Biomedical subjects

Yuan-Yuan Zhao

Publications and source records attributed to Yuan-Yuan Zhao.

3 recordsLinked to original sources

PubMed2006

Determination of microcystins in water using integrated solid-phase microextraction with microbore high-performance liquid chromatography-electrospray quadruple time-of-flight mass spectrometry.

The development of a technique combining solid-phase microextraction (SPME) with microbore high-performance liquid chromatography (micro-HPLC)-tandem quadrupole time-of-flight (QTOF) mass spectrometry (MS) for determination of dissolved microcystins in water is reported. Several important parameters affecting the efficiency of SPME extraction of microcystins are investigated. A microbore C18 column HPLC coupled with tandem QTOF-MS with information-dependent acquisition (IDA) is developed to effectively analyze microcystins in microliter volumes of SPME extracts. The micro-HPLC-QTOF-MS with IDA technique provides comprehensive information, including a survey chromatogram (total ion chromatogram), full scan mass spectrum, and product ion scan mass spectra at different collision energies for individual analytes, which allows for both identification and quantitation in the same run. Linear calibration curves of microcystin standard [microcystin (MC)-arginine (R)R] 1-100 microg/L and of microcystin standard [MC-leucine (L)R] 1-250 microg/L are obtained with a correlation coefficient of 0.996. The combination of SPME with HPLC-QTOF-MS and IDA offers limits of detection of 0.6 pg for MC-RR and 1.6 pg for MC-LR. Analysis of spiked lake-water samples shows a recovery of > 86% for MC-RR and > 70% for MC-LR. This technique requires small sample volumes, minimizes the use of organic solvents, and provides sensitive and information-rich analysis of unknown samples.

Chromatography, High Pressure Liquid↗

PubMed2005

Intact human holo-transferrin interaction with oxaliplatin.

We report the interaction of intact human holo-transferrin (holo-Tf) with oxaliplatin (an anticancer drug), and the characterization of a complex composed of (1:1) intact holo-Tf and the parent oxaliplatin molecule using nanoelectrospray ionization quadrupole time-of-flight mass spectrometry (nanoESI-QTOF-MS). The molecular weight of this complex was determined to be 80,077 Da, which was an increase of 397 mass units compared to the protein alone (79,680 Da), suggesting that a parent drug molecule was bound to the intact protein. We further examined the interaction between the intact protein and oxaliplatin using size-exclusion high-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICPMS). The protein complex and free oxaliplatin were separated by HPLC and quantitatively determined by simultaneous monitoring of both 195Pt and 56Fe using ICPMS. The HPLC/ICPMS detected both Pt and Fe signals at retention time of 2.6 min, identifying the protein-drug complex. The Fe signal at 2.6 min did not change with the increase in incubation time of the reaction mixture containing holo-Tf and oxaliplatin, while the Pt signal at the same retention time increased over time, further demonstrating that the formation of this complex does not affect the protein-bound Fe. The binding constant of the (1:1) intact human holo-Tf-oxaliplatin complex was determined to be 7.7x10(5) M-1. Both nanoESI-MS and HPLC/ICPMS results support that the holo-Tf and parent oxaliplatin molecules form complexes through non-covalent binding, suggesting that holo-Tf may be a useful carrier for oxaliplatin delivery.

Antineoplastic Agents↗

PubMed2003

Determination of aliphatic amines using N-succinimidyl benzoate as a new derivatization reagent in gas chromatography combined with solid-phase microextraction.

A simple, selective and sensitive approach was developed for the quantitation of aliphatic amines in lake water applying a new reagent (N-succinimidyl benzoate, SIBA), synthesized in the laboratory of the authors. Derivatization of the n-C1-C6 aliphatic monoamines and dimethylamine in aqueous solution with SIBA was followed by headspace solid-phase microextraction (SPME). Derivatives were identified by gas chromatography-mass spectrometry and determined by gas chromatography-flame ionization detection. Both derivatization and SPME conditions have been optimized. Derivatizations were performed in borate buffer (pH 8.8), at 60 degrees C for 22 min. SPME was carried out from saturated sodium chloride solution, at 80 degrees C for 60 min, desorption at 250 degrees C for 2 min. Detection limit of derivatized amines proved to be 0.13-7.2 nmol/l, while recovery of amines from lake water samples, in the concentration range of 100-200 microg/l, varied from 94.1 to 102.7%.

Amines↗