Insight into the effect of surfactant modification on the versatile adsorption of titanate-based materials for cationic and anionic contaminants.

The new challenges to adsorption are imposed for the diversity of contaminants in wastewater in recent years. Herein, titanate-based materials (peroxide sodium titanate, PST) were modified by three different kinds of surface charged surfactant: dodecyl dimethyl betaine (BS-PST), sodium dodecyl sulphate (SDS-PST) and dodecyltrimethyl ammonium chloride (DTAC-PST) to enhance the versatile adsorption performance for four typical contaminants including ammonia nitrogen (NH4+, inorganic and cationic), phosphate (H2PO4-, inorganic and anionic), methylene blue (MB, organic and cationic) and Acid Red G (ARG, organic and anionic). The batch adsorption experiments showed that the DTAC-PST exhibited better in the removal of MB, ARG and H2PO4- than that of other adsorbents. The theoretical maximum adsorption capacity of DTAC-PST is 49.28 mg g-1 for NH4+, 34.74 mg g-1 for TP, 81.87 mg g-1 for MB and 545.81 mg g-1 for ARG. The simultaneous adsorption results showed that the concentration (10 mg L-1 of NH4+, 3 mg L-1 of TP, 50 mg L-1 of MB and 50 mg L-1 of ARG) of all the four chemicals in simulated wastewater could be controlled to be below the discharge levels in China (GB, 18918-2002) by DTAC-PST at the pH of 3.0. The FT-IR spectra demonstrated that ion exchange was the main way for NH4+ removal, however, electrostatic attraction and ligand exchange were the reason for MB adsorption. In addition, C-N+ from DTAC modification made main contribution to the excellent adsorption performance for ARG and H2PO4-. The saturated DTAC-PST could be conveniently regenerated by 0.5 mol L-1 NaOH solution and maintained about 80% of adsorption capacity after five cycles.

The stimulatory activities of polysaccharide compounds derived from algae extracts on insulin secretion in vitro.

We prepared two series of polysaccharide compounds derived from algae extracts and investigated their stimulatory activity on insulin secretion in vitro using the rat pancreatic cell line, RIN-5F. Several of the compounds exhibited significant stimulatory activity in a dose-dependent manner without apparent cytotoxicity at concentrations above 10 microM. Glybenclamide, a commonly prescribed sulfonylurea (SU) against diabetes mellitus type II, was used as a positive control and showed moderate cytotoxicity in the cell culture assay system. Amylin (IAPP; islet amyloid polypeptide), an inhibitor for glybenclamide, did not inhibit the activity of the isolated compounds, suggesting that they act through a mechanism(s) different from glybenclamide. Algae-derived extracts could be candidates for a new class of anti-diabetic drugs.

Study of the determination and pharmacokinetics of Compound Danshen Dripping Pills in human serum by column switching liquid chromatography electrospray ion trap mass spectrometry.

Compound Danshen Dripping Pill (CDDP) is an important drug widely used for the treatment of cardiovascular diseases. An active component Danshensu (DS) of CDDP was separated by reversed-phase high performance liquid chromatography using column-switching system and analyzed by electrospray mass spectrometry. With this validated assay the pharmacokinetics of CDDP was studied in 10 healthy volunteers after a single oral administration of 250 mg. After trichloroacetic acid precipitation of serum proteins, the analytes were preconcentrated and black-flushed on a reversed-phase column for separation using a switching valve. The analytes were ionized using negative electrospray ionization (ESI) mode. The precursor ion of m/z 196.6 was used to quantify DS in serum. The linear calibration curve ranged from 1.25 to 175 microg/mL. The limit of quantification (LOQ) for DS was 0.15 microg/mL. The intra-day and inter-day precision (R.S.D.) was less than 7.4 and 7.9%, respectively.