bluuebunny/crossref_metadata_2025 huggingface dataset:
Method Validation for Determination of the 15 European-Priority Polycyclic Aromatic Hydrocarbons in Primary Smoke Condensates by Gas Chromatography/Mass Spectrometry: Interlaboratory Study
Authors: Simon Rupert , Palme Sonja , Anklam Elke , Hanot M W  V ,   Collaborators:, Delaire L , Hanot V , Holzer H , Jira W , Levasseur C , Monteau F , Obiedzinski M W , Ojala; M , Peschke D , Ramakrishnan S , Ranta C , Ruthenschrör A , Schirmacher M , Seidel A , Sopelana P , Wolz G , Wright C
Published: February 2020

A collaborative study was conducted to validate an analytical method for quantification of the 15 polycyclic aromatic hydrocarbons (PAHs) regarded in 2002 as a health concern by the former Scientific Committee on Food of the European Commission (SCF) in primary smoke condensates. The method is based on gas chromatography/mass spectrometry of a cyclohexane extract with solid-phase cleanup through silica gel. The analytes were detected in the selected-ion monitoring mode and quantified by using 3 isotopically labeled internal standard compounds. Seventeen laboratories participated in the collaborative validation study, of which 12 reported valid results. The data were subjected to Cochran, single Grubbs, and double Grubbs tests for statistical outliers. A maximum of 2 outliers was eliminated before further statistical evaluation of the method performance characteristics. Depending on the analyte, the results showed relative standard deviations for repeatability between 4.2 and 30% and for reproducibility from 9.9 to 60%. The recoveries varied between about 50 and 85%, except those for cyclopenta[cd]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene. Nevertheless, because Commission Directive 2005/10/EC allows for a recovery range of 50120% for (BaP) benzo[a]pyrene in various foods, it can be concluded that the method performs appropriately within the analytical range between 5 and 25 μg/kg of primary smoke condensate. For BaP the validated analytical range covered 520 μg/kg, and for benzo[a]anthracene (BaA) 1025 μg/kg. The method is suitable for monitoring BaP and BaA at their respective maximum permitted levels of 10 and 20 μg/kg. Three analytes, benzo[b]-, benzo[j]-, and benzo[k]-fluoranthene could not be separated by all of the participants and were therefore treated as the sum. Nevertheless, with this method the pattern of the respective concentrations of these 15 PAHs can be monitored in primary smoke condensate as suggested by the SCF.
Determining a One-Tailed Upper Limit for Future Sample Relative Reproducibility Standard Deviations
Authors: McClure Foster D , Lee Jung K
Published: February 2020

A formula was developed to determine a one-tailed 100p% upper limit for future sample percent relative reproducibility standard deviations    , where sR is the sample reproducibility standard deviation, which is the square root of a linear combination of the sample repeatability variance (    ) plus the sample laboratory-to-laboratory variance (    ), i.e.,    , and y is the sample mean. The future RSDR, % is expected to arise from a population of potential RSDR, % values whose true mean is    , where R and are the population reproducibility standard deviation and mean, respectively.
Immunobiosensor Detection of Domoic Acid as a Screening Test in Bivalve Molluscs: Comparison with Liquid Chromatography-Based Analysis
Authors: Traynor Imelda M , Plumpton Laura , Fodey Terence L , Higgins Cowan , Elliott Christopher T
Published: February 2020

A rapid and sensitive immuno-based screening method was developed to detect domoic acid (DA) present in extracts of shellfish species using a surface plasmon resonance-based optical biosensor. A rabbit polyclonal antibody raised against DA was mixed with standard or sample extracts and allowed to interact with DA immobilized onto a sensor chip surface. The characterization of the antibody strongly suggested high cross-reactivity with DA and important isomers of the toxin. The binding of this antibody to the sensor chip surface was inhibited in the presence of DA in either standard solutions or sample extracts. The DA chip surface proved to be highly stable, achieving approximately 800 analyses per chip without any loss of surface activity. A single analytical cycle (sample injection, chip regeneration, and system wash) took 10 min to complete. Sample analysis (scallops, mussels, cockles, oysters) was achieved by simple extraction with methanol. These extracts were then filtered and diluted before analysis. Detection limits in the ng/g range were achieved by the assay; however, the assay parameters chosen allowed the test to be performed most accurately at the Euopean Union's official action limit for DA of 20 g/g. At this concentration, intra- and interassay variations were measured for a range of shellfish species and ranged from 4.5 to 7.4% and 2.3 to 9.7%, respectively.
Biosensors for the Analysis of Food- and Waterborne Pathogens and Their Toxins
Authors: Rasooly Avraham , Herold Keith E
Published: February 2020

Biosensors are devices which combine a biochemical recognition element with a physical transducer. There are various types of biosensors, including electrochemical, acoustical, and optical sensors. Biosensors are used for medical applications and for environmental testing. Although biosensors are not commonly used for food microbial analysis, they have great potential for the detection of microbial pathogens and their toxins in food. They enable fast or real-time detection, portability, and multipathogen detection for both field and laboratory analysis. Several applications have been developed for microbial analysis of food pathogens, including E. coli O157:H7, Staphylococcus aureus, Salmonella, and Listeria monocytogenes, as well as various microbial toxins such as staphylococcal enterotoxins and mycotoxins. Biosensors have several potential advantages over other methods of analysis, including sensitivity in the range of ng/mL for microbial toxins and <100 colony-forming units/mL for bacteria. Fast or real-time detection can provide almost immediate interactive information about the sample tested, enabling users to take corrective measures before consumption or further contamination can occur. Miniaturization of biosensors enables biosensor integration into various food production equipment and machinery. Potential uses of biosensors for food microbiology include online process microbial monitoring to provide real-time information in food production and analysis ofmicrobial pathogens and their toxins in finished food. Biosensors can also be integrated into Hazard Analysis and Critical Control Point programs, enabling critical microbial analysis of the entire food manufacturing process. In this review, the main biosensor approaches, technologies, instrumentation, and applications for food microbial analysis are described.
Evaluation of a Polymerase Chain Reaction-Based Heteroduplex Assay for Detecting the Adulteration of Processed Orange Juice with Mandarin Juice
Authors: Mooney Rachel , Chappell Louise , Knight Angus I
Published: February 2020

A polymerase chain reaction (PCR)-based heteroduplex assay was evaluated for the detection of mandarin juice in processed orange juice. PCR amplification of a fragment of the chloroplast trnT-trnL intergenic spacer derived from mixtures of DNA extracted from orange and mandarin juice resulted in heteroduplex formation. The heteroduplex resulted from the co-amplification of a fragment containing an 8 base-pair indel that distinguished mixtures of orange and mandarin juice from orange juice and mandarin juice alone. The heteroduplex assay was evaluated against authentic juices obtained from different citrus species and confirmed that the marker was homogeneous within Citrus. The data obtained demonstrated maternal inheritance of chloroplast type in Citrus sp. and allowed the identification and confirmation of the maternal parentage of unknown and known citrus hybrids. Analysis of the quantitative potential of the PCR and polyacrylamide gel electrophoresis (PAGE) analysis demonstrated good repeatability with a coefficient of variation of 7.5%. Greatest sources of variance in experimental results were attributable to species and varietal differences in the levels of the PCR target. Mandarin juice contained approximately 18% (w/v) less PCR target sequence than did orange juice. The assay was tested in a blind trial using processed juices and correctly identified 20/22 samples with no false-positive results.
An Overview of the Health Effects of Isoflavones with an Emphasis on Prostate Cancer Risk and Prostate-Specific Antigen Levels
Authors: Messina Mark , Kucuk Omer , Lampe Johanna W
Published: February 2020

Soybean isoflavones possess hormonal and nonhormonal properties that may reduce the risk of coronary heart disease, osteoporosis, and certain cancers, and alleviate hot flashes in menopausal women. Among the various cancers whose risk may be reduced by isoflavones, there is particular interest in prostate cancer. Eleven trials have examined the effects of isoflavones on serum prostate-specific antigen (PSA) levels. The dose of isoflavones in these trials from supplements or soy protein ranged from 60 to 900 mg/day (typical Japanese intake is 3050 mg/day), subject number/group ranged from 8 to 62, and study duration from 20 days to 1 year. Isoflavones did not affect serum PSA in healthy subjects. In contrast, in 4 of 8 trials involving prostate cancer patients, isoflavones significantly favorably affected PSA although in no studies was there an absolute decrease in PSA concentrations. The mechanism by which isoflavones affect PSA could not be determined from the existing research, although hormonal changes do not seem to be a factor. The clinical evidence is sufficiently encouraging to justify considering additional Phase II and III clinical trials investigating the efficacy of soy isoflavones in different populations of prostate cancer patients alone and in combination with other treatments.
Mammary Gland Tumor Promotion in F1 Generation Offspring from Male and Female Rats Exposed to Soy Isoflavones for a Lifetime
Authors: Mehta Rekha , Lok Eric , Caldwell Donald , Mueller Rudolf , Kapal Kamla , Taylor Marnie , Cooke Gerard M , Curran Ivan H A
Published: February 2020

The effect of dietary isoflavones in the form of NOVASOY (NS) was investigated on methylnitrosourea-initiated mammary gland cancer in F1 generation female Sprague Dawley rats from parents who had undergone lifetime exposure to variable levels of dietary NS. In comparison to NS-free dietary groups, lifetime exposure of F1 rats to 40 and 1000 mg/kg diets of NS reduced tumor latency, but did not significantly affect tumor incidence, tumor size, or tumor multiplicity. A significantly lower tumor multiplicity was, however, observed in rats fed the soy-based, NS-free diet compared to the casein-based, NS-free diet. An evaluation of a dose-response relationship pointed towards a biphasic effect, with a trend showing lower tumor incidence, lower tumor multiplicity, and lower tumor size in rats fed 1000 mg/kg diet NS compared to 40 mg/kg diet NS; however, the data failed to achieve statistical significance. Histologically, tumor type significantly differed according to the administered basal diet variety and NS dose. Our data and that of others provide conflicting evidence for chemopreventive effects of soy isoflavones on mammary gland tumor induction. We suggest standardization of interlaboratory experimental approaches for establishing low dose-response relationships for soy and its isoflavones to aid in risk assessment.
Ion Chromatographic Determination of Phosphorus Soluble in Different Extracting Media in Fertilizers
Authors: Mazzei Raffaele Antonio , Scuppa Stefano
Published: February 2020

A new method based on ion chromatography (IC) was developed for the determination of phosphorus in fertilizers. Fertilizers were extracted with water, mineral acids, and 2% formic acid, 2% citric acid, and neutral ammonium citrate solutions according to European Regulation No. 2003/2003 of the European Parliament and the Council of October 13, 2003, or the Decree of the Italian Agriculture Minister of June 17, 2002; the extracts were analyzed by direct injection, after simple filtration, by IC on an IonPac AS19 (250 × 4 mm id) column, using a KOH (21-50-21 mM) gradient and suppressed conductivity detection. The calibration plot was linear over the range of 550 mg/L (r2 of >0.999). The method was evaluated by comparison with a gravimetric method according to established norms. Associated uncertainty at the 95% confidence level was established as 0.47% for the determination of 346% P2O5 by IC. A good chromatographic separation of phosphorus forms such as phosphates and phosphites, and some other important anions like nitrates, chlorides, and sulfates present in many commercial fertilizers was also possible, with a linear response over the range of 550 mg/L. After a more complete validation, this IC determination of phosphorus could replace more tedious methods such as those using gravimetric determinations.
Highly Sensitive Spectrofluorimetric Determination of Ephedrine Hydrochloride in Pharmaceutical Preparations
Authors: Ulu Sevgi Tatar
Published: February 2020

A sensitive and specific spectrofluorimetry method was developed and validated for the quantification of ephedrine (EP) in pharmaceutical preparations. The method is based on the fluorescent enhancing reaction of EP with 7-chloro-4-nitrobenzofurazan (NBD-CI; derivatization reagent), in borate buffer of pH 9 to yield a yellow, fluorescent product. Under these experimental conditions, the derivatized product of EP had excitation and emission wavelength maxima at 458 and 516 nm, respectively. The linear range of this method was 202500 ng/mL. The detection limit was 7.3 ng/mL EP. Intra- and interday precisions of the assay at 3 concentrations within this range were 0.0371.77%. The low relative standard deviation values indicate good precision, and high recovery values indicate excellent accuracy of the method. The proposed method was applied to the determination of the examined drugs in pharmaceutical formulations, and the results indicate that the method is equally as accurate, precise, and reproducible as the official method.
Validation of Liquid Chromatography and Liquid Chromatography/Tandem Mass Spectrometry Methods for the Determination of Etoricoxib in Pharmaceutical Formulations
Authors: Brum Liberato , Fronza Marcio , Ceni Danieli Catia , Barth Thiago , Dalmora Sergio Luiz
Published: February 2020

Reversed-phase liquid chromatography (LC) and LC/tandem mass spectrometry (LC/MS/MS) methods were developed and validated for the determination of etoricoxib in pharmaceutical dosage forms. The LC method was performed by reversed-phase chromatography on a Synergi fusion C18 column (150 × 4.6 mm id) maintained at ambient temperature. The mobile phase consisted of 0.01 M phosphoric acid, pH 3.0acetonitrile (62 + 38, v/v) at a flow rate of 1.0 mL/min, and photodiode array detection at 234 nm was used. The chromatographic separation was obtained within 7.0 min, and calibration curves were linear in the concentration range of 0.02-150 μg/mL. The LC/MS/MS method was performed on a Luna C18 column (50 × 3.0 mm id). The mobile phase consisted of acetonitrilewater (95 + 5)0.1% acetic acid (90 + 10, v/v). Detection was performed by positive electrospray ionization in the multiple reaction monitoring mode, monitoring the transitions 359.3 > 280.0 and 332.0 > 95.0 for etoricoxib and piroxicam (internal standard), respectively. The chromatographic separation was obtained within 2.0 min, and calibration curves were linear in the concentration range of 15000 ng/mL. Validation parameters, such as specificity, linearity, precision, accuracy, and robustness, were evaluated, which gave results within the acceptable range for both methods. Moreover, the proposed methods were successfully applied for routine quality control analysis of pharmaceutical products and showed significant correlation (r = 0.9999) of the results.
A Validated Spectrofluorometric Assay for the Determination of Certain Macrolide Antibiotics in Pharmaceutical Formulations and Spiked Biological Fluids
Authors: El-Rabbat Nawal , Askal Hassan F , Khashaba Pakinaz Y , Attia Noha N
Published: February 2020

This paper describes a simple spectrofluorometric method for the analysis of 4 macrolide antibiotics. The method is based on the condensation of 10% (w/v) malonic acid and acetic acid anhydride under the catalytic effect of tertiary amine groups of the studied macrolides. The relative fluorescence intensity of the condensation product was measured at 397/452 nm (excitation/emission) for azithromycin dihydrate and at 392/445 nm (for clarithromycin, erythromycin ethylsuccinate, and roxithromycin. All variables affecting the reaction conditions were studied. The effects of potential interference due to common excipients, such as starch, lactose, sucrose, glucose, gum acacia, and magnesium stearate, as well as trimethoprim and sulfisoxazole acetyl formulated in primomycin capsules and pediazole oral suspension, respectively, were studied. A validation study for the proposed method was carried out according to U.S. Pharmacopeia 2002. The linearity ranges were 380 ng/mL for all of the cited macrolides. The limit of detection range was 0.741.20 ng/mL, while the limit of quantitation range was 2.474.02 ng/mL. The method was applied for the assay of the studied macrolides in pure pharmaceutical formulations and in spiked biological fluids. Results were compared with those obtained from the reported method, where calculated t- and F-values indicated high accuracy and good precision for the proposed method.
Determination of Protein in Milk Powder Using 2-Sulfophenylazo-Rhodanine as a Probe by the Enhanced Resonance Rayleigh Light-Scattering Technique
Authors: Wei Qin , Li Yan , Dong Wenying , Du Bin
Published: February 2020

In this paper, the interaction between 2-sulfophenylazo-rhodanine and protein was investigated by Rayleigh light-scattering technique. Based on this, a novel method for the determination of protein was developed. The effects of different conditions, such as acidity and media, were investigated thoroughly, and the optimum conditions were confirmed. Bis(2-ethylhexyl)sulfosuccinate (AOT) microemulsion, which is introduced into the protein determination, markedly increased the sensitivity of the system by changing the microenvironment. In pH 2.80 Britton-Robinson buffer solution in the presence of AOT microemulsion, the detection limits of bovine serum albumin, human serum albumin, ovalbumin, and -globulin are 5.4, 4.5, 9.8, and 10.1 ng/mL, respectively. The method developed in this paper has been applied to the determination of protein in milk powder with satisfactory results.
Quantitation of Indian Krait (Bungarus caeruleus) Venom in Human Specimens of Forensic Origin by Indirect Competitive Inhibition Enzyme-Linked Immunosorbent Assay
Authors: Brunda Ganneru , Rao Beedu Sashidhar , Sarin Rajendra Kumar
Published: February 2020

An indirect competitive inhibition enzyme-linked immunosorbent assay was reported to detect krait venom in human specimens of forensic origin. Polyclonal anti-krait venom antibodies were characterized by indirect antibody capture assay. The calibration plot was constructed based on linear regression analysis (y = 72.85 12.29x, r2 = 0.98) with concentration ranges from 0.013 to 1000 ng/well of krait venom with a limit of detection of 0.2 ng/mL in the assay system. The IC50 (inhibitory concentration at 50% displacement) value of krait venom was observed to be 70 ng. Spiking studies indicated recoveries of 95100% and 94100% when various concentrations of krait venom were spiked to rat tissues (skin, liver, and kidneys) and pooled human serum, respectively. Polyclonal anti-krait venom antibodies showed no cross-reactivity with cobra and viper venom when tested in the assay system. The coefficient of variation of various concentrations of working range in intra-assay (n = 6) was <5%, whereas in interassay (n = 6) it was observed to be 7%. Further, the method was used to quantitate krait venom in human autopsy and biopsy specimens of forensic origin. Concentration of krait venom was found to be in the range of 4172 ng/100 mg skin or skin scrapings and 64378 ng/mL blood or serum. The methodology may find application in forensic laboratories to assess the cause of death in the cases of krait-bite victims.
A Selective High-Performance Liquid Chromatography Method for the Determination of Reboxetine in Bulk Drug and Tablets
Authors: Önal ArmaĞan , SaĞiri Olcay , Çetin S Müge , Toker Sidika
Published: February 2020

Reboxetine is used as a selective noradrenaline reuptake inhibitor for the treatment of major depressive disorders. It is effective in the treatment of severe depression and safer to use than traditional tricyclic antidepressants. In this study, a novel, simple, and rapid stability-indicating high-performance liquid chromatography (HPLC) method for reboxetine methansulfonate was successfully developed and validated for the assay of tablets. The method was used to quantify reboxetine in tablets; it employed a C18 column (150 4.6 mm id) with an isocratic mobile phase consisting of methanolphosphate buffer (pH 7, 0.02 M; 55 + 45, v/v) at a flow rate of 1.0 μmL/min. Reboxetine was detected by an ultraviolet detector at 277 nm. The retention time of reboxetine was about 4.5 min. The developed HPLC method was validated with respect to linearity, precision, sensitivity, accuracy, and selectivity. The method was linear over the concentration range 150 g/mL (r 0.9999). The limits of detection and the quantitation of reboxetine were 0.1 and 0.3 μg/mL, respectively. The relative standard deviation values for intraday and interday precision were 0.781.01 and 1.081.37%, respectively. Selectivity was validated by subjecting a stock solution of reboxetine to neutral, acid, and alkali hydrolysis, as well as oxidation, dry heat treatment, and photodegradation. The peaks of the degradation products did not interfere with the peak of reboxetine. The results indicated that the proposed method could be used in a stability assay. The proposed method was successfully applied to the determination of reboxetine in tablets. Excipients present in the tablets did not interfere with the analysis.
Determination of Semicarbazide in Fresh Egg and Whole Egg Powder by Liquid Chromatography/Tandem Mass Spectrometry: Interlaboratory Validation Study
Authors: Calle Maria Beatriz De La , Szilagyi Szilard , Berendsen B ,   Collaborators:, Barbosa J , Berendsen B , Bockhorn I , Brandtner M , Delahaut P , Fuerst P , Griffin C , Hager D , Janosi A , Kennedy G , Laska H , Mandix M , Plonevez S , Posyniak A , Verdon E
Published: February 2020

An interlaboratory validation study was conducted according to harmonized protocols to evaluate the effectiveness of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of semicarbazide (SEM) in fresh whole egg and in an industrially processed whole egg powder. The sample was extracted with hydrochloric acid and derivatized with 2-nitrobenzaldehyde, with 1,2-[15N213C]SEM as the internal standard. The extract was neutralized and purified on a solid-phase extraction cartridge. SEM was determined by reversed-phase LC with detection by MS/MS. Five fresh egg samples, of which 3 were obtained from hens fed nitrofurazone (NFZ), one was spiked with SEM at 50 μg/kg and one was a blank sample, and 5 industrial whole egg powder samples, of which 3 were spiked with fresh whole egg from hens fed NFZ, one was spiked with SEM at 350 μg/kg, and one was a blank sample, were sent to 15 laboratories in 10 different European countries. Results were obtained from 12 participants. Average recoveries of SEM from the fresh egg and the egg powder samples were 105.3 and 121.3%, respectively. The relative standard deviation for repeatability (RSDr) ranged from 2.9 to 9.3%, and the relative standard deviation for reproducibility (RSDR) ranged from 22.5 to 38.1%. The method showed acceptable within- and between-laboratory precision for both matrixes, as evidenced by the HorRat values, at the target levels for the determination of SEM.
Liquid Chromatography/Fluorescence Method for Emamectin B1a and Desmethylamino-Emamectin B1a Residues in Lobster Tissue
Authors: Tauber Ronald , Gillan Niall , Crouch Louis , Greenhalgh Roy
Published: February 2020

A liquid chromatography (LC)/fluorescence procedure was validated for emamectin (EM B1a) and desmethylamino-emamectin (DMAEM B1a) residues in lobster tissue. They were extracted by shaking and sonicating with 1% ammonium acetatemethanol in the presence of sand. The extract was concentrated, partitioned with ethylacetate, and cleaned up on a propylsulfonic cation exchange cartridge. The analytes were eluted from the cartridge with 5% ammonium hydroxidemethylacetate, the eluate was concentrated, and the solvent was changed to dry 20% ethylacetateacetonitrile before derivatization with trifluoroacetic anhydrideN-methylimidizole. The products were analyzed by LCfluorescence, and no interference [>limit of detection (LOD)] was detected in the control samples. Lobster tissues fortified with EM B1a and DMAEM B1a at 0.5, 5, 10, 25, and 50 ng/g gave overall mean recoveries of 96.7 12.4%, relative standard deviation (RSD) 12.8% for EM B1 and 83.6 12.1%, RSD 14.5% for DMAEM B1a. Regression analysis of the calibration data gave slopes of 0.90 (EM B1a) and 0.71 (DMAEM B1a) with an r2 0.99 for both compounds. The calculated LOD and limit of quantification (LOQ) for EM B1a were 1.10 and 3.32 ng/g, respectively, and for DMAEM B1a were 0.762 and 2.31 ng/g, respectively. Residues of EM B1a and DMAEM B1a in fortified lobster tissues stored at 20C showed that residues were stable for 1012 months. No loss of EM B1a and DMAEM B1a residues was observed after 3 freeze/thaw cycles of fortified tissue in a 5-day period.
Simultaneous Estimation of Pantoprazole and Domperidone in Pure Powder and a Pharmaceutical Formulation by High-Perfomance Liquid Chromatography and High-Performance Thin-Layer Chromatography Methods
Authors: Patel Bhavesh H , Suhagia Bhanubhai N , Patel Madhabhai M , Patel Jignesh R
Published: February 2020

This paper describes validated high-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC) methods for the simultaneous estimation of pantoprazole (PANT) and domperidone (DOM) in pure powder and capsule formulations. The HPLC separation was achieved on a Phenomenex C18 column (250 mm id, 4.6 mm, 5 μm) using 0.01 M, 6.5 pH ammonium acetate buffer-methanol-acetonitrile (30 + 40 + 30, v/v/v, pH 7.20) as the mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using ethyl acetatemethanol (60 + 40, v/v) as the mobile phase. Quantification was achieved with ultraviolet (UV) detection at 287 nm over the concentration range 400-4000 and 300-3000 ng/mL with mean recovery of 99.35 ± 0.80 and 99.08 ± 0.57% for PANT and DOM, respectively (HPLC method). Quantification was achieved with UV detection at 287 nm over the concentration range 80-240 and 60-180 ng/spot with mean recovery of 98.40 ± 0.67 and 98.75 ± 0.71% for PANT and DOM, respectively (HPTLC method). These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of PANT and DOM in pure powder and capsule formulations.
A Simplified Modification of the AOAC Official Method for Determination of Total Dietary Fiber Using Newly Developed Enzymes
Authors: Tada Shusaku , Innami Satoshi
Published: February 2020

Since 1985, AOAC Method 985.29 has been globally adopted as a standard method for determination of total dietary fiber in foods. Nevertheless, an aspect of AOAC Method 985.29 that needs to be improved is the laborious process to treat 3 enzymes separately at their individual proper pH, which is quite time-consuming. Several examinations have been carried out to resolve this problem. The characteristics of newly developed thermostable -amylase, neutral protease, and amyloglucosidase were evaluated based on the pH-activity profile and the property of starch hydrolysis in comparison with those of the conventional enzyme reagents. These 3 developed enzymes were found to work under the same pH condition and to accomplish sufficient digestion for the typical 3 starches: soluble starch, corn starch, and wheat starch. The experimental results revealed that the dietary fiber determination in foods could be performed without pH adjustment in the enzymatic digestion process. The modified method will be greatly helpful in determining the total dietary fiber contents in food materials with less laborious work and with an accuracy equivalent to that of AOAC Method 985.29.
Stable Competitive Enzyme-Linked Immunosorbent Assay Kit for Rapid Measurement of 11 Active Beta-Lactams in Milk, Tissue, Urine, and Serum
Authors: FitzGerald Stephen P , O’Loan Nuala , McConnell Robert I , Benchikh El Ouard , Kane Nicola E
Published: February 2020

Beta-lactams are used as veterinary drugs for the treatment of food-producing animals. For consumer protection, legislation is in place to set limits for their residues. An enzyme-linked immunosorbent assay (ELISA) was developed which allowed, in a single reaction, the class-specific measurement of 11 beta-lactams, with limits of detection below European maximum residue limits. Determinations were feasible in milk, tissue, urine, and serum with simple and rapid sample preparation. In this format, the specific capture antibodies were precoated on the microtiter plate and horseradish peroxidase-labeled conjugate was used to compete with free beta-lactams. The stability of the precoated microtiter plate and conjugate was at least 1 year when stored at 2 to 8°C; upon reconstitution, the conjugate was stable for 6 days at 2 to 8°C. The stability of lyophilized ampicillin standards was at least 6 months when stored at 2 to 8°C and at least 1 year when stored at 20°C. A low cross-reactivity, 3.6%, was observed with ampicillin with open beta-lactam ring relative to 100% for intact ampicillin. Generic recognition was shown by relative cross-reactivity values ranging from 22 (penicillin V) to 144% (nafcillin). Cross-reactivity for cephalosporins was <0.1%. Intra- and interassay precisions expressed as coefficient of variation were typically 2-8%. The inhibitory concentration with 50% binding for ampicillin was typically 2 ppb. Recovery for different spiked levels was >70% with all the matrixes.
Gas Chromatographic/Mass Spectrometric Analysis of the Essential Oil of Houttuynia cordata Thunb by Using On-Column Methylation with Tetramethylammonium Acetate
Authors: Ch Muhammad Ishtiaq , Wen Yang F , Cheng YiYu
Published: February 2020

This paper describes a simple and novel on-column derivatization procedure used with gas chromatography/mass spectrometry (GC/MS) for the analysis of essential oil of Houttuynia cordata Thunb (HCT), a traditional Chinese medicine. In the procedure, the essential oil was obtained by hydrodistillation, and the fatty acid components were derivatized with tetramethylammonium acetate (TMAA) at 250°C and identified by GC/MS. Methylation improved the determination of both the fatty acids and the other components in the essential oil of HCT. To obtain optimum methylation conditions, several important factors were investigated with pentadecane as the internal standard and a GC inlet temperature of 250°C. Tetramethylammonium hydroxide (TMAH) and TMAA were compared as the derivatization agent, and a 2:1 ratio of TMAA to capric acid was evaluated. Fatty acid methyl esters produced good chromatographic peak shapes and did not interfere with the determination of dodecanal and caryophyllene. TMAA is a neutral methylation reagent, and it yielded no side reactions during derivatization. It was found that the fatty acid content of the essential oil was about 81%; among the methylated fatty acids found were capric acid, methyl (43.66%), methyl laurate (16.15%), methyl hexadecanoate (9.27%), undecanoic acid, methyl (5.62%), methyl oleate (1.98%), and methyl linoleate (1.40%). Other major constituents were (-)-β-pinene (1.02%), β-myrcene (1.62%), 1-terpinen-4-ol (1.59%), decanal (1.49%), and 2-undecanone (1.47%). The results obtained demonstrated good efficiency for the procedure. Pure chromatograms allowed quantitation, which was obtained by total volume integration. The on-column derivatization procedure was simple to perform, and it improved the sensitivity, the peak resolution, and the selectivity of the GC/MS determination.
Development and Validation of a Spectrophotometric Method for the Determination of Macrolide Antibiotics by Using 2,4-Dinitrophenylhydrazine
Authors: Abdelmageed Osama H
Published: February 2020

A simple, novel, sensitive, and specific spectrophotometric method was developed and validated for the determination of azithromycin (AZ), clarithromycin (CLA), and roxithromycin (ROX) in bulk powders and their dosage forms. The proposed method was based on the interaction of any of the cited drugs with 2,4-dinitrophenylhydrazine in the presence of an acid catalyst, followed by treatment with a methanolic solution of potassium hydroxide; an intensely colored chromogen was formed that was measured in dimethylformamide, as the diluting solvent, at 542−545, 523−526, and 539−542 nm for AZ, CLA, and ROX, respectively. All variables affecting the development of the measured chromogens were studied and optimized. Beer's law was obeyed in the concentration ranges of 540, 535, and 535 μg/mL for AZ, CLA, and ROX, respectively, with good correlation coefficients (0.99910−9999). The limits of detection for this method ranged from 0.77 to 1.47 μg/mL, and the relative standard deviations were 1.24−1.8%. The proposed method was applied successfully to the determination of the 3 drugs in pure bulk form, tablets, and suspensions without interference from commonly encountered additives. The results compared favorably with those of a previously reported method. The mechanism of the reaction was also studied.
Spectrophotometric Determination of Pipazethate Hydrochloride in Pure Form and in Pharmaceutical Formulations
Authors: El-Shiekh Ragaa , Amin Alaa S , Zahran Faten , Gouda Ayman A
Published: February 2020

Three simple, sensitive, and reproducible spectrophotometric methods (AC) for the determination of pipazethate hydrochloride (PiCl) in pure form and in pharmaceutical formulations are described. The first and second methods, A and B, are based on the oxidation of the drug by Fe3+ in the presence of o-phenanthroline (o-phen) or bipyridyl (bipy). The formation of tris-complex upon reactions with Fe3+-o-phen and/or Fe3+-bipy mixture in an acetate buffer solution of the optimum pH values was demonstrated at 510 and 522 nm, respectively, with o-phen and bipy. The third method, C, is based on the reduction of Fe(III) by PiCl in acid medium and subsequent interaction of Fe(II) with ferricyanide to form Prussian blue, which exhibits an absorption maximum at 750 nm. The concentration ranges are from 0.5 to 8, 2 to 16, and 3 to 15 g/mL for Methods AC, respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, and detection and quantitation limits were calculated. The developed methods were successfully applied to the determination of PiCl in bulk and pharmaceutical formulations without any interference from common excipients. The relative standard deviations were 0.83% with recoveries of 98.9101.15%.
Spectrofluorometric Determination of Ketorolac Tromethamine Via Its Oxidation with Cerium(IV) in Pharmaceutical Preparations and Biological Fluids
Authors: Eid Manal , El-Brashy Amina , Aly Fatma , Talaat Wael
Published: February 2020

A simple and sensitive fluorometric method for determination of ketorolac tromethamine was studied. The method depends on oxidation of the drug with cerium(IV) and subsequent monitoring of the fluorescence of the induced cerium(III) at em 365 nm after excitation at 255 nm. Different variables affecting the reaction conditions, such as the concentrations of cerium(IV), sulfuric acid concentration, reaction time, and temperature, were carefully studied and optimized. Under the optimum conditions, a linear relationship was found between the relative fluorescence intensity and the concentration of the investigated drug in the range of 0.10.8 g/mL. No interferences could be observed from the excipients commonly present in dosage forms. The proposed method was successfully applied to the analysis of the investigated drug in its pure form, pharmaceutical preparations, and biological fluids with good accuracy and precision. The recoveries for pharmaceutical formulations ranged from 99.8101.0 0.6% for tablets, 98.5101.0 1.0% for ampoules, and 99.0100.5 0.7% for eye drops. The results obtained by the proposed method were satisfactory compared with those obtained by the official method. The recoveries for biological fluids were 99.1100.4 0.7 and 99.0100.0 0.5% for plasma and urine, respectively.
Development and Validation of Chemometrics-Assisted Spectrophotometry and Liquid Chromatography Methods for the Simultaneous Determination of the Active Ingredients in Two Multicomponent Mixtures Containing Chlorpheniramine Maleate and Phenylpropanolamine Hydrochloride
Authors: Hadad Ghada M , El-Gindy Alaa , Mahmoud Waleed M M
Published: February 2020

Multivariate spectrophotometric calibration and liquid chromatography (LC) methods were used for the simultaneous determination of the active ingredients in 2 multicomponent mixtures containing chlorpheniramine maleate and phenylpropanolamine hydrochloride with ibuprofen and caffeine (mixture 1) or with propyphenazone (mixture 2). For the multivariate spectrophotometric calibration methods, principal component regression (PCR) and partial least squares (PLS-1), a calibration set of the mixtures consisting of the components of each mixture was prepared in distilled water. A leave-1-out cross-validation procedure was used to find the optimum numbers of latent variables. Analytical parameters such as sensitivity, selectivity, analytical sensitivity, limit of quantitation, and limit of detection were determined for both PLS-1 and PCR. The LC method depends on the use of a cyanopropyl column with the mobile phase acetonitrile-12 mM ammonium acetate, pH 5.0 (25 + 75, v/v), for mixture 1 or acetonitrile10 mM potassium dihydrogen phosphate, pH 4.7 (45 + 55, v/v), for mixture 2; the UV detector was set at 212 nm. In spite of the presence of a high degree of spectral overlap of these components, they were rapidly and simultaneously determined with high accuracy and precision, with no interference from the matrix excipients. The proposed methods were successfully applied to the analysis of pharmaceutical formulations and laboratory-prepared mixtures containing the 2 multicomponent combinations.
High-Performance Liquid Chromatographic Determination of Proquazone and Its m-Hydroxy Metabolite in Spiked Human Plasma and Urine
Authors: Hassan Ekram M , Gazy Azza A , Abdel-Hay Mohamed H , Belal Tarek S
Published: February 2020

A simple and rapid high-performance liquid chromatographic method for the determination of proquazone (PQZ) and its major metabolite, m-hydroxyproquazone, in spiked human plasma and urine was developed. Plasma samples were purified using acetonitrile as a protein precipitant, while urine samples were diluted only with the mobile phase and filtered prior to injection. Samples containing the parent compounds and glafenine (internal standard) were eluted from a reversed-phase C8 column using acetonitrile-0.025 M sodium acetate (60 + 40) adjusted to pH 5 as the mobile phase and detected at 234 nm. Peak area ratios of the analytes versus internal standard were used for calibration. The mean recoveries from plasma and urine samples spiked with PQZ and its m-hydroxy metabolite ranged from 97.87 to 103.88%. The relative standard deviation for the within- and between-day analyses were <4%. The proposed method was applied for the assay of PQZ in laboratory-made tablets.
Convenient Analysis of Vitamin D in Cheese and Other Food Matrixes by Liquid Chromatography/Mass Spectrometry
Authors: Dimartino Gianluca
Published: February 2020

A convenient method is presented for determination of vitamin D in natural cheese, processed cheese, milk, cereals, noncarbonated soft drinks, and juice by liquid chromatography/mass spectrometry (LC/MS). Samples were saponified, extracted, evaporated, redissolved in acetonitrile, and injected into an LC-atmospheric pressure chemical ionization-MS system with no preparative chromatographic steps. Vitamin D was determined by selected ion monitoring. MS response was linear for vitamin D3 and its internal standard vitamin D2, and overall average recoveries ranged from 98 to 105. A blending experiment in which shredded vitamin D3-fortified cheddar was mixed with control nonfortified cheddar showed linearity. The limit of detection for vitamin D was 1.3 ng and the limit of quantitation was 3 ng. The method gave good accuracy and precision, with a standard deviation of 9.5 and relative standard deviation of 6.7. Results for vitamin D3 obtained with this method for different food matrixes, at different levels, were in agreement with those obtained with the reference LC/UV method currently used by many laboratories and derived from AOAC Official Method 982.29.
A High-Throughput Analytical Method for Determination of Aminoglycosides in Veal Tissues by Liquid Chromatography/Tandem Mass Spectrometry with Automated Cleanup
Authors: Babin Yves , Fortier Serge
Published: February 2020

A liquid chromatographic/tandem mass spectrometric (LC/MS/MS) method was developed for determining dihydrostreptomycin, gentamicin C1, and neomycin in veal kidney, liver, and muscle. The extraction prior to injection on the automated cleanup/analysis system is very simple, permitting preparation of 24 veal samples for analysis in half a day of work. The extracts are purified online on a reversed-phase column, with the help of an ion-pairing agent, and the analytes are separated on a Nucleosil C18 column prior to analyses by electrospray MS/MS. The cleanup is sufficient to minimize ion suppression/enhancement phenomena and permits quantification of the analytes extracted from veal tissues. Four secondary ions were measured for every analyte, which gives unambiguous identification of the compounds under analysis. Calibration curves were linear for all analytes between 50 and 5000 ppb, and recoveries in kidney were 76, 57, and 51, respectively, for dihydrostreptomycin, gentamicin C1, and neomycin. Estimated limits of detection for kidney were, respectively, 0.1, 0.1, and 0.4 ppb. When compared to an LC method with fluorescence detection, the method gave equivalent results for kidneys incurred with neomycin. This rugged method has been applied to the analysis of more than 1000 veal samples over a 1-year period.
Analytical Method Performance Evaluation (AMPE)A Software Tool for Analytical Method Validation
Authors: Acutis Marco , Trevisiol Patrizia , Confalonieri Roberto , Bellocchi Gianni , Grazioli Emanuele , Eede Guy Van Den , Paoletti Claudia
Published: February 2020

A Windows-based software tool [Analytical Method Performance Evaluation (AMPE)] was developed to support the validation of analytical methods. The software implements standard statistical approaches commonly adopted in validation studies to estimate analytical method performance (limits of detection and quantitation, accuracy, specificity, working range, and linearity of responses) according to ISO 5725. In addition, AMPE proposes the application of innovative and unique approaches for the assessment of analytical method performance. Specifically, AMPE proposes the use of difference-based indexes to quantify the agreement between measurements and reference values, the use of pattern indexes to quantify methods bias with respect to specific external variables, and the application of fuzzy logic to aggregate into synthetic indicators the information collected independently via the different performance statistics traditionally estimated in validation studies. Aggregated measures are particularly useful for methods comparison, when more than one method is available for a specific analysis and itmay be of interest to identify the best performing one taking into account, simultaneously, the information available from different performance statistics. Illustrative examples of the type of outputs expected from AMPE-based validation sessions are given. The extensive data handling capabilities and the wide range of statistics supplied in the software package makes AMPE suitable for specific needs that may arise in different validation studies. The installation package, complete with a fully documented help file, is distributed free of charge to interested users along with input files exemplary of the type of entry data required to run validation data analyses.
Application of Fractional Factorial Design and Doehlert Matrix in the Optimization of Experimental Variables Associated with the Ultrasonic-Assisted Acid Digestion of Chocolate Samples for Aluminum Determination by Atomic Absorption Spectrometry
Authors: Jalbani Nusrat , Kazi Tasneem Gul , Jamali Muhammad Khan , Arain Muhammad Balal , Afridi Hassan Imran , Sheerazi Syed T , Ansari Rehana
Published: February 2020

A simple and rapid method based on ultrasound energy is described for the determination of aluminum (Al) in complex matrixes of chocolate and candy samples by electrothermal atomic absorption spectrometry. The optimization strategy was carried out using multivariate methodologies. Five variables (temperature of the ultrasonic bath; exposure time to ultrasound energy; volumes of 2 acid mixtures, HNO3H2SO4H2O2 (1 + 1 + 1) and HNO3H2O2 (1 + 1); and sample mass) were considered as factors in the optimization process. Interactions between analytical factors and their optimal levels were investigated using fractional factorial and Doehlert matrix designs. Validation of the ultrasonic-assisted acid digestion procedure was performed against standard reference materials, milk powder (SRM 8435) and wheat flour (SRM 1567a). The proposed procedure allowed Al determination with a detection limit of 2.3 g/L (signal-to-noise = 3) and a precision, calculated as relative standard deviation, of 2.2 for a set of 10 measurements of certified samples. The recovery of Al by the proposed procedure was close to 100, and no significant difference at the 95 confidence level was found between determined and certified values of Al. The proposed procedure was applied to the determination of Al in chocolate and candy samples. The results indicated that cocoa-based chocolates have higher contents of Al than milkand sugar-based chocolates and candies.
Determination of Some Aldehydes by Using Solid-Phase Microextraction and High-Performance Liquid Chromatography with UV Detection
Authors: Kumar Ashwini , Singh Baldev , Malik Ashok Kumar , Tiwary Dhananjay K
Published: February 2020

A new approach has been developed for the extraction and determination of aldehydes such as veratraldehyde, m-nitrobenzaldehyde, cinnamaldehyde, benzaldehyde, and p-chlorobenzaldehyde by using solid-phase microextraction (SPME) and high-performance liquid chromatography with UV detection (HPLC/UV). The method involves adsorption of the aldehydes on polydimethylsiloxane/divinylbenzenecoated fiber, followed by desorption in the desorption chamber of the SPME-HPLC interface, using acetonitrilewater (70 + 30) as the mobile phase; UV detection was at 254 nm. A good separation of 5 aldehydes was obtained on a C18 column. The detection limits of veratraldehyde, m-nitrobenzaldehyde, cinnamaldehyde, benzaldehyde, and p-chlorobenzaldehyde are 25, 41, 13, 12, and 11 pg/mL, respectively, which are about 100 times better than the detection limits for other SPME methods using gas chromatography. The proposed method was validated by determining benzaldehyde in bitter almonds and cinnamaldehyde in cinnamon bark. The recoveries of the 5 analytes were determined by analysis of spiked drinking water.