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.

The coupling reaction of 4-aminoantipyrine (4-AAP) with phenol using the superoxide anion radical(O-*2 ) as oxidizing agent under the catalysis of horseradish peroxidase (HRP) was studied. Based on the reaction, produced by irradiating vitamin B2 (VB2) was spectrophotometrically determined at 510nm. Under the optimum experimental conditions, the relationship between A510 and O-*2 concentration was linear in the range 9.14

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.

The supramolecular interaction between N,N-diethyl-2-(1-naphthalenyloxy)propanamide (napropamide) and -cyclodextrin (-CD) has been studied by spectrofluorimetry. The results showed that -CD reacted with napropamide to form an inclusion complex with an association constant of 3.18×103mol−1. The composition of the complex was 1:1 (-CD: napropamide). Based on the significant enhancement of fluorescence intensity of napropamide in inclusion complex, a spetrofluorimetric method with high sensitivity and selectivity was developed for the determination of napropamide in aqueous solution. Under the optimum conditions, the complex had excitation and emission maxima at 285 and 339nm, respectively. The linear range of the method was 3.7-1500ngml−1 with a detection limit of 1.1ng ml−1. The proposed method was successfully used to determine napropamide in river water.

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.

A novel fluorescent reagent o-vanillin-8-aminoquinoline (OVAQ) was synthesized, and its infrared spectrum, elemental analysis and acid-base dissociation constants were obtained. The fluorescent reaction of this reagent with Cr (III) was studied. In acetonitrile-water (1:1, (v/v)) medium of pH 6.00, Cr (III) could react with fluorescent reagent OVAQ (λex/em=280/314 nm) to form a 1:1 non-fluorescent complex. The linear range of the spectrofluorimetric method proposed was from 8.2 to 130g l−1, and the detection limit was 2.5g l−1. The interferences of 25 foreign ions were also studied. This method could be easily performed and was successfully applied to the determination of Cr(III) and total chromium in domestic and industrial waste water samples.

A novel spectrofluorimetric method using vanillin-8-aminoquinoline (VAQ) as fluorescent probe was developed for the determination of superoxide anion radical (O2). The new fluorescent probe was characterized by elemental analysis and IR spectra. Under the optimum conditions of the determination, the linear calibration range and the detection limit of the developed method for superoxide anion radical were in the range (0.0-1.0)×10−5 and 2.0×10−8mol l−1, respectively. The effect of interferences was studied. The proposed method was applied to determine the generation rate of superoxide anion radical in the course of aging in red sage successfully.

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.

The supramolecular interaction of gemfibrozil and β-cyclodextrin has been studied by flow injection spectrofluorimetry. The results show that β-CD reacts with gemfibrozil to form a 1:1 complex with an apparent association constant of 7.57×102 L/mol. Based on the enhancement of the fluorescence intensity of gemfibrozil, a flow injection spectrofluorimetric method for the determination of gemfibrozil in bulk aqueous solution in the presence of β-CD was developed. The linear range was 0.032-70.00g/mL. The detection limit was 9.6ng/mL with a sampling rate of 80h−1. There was no interference from the excipients normally used in tablet formulations and the serum compositions. The proposed method was successfully applied to the determination of gemfibrozil in capsules and serum.

2-Pyridine carboxaldehyde furfuralhydrazone (PCFH) was newly synthesized and its ionization, IR and elemental analysis were established. An on-line separation and preconcentration systemwas developed for the flowinjection (FI) catalytic kinetic spectrofluorimetric determination of trace amounts of gold. The methodwas based on the fluorescence enhancing reaction of PCFH with potassium bromate, whichwas catalysed by Au3+ in aqueous medium at pH 4.20 and 35℃. Amicro polyamide resin columnwas used to separate and collect gold from sample solution. Under these experimental conditions, the oxidized product of PCFH had excitation and emission maxima at 296 and 404 nm, respectively. The linear range of this method was 0.53-144ngml−1 with the RSD of 1.6%. The detection limit was 0.16ngml−1. A high analysis rate of 15 samples h−1 was obtained. The proposed method had been applied successfully to the determination of gold in synthetic mixture and mineral sample with satisfactory results.