Papers by Author: Xiao Ling Zhang

Abstract: In this study, the feasibility of single-walled carbon nanotubes (SWCNTs) as solid-phase extraction (SPE) adsorbent for the determination of bioactive crocin analogues in the traditional Chinese Medicine (TCM) of Gardenia Jasminoides Ellis prior to HPLC analysis was studied. Various experimental factors influencing SPE efficiency and HPLC conditions were studied. By using SWCNTs as the SPE adsorbent, the detection limit of 1.19-2.21 fmol (at S/N of 3) were achieved with the preconcentration efficiency of more than 120-folds, indicating this proposed method was very practical for increasing the sensitivity prior to HPLC analysis, and it may provides useful clue for the efficient extraction for the bioactive compounds in TCMs.

Abstract: In the present study, the development of the tandem liquid chromatography-mass spectrometry (LC-MS) method for the sensitive and selective determination of eight paralytic shellfish poisoning (PSP) (GTX1, GTX2, GTX3, GTX4, GTX5, dcGTX2, dcGTX3 and dcNEO-b) toxins was investigated. Various experimental factors affecting the pretreatment and LC-MS procedures were optimzed, respectively. Using slected reaction monitoring (SRM) mode in LC-MS analysis, the acquired calibration curves were strictly linear with the value of r² more than 0.996 for the eight targeted analyses. The obtained data expressed as relative standard deviations (RSDs), for the within-laboratory reproducibility and repeatability were less than 6.9% and 7.9%, respectively. The feasibility of the proposed method was finally validated by analyzing the eight PSPs in shellfish samples from diverse Chinese sea areas for the quality assurance of the aquatic producs and enviroment protection monitoring.

Abstract: In the present study, the feasibility of the poly(divinyl-benzene vinylpyrrolidone) as solid-phase extraction (SPE) nanoscale adsorbent prior to LC-MS-MS method for the sensitive and selective determination of eight paralytic shellfish poisoning (PSP) (GTX1, GTX2, GTX3, GTX4, GTX5, dcGTX2, dcGTX3 and dcNEO-b) toxins in the shellfish was investigated. Various parameters affecting SPE efficiency including the eluent and its volume, and sample volume were studied. The application of the SPE can remove most of the ematrix interference compared with the conventional SPE procedure. By using slected reaction monitoring (SRM) mode in LC-MS-MS analysis, the acquired calibration curves were strictly linear (r2 > 0.996) for the eight targeted analyses. The feasibility of the proposed method was finally validated by quantifing the eight PSPs in the shellfish samples (scallop, Crassostrea gigas and Ruditapes philippinarum) with the satisfitory recoveries of more than 80% with RSDs less than 10%.

Abstract: Carbon nanotubes are a kind of new carbon-based nanomaterials, which have drawn great attention in many application fields including the biomarker analysis in biomedical and clinical research. In the present study, the feasibility of single-walled carbon nanotubes (SWCNTs) as solid-phase extraction (SPE) adsorbent for the determination of amino acid neurotransmitters (AANs) (glutamic, dopamine and γ-amino-n-butyric acid) in human cerebrospinal fluids (CSFs) was investigated. Various parameters affecting SPE efficiency including the eluent and its volume, adsorbent amount and sample volume were systematically studied. The acquired calibration curves were linear (r2 > 0.999) over the concentration range 10 to 500 ng per injection. By using SWCNTs as the SPE adsorbent, the detection limit of 12.9-42.5 fmol (at S/N of 3) were achieved with the preconcentration efficiency of more than 500-folds. The feasibility of the proposed method was validated by successfully applied to the measurements of ANNs in human CSFs sampled from healthy subjects and the patients with human immunodeficiency virus (HIV) infection, malignant melanoma and hypertension. This original application represents a powerful tool to study the kinetics of ANNs release by neuronal cells during neurotransmission, as well as for the understanding of the pathobiological and therapeutic basis of these remarkable molecular for diverse diseases.