روش ساده، حساس، سریع و دقیق اسپکتروفتومتری برای اندازه گیری هم زمان تتراسایکلین (TC)، اکسی تتراسایکلین (OTC) و داکسی سایکلین (DXC) در نمونه های عسل به کارگرفته شد. روش های کمومتریکس برای اندازه گیری ترکیباتی است که با یکدیگر هم پوشانی طیفی دارند. در این تحقیق، دو روش کالیبراسیون کمترین مربعات جزیی (PLS) و آنالیز فاکتورهای موازی ((PARAFAC برای اندازه گیری تتراسایکلین ها استفاده شد. محدوده خطی کالیبراسیون برای تتراسایکلین 16-1/0، اکسی تتراسایکلین 20-1/0 و داکسی سایکلین 30-1/0 میکروگرم بر میلی لیتر است. دو سری محلول شامل سری کالیبراسیون و سری پیش گویی غلظت ها ساخته شده و آزمایش در pH های مختلف تکرار شد. توسط سری کالیبراسیون مدل PLS در هر pH ساخته شده و سپس این مدل ها برای پیش گویی غلظت در سری نمونه های سنتزی مورد استفاده قرار گرفت. با مقایسه خطای مرحله پیش گویی، بهترین مدل در 0/8 =pH انتخاب شد. با استفاده از داده های طیفی حاصل از pH های مختلف، مدل 3 بعدی PARAFAC طراحی شد. RMSEP برای DXC،OTC وTC با PLS و PARAFAC به ترتیب 123/0، 236/0، 167/.0 و 0196/0، 0480/0، 0316/0 به دست آمد. مقایسه RMSEPدر دو مدل نشان می دهد که مدل حاصل از PARAFAC قادر به پیش گویی بهتری نسبت به PLS است. Manuscript profile

An analytical methodology based on spectrophotometric and partial least squares (PLS) algorithm for thesimultaneous determination of ampicillin and penicillin in human plasma was developed and validated. Themultivariate model was developed as a binary calibration model and it was built and validated with anindependent set of synthesis and real samples in presence of matrix. It is shown how a developed techniquefor signal filtering, orthogonal signal correction (OSC), can be applied in multivariate calibration to enhancepredictive power. The experimental calibration matrix was constructed with 25 samples. The concentrationranges considered were 1.0-40.0 and 0.5-20.0 μg mL-1 for ampicillin and penicillin, respectively. Thisprocedure allows the simultaneous determination of ampicillin and penicillin in synthetic and human plasmagood reliability of the determination was proved. The results obtained by the OSC-PLS and HPLC werestatistically compared. Very similar values were found by two methods. No time consuming pretreatmentwas needed and this method also provides rapid, accurate and economical analysis of these drugs. Manuscript profile

A novel optical sensor has been proposed for sensitive determination of bismuth ion basedon immobilization of 4-(4-nitrophenylazo)-1-naphthol on a triacetylcellulose membrane.Chemical binding of bismuth ions in solution with a 4-(4-nitrophenylazo)-1-naphtholimmobilized on the triacetylcelluse surface could be monitored spectrophotometrically. Theoptode shows excellent response over wide concentration range 0.4-3.6 μg mL-1 bismuth with alimit of detection of 0.14 μg mL-1 bismuth. The influence of factors responsible for the improvedsensitivity of the sensor were studied and identified. The response time of the optode was 30 secfor a stirrer solution. The influence of potential interfering ions on the determination of 0.4 μgmL-1 bismuth was studied. The proposed optode was applied to the determination of bismuth inpharmaceutical formulation samples. Manuscript profile

A cloud point extraction process using the nonionic surfactant Triton X-114 to extracturanium from aqueous solutions was investigated. The method is based on the complexationreaction of uranium with Arsenazo III and micelle-mediated extraction of the complex. Theoptimal extraction and reaction conditions (e.g., pH, reagent concentration, effect of time) werestudied, and the analytical characteristics of the method (e.g., limit of detection, linear range)were obtained. Linearity was obeyed in the range of 1.0-150.0 ng mL-1 of U(IV) ion. Thedetection limit of the method was 0.3 ng mL-1 of uranium ion. The interference effect of someanions and cations was also tested. The method was applied to the determination of uranium inwater samples. Manuscript profile

A new simple and rapid dispersive liquid-liquid microextraction has been applied to preconcentrate tracelevels of zinc as a prior step to its determination by spectrophotometric method. In the proposed method, 4-(2-pyridylazo) resorcinol (PAR) is used as a chelating agent, and chloroform and ethanol are selected asextraction and dispersive solvent. The optimization strategy is carried out by using two level full factorialdesigns. Results of the two level full factorial design (24) based on an analysis of variance demonstrated thatthe pH, concentration of PAR, amount of dispersive and extraction solvents are statistically significant.Optimal condition for three variables: pH, concentration of PAR, amount of dispersive and extractionsolvents are obtained by using Box-Behnken design. Under the optimum conditions, the calibration graphsare linear in the range of 30-220 ng mL-1 with detection limit of 11.2 ng mL-1 (3δB/m) and the enrichmentfactor of this method for zinc reached at 130. The relative standard deviation (RSD) is 1.4% (n=7) at 50 ngmL-1 level. The method is successfully applied to the determination of trace amount of zinc in water andhuman blood samples. Manuscript profile