Lysosome-Targeted Turn-On Fluorescent Probe for Endogenous Formaldehyde in Living Cells.

As one of the simplest reactive carbonyl species, formaldehyde is implicated in nervous system diseases and cancer. Organelles play crucial roles in various physiological processes in living cells. Accordingly, the detection of endogenous formaldehyde at the subcellular level is of high interest. We herein describe the development of the first organelle-targeted fluorescent formaldehyde probe (Na-FA-Lyso). The new probe exhibits favorable features including a large fluorescence enhancement (about 350-fold) and a fast response to formaldehyde. Significantly, the novel probe Na-FA-Lyso was employed to visualize the endogenous formaldehyde in the lysosomes in living cells for the first time.

Hydrolysis and photolysis of diacylhydrazines-type insect growth regulator JS-118 in aqueous solutions under abiotic conditions.

JS-118 is a diacylhydrazines-type insect growth regulator which is now used extensively in China. The hydrolysis and photolysis of the pesticide JS-118 in aqueous solutions have been assessed under natural and controlled conditions in this project. Hydrolysis experimental results show that JS-118 is quite stable in aqueous solutions in dark, with no significant variations be observed in degradation under various conditions. Abiotic hydrolysis is relatively unimportant compared to photolysis. The rate of photodecomposition of JS-118 in aqueous solutions follows first-order kinetics both in UV radiation and natural sunlight. The degradation rates are faster under UV light than sunlight, with the half-lives (t (1/2) = ln2/k) of 6.00-10.85 min and 6.63-10.16 day, respectively. Under UV light, two major photoproducts are detected, and tentatively identified according to HPLC-MS spectral information as N-t-butyl-N-(3,5-dimethylbenzoyl) and 3,7-dimethyl-benzoatedihydrofuran. The corresponding photolysis pathways of JS-118 are also proposed. The results obtained indicate that direct photoreaction is an important dissipation pathway of JS-118 in natural water systems.

Controlled microwave derivatization reaction for reproducible trace analysis of budesonide in human plasma.

Microwave reactors with on-line controlled reaction conditions have been recently innovated to improve reaction kinetics and reproducibility. Herein, a modern microwave reactor was dedicated to develop a new, sensitive and reproducible approach for trace analysis of budesonide (BUD) in human plasma. The method was based on fast microwave reaction of BUD with dansyl hydrazine (DNS-HZ) reagent under controlled conditions coupled with high-performance liquid chromatography (HPLC)-fluorescence detection. The microwave irradiation and dansylation conditions were optimized for the best sensitivity and selectivity. The controlled microwave derivatization reaction (CMDR) decreased the reaction time, amplified the reaction yield and enhanced product purities by reducing the unwanted side reactions. The chromatographic separation was attained by isocratic elution on reversed phase column via a mobile phase consisted of methanol and phosphate buffer (10 mM, pH 7.0) at ratio 80:20 (v/v). The fluorescence detector was set at 500 nm after excitation at 330 nm. Betamethasone dipropionate (BDP) was used as an internal standard. CMDR-HPLC method validation was performed in agreement with bioanalytical method validation guidelines by the US food and drug administration (US-FDA). The obtained linearity range was 0.2-100 ng mL-1 with correlation coefficient 0.9991 and the lower limit of quantitation (LLOQ) in human plasma was 0.21 ng mL-1. The developed CMDR -HPLC method was applied successfully for assessment of plasma levels of BUD in allergic rhinitis patients after intranasal administration of the micronized BUD.

Effect of coal ash on hydrazine degradation under stirring and ultrasonic irradiation conditions.

The degradation of hydrazine (N(2)H(4)) with concentrations of 0.1-5.0 mmol/L was investigated as a function of amount of coal ash (0.0-5.0 wt%) under the stirring (300 rpm) and ultrasonic irradiation (200 kHz, 200 W) conditions. It was found that the rate of decrease in the hydrazine concentration depended upon an amount of coal ash under the stirring and ultrasonic irradiation condition. It was considered under the stirring condition that hydrazine was adsorbed and degraded partly on coal ash. Furthermore, the sonochemically formed OH radicals were more effective in the hydrazine degradation than stirring condition in the presence of an intermediate amount of coal ash (0.6-2.4 wt%), whereas the effect of OH radicals disappeared in the presence of coal ash more than 2.4 wt%.

Photooxidation mechanism of nitrogen-containing compounds at TiO2/H2O interfaces: an experimental and theoretical examination of hydrazine derivatives.

The photocatalytic oxidation of oxalyldihydrazide, N,N'-bis(hydrazocarbonyl)hydrazide, N,N'-bis(ethoxycarbonyl)hydrazide, malonyldihydrazide, N-malonyl-bis[(N'-ethoxycarbonyl)hydrazide] was examined in aqueous TiO2 dispersions under UV illumination. The photomineralization of nitrogen and carbon atoms in the substrates into N2 gas, NH4+ (and/or NO3-) ions, and CO2 gas was determined by HPLC and GC analysis. The formation of carboxylic acid intermediates also occurred in the photooxidation process. The photocatalytic mechanism is discussed on the basis of the experimental results, and with molecular orbital (MO) simulation of frontier electron density and point charge. Substrate carbonyl groups readily adsorb on the TiO2 surface, and the bonds between carbonyl group carbon atoms and adjacent hydrazo group nitrogen atoms are cleaved predominantly in the initial photooxidation process. The hydrazo groups were photoconverted mainly into N2 gas (in mineralization yields above 70%) and partially to NH4 ions (below 10%). The formation of NO3- ions was scarcely recognized.