ABSTRACT
Objective@#To determine human tear proteins using nanoliter liquid chromatography coupled to quadrupole orbitrap mass spectrometry (NanoLC-Q-Orbitrap-MS), and perform a bioinformatics analysis of main proteins.@*Methods@#Human tear samples were collected with capillary, transferred to 3 kDa ultrafiltration tubes containing 400 μL of superpure water and centrifuged at 12 000×g for 15 min. Repeated extraction of tear proteins were performed four times, and following digestion with trypsin, the proteins were separated using the Waters NanoAcquity peptide BEH C18 column (1.7 μm, 100 μm×100 mm) and determined using NanoLC-Q-Orbitrap-MS with the mobile phase of 0.1% formic acid aqueous solution and acetonitrile (0.1% formic acid) in the full MS/dd-MS2 mode. The types of proteins were characterized in the Uniprot database using the software Proteome Discoverer version 2.1 and verified using bovine serum albumin. The tear proteins were subjected to gene annotation analysis using the String database.@*Results@#A total of (387±160) human tear proteins were yielded, with a relative standard deviation (RSD) of 4.13%, and there were 25 types of proteins with a relative high abundance, including lipocalin 1, lysozyme and lactoferrin. The peptide sequence coverage of bovine serum albumin was (86.08±2.61)%, with a RSD of 3.03%. The 25 major tear proteins were involved in substance transduction among cells, homeostasis process, negative regulation of the endopeptidase activity, detection of chemical stimulants and humoral immune responses, and the 16 proteins had close interactions. Lacritin, lipocalin 1, lactoferrin, lysozyme and zinc-α 2-glycoprotein, which had a relative high abundance, had close biological connections.@*Conclusion@#NanoLC-Q-Orbitrap-MS is stable, reliable and feasible for detection of multiple proteins in tears.
ABSTRACT
Objective@#To quickly determine bongkrekic acid（BKA）in plasma qualitatively and quantitatively by liquid chromatography-tandem mass spectrometry（LC-MS/MS）,and to provide technical support for etiological identification of food poisoning events.@*Methods@#The plasma sample was protein precipitated with acetonitrile,diluted with water and purified with anion exchange solid phase extraction cartridge of PAX. The sample extract was separated by an XBridgeTM BEH C18 chromatographic column. Gradient elution was conducted with the mobile phase of 0.01 %（v/v）ammonia and methanol. Then BKA was detected by LC-MS/MS. @*Results@#The equation of linear regression was y=16 509x+3 134.3. Good linear relationship was obtained for BKA at a range from 1 to 400 ng/mL in plasma,with the correlation coefficient of 0.999 3. The limit of detection（LOD）was 0.5 ng/mL and the limit of quantitation（LOQ）was 1 ng/mL. The average recoveries were 76.0%-96.7% with relative standard deviations（RSDs,n=6）of 5.2%-12.8% at three spiking levels of 1（LOQ）,10（10 times of LOQ）and 200 ng/mL（medium of linear range）. The concentrations of BKA in plasma obtained from two patients suffering from food poisoning were 394 and 92.3 ng/mL. @*Conclusion@#The optimized sample pretreatment and chromatographic separation conditions can achieve rapid,accurate,qualitative and quantitative analysis of BKA in plasma.
ABSTRACT
<p><b>OBJECTIVE</b>To study correlations of polychlorinated biphenyls (PCBs), DIOXIN, and polybrominated diphenyl ethers (PBDE) with thyroid stimulating hormone(TSH) in children, and assess the impact on children's health.</p><p><b>METHODS</b>Three hundred and sixty nine children aged from 6 to 8, including 195 from Luqiao, the computer E-waste recycling area, and 174 from Longyou, the control area, were selected for this investigation to elucidate the correlation of PCBs, DIOXIN, and PBDE with TSH in children's blood samples. The children had a physical examination and their blood levels of PCBs, DIOXIN, PBDE, and TSH were detected after sample collection.</p><p><b>RESULTS</b>In the E-waste recycling area, the contents of PCBs, PBDE, DIOXIN, and TSH in the blood samples of children were 484.00 ± 84.86 ng·g(-1) lipid weight, 664.28 ± 262.38 ng·g(-1) lipid weight, 26.00 ± 19.58 ng·g(-1) lipid weight and 1.88 ± 0.42 μIU/mL (serum) respectively, while in the control area, the PCBs, PBDE, DIOXIN, and TSH contents were 255.38 ± 95 ng·g(-1) lipid weight, 375.81 ± 262.43 ng·g(-1) lipid weight, 39.64 ± 31.86 ng·g(-1) lipid weight, and 3.31±1.04 μIU/mL respectively.</p><p><b>CONCLUSION</b>The health status of children in the control area are better than that in the contaminated area. Among children who are exposed to persistent organic pollutants, the pollutant content increases significantly in their serum, and the distribution of TSH levels in their bodies are also affected.</p>