In this study, reversed flow injection analysis (rFIA) spectrophotometric method was used for determination of Tenoxicam (TNX) in pure and pharmaceutical forms. This method was based on the charge transfer interaction of TNX with 0.005 M of Metol reagent (MFS) in the presence of 0.02 M of potassium persulfate as oxidant agent. Color product was formed give absorbance measured at λmax=530 nm with ratio 2:1. All optimum physical and chemical conditions were studied. Linearity of TNX was observed at the range of 2-140 µg.mL-1 and the detection limit was 1.393. However, quantitation limit was 4.643 µg.mL-1. The method offered correlation coefficient, (r:0.9997) in rFIA applied for TNX pharmaceutical tablets give good values, by the comparison between rFIA results and UV results, using the standard addition method taken 20 µg/ml amount for one concentration of Tenoxicam give accurate quantitation of drug, the rFIA, the best analysis and the suggested method could be utilized for pharmaceutical analysis.

Hyoscine butyl bromide (HBB), also known as scopolamine butyl bromide, is an anticholinergic medication used to treat bladder spasms, renal colic, esophageal spasms, and crampy abdominal pain. A fast and simple spectrophotometric approach is developed for the determination of hyoscine butyl bromide in pure and pharmaceutical formulations using batch and flow injection methods. The proposed approach is based on the reduction of ferrate ion to ferrous ion by HBB and the subsequent formation of excess Fe(III)-thiocyanate complex which gave maximum absorbance at 478 nm. The experimental conditions of both methods for the assay were studied and optimized. The absorbance was found to decrease linearly with the drug concentration to give a calibration curve which obeys Beer’s law in the range of 0.5-200, and 5.0-200 μg/mL with a linear regression coefficient of 0.9964, and 0.9909 with detection limits of 1.40, and 2.10 µg/mL for both batch and rFIA methods, respectively. The proposed approaches were successively applied for the determination of the studied drugs in their different pharmaceutical dosage forms and gave an excellent per cent of recovery compared with the official international pharmacopoeia method.

The detection of Hesperidin (HSP) and Naringenin (NAR) in dietary supplements and human urine samples is recommended using a reversed flow-injection analysis (rFIA) technology that is quick, accurate, and highly responsive. Using 3-methyl-2-benzothiazolinone Hydrazone Hydrochloride (MBTH) in the presence of sodium periodate as an oxidizing agent, the suggested approach uses oxidative coupling procedures. With a peak absorbance for HSP at 507 nm and for NAR at 495 nm, a red complex is the resultant product. An extensive analysis of the physical and chemical elements influencing the reaction has been conducted. Between 2 and 150 µg/mL, the calibration curve showed a steady and proportionate relationship. It was found that the detection limits for NAR and HSP were 0.911 µg/mL and 0.856 µg/mL, respectively. For HSP and NAR, the relative standard deviation (RSD) was found to be 0.79% and 0.64%, respectively. Drug quantitation was effectively accomplished using the recommended methods.

In recent decades, reverse flow analysis in mixed convection flow has attracted the attention of many researchers owing to its applications in the design of medical and engineering systems. The presence of reverse flow is unfavorable in many respects; therefore, it is crucial to find values of critical parameters affecting the reverse flow to eliminate it. In this paper, the thermal and hydrodynamic behavior of MWCNT-Fe3O4 hybrid nanofluid is explored in a vertical cylindrical annulus and in the adjacency of radial magnetic field by achieving the results of the exact solution. Furthermore, the effective factors on the reverse flow are investigated, considering the effects of wall movement and suction/injection on it. The range of changes of the governing parameters includes constant velocity of cylinders’ walls A=0−10, B=0−10, Mixed convection parameter η=-1500−1500, dimensionless temperature difference ratio ξ=0−1, Hartman number Ha=0−50, Suction/injection S=-6−6, nanocomposite particles concentration φ=0−0.3% and radios ratio λ=2−10. The results reveal that hybrid nanofluid enhances the heat transfer rate. Moreover, by changing the above-mentioned parameters and selecting the appropriate values for them, the flow, heat transfer and occurrence of reverse flow can be optimally controlled. Meanwhile, such parameters as Ha, S and ξ perform better in eliminating reverse flow.

New Page 1 A chemiluminescence system is described for the determination of nitrite ion based on new designs for an ozone generator, liquid-gas separator and chemiluminescence reaction cell. The method is based on the gas-phase chemiluminescence reaction between ozone and nitric oxide, which is generated from the reduction of nitrite with iodide in sulfuric acid solution. The efficiency of the system was evaluated by investigation of the analytical performance characteristics of the system for nitrite determination in batch and flow injection procedures. Under optimal conditions, the chemiluminescence response of the system was linear against the nitrite concentration over the range 1 to 1 ´ 104 ng ml-1 in the batch procedure and 10 to 5 ´ 103 ng ml-1 in the flow injection procedure, with detection limits of 1 and 10 ng ml-1, respectively. The method is highly selective and allows for the determination of nitrite in the presence of high concentrations of several cationic, anionic and nitrogen containing species. It has been successfully applied to the analysis of nitrite in natural water and soil extracts.