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.

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.

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.

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.