drugs and Carbamate Pesticides by Coupling with Diazotized 2,4,6-Trimethylaniline
Authors: Alvarez-Rodriguez Lluis , Josep Esteve-Romero , Escrig-Tena Imma , Alvarez-Coque M Celia Garcia
Published: February 2020

A flow-injection (FI) spectrophotometric system is proposed for the determination of phenols and carbamates. In the FI manifolds, the solutions of phenols or carbamates (the latter after hydrolysis with NaOH) were injected into a diazonium ion carrier stream at pH 9.5 (buffered with tetrahydroborate), which was formed by mixing 2,4,6-trimethylaniline (TMA) with nitrate in a sodium dodecyl sulfate aqueous micellar medium. Absorbance was measured at 550 nm. The system combines the advantages derived from the use of TMA for the coupling of phenols in basic micellar media, because of the inhibition of the self-coupling reaction of the reagent, with the precision and speed of the FI procedures. Other diazotized reagents produced excessive blank signals. The procedures were successfully applied to the determination of phenolic drugs (epinephrine, acetaminophen, and guaiacol) in pharmaceuticals and carbamates (bendiocarb, benfuracarb, carbaryl, carbofuran, methiocarb, promecarb, and propoxur) in pesticide products and water samples.
Monitoring Pesticide Residues in Egyptian Fruits and Vegetables in 1995
Authors: Dogheim Salwa M , Alla Sohair A Gad , El-Marsafy Ashraf M , Fahmy Safaa M
Published: February 2020

Organophosphorus, dithiocarbamates, and some synthetic pyrethroids pesticides, which are commonly used in Egypt for pest control, were monitored, as well as persistent organochlorines, which had been prohibited from use several years ago. Fruit and vegetable samples (397) were collected from 8 local markets and examined for 52 pesticides. Of all analyzed samples, 42.8% contained detectable residues, of which 1.76% exceeded their maximum residue limits (MRLs). The rates of contamination with the different pesticides were 0-86%. However, violation rates among contaminated products were very low, ranging from 0 to 4.6%. In general, organochlorine pesticide residues were not detected in most samples. Dithiocarbamate residues were found in 70.4% of 98 samples analyzed for dithiocarbamates, but only one grape sample had residues exceeding the MRL established by the Codex Committee on Pesticide Residues.
Determination of Arsenic in Traditional Chinese Medicine by Microwave Digestion with Flow Injection-Inductively Coupled Plasma Mass Spectrometry (FI-ICP-MS)
Authors: Ong Eng-Shi , Yong Yuk-Lin , Woo Soo-On
Published: February 2020

A simple, rapid, and sensitive method with high sample throughput was developed for determining arsenic in traditional Chinese medicine (TCM) in the form of uncoated tablets, sugar-coated tablets, black pills, capsules, powders, and syrups. The method involves microwave digestion with flow injection-inductively coupled plasma mass spectrometry (FI-ICP-MS). Method precision was 2.7-10.1 % (relative standard deviation, n = 6) for different concentrations of arsenic in different TCM samples analyzed by different analysts on different days. Method accuracy was checked with a certified reference material (sea lettuce, Ulva lactuca, BCR CRM 279) for external calibration and by spiking arsenic standard into different TCMs. Recoveries of 89-92% were obtained for the certified reference material and higher than 95% for spiked TCMs. Matrix interference was insignificant for samples analyzed by the method of standard addition. Hence, no correction equation was used in the analysis of arsenic in the samples studied. Sample preparation using microwave digestion gave results that were very similar to those obtained by conventional wet acid digestion using nitric acid.
Simultaneous Determination of Chlorthalidone and Spironolactone with Univariate and Multivariate Calibration: Wavelength Range Selection
Authors: Luis M Luz , García José M , Jiménez Francisco , Jiménez Ana I , Arias Juan J
Published: February 2020

Chlorthalidone and spironolactone were determined simultaneously with the aid of univariate and multivariate calibration methods. Univariate calibration was performed by the zero-crossing and derivative ratio spectrum methods. Extensive spectral overlap and the scarcity of wavelengths in derivative spectra allowing one analyte to be distinguished and quantitated in the presence of the other gave rise to poor results that called for multivariate calibration. Partial least-squares regression was used in combination with a suitable method for selecting the optimum wavelength range and number of factors for analysis. The ensuing method was applied to simultaneous determination of chlorthalidone and spironolactone in a commercially available pharmaceutical preparation. The results were validated by high-performance liquid chromatography.
Solid-Phase Extraction Method for Patulin in Apple Juice and Unfiltered Apple Juice
Authors: Trucksess Mary W , Tang Yifeng
Published: February 2020

Patulin, a mold metabolite, is commonly found in rotting apples. Some countries regulate patulin at levels ranging from 30 to 50 μg/L. Most analytical methods for patulin in apple juice include liquid—liquid partitions. A solid¯phase extraction method has been developed for apple juice and unfiltered apple juice in the United States. A portion of the test sample (5 mL) was passed through a macroporous copolymer cartridge and was washed with 1 mL 1 % sodium bicarbonate and then with 1 mL 1 % acetic acid. Patulin was eluted with 3 mL 2% acetonitrile in anhydrous ethyl ether and was determined by reversed-phase liquid chromatography with UV detection at 276 nm. Recoveries ranged from 93 to104% in test samples spiked at 20-100 μg/L.
Determination of Benzoylphenylurea Insecticides in Pome Fruit and Fruiting Vegetables by Liquid Chromatography with Diode Array Detection and Residue Data Obtained in the Dutch National Monitoring Program
Authors: Hiemstra Maurice , Toonen Arnold , Kok André De
Published: February 2020

Liquid chromatography (LC) with diode array detection was used to screen for residues of the benzoylphenylurea (BPU) insecticides diflubenzuron, teflubenzuron, triflumuron, hexaflumuron, lufenuron, chlorfluazuron, flufenoxuron, and flucycloxuron in pome fruit and fruiting vegetables. The general sample preparation and extraction method for our gas chromatography (GC) and LC multiresidue methods scheme was used as a starting point. Crop samples were extracted with acetone and partitioned into di-chloromethane-petroleum ether. Solid-Phase extraction on aminopropyl-bonded silica cartridges was used to separate the BPU insecticides from major interfering sample components. LC separations were performed on a reversed-phase column, with an acetonitrile-water gradient as mobile phase. A diode array detector was used to monitor the insecticides at 260 nm and to acquire spectral information for additional confirmation. Recoveries and repeatability data were collected for 7 benzoylphenylurea insecticides in mushroom, Chinese cabbage, apple, and cucumber samples representing different commodity groups at one spike level. The limits of detection ranged from 20 to 50 μg/kg for all BPU insecticides studied and is dependent on the matrix-pesticide combination. A confirmation method for BPU insecticides based on GC-mass spectrometry (ion-trap detector) of the characteristic degradation products is also reported. Residues of BPU insecticides in pome fruit and fruiting vegetables found during our Dutch pesticide residue monitoring program in 1995-1998 are presented.
Liquid Chromatographic Determination of Tylosin in Mastitic Cow's Milk Following Therapy
Authors: Dudriková Eva , Jozef Sokol , Jozef Nagy
Published: February 2020

Liquid chromatographic analysis of milk samples from 6 cows treated with tylosin in a veterinary practice indicated that tylosin persisted in milk for more than 3 days after the final treatment. The concentration of tylosin was not below the stated maximum residue limit (0.05 mg/kg). The milk from 3 cows being treated for mastitis catarrhalis chronica contained tylosin residues for 3.5 days after the last withdrawal time (72 h). No residue was detected in the milk of any animal 6 days after cessation of therapy.
Determination of Propionylpromazine Hydrochloride in Formulation Matrixes Using Reversed-Phase Ion-Pair Small Bore Liquid Chromatography
Authors: Hurlbut Daniel B , Primus Thomas M , Goodall Margaret J , Volz Stephanie A , Johnston John J
Published: February 2020

Propionylpromazine hydrochloride (PPZHCI) has been investigated for use with leghold traps to reduce the amount of self-inflicted trauma experienced by animals restrained by these traps. Three types of PPZHCI formulations made with Karo dark syrup, K-Y Jelly, and Vaseline were used in 2 types of tranquilizer trap devices (TTDs). A reversed- phase ion-pair liquid chromatography (LC) method using a small bore C18 column was used to: (1) determine the purity of the PPZHCI material used in these formulations, and (2) to determine the resulting PPZHCI content of each formulation. Analyte quantitation was done using UV absorption at 280 nm. Regression analysis of calibration standard solutions indicated a linear and directly proportional relationship between analyte response and PPZHCI concentration over the range evaluated. Recovery data from: (1) Vaseline formulations containing 38.8,16.2, and 8.78% PPZHCI were 104,92.9, and 90.2%, respectively, (2) Karo dark syrup formulations containing 26.5,18.1, and 10.3% PPZHCI were 97.7,99.3, and 106%, respectively, and (3) K-Y Jelly formulations containing 33.0, 23.5, and 13.4% PPZHCI were 100,99.4, and 88.7%, respectively. The relative standard deviation (RSD) values from triplicate analysis of these formulations ranged from 0.7 to 6.7%. The PPZHCI content from 9 manufactured TTDs, 3 for each formulation type, were analyzed in triplicate and produced RSD values ranging from 0.7-6.8%. These results indicate that the formulation extraction presented could be used to evaluate the PPZHCI content in TTDs prior to field use. The use of a small bore LC column reduced the amount of solvents consumed and hazardous waste generated, compared to sample analysis that uses a more conventional analytical LC column.
Rapid Determination of Citrinin in Corn by Fluorescence Liquid Chromatography and Enzyme Immunoassay
Authors: Abramson David , Usleber Ewald , M�rtlbauer Erwin
Published: February 2020

A rapid assay procedure was developed for mycotoxin citrinin in corn using liquid-liquid extraction (LLE) cartridges. Ground corn was extracted with methylene chloride and 0.5N phosphoric acid. The extract was added to an LLE cartridge containing a diatomaceous-earth adsorbant, previously impregnated with sodium bicarbonate solution. After aspiration to dryness, the cartridge was eluted with methanol-water (4 + 1), and aliquots were taken for quantitation by reversed-phase liquid chromatography with fluorescence detection. Recoveries of citrinin added to ground corn at 200-1600 ng/g ranged from 71.2 to 86.3%, with coefficients of variation between 4.1 and 10.6%. An indirect enzyme immunoassay was also evaluated, using sodium carbonate solution for extraction. Recoveries of citrinin added to ground corn at 200-2000 ng/g ranged from 53.2 to 67.2%, but the coefficients of variation varied between 18.4 and 51.5%. The LLE cartridge procedure offers the advantages of low solvent consumption and speed, and is amenable to automation.
Multiresidue Method for Determination of Sulfonylurea Herbicides in Water by Liquid Chromatography with Confirmation by Capillary Electrophoresis
Authors: Hickes Heidi , Watrous Matthew
Published: February 2020

A liquid chromatographic method with comfirmation by capillary electrophoresis was used to determine 12 sulfonylurea herbicides in agricultural water. Analysis of 3 different water matrixes fortified at 2 levels gave good recoveries with adequate sensitivity at the 0.1 ppb level. A portion of the water was acidified with acetic acid and loaded onto an RP-102 solid-phase extraction (SPE) cartridge, and the extract was cleaned up on an alumina SPE cartridge. Extracts were desalted with an RP-102 SPE cartridge before instrumentation. Samples needing chemical filtration, such as pond water, required additional cleanup with a SAX SPE cartridge before the alumina cleanup step. Data were compiled for both determinative techniques and evaluated.
Comparison of Capillary Electrophoresis and Liquid Chromatography for Determination of Sulfonylurea Herbicides in Soil
Authors: Menne Hubert J , Janowitz Karin , Berger Bernhard M
Published: February 2020

Two analytical methods developed for degradation studies in soil were compared for the simultaneous determination of sulfonylurea herbicides. The compounds were extracted with phosphate buffer from soil samples after purification and enrichment steps by solid-phase extraction. Samples were analyzed by liquid chromatography (LC) or capillary electrophoresis (CE) with UV detection. Amidosulfuron, bensulfuron-methyl, chlorimuron-ethyl, chlorsulfuron, ethametsulfuron-methyl, metsulfuron-methyl, nicosulfuron, primisulfuron-methyl, sulfometuron-methyl, thifensulfuron-methyl, triasulfuron, and tribenuron-methyl were separated within 90 and 35 min by LC and CE, respectively. Average recoveries, determined with LC for 5 sulfonylureas in 1–100 μg/kg soil ranged from 74 to 103%, and those determined with CE for 10 sulfonylureas in 2-20 μg/kg soil ranged from 87 to 105%. Bensulfuron-methyl was recovered at lower levels of 52%. The limits of quantitation were 1.0 and 2.0 μg/kg soil for LC and CE, respectively. Coefficients of variation were higher for CE than for LC. Although both methods are suitable, the LC method, which is more sensitive and accurate than the CE method, is preferred for field studies. However, CE, which was shown to be faster with lower operating costs and unlimited repeatability of the analysis due to little injection volumes, is preferred for laboratory studies.
Electrically Driven Microseparation Methods for Pesticides and Metabolites: I. Micellar Electrokinetic Capillary Chromatography of Carbamate Insecticides with MEGA-Borate and SDS Surfactants
Authors: Tegeler Tony , El Rassi Ziad
Published: February 2020

The migration behavior of some representative carbamate insecticides in micellar electrokinetic capillary chromatography (MECC) was investigated over a wide range of elution conditions, including the nature and concentration of the surfactant and the concentration of added urea in the running electrolyte. Decanoyl-N-methylglucamide (MEGA 10) surfactant was compared with the traditionally used sodium dodecyl sulfate (SDS) surfactant for separation of the carbamate insecticides under investigation. The MEGA 10 micellar system is based on the complexation of MEGA 10 with borate, yielding an in situ charged micelle (i.e., MEGA 10-borate micelle), whose surface charge density can be readily manipulated by varying the pH and the concentrations of borate and MEGA 10 in the running electrolyte. This flexibility, in turn, allowed the modulation of the migration time window and, consequently, the analysis time. Because of its relatively weaker hydrophobic character, the MEGA 10-borate micellar system permitted the resolution of 9 different carbamate insecticides in about 12 min. Conversely, with the SDS micellar system, whose hydrophobicity is higher, the separation of all 9 solutes necessitated the addition of 4.0M urea, a condition that brought about a doubling of the analysis time. In addition, the MEGA 10-borate micellar system produced twice as many plates per min as did the SDS micellar system. Because MEGA 10-borate yielded results superior to those of the SDS micellar system, on-column preconcentration of the carbamate insecticides was attempted in MEGA 10-borate by using the concept of field-amplified sample stacking (FASS). Thus far, only a few attempts have been made toward the application of FASS in MECC of neutral compounds such as carbamate insecticides.
Mobility Distribution of Synthetic and Natural Polyelectrolytes with Capillary Zone Electrophoresis
Authors: Schmitt-Kopplin Philippe , Hertkorn Norbert , Freitag Dieter , Kettrup Antonius , Garmash Andrey V , Kudryavtsev Alexey V , Perminova Irina , Petrosyan Valery S
Published: February 2020

Parameters are proposed to describe the distribution of the effective electrophoretic mobilities of various anionic polyelectrolytes such as poly(styrene-4-sulfonates) and humic substances of different origins analyzed by capillary zone electrophoresis. The first step of the data treatment is a baseline correction and conversion of the electrophoretic raw time data to effective electrophoretic mobilities (μ-scale), taking into account the electroosmotic flow. With this new μ-scaling, the electropherograms are more representative of velocity-based separation phenomena than those using migration times, and a direct comparison of electropherograms is possible. Four different average electrophoretic mobilities were defined: the number-average effective mobility (μn), the weight-average effective mobility (μw), the z-average effective mobility (μz), and the peak-average electrophoretic mobility (μp). The polydispersity of the mobility of mixtures was described by the μw/μ⊓, μz/μw, and μp/μw ratios. These parameters were used to describe the electrophoretic mobility distributions of different fractions of restricted molecular size: those obtained by ultrafiltration from a soil humic acid at neutral pH and reference humic substances of the International Humic Substances Society at different values of pH and ionic strength. The data clearly show the influence of both molecular size and charge distribution of the analyzed mixtures on the mobility distributions.
Thrombin binding aptamer G-quadruplex stabilized by pyrene-modified nucleotides
Authors: Kovačič Matic , Podbevšek Peter , Tateishi-Karimata Hisae , Takahashi Shuntaro , Sugimoto Naoki , Plavec Janez
Published: February 2020

Guanine-rich regions of the human genome can adopt non-canonical secondary structures. Their role in regulating gene expression has turned them into promising targets for therapeutic intervention. Ligands based on polyaromatic moieties are especially suitable for targeting G-quadruplexes utilizing their size complementarity to interact with the large exposed surface area of four guanine bases. A predictable way of (de)stabilizing specific G-quadruplex structures through efficient base stacking of polyaromatic functional groups could become a valuable tool in our therapeutic arsenal. We have investigated the effect of pyrene-modified uridine nucleotides incorporated at several positions of the thrombin binding aptamer (TBA) as a model system. Characterization using spectroscopic and biophysical methods provided important insights into modes of interaction between pyrene groups and the G-quadruplex core as well as (de)stabilization by enthalpic and entropic contributions. NMR data demonstrated that incorporation of pyrene group into G-rich oligonucleotide such as TBA may result in significant changes in 3D structure such as formation of novel dimeric topology. Site specific structural changes induced by stacking of the pyrene moiety on nearby nucleobases corelate with distinct thrombin binding affinities and increased resistance against nuclease degradation.
The Role of Nutrition for Pressure Injury Prevention and Healing: The 2019 International Clinical Practice Guideline Recommendations
Authors: Munoz Nancy , Posthauer Mary Ellen , Cereda Emanuele , Schols Jos M. G. A. , Haesler Emily
Published: February 2020

GENERAL PURPOSE

To review the nutrition-related recommendations presented in the 2019 European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory Panel, and Pan Pacific Pressure Injury Alliance Prevention and Treatment of Pressure Ulcers/Injuries: Clinical Practice Guideline with further discussion of nutrition for pressure injury management in the context of the recommendations.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After participating in this educational activity, the participant should be better able to:

1. Distinguish nutrition and malnutrition, especially as they relate to the development and healing of pressure injuries.

2. Differentiate the tools and techniques that help clinicians assess nutrition status as well as the causes of pressure injuries in specific populations.

3. Identify interventions for improving nutrition status and promoting pressure injury healing.

Macro- and micronutrients are required by each organ system in specific amounts to promote the growth, development, maintenance, and repair of body tissues. Specifically, nutrition plays an important role in the prevention and treatment of pressure injuries. The purpose of this manuscript is to review the nutrition-related recommendations presented in the 2019 European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory Panel, and Pan Pacific Pressure Injury Alliance Prevention and Treatment of Pressure Ulcers/Injuries: Clinical Practice Guideline. Nutrition for pressure injury management is discussed in the context of the recommendations.
A Multicenter, Comparative Study of Two Pressure-Redistribution Mattresses with Repositioning Intervals for Critical Care Patients
Authors: Jiang Qixia , Liu Yuxiu , Yu Hui , Song Siping , Li Guohong , Liu Haiying , Zhou Yi , Zhu Yajun , Jia Jing , Huang Yunjuan , Wang Jiandong
Published: February 2020

OBJECTIVE

To compare the effectiveness of two protocols for preventing pressure injuries (PIs) in Chinese hospitals.

DESIGN AND SETTING

A multicenter, open-label, comparative study conducted in seven Chinese acute care hospitals.

PATIENTS AND INTERVENTION

In total, 1,654 eligible patients were identified, and 1,204 were enrolled in the study. Enrolled patients were randomly assigned into the trial group (4-hour repositioning combined with a viscoelastic foam mattress; n = 602) or the control group (2-hour repositioning combined with a powered air pressure redistribution mattress; n = 602). Participants received their respective protocols until they were discharged, died, or for at least 7 days.

MAIN OUTCOME MEASURES

The incidence of PIs, Braden Scale scores, and the time to development of PIs.

MAIN RESULTS

Ultimately, 596 trial group patients and 598 control group patients were analyzed. Thirteen patients had single new stage 2 or worse PIs. The total incidence of PIs was 1.1%. The difference between the two groups was significant (0.3% vs 1.8%). However, the difference between the groups’ Braden Scale score median during the intervention was not significant (13 vs 13.5).

CONCLUSIONS

The 4-hour repositioning interval combined with a viscoelastic foam mattress did not increase PI incidence or risk. These findings could help providers select the right pressure redistribution mattresses and repositioning intervals for critical care patients.
Overlapping Mechanisms of Recovery Between Professional Psychotherapies and Alcoholics Anonymous
Authors: Marcovitz David E. , McHugh Kathryn R. , Roos Corey , West Jule J. , Kelly John
Published: February 2020

Background:

Much research over the past 25 years has focused on elucidating the mechanisms by which Alcoholics Anonymous (AA) affects behavioral change in its participants. In addition to research on the spiritual mechanisms for which AA is best known in the popular conception, research on mechanisms of recovery (MOR) has predominantly supported social, cognitive, and affective mechanisms that are also present in many professional psychotherapies.

Aim:

This paper compares and contrasts the theorized MOR of AA with those found in several common professional psychotherapies to illustrate analogous elements.

Methods:

Literature review, summary, and synthesis of studies examining the MOR of both AA and common psychotherapies including analytic/dynamic therapies, cognitive-behavioral therapies, and acceptance and mindfulness-based therapies.

Results:

There exists a significant overlap in theorized MOR of AA and mainstream, professional psychotherapies. Mechanisms with the greatest overlap include those mobilizing stress and coping theory, behavioral choice theory, and social learning theory, while mechanisms more unique to AA compared to professional psychotherapies mobilize social control theory to a greater degree.

Conclusions:

In caring for patients with addiction, practicing clinicians will find it useful to be aware of overlapping analogous elements found in the AA program and professional psychotherapies and how they can complement one another.
Effects of Directional Microphone and Noise Reduction on Subcortical and Cortical Auditory-Evoked Potentials in Older Listeners With Hearing Loss
Authors: Slugocki Christopher , Kuk Francis , Korhonen Petri
Published: February 2020

Objectives:

Understanding how signal processing influences neural activity in the brain with hearing loss is relevant to the design and evaluation of features intended to alleviate speech-in-noise deficits faced by many hearing aid wearers. Here, we examine whether hearing aid processing schemes that are designed to improve speech-in-noise intelligibility (i.e., directional microphone and noise reduction) also improve electrophysiological indices of speech processing in older listeners with hearing loss.

Design:

The study followed a double-blind within-subjects design. A sample of 19 older adults (8 females; mean age = 73.6 years, range = 56–86 years; 17 experienced hearing aid users) with a moderate to severe sensorineural hearing impairment participated in the experiment. Auditory-evoked potentials associated with processing in cortex (P1-N1-P2) and subcortex (frequency-following response) were measured over the course of two 2-hour visits. Listeners were presented with sequences of the consonant-vowel syllable /da/ in continuous speech-shaped noise at signal to noise ratios (SNRs) of 0, +5, and +10 dB. Speech and noise stimuli were pre-recorded using a Knowles Electronics Manikin for Acoustic Research (KEMAR) head and torso simulator outfitted with hearing aids programmed for each listener’s loss. The study aid programs were set according to 4 conditions: (1) omnidirectional microphone, (2) omnidirectional microphone with noise reduction, (3) directional microphone, and (4) directional microphone with noise reduction. For each hearing aid condition, speech was presented from a loudspeaker located at 1 m directly in front of KEMAR (i.e., 0° in the azimuth) at 75 dB SPL and noise was presented from a matching loudspeaker located at 1 m directly behind KEMAR (i.e., 180° in the azimuth). Recorded stimulus sequences were normalized for speech level across conditions and presented to listeners over electromagnetically shielded ER-2 ear-insert transducers. Presentation levels were calibrated to match the output of listeners’ study aids.

Results:

Cortical components from listeners with hearing loss were enhanced with improving SNR and with use of a directional microphone and noise reduction. On the other hand, subcortical components did not show sensitivity to SNR or microphone mode but did show enhanced encoding of temporal fine structure of speech for conditions where noise reduction was enabled.

Conclusions:

These results suggest that auditory-evoked potentials may be useful in evaluating the benefit of different noise-mitigating hearing aid features.