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The research is included determination of Fe(II) via its reaction with 1,10-phenanethroline to form light-red complex which is absorbed at λ max =510 nm. Home-made flow injection valve is designed with two loading loops, L1 and L2. A series of studies are conducted represented by fixing physical and chemical optimum conditions, dead volume, repeatability, dispersion coefficient, construction calibration graph, and application of the method. The dead volume is zero for the system which it has high repeatability (n=8) with RSD and SD 0.6 and 0.05 respectively. The dispersion coefficient is 1.68 at the concentration 10 ppm. The range of measurements of calibration graph is (0.05-18.00) ppm with limit of detection (S/N=3) 0.05 ppm.

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A fast, simple, and high throughput sample merging-zone flow injection design was developed to determine copper(II) in aqueous solution. The procedure is based on the reduction of copper(II) to copper(I) by uric acid followed by a direct reaction with Neocuproine reagent (NC). The orange-yellow complex that forms absorb light at 454 nm. All conditions of the new flow injection unit were investigated. The analytical curve of copper(II) was linear with (r2) value of 0.9978, in the range of 0.4 to 40 mg/L with a detection limit of 0.1 mg/L and a quantification limit of 0.3 mg/L. the molar absorptivity was 1.661 × 105 L/mol cm and the recovery range was between 104.9 and 97%. The homemade acrylic valve was low-cost with zero dead volume and high repeatability (n = 7) with an RSD of 2.31%. The dispersion coefficient values were 1.8,1.62, and 1.31 for the concentrations of 5, 15, and 25 mg/L, respectively. The sample throughput was 69 h–1.

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spectrophotometric method was applied for determination of GSH by reaction iodate and iodide at λmax=350 nm with high efficiency. The calibration curve was fabricated with linear range (1-35)ppm. The linearity (R2) value was 0.9980. The limit of detection value was 0.0002 ppm. The limit of quantification value was 0.0004 ppm. The effect of interferences on the determination of GSH was studed under optimum conditions. The interferences with 10 twice of concentration (100) ppm were added individually to the sample solution containing 10 ppm of GSH. It was noticed that the interfering components not effected on determination of GSH. Composition of complex (GSH/KIO3) was determined by mole ratio method which appear ratio about (1:1). Determination of GSH was applied on standard solutions, which gave high precision and accuracy with recovery in well worthily.

Background: A new technique was designed for determining copper in an aqueous solution. Copper was determined by a hybrid system microfluidic coupled with flow injection. The homemade microfluidic chip (MFC) is used for injecting copper and 2,9-Dimethyl-1,10-phenanthroline (2,9DMP) reagent as a merging zone technique, whereas uric acid is used as a reducing agent and carrier. Methods: A microfluidic chip was made by a Computer Numerical Control (CNC) laser machine using the AutoCAD application for the study of copper by the hybrid system. The chip contains two microchannels with a volume of 60 μL for copper(II) and 2,9DMP reagent. As a carrier solution and reducing agent, 40 mg/L of uric acid was pumped at a flow rate of 5.2 mL/min. Conditions of the coupled technique and analyses were measured at 454 nm. Results: This system's approach has a linear range, a detection limit (S/N=3), and a quantitation limit (S/N=10) at 0.1-25 mg/L (r2 0.9979), 0.03 and 0.09 mg/L, respectively. Also, repeatability of analyses (n=7) with an average RSD of 0.97 % for concentrations of 5, 10, and 20 mg/L. The dispersion coefficients were 1.977, 1.789, and 1.555 for the three concentrations 5,10, and 20 mg/L, respectively. The recovery of copper in the aqueous solution was estimated to be 103.5%. Dead volume and throughput were zero and 62 per hour, respectively. Sandell’s sensitivity and molar absorptivity were 2.467×10-3 µg/cm2 and 1.947×105 L/mol cm, respectively. Conclusion: The analysis in the novel hybrid microfluidic-flow injection system is efficient, simple, and fast, and it can be used to determine the concentration of copper in an aqueous solution. The homemade microfluidic chip is a low-cost component that uses only an small volume of copper and reagent during analysis.