A flow injection (FI) kinetic spectrofluorimetric method is described for the determination of osmium (IV) and the possible mechanism of catalytic reaction is discussed. The method is based on the fluorescence enhancing reaction of o-vanillin furfuralhydrazone (OVFH) with potassium bromate, which is catalyzed by Os (IV) in water medium at pH 6.10 and 45℃. OVFH is newly synthesized and its ionization, IR and elemental analysis are established. Under these experimental conditions, the oxidized product of OVFH has excitation and emission maxima at 337 and 490 nm, respectively. The linear range of this method is 0-600ng/ml−1 with the R.S.D. of 1.2%. The detection limit is 1.0ng ml−1 of Os (IV). A high analysis rate of 24 samples h−1 is obtained by the FI method. The proposed method is applied successfully to determine Os (IV) in synthetic mixture and mineral samples, and the results are well consistent with the standard values.

This paper presents an automatic spectrofluorimetric method (flow injection analysis spectrofluorimetry) for detecting hydroxyl radicals. Based on H2O2 catalyzed by Co2+yielding HO•, the method utilized sodium terephthalate to trap hydroxyl radicals and obtained sodium 2-hydroxyterephthalate by aromatic hydroxylation, which resulted in an increase in the fluorescence intensity. The relative fluorescence intensity was proportional to the concentration of hydroxyl radicals. Hydroxyl radicals could be determined indirectly, based on the increase of fluorescence. It was a simple, rapid, precise, sensitive and automatic technique for the determination of HO•. The relative standard deviation of 11 determinations was 0.57%. The method can be used to sieve antioxidant medicines and will have theoretical and practical guidance on the mechanism of hydroxyl radicals-damaging biology.

La(OH)3 nanospheres have been synthesized with La(NO3)3 and KOH as the starting materials and citric acid as a protective agent through a facile controllable hydrothermal method. The obtained products were analysed with x-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The formation mechanism of the La(OH)3 nanospheres was investigated in detail.

A novel host inclusion complex of cross-linking-polymeric-cyclodextrin-o-vanillin furfuralhydrazone ( -CDP-OVFH) was synthesized and characterized with IR and 1H NMR spectra to confirm its structure. The coordination reaction of the host reagent with Cd2+ was studied and the optimum reacting conditions were observed carefully. A highly selective and sensitive spectrofluorimetric determination of trace amount of cadmium was proposed based on the reaction of Cd2+ with -CDP-OVFH in ammonia water-ammonium acetate buffer medium of pH=11.0. The molar ratio of -CDP-OVFH to Cd2+ was 1:1. The maximum excitation and emission wavelengths were 393 and 494 nm, respectively. The linear range of this method was from 3.0 to 500gl−1 with a detection limit of 0.80gl−1. The effect of interferences in the determination of cadmium was investigated and the results showed that the host reagent had quite high capacity of identifying Cd2+. The proposed method was successfully applied to the determination of trace amount of Cd2+ in mussel and tea samples.

This paper presents an automatic spectrofluorimetric method (flow injection spectrofluorimetry) using a novel fluorescent probe named H. Py. Bzt (2-(2-pyridil)-benzothiazoline) for determining superoxide dismutase (SOD) activity. The fluorescent probe was synthesized in house and fully characterized by elemental analysis and by infrared and 1H nuclear magnetic resonance spectra. It could specially identify and trap O2 and was oxidized by O2 to form a strong fluorescence product. Based on this reaction, the flow injection spectrofluorimetric method was proposed and successfully used to determine SOD activity. The proposed method has a better selectivity in the determination of reactive oxygen species because the probe can be oxidized only by O2 excluding H2O2. As a kind of simple, rapid, precise, sensitive and automatic technique, it was applied to measurement of SOD activity in scallion, garlic, and onion with satisfactory results.