A Gold Electrode QCM Study on the Self-Assembling Process of Thioglycollic Acid in Aqueous Solution

In this letter, the self-assembling process of thioglycollic acid on gold in aqueous solutions was studied by QCM technique. Frequency information suggests bilayer or multilayer adsorbate formation in 0.5 mol/L HCl solution but only monolayer one in 0.5 mol/L KOH solution. This phenomenon is explained by hydrogen bond effect.

Electro-generation of TGA by Ni-mSA-mCS bipolar membrane

Ni-mSA-mCS bipolar membrane （BM） was prepared by sodium alginate （SA） and chitosan （CS）, which were modified by Ca^2＋ and glutaraldehyde as linking reagents, respectively, mSA-mCS membrane was characterized by FTIR, SEM, TG and used as a separator in the electrolysis cell to produce thioglycolic acid （TGA）. The experiment results show that TGAwas prepared effectively by electro-reduction of dithiodiglycolic acid （DTDGA） with the mixture of TGA and DTDGA in the cathodic chamber. The current efficiency was up to 66.7% at the room temperature （25 ℃） during the current density of 10 mA/cm^2. Compared with the traditional metal reduction method, the electro-reduction technology saves the zinc powder and eliminates the pollution to environment.

Synthesis of Water-Dispersed Thioglycolic Acid-Capped ZnSe Quantum Dots in Aqueous Media

Water-dispersible ZnSe quantum dots （ZnSe QDs） were prepared in aqueous media and characterized by ultraviolet-visible absorption, fluorescence emission spectroscopy, X-ray powder diffraction, transmission electron microscopy, energydispersive spectroscopy, and inductively coupled plasma atomic emission spectroscopy. The influences of various experimental variables on the photoluminescence properties of ZnSe QDs were investigated. The results showed that the average diameter of these nanocrystals was 4 nm with narrow size distribution. The optimized conditions were as follows： pH value of 9.5, Zn/NaHSe molar ratio of 10：1, Zn/TGA molar ratio of 1：3, heating time of 1 h, and irradiation time of 19 h. Under optimized conditions, the photoluminescence quantum yield of ZnSe QDs in aqueous solution reached 20%.

Boric Acid-Based Dual Modulation Photoluminescent Glucose Sensor Using Thioglycolic Acid-Capped CdTe Quantum Dots

Most luminescent glucose sensors based on the interaction of glucose with organic boric acids or borates.Herein,a new luminescent glucose sensor is designed using thioglycolic acid-capped CdTe quantum dots in the presence of cheap inorganic boric acid.Both peak position and intensities change upon the addition of glucose because of the interaction of boric acid with glucose and thioglycolic acid-capped CdTe quantum dots,which enables glucose detection by either color change or intensity change.The luminescent intensities change linearly with glucose concentrations in the ranges from 0.03 to 1 mM and 1–25 mM with a detection limit of 10μM(S/N=3).Moreover,glucose concentrations can be conveniently detected by color change in the range from 1 mM–25 mM.It displays a highly selective response to glucose over other interfering but biologically important saccharides,amino acids,and common ions.Graphical Abstract A thioglycolic acid-capped CdTe QD-based sensor can detect glucose with wide linear range by change in intensity or color in the presence of cheap inorganic boric acid.

Supercritical fluid extraction and gas chromatography analysis of arsenic species from solid matrices

A method in combination with derivatization-supercritical fluid extraction（SFE） and gas chromatography（GC） for the speciation and quantitative determination of dimethylarsinate（DMA）, monomethylarsonate（MMA） and inorganic arsenic in solid matrices was investigated. Thioglycolic acid methyl ester（TGM） and thioglycolic acid ethyl ester（TGE） were evaluated as derivatization reagents. The effects of pressure, temperature, flow rate of supercritical CO_2, extraction time, modifier and microemulsion on the efficiency of extraction were systematically investigated. The procedure was applied to the analysis of real soil and sediment samples. Results showed that TGE was more effective for arsenic speciation as a derivatization reagent. Modifying supercritical CO_2 with methanol can greatly improve the extraction efficiency. Further, the addition of microemulsion containing surfactant Triton X-100 can further enhance recoveries of arsenic species. The optimum extraction conditions were 100 ℃, 30 MPa, 10 min static and 25 min dynamic extraction with 5%（v/v） methanol, and surfactant modified supercritical CO_2. Detection limits in solid matrices were 0.15, 0.3 and 1.2 mg/kg for DMA, MMA and inorganic arsenic,respectively. The method was validated by the recovery data. The resulting method was fast, easy to perform and selective in the extraction and detection of various arsenic species in solid matrices.

Characteristics of CdTe nanocrystals synthesized by a Na_2TeO_3 source

Water-soluble cadmium telluride （CdTe） nanocrystals were synthesized in aqueous solution with thioglycolic acid （TGA） molecules as a stabilizer. A series of TGA-stabilized CdTe nanocrystals were prepared using sodium tellurite as a tellurium source, which avoids the cumbersome processes associated with H2Te or NaHTe sources. The synthesized TGA-stabilized CdTe were characterized with X-ray diffraction, TEM and fluorescence spectrophotometer. The particles crystallized predominantly in cubic phase with narrow photoluminescence emission. The effects of reaction time, pH value, and precursor concentration on the photoluminescence properties were investigated in detail.