Determination of Salt in Butter

1966 ◽  
Vol 49 (3) ◽  
pp. 518-521
Author(s):  
Robert W Weik
Keyword(s):  
Individual Differences ◽  
Salt Content ◽  
Official Method ◽  
Significant Difference ◽  
Present Official Method ◽  
International Dairy Federation

Abstract The official AOAC, 15.135, and International Dairy Federation (IDF) methods for determining the salt content of butter have been collaboratively studied. Results indicated that there was no significant difference (P > 0.05) between the method means. A highly significant difference (P < 0.001) was found between laboratory means which reflected individual differences in performing titration procedures and slight deviations from the prescribed procedure. The overall results indicated that the IDF method as studied was as accurate as the longer present official method, and the IDF method is recommended for adoption as official, first action.

Selective Determination of Entecavir in the Presence of Its Oxidative Degradate by Spectrophotometric and Chromatographic Methods

2021 ◽  
Author(s):  
Heba M El-Sayed ◽  
Laila E Abdel Fattah ◽  
Hisham E Abdellatef ◽  
Maha A Hegazy ◽  
Mai M Abd El-Aziz
Keyword(s):  
High Selectivity ◽  
Oxidative Degradation ◽  
Hplc Method ◽  
Peak Amplitude ◽  
Quality Analysis ◽  
Official Method ◽  
Selective Determination ◽  
Significant Difference ◽  
Development And Validation

Abstract Background Entecavir (ENT) is an antiretroviral agent prescribed for treatment of HBV and HIV. Objective Development and validation of three simple, sensitive, selective, and precise methods for determination of ENT in presence of its oxidative degradation product (ENT deg.). Methods The first method was based on second derivative (D2) spectrophotometry through measuring the peak amplitude of D2 spectra at 293.6 nm. The second one is mean centering of the ratio spectra (MCR), which allowed measuring the peak amplitude at 280.0 nm. While the third method was HPLC; where ENT was separated from ENT deg. using Zobrax C18column and methanol: water (30:70, v/v), pH 3 as a mobile phase. The three developed methods were validated according to ICH guidelines. Results Linearity range of ENT was 5.00–50.00 μg/mL for both D2and MCR. However, higher sensitivity was achieved using HPLC (1.00–50.00 μg/mL). Accuracy of ENT were 100.60%±0.547, 101.55%±1.2071 and 100.61%±1.207 for D2, MCR and HPLC methods, respectively, and precision was within 1.280. Conclusions The developed methods were successfully applied for the determination of ENT in Tecavir® tablets without interference from ENT deg. They showed no significant difference compared with the official method as well as they could be applied in the quality analysis of ENT with high selectivity, accuracy, and precision. Highlights ENT was quantified using two spectrophotometric (D2 and MCR) methods and an HPLC method in presence of ENT deg. The proposed methods were applied to analysis of ENT tablets with high selectivity, sensitivity, and accuracy.

scholarly journals Development of a Solid-Phase Extraction Method for Determination of Pheophorbide a and Pyropheophorbide a in Health Foods by Liquid Chromatography

2004 ◽  
Vol 87 (4) ◽  
pp. 937-942 ◽  
Author(s):  
Harumi Oshima ◽  
Eiji Ueno ◽  
Isao Saito ◽  
Hiroshi Matsumoto
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Official Method ◽  
Phase Extraction ◽  
Pheophorbide A ◽  
Significant Difference ◽  
Spe Method

Abstract A simple solid-phase extraction (SPE) method was developed for the liquid chromatography (LC) determination of pheophorbide (Phor) a and pyropheophorbide (Pyro) a in health foods such as chlorella, spirulina, etc. The food sample was extracted with 85% (v/v) acetone. The extract was acidified with hydrochloric acid and loaded on a C18 cartridge. After washing with water, Phor a and Pyro a were eluted with the LC mobile phase. Phor a and Pyro a were separated by isocratic reversed-phase LC and quantitated by fluorescence detection. The recoveries for spiked samples of chlorella and the extract were 87.1–102.0%. Commercial health foods (chlorella, spirulina, aloe, kale, Jews mallow, and green tea leaves) were analyzed using the SPE method. The values found for Phor a and Pyro a ranged from 2 to 788 μg/g and from <1 to 24 μg/g, respectively. There was no significant difference between the SPE method and the official method in Japan (spectrophotometry after liquid–liquid extraction). The advantages of the SPE method are the short extraction times, lack of emulsions, and reduced consumption of organic solvents compared with the official method in Japan. The SPE method is considered to be useful for the screening of Phor a and Pyro a in health foods.

scholarly journals Polymeric Matrix Membrane Sensors for Stability-Indicating Potentiometric Determination of Oxybutynin Hydrochloride and Flavoxate Hydrochloride Urogenital System Drugs

2008 ◽  
Vol 91 (6) ◽  
pp. 1318-1330 ◽  
Author(s):  
Mohamed Heba ◽  
Nesrin Ramadan ◽  
Moustafa El-Laithy
Keyword(s):  
Degradation Products ◽  
Pharmaceutical Formulations ◽  
Official Method ◽  
Urogenital System ◽  
Electroactive Materials ◽  
Significant Difference ◽  
Ph Range ◽  
Oxybutynin Hydrochloride ◽  
Flavoxate Hydrochloride

Abstract Four polyvinyl chloride (PVC) matrix membrane electrodes responsive to 2 drugs affecting the urogenital systemoxybutynin hydrochloride (OX) and flavoxate hydrochloride (FX)were developed, described, and characterized. A precipitation-based technique with tungstophosphate (TP) and ammonium reineckate (R) anions as electroactive materials in a PVC matrix with an OX cation was used for electrode 1 and 2 fabrication, respectively. Electrode 3 and 4 fabrication was based on use of the precipitation technique of FX cation with tetrakis (4-chlorophenyl) borate and R anions as electroactive materials. Fast and stable Nernstian responses in the range 1 1021 106 M for the 2 drugs over the pH range 58 revealed the performance characteristics of these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The method was applied to FX and OX in their pharmaceutical formulations and in human plasma samples. The 4 proposed sensors were found to be specific for the drugs in the presence of up to 60 of their degradation products. Validation of the method according to the quality assurance standards showed suitability of the proposed electrodes for use in the quality control assessment of these drugs. The recoveries for determination of the drugs by the 4 proposed selective electrodes were 99.5 0.5, 100.0 0.4, 99.9 0.4, and 100.1 0.4 for sensors 14, respectively. Statistical comparison between the results obtained by this method and the official method of the drugs was done, and no significant difference found.

Determination of the Freezing Point of Milk by Thermistor Cryoscopy

1967 ◽  
Vol 50 (3) ◽  
pp. 533-537
Author(s):  
R W Henningson
Keyword(s):  
Freezing Point ◽  
Official Method ◽  
Milk Samples ◽  
Present Official Method ◽  
Proper Condition

Abstract Specific directions for the thermistor cryoscopic method, including uniformity in cooling, degree of supercooling, seeding, and reading procedures, are proposed for the present official method. It is emphasized that the instrument must be in the proper condition for use, must be properly calibrated, and must be properly utilized by the analyst. Each analyst should individually calibrate with standards by the same uniform procedure for standards and milk samples. The precautions necessary in the determination are part of the method and must be observed if the same sample is to yield the same freezing point value for different analysts, in different laboratories, at different times

Microbiological Assay of Oxytetracycline in Liquid Supplements

1972 ◽  
Vol 55 (6) ◽  
pp. 1354-1357
Author(s):  
Donald W Clarke
Keyword(s):  
Low Temperature ◽  
Coefficient Of Variation ◽  
Extraction Procedure ◽  
Microbiological Assay ◽  
Official Method ◽  
Average Recovery ◽  
Low Temperature Storage ◽  
Present Official Method ◽  
Temperature Storage

Abstract The extraction procedure of the official final action method for the determination of oxytetracycline in dry feeds, 38.208–38.213, has been modified for the analysis of liquid supplements. Ten g samples were extracted with 50 ml acid-methanol and diluted to 100 ml with the same solvent. Aliquots of the extract prepared according to the modified extraction procedure were assayed by the present official method and gave an average recovery of 100.6% and a coefficient of variation of 6.2% at a medication level of 500 mg/lb. Assays performed on liquid supplements containing oxytetracycline stored for an average of 26 days at 37 and 21°C, and for 37 days at – 4°C showed potency retentions of 21, 80, and 97%, respectively, indicating a need for low-temperature storage prior to analysis.

scholarly journals Use of a diazocoupling reaction for sensitive and selective spectrophotometeric determination of furosemide in spiked human urine and pharmaceuticals

2010 ◽  
Vol 64 (4) ◽  
Author(s):  
Kalsang Tharpa ◽  
Kanakapura Basavaiah ◽  
Kanakapura Vinay
Keyword(s):  
Correlation Coefficient ◽  
Human Urine ◽  
Pharmaceutical Formulations ◽  
Chromotropic Acid ◽  
Disulfonic Acid ◽  
Official Method ◽  
Spectrophotometric Methods ◽  
Significant Difference ◽  
Spiked Human Urine

AbstractTwo simple, sensitive, and selective spectrophotometric methods for the determination of 5-(aminosulfonyl)-4-chloro-2-((2-furanylmethyl)amino)benzoic acid (furosemide, FUR) are described. The methods are based on acid hydrolysis of FUR to free primary aromatic amine and diazotization followed by coupling with N-1-napthylethylene diamine (NEDA) (method A) or 4,5-dihydroxynaphthalene-2,7-disulfonic acid (chromotropic acid, CTA) (method B). The colored reaction product can be measured spectrophotometrically at 520 nm (method A) or 500 nm (method B). Beer’s law is obeyed over the ranges of 1.75–21.0 μg mL−1 and 2.5–30.0 μg mL−1, for method A and method B, respectively. Apparent molar absorptivities and Sandell’s sensitivities (in L mol−1 cm−1 and μg cm−2 per 0.001 absorbance unit, respectively) were 1.34 × 104 and 0.0253 using NEDA as the coupling agent, and 8.5 × 103 and 0.0389 using CTA for the same purpose. Analysis of solutions containing seven different concentrations of FUR gave a correlation coefficient of 0.9979 using NEDA and 0.9984 using CTA, while the slope and the correlation coefficient of the regression equation were calculated. The reaction stoichiometry in both methods was evaluated by the limiting logarithmic method and was found to be 1: 1 (diazotized FUR: NEDA or diazotized FUR: CTA). The methods were successfully applied to the determination of FUR in spiked human urine and in pharmaceutical formulations. The recovery of FUR from spiked urine was satisfactory resulting in the values of (109.4 ± 4.37) % using NEDA and (113.0 ± 4.74) % using CTA. Results of the analysis of pharmaceuticals demonstrated that the proposed procedures are at least as accurate and precise as the official method while a statistical analysis indicated that there was no significant difference between the results obtained by the proposed methods and those of the official method.

scholarly journals Extractive spectrophotometric determination of Quetiapine fumarate in pharmaceuticals and human urine using calmagite as an ion-pair reagent

2011 ◽  
Vol 17 (3) ◽  
pp. 259-267 ◽  
Author(s):  
Nagaraju Rajendraprasad ◽  
Kanakapura Basavaiahf ◽  
Basavaiah Vinay
Keyword(s):  
Human Urine ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Official Method ◽  
Quetiapine Fumarate ◽  
Relative Standard ◽  
Significant Difference ◽  
Comparison Of The Results

Quetiapine fumarate (QTF) is an antipsychotic drug belonging to the benzisoxazole derivatives indicated for the treatment of schizophrenia. A sensitive and selective method based on dichloromethane-extractable ion-pair of QTF with calmagite (CGT), which exhibited an absorption maximum at 490 nm, is described. At this wavelength, Beer?s law is obeyed over the concentration range of 3.0 - 30.0 ?g ml-1. The apparent molar absorptivity, limit of detection (LOD) and quantitation (LOQ) values are 1.32 ? 104 l mol-1 cm-1, 0.27 and 0.81 ?g ml-1 respectively. The reaction is extremely rapid at room temperature and the absorbance values remain unchanged upto 19 h. The precision results, expressed as intra-day and inter-day relative standard deviation values, are satisfactory (RSD ? 2.2%). The accuracy is satisfactory as well (RE ? 2.44%). The method was successfully applied to the determination of QTF in pharmaceuticals and spiked human urine with satisfactory results. No interference was observed from common pharmaceutical adjuvants in tablets. Statistical comparison of the results with official method showed an excellent agreement and indicated no significant difference in precision.

scholarly journals Membrane Electrodes for Determination of Some -Blocker Drugs

2007 ◽  
Vol 90 (4) ◽  
pp. 987-994 ◽  
Author(s):  
Nesrin K Ramadan ◽  
Hala E Zaazaa
Keyword(s):  
Pharmaceutical Formulations ◽  
Official Method ◽  
Membrane Electrodes ◽  
Timolol Maleate ◽  
Electroactive Material ◽  
Poly Vinyl Chloride ◽  
Significant Difference ◽  
Ph Range ◽  
Quality Assurance Standards

Abstract Five poly(vinyl chloride) (PVC) matrix membrane electrodes responsive to the -blockers atenolol (AT), bisoprolol fumarate (BI), timolol maleate (TI), and levobunolol HCl (LV) were developed and characterized. A precipitation-based technique with ammonium reineckate anion as an electroactive material in PVC matrix with AT, BI, TI, and LV cations was used for fabrication of Electrodes 14, respectively. Electrode 5 fabrication was based on precipitation of LV cation with tungstophosphate anion as an electroactive material. Fast and stable Nernstian responses at 1 1021 107 M for different -blockers over the pH range of 28 were found for these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The method was successively applied for the determination of -blockers in their pharmaceutical formulations. Validation of the method according to quality assurance standards showed the suitability of the proposed electrodes for use in the quality control assessment of these drugs. The recoveries for the determination of the -blocker drugs by the 5 proposed selective electrodes were 100.1 0.7, 99.9 0.8, 100.0 1.1, 100.5 1.1, and 100.6 0.7% for Sensors 15, respectively. Statistical comparison between the results obtained by this method and the official method of the drugs was performed and no significant difference was found.

scholarly journals Spectrophotometric Determination of Thioridazine Hydrochloride in Tablets and Biological Fluids by Ion-Pair and Oxidation Reactions

2012 ◽  
Vol 27 ◽  
pp. 129-141 ◽  
Author(s):  
Akram El-Didamony ◽  
Sameh Hafeez
Keyword(s):  
Methylene Chloride ◽  
Biological Fluids ◽  
Indigo Carmine ◽  
Ion Pair ◽  
Bromocresol Green ◽  
Official Method ◽  
Bromocresol Purple ◽  
Accuracy And Precision ◽  
Significant Difference

Two simple, sensitive and selective spectrophotometric methods have been described for the determination of the psychoactive drug, thioridazine HCl in tablets and in biological fluids. The first method is based on the oxidation of thioridazine HCl with measured excess of KMnO4under acidic conditions followed by the determination of unreacted oxidant using indigo carmine and methyl orange. The second method is based on the formation of ion-pair complexes with the acidic sulphophthalein dyes such as bromocresol green and bromocresol purple at pH 1.8 of KCl-HCl buffer. The formed complexes were extracted into methylene chloride and their absorbance was measured at 412 nm. Optimizations of the different experimental conditions are described for both methods. The proposed methods were successfully applied for determination of the drug in tablets and biological fluids with good accuracy and precision. Statistical comparison of the results with those obtained by an official method showed good agreement and indicated no significant difference in accuracy and precision.

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