Yuanna Zhu

Catalytic dynamic spectrofluorimetry determination of trace antimony using new type arsenoxylphenylazo rhodanine

A precise, simple, new spectrofluorimetry method is proposed for determination of trace antimony which is based on the reaction between potassium periodate and the new type fluorescent reagent 3-o-chlorophenyl-5-(2- arsenoxylphenylazo) rhodanine (2ClRAAP). The possible mechanism is proposed. The fluorescence intensity is investigated to be sharply enhanced by the oxidation of 3-o-chlorophenyl-5-(2-arsenoxylphenylazo) rhodanine by potassium periodate with antimony as catalyst in the buffer medium of potassium hydrogen phthalate-sodium hydroxide (pH 5.2). Under the optimum conditions the great increase of fluorescence intensity has a linear relationship against the concentration of antimony in the range of 0.2-10 microg L(-1) with a detection limit of 1.65 x 10(-10) g mL(-1). This proposed method led to the satisfied determination of antimony in environment water.

Analysis of the interaction of a new series of rhodanine derivatives with bovine serum albumin by fluorescence quenching

The interaction between a series of rhodanine derivatives with different substituent groups and bovine serum albumin (BSA) was studied using fluorescence quenching spectra, which showed that the type of quenching of BSA by rhodanine derivatives was static in each case. Binding constants, binding site numbers, action distances, and energy transfer efficiencies between donor (BSA) and acceptors (rhodanine derivatives) were calculated and showed that introduction of –NO2 (electron-withdrawing group) is more favorable for rhodanine–BSA interaction than that of –CH3 and –OCH3 (electron-donating groups). Finally, strength of interaction between rhodanine derivatives and BSA was simulated theoretically using quantum chemistry and showed that introduction of groups with small steric hindrance is beneficial to promote the interaction. These investigations are very important to simulate the interaction of small molecules with biomacromolecules and to synthesize drug molecules that interact with protein easily.Graphical abstract

Determination of thallium(III) with novel arsenoxylphenylazo rhodanine after pre-concentration and separation

A new catalytic kinetic fluorescent method for determination of trace thallium(III) was investigated. The method was based on the catalytic effect of thallium on oxidation of 3-p-chlorophenyl-5-(2′-arsenoxylphenylazo) rhodanine (4ClRAAP) by hydrogen peroxide in potassium hydrogen phthalate-hydrochloric acid (pHu2009=u20095.2). Under the optimum conditions the great increase of fluorescence intensity had a linear relationship against the concentration of thallium in the range of 0.43 to 10.0u2009µgu2009L−1 with a detection limit of 2.6u2009×u200910−10u2009gu2009L−1. The coexistent metal ions can be separated, and thallium can be enriched by polyamide, which greatly improved the selectivity and sensitivity of the system. The method was applied to determine trace amount of thallium in wine, water and mineral samples, with satisfactory results.

Determination of BSA by Its Enhancement Effect on Second Order Scattering of Chrome Azurol S

Second order scattering (SOS) used to be regarded as a kind of interfere of spectrofluorometry. The characteristic and principle of SOS have not been studied deeply. In this paper SOS was found to be a new method to determine trace substance with good potential of analysis. The reaction between Chrome Azurol S (CAS) and bovine serum albumin (BSA) was investigated by the method of second order scattering. It was found the SOS intensity of CAS and that of BSA is weak respectively in the BR (Britton-Robinson) buffer solution at PH 4.10 with the presence of SDS micelle, but sharply enhanced when the two compounded, based on which a new method for determination of BSA was established, which has high sensitivity and calls for simple operation. The concentration of BSA is linear with CAS in the range of 1.0~2.0 mugldrmL-1. The new method was applied to determination of BSA in real samples with satisfactory results.

Determination of Tetracycline Residue in Food by a Simple Resonance Rayleigh Scattering Method

A novel method for the determination of TC using resonance rayleigh scattering (RRS) technique was established. The resonance rayleigh scattering (RRS) spectra of 3-(4-nitrophenyl)-5-(2-sulfonicphenylazo) rhodanine (4NRASP) with tetracycline (TC) was studied. Experimental result showed that when lambda ex = lambda em = 394 nm, the RRS peak of 4NRASP was greatly enhanced with the increase of TC concentration at a pH of 5.5 Britton-Robinson(B-R) buffer solution and the medium of SDS micro-emulsion. The linear range of the calibration curve for TC was 0.05~3.30 mug-mL -1 . The detection limit was 2.95 times 10 -10 g-mL -1 . The method has been applied to the determination of the trace amount of TC in food samples with satisfactory results. The reaction mechanism was discussed in this work.

Catalytic Dynamic Spectrofluorimetry Determination of Trace Tin Using New Type Arsenoxylphenylazo Rhodanine

A new catalytic dynamic spectrofluorimetry method is proposed for determination of trace tin which is based on the reaction between potassium periodate and the new type fluorescent reagent 3-m- chlorophenyl-5-(2- arsenoxylphenylazo) rhodanine (3CIRAAP). The fluorescence intensity is investigated to be sharply quenched by the oxidation of 3-m-chlorophenyl-5- (2-arsenoxylphenylazo) rhodanine by potassium periodate with tin as catalyst in the buffer medium of potassium hydrogen phthalate-sodium hydroxide(pH = 5.2). Under the optimum conditions the great quenchment of fluorescence intensity has a linear relationship against the concentration of tin in the range of 0.02 to 10 mug ldr L -1 with a detection limit of 2.25 times 10 -10 gldrmL -1 . This proposed method led to the satisfied determination of tin in real samples.