[Determination of 1-methoxy-2-propanol in urine by headspace solid-phase microextraction coupled with gas chromatography].

Objective: To establish a method for the determination of 1-methoxy-2-propanol in urine using headspace solid phase micro-extraction coupled with gas chromatography. Methods: The 1-methoxy-2-propanol was enriched by headspace solid phase micro-extraction fiber coated with carbene/polydimethylsiloxane (CAR/PDMS) . Single factor rotation method was used to optimize the conditions of extraction temperature, salt amount, and extraction time. The separation was performed on DB-5 (30 m×0.32 mm×0.25 µm) capillary column and detected with flame ionization detector. The quantification was based on the standard curve. Results: The concentration of 1-methoxy-2-propanol in urine was linear in the range of 0.50-10.0 mg/L, and the linear correlation coefficient was 0.9993. The detection limit of the method was 0.14 mg/L, and the limit of quantification was 0.45 mg/L. The recovery was 85.8% to 104.7%, and the RSD of intra- and inter-batch precision were 3.25%-6.65% and 0.81%-3.96%, respectively. Conclusion: The method is high sensitivity and simple operation, and is suitable for the determination of 1-methoxy-2-propanol in urine of occupational exposure population.

[Determination of metabolites of styrene in urine by dispersive liquid-liquid microextraction coupled with high performance liquid chromatography].

Objective: To establish a method for the determination of mandelic acid and phenylglyoxylic acid in the urine of styrene by dispersive liquid-liquid microextraction-high coupled with high performance liquid chromatography. Methods: N-octanol was used as an extractant and ethanol was used as a dispersing agent. The phenylglycolic acid and phenylglyoxylic acid in the urine were extracted, and the upper liquid was taken after vortexing and centrifuged, and then was injected into HPLC for analysis. Results: The linear correlation coefficient of the concentration of phenylglycolic acid in the range of 0~10.0 mg/L was greater than 0.999. The detection limit of the method was 9.9 µg/L, the recovery rates were 86.1%~101.6%. The intraday RSDs of the method were 1.07%~3.76%, and the interday RSDs were 1.24%~3.33%. The linear correlation coefficient of phenylglyoxylic acid in the range of 0.0~2.0 mg/L is greater than 0.999. The detection limit of the method was 2.6 µg/L, the recovery rates were 88.8%~100.3%. The intraday RSDs of the method were 1.02%~ 3.17%, and the interday RSDs were 1.59%~2.41%. Conclusion: The method has low detection limit, high enrichment ratio and good sensitivity, and is suitable for determination of phenylglycolic acid and phenylglyoxylic acid in urine of occupational exposure to styrene.

[Outcome of kidney transplantation with graft from intracerebral hemorrhage donors].

Objective: To analyze the data of kidney transplantation with allografts from intracerebral hemorrhage donors of China donation after citizen's death (CDCD) and provide evidence to guide the clinical practice. Methods: The clinical data of CDCD donors (age ≥10 years)and corresponding kidney allograft recipients, which were done by Second Xiangya Hospital of Central South University during January 1 2013 to December 31 2017, were analyzed retrospectively. Results: 327 CDCD cases were analyzed, the number and percentage of intracerebral hemorrhage donors were gradually increasing and the percentage reached to 39.5% in 2017. The discarding rateof kidney allografts donated by intracerebral hemorrhage donors was higher than those donated by non-intracerebral hemorrhage donors, but intracerebral hemorrhage donor may not be a risk factor for DGF after the rigorous evaluation of kidney allografts. For 145 primary recipients transplanted in 2016 and had a 22±4 month follow-up, the recipients accepted the kidney from intracerebral hemorrhage donors had a higher level of serum creatinine[(130±60)µmol/L vs (111±38) µmol/L,P<0.05]and a lower eGFR[(61±23) ml·min(-1)·(1.73m(2))(-1) vs (70±23) ml·min(-1)·(1.73m(2))(-1),P<0.05] compared to the recipients accepted the kidney from non-intracerebral hemorrhage donors. Conclusion: The number and percentage of organ donation from intracerebral hemorrhage donor is increasing, but the intracerebral hemorrhage donor may be a risk factor for long-term outcome of kidney transplantation.

Synthesis and molecular characterization of acrylate liquid crystalline resin monomers (ALCRM).

A novel biocompatible resin monomer 4—3—(acryloyloxy)—2—hydroxypropoxy) phenyl 4—(3—(acryloyloxy)—2—hydroxypropoxy) benzoate, as an oral restorative — acrylate liquid crystalline resin monomer (ALCRM) was synthesized. The intermediate product and the final product were characterized by differential scanning calorimetry (DSC), polarized optical microscope (POM), and nuclear magnetic resonance (NMR). A resin matrix which has a potential application in dental composites was prepared by photopolymerizing ALCRM and triethylene glycol dimethacrylate (TEGDMA) as a primary and diluted monomer with a photosensitizer of camphorquinone (CQ) and 2—(Dimethylamino)ethyl methacrylate (DMAEMA) mixture. The molar ratio of ALCRM and TEGDMA was 7:3. The properties such as the curing depth, curing time, and the volumetric shrinkage of the resin matrix were investigated and compared with a traditional composite resin matrix Bis—GMA. After photocuring polymerization, the conversion degree of the resin matrix is 68.06%, higher than Bis—GMA/TEGDMA; the curing time is 4.08±0.20min, the curing depth is 2.10±0.17mm, and the volumetric shrinkage is 3.62%±0.26%. All the properties exhibit a better performance of the prepared resin matrix than Bis—GMA.