The chemiluminescent determination of Sulfamethoxazol is proposed by using the photo-degradation of the drug in a continuous-flow Multicommutation assembly. The light emission is the product of the drug oxidation with potassium permanganate in polyphosphoric acidic medium after irradiation (stopped-flow, 5 s) on the sample solution in alkaline medium. The method is completely automated with the aid of the emergent Multicommutation methodology, a continuous-flow modality. The new procedure allows the Sulfamethoxazol determination over the range 0,01 –250 mg l^-1 with a dynamic linear range from 0,01 to 100 mg l^-1; and it is applied to different types of samples. The maximum sample throughput was calculated from the avarage of base-peak wide; obtained result was 40 h^-1.

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A continuous-flow system for the separation of lead(II) (Pb^II) from zinc(II) (Zn^II) was developed. The system consists of two extraction coils—one for forward-extraction and the other for back-extraction—connected in series through a phase separator. Firstly, in the forward-extraction process, most Pb^II and a small amount of Zn^II are extracted into chloroform phase with dithizone (H₂dz). Subsequently, in the back-extraction process, Pb^II is back-extracted into the aqueous phase with nitric acid while the Zn^II is retained in the organic phase. The experimental conditions were optimized based on the kinetic constants of Zn^II and Pb^II in forward- and back-extraction. The optimal flow system can quantitatively separate Pb^II from Zn^II by a single injection of a sample solution. This method is also applicable to a sample solution containing a much higher concentration of Zn^II (4.89 × 10^-3 mol dm^-3) than that of Pb^II (5.14 × 10^-6 mol dm^-3).

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In the present work a reliable and highly sensitivity method for selenium speciation, based on sorbent pre-concentration using a mini column of anionic exchanger (LC-SAX) coupled in line to Graphite Furnace Atomic Absorption Spectrometry (GFAAS) is described. Chemometric approaches for those factors that exert influence on pre-concentration has been employed using a full 2³ factorial design. Under acid medium (pH 2) only Se(VI) was determined while in the pH range of 6 up to 8, both Se(IV) and Se(VI) can be determined. Unlike from some previously published methods for selenium speciation, in which Se(VI) is determined by subtracting Se (IV) from total selenium, in the present work a system with three equations was proposed and this system was based on the principle of additivity of absorbances. The limit of detection and quantification for Se(IV) were 3.1 x 10^-2 μg L^-1 and 1.0 x 10^-1 μg L^-1 , respectively and for Se(VI) were 4.9 x 10^-2 μg L^-1 and 1.6 x 10^-1 μg L^-1, respectively.

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A simple and sensitive spectrophotometric flow injection analysis system has been developed for the determination of trace amounts of nitrite. The method is based on the reaction of nitrite with sulfanilamide in acidic medium to form a diazonium salt which then couples with thenoyltrifluoroacetone in alkaline medium to give an azo dye. Beer’s law is obeyed at 470 nm over a nitrite concentration range of 1-1200 μg L^-1, and a detection limit for nitrite is 0.3 μg L^-1 is achieved with a relative standard deviation of 1.4% at 50 μg L^-1 (n=8). An injection rate of about 40 h^-1 is possible using this method, which was successfully applied to the determination of nitrite in rain water, tap water, pond water, and river water samples.

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Trace amounts of aluminum in water samples were determined by fluorophotometric flow injection analysis. Less harmful 8-quinolinol and Triton X-100 were used as a fluorophotometric derivatizing reagent for Al³⁺ and a micelle sensitizer, respectively. Even with the traditional and conventional reagents, a linear calibration graph was obtained for Al³⁺ at the concentration range of 10^-7 mol/l level with a limit of detection at 2.8x10^-9 mol/l. The sample throughput was 60 h^-1. The proposed method was applied to the analysis of a standard reference substance, and the analytical result agreed well with the certified value. The proposed system was also applied to the speciation analysis of tap water and river water samples; aluminum species of free Al³⁺, hydrolyzed Al species, and Al in suspended particles were fairly evaluated. The recovery test of Al³⁺ to the water samples was in the ranges of 92–106%.

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An automated method for the photometric determination of phenol in air has been developed. This method includes liquid-absorption isolation of phenol from a gas phase. The isolation proceeds directly in a reaction vessel by a hydraulic scheme of a stepwise injection analyzer with subsequent generation of an analytical form reacted with 4-aminoantipyrine. The determination concentration range is from 10 to 200 μg m^-3 at the sample volume of 4.8 L and time of concentration of phenol is 6 min. Time for analysis is 10 min.

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