Biomedical subjects

Xiangmin Zhang

Publications and source records attributed to Xiangmin Zhang.

At least 37 records · Page 2Linked to original sources

PubMed2005

Gas chromatography-mass spectrometric analysis of hexanal and heptanal in human blood by headspace single-drop microextraction with droplet derivatization.

In this work, we developed a new approach to the analysis of the lung cancer biomarkers, hexanal and heptanal in human blood that was based on headspace single-drop microextraction (HS-SDME) with droplet derivatization, followed by gas chromatography-mass spectrometry (GC-MS). Aldehydes in blood were headspace extracted, concentrated, and derivatized by a suspended microdrop solvent containing the derivatization agent O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride. The aldehyde oximes formed in the microdrop solvent were analyzed by GC-MS. The optimal HS-SDME with droplet derivatization parameters extraction solvent of decane, sample temperature of 40 degrees C, extraction time of 6 min, stirring rate of 1100 rpm, and solvent volume of 2.0 microL were obtained and used for analysis of hexanal and heptanal in blood. The method reproducibility, linearity, recovery, and detection limit were studied and the obtained results demonstrated the method feasibility. Finally, the proposed method was applied to the quantification of hexanal and heptanal in cancer blood and normal blood. Due to sample extraction, concentration, and derivatization being performed in a single step, the method provided a simple, rapid, low-cost, and efficient approach to analysis of aldehydes in blood samples.

Adult↗

PubMed2005

Rapid analysis of essential oil from Fructus Amomi by pressurized hot water extraction followed by solid-phase microextraction and gas chromatography-mass spectrometry.

In this paper, a simple, rapid, solvent-free and low-cost method of pressurized hot water extraction (PHWE) followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) was developed for the analysis of essential oil in a traditional Chinese medicine (TCM) of the dried ripe fruit of Fructus Amomi (Sha Ren). The essential oil in the TCM (0.050 g) was extracted by water at 50 bar and 150 degrees C, followed by extraction and concentration by SPME fibers at 80 degrees C for 15min and analysis by GC-MS. The PHWE and HS-SPME parameters were optimized. Thirty-five compounds in the TCM were identified by PHWE-HS-SPME. Among them, camphor, an active compound, in the TCM samples was quantitatively analyzed. The proposed method required little time to prepare the sample. Moreover, little sample mass and no organic solvent was needed. The precision of the present method was found to be good (R.S.D. <10.0%). It is shown that PHWE-SPME-GC-MS is an alternative method for the determination of volatile components in TCMs and can be used as a powerful tool for TCM quality assessment.

Amomum↗

PubMed2005

Large-bore particle-entrapped monolithic precolumns prepared by a sol-gel method for on-line peptides trapping and preconcentration in multidimensional liquid chromatography system for proteome analysis.

The present report describes the preparation and characterization of large-bore particle-entrapped monolithic precolumns, which are suitable for incorporation into a two-dimensional liquid chromatography (2D-LC) system for proteome analysis. The fritless precolumns with different inner diameter (i.d.) (320 and 530 microm) were rapidly and successfully prepared by entrapping octadecylsilica (ODS) particles (5 microm, 300 A) prepacked into fused silica capillaries with a sol-gel network, which was formed by hydrolysis and polycondensation of methyltriethoxysilane (MTES). By optimizing the composition of the sol solution, the resulting large-bore monolithic precolumns of 5 mm length allow a flow rate of 20 microL/min loading buffer at a reasonable low back pressure of 25 bar or less and are capable of withstanding up to 300 bar inlet pressure. Scanning electron micrograms of the precolumns profile showed that the evolving sol-gel network joined particles to each other and onto the column wall, and no cracking or shrinkage of the column bed was observed even in 530 microm-i.d. capillary. The performance of the particle-entrapped monolithic precolumns used for preconcentration and desalting of proteolytic digest was evaluated by on-line coupling the large-bore precolumns with a capillary reversed-phase liquid chromatographic (RPLC) column followed by UV detection. The laboratory-made monolithic precolumns with 320 and 530 microm i.d. were characterized by using BSA tryptic digest or peptide standards as the analytes with respect to sample loading capacity, linearity, recovery and reproducibility, etc. The results indicate that the large-bore and short precolumns (5 mm x 320 microm i.d. or 5 mm x 530 microm i.d.) allow sample fast loading at a flow rate of 30 or 60 microL/min. The precolumns also have a mass loading capacity for BSA peptides of about 70 microg and for standard peptides of about 80 microg. Good linear calibration curves (R2 > 0.99) were obtained and the limits of detection (signal-to-noise ratio, S/N = 3) were improved by more than 60-fold and were between 0.53 and 1.32 ng/microL even with a UV absorbance detector. The total recovery was found to be approximately 90-100% for BSA digest and standard peptides. The day-to-day relative standard deviation (RSD) values for recoveries of BSA peptides on a single precolumn ranged from 4.66 to 7.56% and 2.68 to 3.05% for precolumn back pressure, while the column-to-column RSD values were 3.51-6.13% and 1.22-1.26% for recoveries of BSA peptides and precolumn back pressure, respectively. With good precolumn reproducibility, no significant degradation or decrease in precolumn performance was showed even after approximately 150 preconcentration/desorption cycles. The precolumns also proved to be resistant to salt buffer with high concentration and low-pH mobile phase. The large-bore particle-entrapped monolithic precolumns will be further used in a high-throughput 2D-LC array system coupled with tandem matrix assisted laser desorption/ionization-time of flight-time of flight-mass spectrometry (MALDI-TOF-TOF-MS) detection for proteome analysis.

Calibration↗

PubMed2005

Development of pressurized hot water extraction followed by headspace solid-phase microextraction and gas chromatography-mass spectrometry for determination of ligustilides in Ligusticum chuanxiong and Angelica sinensis.

In this work, a simple, rapid, solvent-free, and low-cost method was developed for the determination of ligustilides in traditional Chinese medicines (TCMs), which was based on pressurized hot water extraction (PHWE) followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The two bioactive compounds Z-ligustilide and E-ligustilide in two common TCMs, viz. Ligusticum chuanxiong and Angelica sinensis, were extracted by water at 150 degrees C and 40 bar, followed by concentration with HS-SPME and detection by GC-MS. PHWE and HS-SPME parameters were investigated and method validation (precision and recovery) was studied. It has been shown that the proposed method provides a powerful approach for quantitative analysis of ligustilides in TCMs. The method was applied to determination of ligustildes in the TCMs from different growing areas. The results indicate that PHWE-HS-SPME-GC-MS is a potential tool for TCM quality assessment.

4-Butyrolactone↗

PubMed2005

Rapid determination of methyl salicylate, a plant-signaling compound, in tomato leaves by direct sample introduction and thermal desorption followed by GC-MS.

Many plants infested by herbivores or viruses can rapidly produce and accumulate a plant-signaling compound, methyl salicylate (MeSA), in their leaves to activate disease resistance. In the present work, a simple, rapid, and sensitive method was developed for the determination of MeSA in tomato leaves by direct sample introduction and thermal desorption followed by GC-MS. Results show that the proposed method has a low detection limit (0.08 ng mg(-1)) and good precision (RSD = 8.9%). The present method was applied to the investigation of tomato plant defense response to tobacco mosaic virus (TMV) by rapid analysis of volatile compounds in plant leaves. It was found that tomato plants can produce large amounts of MeSA as a defense response to TMV. This indicates that MeSA may be a plant-signaling compound in tomato plant defense response to TMV.

Gas Chromatography-Mass Spectrometry↗

PubMed2005

Rapid determination of C6-aldehydes in tomato plant emission by gas chromatography-mass spectrometry and solid-phase microextraction with on-fiber derivatization.

A simple, rapid, sensitive, and solvent-free method was developed for determination of plant-signalling compounds, the three C6-aldehydes hexanal, (Z)-3-hexenal, and (E)-2-hexenal, in tomato plant emission by gas chromatography-mass spectrometry (GC-MS) and solid-phase microextraction (SPME) with on-fiber derivatization. In this method, O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine (PFBHA) in aqueous solution was first headspace adsorbed onto a 65 microm poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber at 25 degrees C for 5 min, and then the fiber with adsorbed PFBHA was used for headspace extraction of tomato plant emission at 25 degrees C for 6 min. Finally, the resulting oximes adsorbed on the fiber were desorbed and analyzed by GC-MS. Extraction conditions and method validation were studied. The proposed method had low detection limit values for the three aldehydes from 0.1 to 0.5 ng/L and good precision (RSD less than 10%). In this work, the method was applied to investigation of tomato plant defense response to Helicoverpa armigera.

Adsorption↗

PubMed2005

Headspace single-drop microextraction with in-drop derivatization for aldehyde analysis.

A new technique, headspace single-drop microextraction (HS-SDME) with in-drop derivatization, was developed. Its feasibility was demonstrated by analysis of the model compounds, aldehydes in water. A hanging microliter drop of solvent containing the derivatization agent of O-2,3,4,5,6-(pentaflurobenzyl)hydroxylamine hydrochloride (PFBHA) was shown to be an excellent extraction, concentration, and derivatization medium for headspace analysis of aldehydes by GC-MS. Using the microdrop solvent with PFBHA, acetaldehyde, propanal, butanal, hexanal, and heptanal in water were headspace extracted and simultaneously derivatized. The formed oximes in the microdrop were analyzed by GC-MS. HS-SDME and in-drop derivatization parameters (extraction solvent, extraction temperature, extraction time, stirring rate microdrop volume, and the headspace volume) and the method validations (linearity, precision, detection limit, and recovery) were studied. Compared to liquid-liquid extraction and solid-phase microextraction, HS-SDME with in-drop derivatization is a simple, rapid, convenient, and inexpensive sample technique.

Journal Article↗

PubMed2005

Rapid determination of acetone in human blood by derivatization with pentafluorobenzyl hydroxylamine followed by headspace liquid-phase microextraction and gas chromatography/mass spectrometry.

In the current work, a simple, rapid, accurate and inexpensive method was developed for the determination of acetone in human blood. The proposed method is based on derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA), followed by headspace liquid-phase microextraction (HS-LPME) and gas chromatography/mass spectrometry (GC/MS). In the present method, acetone in blood samples was derivatized with PFBHA and acetone oxime formed in several seconds. The formed oxime was enriched by HS-LPME using the organic solvent film (OSF) formed in a microsyringe barrel as extraction interface. Finally, the enriched oxime was analyzed by GC/MS in electron ionization (EI) mode. HS-LPME parameters including solvent, syringe plunger withdrawal rate, sampling volume, and extraction cycle were optimized and the method reproducibility, linearity, recovery and detection limit were studied. The proposed method was applied to determination of acetone in diabetes blood and normal blood. It has been shown that derivatization with HS-LPME and GC/MS is an alternative method for determination of the diabetes biomarker, acetone, in blood samples.

Acetone↗

PubMed2005

Development of microwave-assisted derivatization followed by gas chromatography/mass spectrometry for fast determination of amino acids in neonatal blood samples.

Analysis of amino acids in blood samples is an important tool for the diagnosis of neonatal amino acid metabolism disorders. In the work, a novel, rapid and sensitive method was developed for the determination of amino acids in neonatal blood samples, which was based on microwave-assisted silylation followed by gas chromatography/mass spectrometry (GC/MS). The amino acids were derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) under microwave irradiation. The controlled reaction was carried out employing BSTFA under conventional heating at 120 degrees C for 30 min. Experimental results show that microwave irradiation can accelerate the derivatization reaction of amino acids with BSFTA, and much shorten analysis time. The method validations (linear range, detection limit, precision and recovery) were studied. Finally, the method was tested by determination of amino acids in neonatal blood by the measurement of their trimethylsilyl derivatives by GC/MS in electron impact (EI) mode. Two biomarkers of L-phenylalanine and L-tyrosine in phenylketonuria (PKU)-positive blood and control blood were quantitatively analyzed by the proposed method. The results demonstrated that microwave-assisted silylation followed by GC/MS is a rapid, simple and sensitive method for amino acid analysis and is also a potential tool for fast screening of neonatal aminoacidurias.

Amino Acids↗

PubMed2005

Diagnosis of congenital adrenal hyperplasia by rapid determination of 17alpha-hydroxyprogesterone in dried blood spots by gas chromatography/mass spectrometry following microwave-assisted silylation.

17alpha-Hydroxyprogesterone (17OHP) is considered to be the biomarker of congential adrenal hyperplasia (CAH). Screening for CAH in newborns by measuring levels of the biomarker of 17OHP has become routine. In the work, a rapid, simple and sensitive technique was developed for the diagnosis of neonatal CAH by the quantitative analysis of 17OHP in neonatal blood spots. The technique was based on microwave-assisted silylation (MAS) followed by gas chromatography/mass spectrometry (GC/MS). In the method, fast derivatization of 17OHP with N,O-bis(trimethylsilyl)trifluoroacetamide was performed by using microwave irradiation, and the trimethylsilyl derivative thus formed was analyzed by GC/MS. The results of the experiment indicate that MAS followed by GC/MS analysis is a rapid, simple and sensitive method for the determination of 17OHP in blood samples. The proposed technique has been shown to have potential as a powerful tool for the rapid diagnosis of neonatal CAH.

17-alpha-Hydroxyprogesterone↗

PubMed2005

A new analysis method with GC or GC-MS for the quick detection of pesticide residues in vegetables.

A new analytical method for gas chromatography (GC) or GC-mass spectrometry (MS) using the direct sampling technique is described. This direct sampling technique, which bypasses the conventional complicated sample pretreatment process, is applicable to cases of fast detection of pesticide residues in foods and large-scale screening of samples by portable GC in field detection. By a direct sampling technique, the vegetable sample is ground into paste, and 30 mg is placed directly into the evaporating chamber for GC-MS identification and quantitation (by full-scan mode). The GC column used is an HP-5 (30.0-m x 250-microm x 0.25-microm, 5% phenyl methyl siloxane). Chlorpyrifos, bromophos, fenpropathrin, gamma-666, and pp'-DDT are chosen to represent organophosphorus, pyrethrins, and organochlorine pesticides because they are chief objects of the detection of pesticide residues in vegetables. Rape, a common and mass-consumed vegetable in China, is chosen as the sample in this study. The detection limits for these pesticides by the full-scan mode are all below the maximum pesticide residue limit of vegetables set by the Ministry of Agriculture of China, and the reproducibility of this method is acceptable. This analysis method is proven to be simple, quick, and reliable and is suitable for multipesticide residues analysis of vegetables. It can also be used in the analysis of vegetable components and signal chemicals.

Chromatography, Gas↗

PubMed2005

A novel miniaturized flame ionization detector for portable gas chromatography.

A novel miniaturized flame ionization detector (FID) operated by battery, which can be used as a detector in portable gas chromatography (GC) is devised and manufactured. It is characterized by the structure of building blocks, small volume, low energy consumption, and needing only two gases, which can be used for detection of hydrocarbons in portable GC. The miniaturized detector mainly includes a porous metallic diffuser plate, bugle-figuration collector, quartz capillary flame tip, and self-heated system. The miniaturized FID is easy to fabricate and assemble because of its structure of building blocks. The FID response is linear over six orders of magnitude and the detection limit of 0.518 ng for benzene, 0.430 ng for n-dodecane, 0.473 ng for naphthalene, and 0.509 ng for n-tetradecane.

Alkanes↗

PubMed2005

[Analyze the role of endoscopic operation in the cerebrospinal fluid rhinorrhea repair].

OBJECTIVE: To explore the effect of the different operative methods on the results with endoscopy in the cerebrospinal fluid rhinorrhea according to different location and different size. METHOD: All clinical records and data were studied retrospectively, compare repair measure under different size and different location of fistula. RESULT: (1) Size of fistulas: 1 mm x 1 mm - 20 mm x 20 mm; (2) Repair methods: 2 cases were repaired by "Bath-plug" method, 10 by onlay, 18 by underlay, and 1 by "Button with fascia". CONCLUSION: (1) The suitable repair methods were selected according to size and location. Underlay is superior to resist intracranial pressure and better for middle size fistula. Onlay is simple and fit to small fistula. "Bath-plug" method was more reliable for the small-middle size fistula. "Button with fascia" was more suitable to large size fistula. (2) Advantages of the endoscopic technique include exact identification of the site of the dural tear, excellent field of vision, less complication and precise placement of graft.

Cerebrospinal Fluid Rhinorrhea↗

PubMed2005

[Nano flow multidimensional liquid chromatography for proteome analysis of rat liver].

A nano flow comprehensive multidimensional liquid chromatography was developed. By using this separation platform, complex samples can be injected, desalted, separated and analyzed in complete automatization. Coupling of the strong cation-exchange (SCX) with capillary reversed-phase liquid chromatography (cRPLC) is described for proteomics of rat liver. A step gradient was applied for SCX column, and a linear gradient was applied for RPLC. The flow rate through the nano scale analytical column during the separation process was maintained at 200 nL/min. The peak capacity for the nano-2D-LC was up to 620 under these conditions.

Animals↗

PubMed2005

[The observation of the ciliotoxicity of nasal mucosa with nasal decongestant].

OBJECTIVE: To study the ciliotoxicity of nasalmucosal with nasal decongestant, in order to choose the appropriate nasal decongestant. METHOD: (1) Selected 100 healthy volunteers, by using 0.05% hydrochloride oxymetazoline, 0.025% hydrochloride oxymetazoline, 1.0% ephedrine and 0.5% ephedrine for 7 days with sacchariu technique to test nasal mucociliary transport, and compared with the normal saline. (2) To observe the mucosa of inferior turbinate with Electron Microscopy. RESULT: After using nasal decongestant for 7 days, Mean nasal mucociliary transport rate (MTR) in 0.0500 hydrochloride oxymetazoline groups was (7.64+/-1.56) mm/min and (7.46+/-1.65) mm/min in 0.25% hydrochloride oxymetazoline groups, Mean nasal mucociliary transport rate (MTR) in 1.0% ephedrine groups was (4.73+/-2.03) mm/min and (4.38+/-2.04) mm/min in 0.5% ephedrine groups,The normal saline groups was (7.14+/-1.76) mm/min. MTR was obviously different (F = 16.50, P <0.01). (2)With electron microscopy, it was found that the cilia of epithelial cells were in good order, uniformed in hydrochloride oxymetazoline groups and exfoliated in ephedrine groups. CONCLUSION: Ephedrine has ill effects on nasal mucosa; Hydrochloride oxymetazoline has neither effect on nasal mucosa, nor destroying the physical function of nose, it is an ideal nasal decongestant.

Adolescent↗

PubMed2005

[AquacelAg used in nasal packing after endoscopic sinus surgery].

OBJECTIVE: To compare the packing efficacy of AquacelAg with Merocel after endoscopic sinus surgery. METHOD: Twenty-four patients (48 sides) were observed. The right nasal side was used as AquacelAg group, and left side contrast group . Bleeding pain and mucosal edema in nasal cavity were observed. RESULT: The AquacelAg showed more efficacy in less pain than Merocel (P < 0.01). Bleeding and mucosal edema in nasal cavity was no significant difference with the control group. CONCLUSION: AquacelAg is a better nasal packing material.

Adult↗

PubMed2004

Development of headspace solid-phase microextraction with on-fiber derivatization for determination of hexanal and heptanal in human blood.

Hexanal and heptanal in human blood have been regarded as potential biomarkers of lung cancer. Owing to their high volatilities and activities, it is difficult to accurately measure the two biomarkers. In the current work, headspace solid-phase microextraction (HS-SPME) with on-fiber derivatization technique was developed for quantitative analysis of hexanal and heptanal in human blood. In the proposed method, the two aldehydes in blood were headspace extracted by using a poly (dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber with O-2,3,4,5,6-(pentafluorobenzyl) hydroxylamine (PFBHA) at 60 degrees C for 8 min. The aldehyde oximes formed on the fiber were desorbed and analyzed by gas chromatography-mass spectrometry (GC-MS). The method validations including detection limit, recovery and precision were studied. It was found that the method provided low detection limits of 0.006 nM for hexanal and 0.005 nM for heptanal, recoveries from 89% to 95% and R.S.D. values less than 8.5%. The present method was applied to quantitative analysis of hexanal and heptanal in normal blood and lung cancer blood. Hexanal concentrations from 7.33 to 15.23 microM and heptanal concentrations from 2.47 to 9.23 microM were found in the lung cancer blood, while both hexanal and heptanal in the control blood were lower than 0.6 microM. This further demonstrated that hexanal and heptanal might be the biomarkers of lung cancer. The experimental results showed that GC-MS and HS-SPME with on-fiber derivatization is a simple, rapid, sensitive and solvent-free method for determination of in hexanal and heptanal human blood.

Aldehydes↗

PubMed2004

Rapid determination of essential oil in Acorus tatarinowii Schott. by pressurized hot water extraction followed by solid-phase microextraction and gas chromatography-mass spectrometry.

A simple, rapid, efficient and inexpensive method for the determination of essential oil in a traditional Chinese medicine (TCM), Acorus Tatarinowii Schott. was developed by using pressurized hot water extraction (PHWE) combined with solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). Acorus Tatarinowii Schott. (0.050 g) was subjected to dynamic extraction with water at 50 bar, 150 degrees C and 1.0 ml/min for 5.0 min, and then the essential oil in the aqueous extract were extracted by SPME fibers at 60 degrees C for 10 min, finally the compounds on the fiber were desorbed and analyzed by GC-MS. The PHWE and SPME parameters were studied. The key active compound of alpha-asarone in the TCM samples from three different growing areas was quantitatively analyzed by external standard method. Compared to steam distillation (SD), the proposed method required little time (only 15 min) to prepare sample. Moreover, little sample mass and no organic solvent was needed. The present method provided good repeatability (R.S.D. less than 13.0%) and recovery (92% for alpha-asarone). It has been shown that PHWE-SPME-GC-MS is an alternative method for determination of essential oils in TCMs and a potential tool for TCM quality assessment.

Acorus↗