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    Chinese Journal of Chromatography
    2008, Vol. 26, No. 6
    Online: 30 November 2008

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    Articles
    Development of hydrophilic interaction chromatographic hyphenated techniques and their applications
    WANG Yuan, GU Huixin, LU Xin, XU Guowang
    2008, 26 (6):  649-657. 
    Abstract ( 2846 )   [Full Text(HTML)] () PDF (3966KB) ( 1453 )  
    Hydrophilic interaction chromatography (HILIC) is popular in the analysis of hydrophilic solutes in recent years. As a unique liquid chromatographic (LC) separation mode, it has not only been successfully utilized for the separation of target compounds from complex matrixes, but also been hyphenated with other separation modes, such as reversed-phase LC (RPLC), ion-exchange chromatography, and various HILIC, to increase the resolution and peak capacity for “entire-component” analysis of complex samples. Here we briefly review the origin and concept of HILIC, its retention behavior, and the frequently used stationary phases. After discussing the selectivity orthogonality between HILIC and RPLC, several application areas of HILIC are introduced, including HILIC tandem mass spectrometry (HILIC-MSn), on-line HILIC pretreatment, comprehensive two-dimensional HILIC-MSn and on-line hyphenation of HILIC and RPLC. With abundant references, HILIC has been proved to be a powerful analytical tool for hydrophilic and polar complexes.
    Quantitative monitoring the concentration changes of organic acids in fermentation process of Clostridium acetobutylicum using capillary ion electrophoresis
    CHENG Jiayi, WANG Tongdan, KANG Jingwu
    2008, 26 (6):  658-661. 
    Abstract ( 2540 )   [Full Text(HTML)] () PDF (344KB) ( 773 )  
    A method for monitoring the concentration changes of organic acids in the fermentation process of Clostridium acetobutylicum by capillary ion electrophoresis has been developed. In this study, 4-methoxybenzoic acid was used as the background electrolyte for the indirect ultraviolet detection, and cetyltrimethylammonium chloride (CTAC) was employed as the electroosmotic flow modifier. The sample of fermentation was simply treated by centrifugation and dilution. The optimal conditions for the separation were established as 10 mmol/L of 4-methoxybenzoic acid solution (pH 5.8) and 0.15 mmol/L of CTAC solution. The limits of quantification for lactate, acetate and n-butyrate were 1.22, 0.38 and 0.58 mg/L, respectively. The method can be successfully used for the metabolic flux analysis of Clostridium acetobutylicum.
    Differential proteins revealed with proteomics in the brain tissue of Paralichthys olivaceus under the stress of methyl parathion
    NA Hongkun, HUANG Qingyu, CHEN Yingying, HUANG Heqing,
    2008, 26 (6):  662-666. 
    Abstract ( 2498 )   [Full Text(HTML)] () PDF (176KB) ( 813 )  
    The proteins from the brain tissue of the fish Paralichtys olivaceus (PO) were separated by the optimized two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Approximately 650 protein spots in each gel were detected from the brain sample when applying 200 mg protein to a 2D-PAGE gel in the pH range of 3.0-10.0. The differential proteins from the PO brain were separated and identified by proteomic technologies and they were further selected as the potential protein markers to monitor the contamination levels of methyl parathion (MP). Compared with the control group, 17 differential proteins were obtained from the PO brain under the stress of MP at 3 mg/L. Among these spots, fourteen were up-regulated and three were down-regulated. Then these differential proteins were further identified by peptide mass fingerprint (PMF) and database search. The results showed that heat shock protein 70, glutathione S-transferase and cytochrome P450 were significantly found in those differential proteins. These proteins might have strong potential for monitoring the contamination levels of MP and searching for the toxicological mechanism, as well as to evaluate the degree of risk of human fatalities under the condition of MP pollution. The results indicated that the application of the multiple biomarkers has the advantages over that of the single biomarker for monitoring the levels of MP contamination in the flowing seawater.
    Determination of inorganic ions in explosive residues by capillary zone electrophoresis
    FENG Junhe, GUO Baoyuan, LIN Jin-Ming, XU Jianzhong, ZHOU Hong, SUN Yuyou, LIU Yao, QUAN Yangke, LU Xiaoming
    2008, 26 (6):  667-671. 
    Abstract ( 2640 )   [Full Text(HTML)] () PDF (472KB) ( 742 )  
    Five anions (chlorate, perchlorate, nitrate, nitrite, and sulfate) and two cations (ammonium and potassium) in explosive residues have been separated and determined by capillary zone electrophoresis (CZE) with indirect ultraviolet detection. The electrolyte buffer for the cation separation was 10 mmol/L pyridine (pH 4.5)-3 mmol/L 18-crown-6-ether. Ammonium and potassium ions were baseline separated in less than 2.6 min with the detection limits of 0.10 mg/L and 0.25 mg/L (S/N=3), respectively. The electrolyte buffer for the anion separation consisted of 40 mmol/L boric acid-1.8 mmol/L potassium dichromate-2 mmol/L sodium tetraborate (pH 8.6), and tetramethyl ammonium hydroxide (TMAOH) was used as electro-osmotic flow modifier. All five anions were well separated in less than 4.6 min with the detection limit range of 0.10-1.85 mg/L (S/N=3). The method was successfully used in real sample investigations to confirm the type of explosives.
    Evaluation of absorption of organic compounds in human body using liposome capillary electrophoresis
    ZOU Xiaobing, JIANG Honggui, DONG Zhiqiang, XIA Zhining, JIANG Xuemei
    2008, 26 (6):  672-676. 
    Abstract ( 2484 )   [Full Text(HTML)] () PDF (265KB) ( 719 )  
    Liposome capillary electrophoresis (LCE) was used as a model for the in vitro evaluation of the degree of membrane penetration of organic compounds. The hydrophobic parameters of 9 compounds were determined by LCE. In comparison of the correlation coefficient of log Plw ( the logarithm of the partition coefficient of liposome/water system, calculated from retention factor) vs. log Pm (the logarithm of osmotic coefficient) with that of log Pow (the logarithm of the partition coefficient of octanol/water system) vs. log Pm, the former was 0.94, much greater than the latter 0.78. It means that as the biomembrane model, liposome is more similar than the octanol/water system. The LCE method has the potential to be an in vitro screening model.
    Separation of enantiomers of three chiral drugs by capillary electrophoresis based on achiral ionic liquid
    XIA Chen, CHEN Zhitao, XIA Zhining,
    2008, 26 (6):  677-681. 
    Abstract ( 2728 )   [Full Text(HTML)] () PDF (447KB) ( 918 )  
    Using an achiral ionic liquid, 1-butyl-3-methylimidazolium chlorine ([BMIM]Cl), as an additive and beta-cyclodextrin (β-CD) as a chiral selector, the enantiomers of chlorpheniramine, the precursor of chloramphenicol and ofloxacin were separated by capillary zone electrophoresis. This work was directed to the study of the association of [BMIM]Cl to the chiral selector β-CD and the possible effects of [BMIM]Cl on chiral separation. Simultaneously, the separation performances were studied when only containing β-CD in the buffer. The results showed that there are synergistic effects of [BMIM]Cl as an additive for the enantiomeric separations. [BMIM]Cl can not only remarkably increase the separation selectivity and resolution of the enantiomers, but also effectively restrain the adsorption of the sample molecules and improve the peak shape. [BMIM]Cl as an additive of chiral separation can provide a new method for the separation of chiral drugs which are hard separable under common electrophoresis conditions.
    Simultaneous determination of four β-lactam antibiotics in milk by solid-phase extraction-micellar electrokinetic chromatography
    ZHANG Qi, YE Nengsheng, GU Xuexin, HAO Xiaoli, LIU Ni
    2008, 26 (6):  682-686. 
    Abstract ( 2481 )   [Full Text(HTML)] () PDF (565KB) ( 884 )  
    A solid-phase extraction (SPE)-micellar electrokinetic chromatography (MEKC) method was developed for the simultaneous determination of four β-lactam antibiotics (ampicillin, amoxicillin, penicillin V and cephalexin) in spiked milk samples. The milk samples were extracted by SPE after protein precipitation. The analysis was performed by MEKC at 18 kV with phosphate buffer containing sodium dodecyl sulfate (SDS) and the detection was carried out at 210 nm. The four antibiotics could be baseline-separated less than 9 min. The linearities in 0.5-20 mg/L could be constructed with the correlation coefficients between 0.9943-0.9976, and the limits of detection were 0.16-0.20 mg/L. The average recoveries of antibiotics from milk were over 70% except amoxicillin. The method is sensitive, specific and easy for the determination of β-lactam antibiotic residues in milk.
    Fast determination of polybrominated diphenyl ethers in human milk using gas chromatography-negative chemical ionization/mass spectrometry
    LIU Yinping, DAI Peng, LI Jingguang, ZHANG Lei, ZHAO Yunfeng, WU Yongning, ZHU Lingyan
    2008, 26 (6):  687-691. 
    Abstract ( 2484 )   [Full Text(HTML)] () PDF (273KB) ( 822 )  
    A method for the quantitative determination of 8 polybrominated diphenyl ethers (PBDEs) in human milk was established using gas chromatography-negative chemical ionization/mass spectrometry (GC-NCI/MS). After extraction by Soxhlet extractor, the lipid in the extract was removed by acidic silica, and the analyte was further purified by the multilayer silica-alumina column. The concentrations of BDE28, BDE47, BDE99, BDE100, BDE153, BDE154, BDE183 and BDE209 in human milk were fast determined by GC-NCI/MS in selected ion monitoring (SIM) mode on a 7 m column. The quantitative analysis was performed by isotope dilution method for BDE209 and internal standard method for other PBDEs. The limits of detection (LODs) of PBDEs in the lipid ranged from 1.74 to 6.35 pg/g. The recoveries of the spiked PBDEs were between 61.5% and 108% and their relative standard deviations (RSDs) (n=6) were between 2.06% and 10.1%. The method was further validated by the analysis of the reference materials of human milk. It was demonstrated that it is a low cost, rapid and reliable alternative for the trace analysis of selected PBDEs, especially for BDE209 in human milk
    Analysis of volatile and non-volatile compositions in ginger oleoresin by gas chromatography-mass spectrometry
    ZHAN Kunyou, WANG Chao, XU Kun, YIN Hongzong
    2008, 26 (6):  692-696. 
    Abstract ( 3262 )   [Full Text(HTML)] () PDF (432KB) ( 1004 )  
    Ginger oleoresin was extracted from Zingiber officinale Rosc.var. Laiwudajiang by the technique of supercritical fluid extraction. Gas chromatography and mass spectrometry technique were employed to analyze the ginger oleoresin. This analysis resulted in the detection of 3 hitherto unknown natural compounds, 24 compounds previously reported as pungent compounds and 50 volatile compounds from ginger. The volatile compounds were mainly α-zingiberene (22.29%), β-sesquiphellandrene (8.58%), α-farnesene (3.93%), β-bisabolene (3.87%), α-curcumene (2.63%), which were mostly consisted of sesquiterpene hydrocarbons. The pungent compounds of ginger were mainly 6-gingerol (9.38%), 6-shogaol (7.59%), zingerone (9.24%) produced by the thermal degradation of gingerols or shogaols. The mass spectral fragmentation patterns for the three new compounds (6-isogingerol, (Z)-10-isoshogaol, (E)-10-isoshogaol) are discussed and interpreted.
    Determination of organochlorine pesticides in soils using gas chromatography-tandem mass spectrometry
    JIA Lijuan, DENG Yunyun
    2008, 26 (6):  697-703. 
    Abstract ( 2817 )   [Full Text(HTML)] () PDF (339KB) ( 1089 )  
    A method was developed for the determination of organochlorine pesticides (OCPs) in soils using accelerated solvent extraction (ASE, Florisil cleanup in the extraction cell) and gel permeation chromatography (GPC) on-line concentration prior to the determination by gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). And then 20 agricultural soil samples in Shanghai suburbs were determined. Multiple reaction monitoring (MRM) was applied to qualify and quantify the target compounds. In the different linear ranges (included in 0.001-0.2 mg/L) of each pesticide, the correlation coefficients were higher than 0.995. The average recoveries in spiked soils were 65.9%-140.0% with the relative standard deviations of 1.5%-20.3%(n=5). The limits of detection (LOD) (S/N=3)for these pesticides were from 0.1 to 3.0 μg/kg and the limits of quantification (LOQ) (S/N=10)were from 0.3 to 8.0 μg/kg. Among these soils, hexachlorocyclohexane (HCHs) and hexachlorobenzene (HCB) were detected little with a content ranges of 1.82-3.70 and 0.94-9.8 μg/kg, respectively. DDTs (including 2-(2-chlorophenyl)-2-(4-chloropenyl)-1,1,1-trichloroethane (p,p′-DDT), 2,2-bis(4-chlorophenyl)-1,1-dichloro-ethylene (p,p′-DDE), 2,2-bis(4-chlorophenyl)-1,1-dichloroethane (p,p′-DDD)) were found widely with a range of 1.08-308.76 μg/kg and mean value of 53.28 μg/kg. The content ratio of DDT/(DDE+DDD) were less than 1.0 in 85% soil samples, indicating that DDT might come from the early days.
    Determination of nine triazole pesticides in environmental waters using solid phase extraction and gas chromatography-mass spectrometry
    YOU Minghua, SUN Guangda, CHEN Meng, YUAN Dongxing
    2008, 26 (6):  704-708. 
    Abstract ( 2368 )   [Full Text(HTML)] () PDF (204KB) ( 945 )  
    A method was developed for the simultaneous determination of 9 triazole pesticides in environmental water using C18 cartridge for the extraction and enrichment, NH2 cartridge for the clean-up and gas chromatography-mass spectrometry for the detection. The linear range of calibration curves for the 9 target pesticides was between 0.025 mg/L and 0.500 mg/L. The detection limits were in the range of 0.002-0.009 μg/L. The 9 target pesticides were measured in river water and sea water at 0.025 μg/L and 0.100 μg/L spiking levels, recoveries and relative standard deviations (RSD, n=3) were 68.4%-113.9% and 1.6%-6.9% for river water and 70.3%-115.2% and 0.8%-8.2% for sea water, respectively. The method is simple, sensitive, selective and suitable for the qualification of pesticide multiresidue analysis. It has been successfully applied to the survey of 9 triazole pesticide residues in Jiulong River Estuary, Fujian.
    Simultaneous determination of nine β-agonist residues in animal derived foods by ultra performance liquid chromatography-tandem mass spectrometry
    SUN Lei, ZHANG Li, ZHU Yonglin, WANG Shuhuai, WANG Xia
    2008, 26 (6):  709-713. 
    Abstract ( 2400 )   [Full Text(HTML)] () PDF (337KB) ( 828 )  
    An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous determination of terbutaline, cimaterol, salbutamol, fenoterol, clorprenaline, ractopamine, clenbuterol, tulobuterol, penbutolol residues in animal derived foods. After enzymolysis, the samples were extracted by perchloric acid, centrifuged, neutralized, followed by liquid-liquid extraction with ethyl acetate and tert-butyl methyl ether, separately. The combined extracts were applied to a solid phase extraction MCX cartridge for cleanup. The separation of β-agonists was performed on Waters Acquity UPLC system with a BEH C18 column (50 mm×2.1 mm, 1.7 μm) and the gradient elution solvent of acetonitrile (containing 0.1% formic acid) and water (containing 0.1% formic acid) at a flow rate of 0.3 mL/min. The method was quantified by external standard method. The calibration curves were good linear between the peak areas and the concentrations of 0.25-5 μg/kg with the correlation coefficient r>0.990. The limit of detection of the 8 β-agonists was 0.1 μg/kg, and the limit of quantification was 0.25 μg/kg. The limit of detection of penbutolol was 0.25 μg/kg, and the limit of quantification was 0.5 μg/kg. The average recoveries from spiked animal tissues at three concentrations of 0.5, 1 and 2 μg/kg ranged 87.1%-108.6%. The relative standard deviations of intra- and inter-batch were both less than 20%.
    Determination of eleven steroid hormones in animal muscle tissues and eggs using ultra-performance liquid chromatography-tandem mass spectrometry
    HE Limin, HUANG Xianhui, FANG Binghu, HUANG Shixin, CAO Ying, CHEN Jianxin, ZENG Zhenling, CHEN Zhangliu
    2008, 26 (6):  714-719. 
    Abstract ( 2671 )   [Full Text(HTML)] () PDF (538KB) ( 1774 )  
    A credible method was developed for the simultaneous determination of eleven steroid hormone residues in animal muscle tissues and eggs based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The eleven steroid hormones were testosterone, methyltestosterone, trenbolone, boldenone, nandrolone, methandienone, stanozolol, progesterone, nadrolone propionate, testosterone propionate and nadrolone phenylpropionate. The samples were extracted with tert-butyl methyl ether at alkaline pH and then cleaned up by freezing-lipid filtration. All these drugs can be assayed in 10 min by UPLC-MS/MS using electrospray ionization in positive ion mode and multiple reaction monitoring mode. The limits of detection were 0.3 μg/kg for testosterone, methyltestosterone, boldenone, methandienone and stanozolol, and 0.4 μg/kg for trenbolone nandrolone, progesterone, testosterone propionate and nadrolone phenylpropionate. Overall recoveries of testosterone, methyltestosterone, boldenone, methandienone and stanozolol were 62.3%-105% from pork, beef, mutton and chicken muscle tissues, and eggs fortified at the 1, 2 and 10 μg/kg levels , and the relative standard deviations (RSDs) were 0.5%-15%. The recoveries of trenbolone nandrolone, progesterone, testosterone propionate and nadrolone phenylpropionate were higher than 50.0%, and the RSDs were lower than 16%. The matrix calibration curve for each drug was linear (r>0.99) from 1 to 100 μg/L. The established method is simple, rapid, sensitive and specific, and is appropriate for the identification and quantification of anabolic androgenic steroids in animal muscle tissues and eggs
    Determination of pesticide residues from seed coating reagent in agricultural products using ultra performance liquid chromatography-tandem mass spectrometry
    CHEN Yue, WANG Jinhua, LU Xiaoyu, WANG Wanchun, HUANG Mei, XU Chaoyi
    2008, 26 (6):  720-725. 
    Abstract ( 2362 )   [Full Text(HTML)] () PDF (705KB) ( 953 )  
    An ultra performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) has been developed for the simultaneous determination of eight pesticide residues from seed coating in fruits, vegetable and grain. The sample was extracted by methanol-water (1∶1, v/v) and determined by ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry in positive mode (ESI+) and multiple reaction monitoring (MRM) mode. The UPLC analyses were performed on an Acquity UPLC C18 column with gradient eluation. The utility of the method was demonstrated by the analysis of crude extracts, with no sample clean up, from soybean. The linear range was 1-200 μg/L. The correlation coefficients (r) were under 0.997. The average recoveries of eight pesticides in samples (from 0.006 to 1.2 mg/kg) ranged from 60% to 110%, and the relative standard deviations (RSDs) were less than 10%. The results indicate that the method is easier, faster, more sensitive, and suitable for the qualitative and quantitative confirmation of pesticide residues from seed coating reagent in fruit, vegetable and grain samples.
    Simultaneous determination of residues of six imidazolinone herbicides in adzuki beans by high performance liquid chromatography-electrospray ion trap tandem mass spectrometry
    LI Cheng, SUO Ran, WANG Fengchi, MA Hongying
    2008, 26 (6):  726-730. 
    Abstract ( 2515 )   [Full Text(HTML)] () PDF (330KB) ( 669 )  
    A method for the simultaneous determination of six pesticides in adzuki beans by high performance liquid chromatography-electrospray ion trap tandem mass spectrometry was developed and evaluated. The sample was extracted with 0.1 mol/L NH4HCO3 (pH 5)-methanol (70∶30, v/v). The extract was partitioned with dichloromethane, and cleaned up with gel permeation chromatography. The separation was performed on an Inertsil ODS-3 column (150 mm×2.1 mm, 5 μm) with the gradient elution of methanol and 1% acetic acid as mobile phase. The identification and quantification were performed by electrospray ion trap mass spectrometry with selected ion monitoring mode. The calibration curves of imidazolinone herbicides showed good linearities in the range of 10-200 μg/L (5-100 μg/L for imazaquin) with the correlation coefficients between 0.9987 and0.9997. The limits of detection ranged between 0.2 μg/kg and 0.5 μg/kg (S/N=3). The average recoveries of six imidazolinone herbicides spiked in adzuki beans ranged between 81.6% and 99.4%(n=6) with the relative standard deviations of 3.1%-7.8%. The method has been used for the determination of 6 imidazolinone herbicides simultaneously in adzuki beans with easy operation, high accuracy and good precision.
    Determination of ginkgolic acids in Ginkgo biloba leaves by gas chromatography with on-line pyrolytic methylation
    WANG Lili, JIA Yilü, PAN Zaifa, XU Hongxing, ZHENG Xusong, Lv Zhongxian
    2008, 26 (6):  731-735. 
    Abstract ( 2541 )   [Full Text(HTML)] () PDF (303KB) ( 712 )  
    A method to determine ginkgolic acids in Ginkgo biloba leaves was developed on the basis of pyrolytic methylation-gas chromatography. Pyrolytic methylation of G. biloba leaves in the injector at 300 ℃ in the presence of an organic alkali, tetramethylammonium hydroxide (TMAH, 25% methanol), allowed quantitative analysis of ginkgolic acids as their corresponding methyl derivatives. On the basis of the relative areas of these peaks, chemical composition of the ginkgolic acids in G. biloba leaves was determined with the relative standard deviations (RSDs) less than 3.4%(n=3). The calibration curves of 5 main ginkgolic acids showed good linearity with the correlation coefficients greater than 0.9966. The detection limits were between 0.8-2.8 mg/kg for the 5 compounds (S/N=3). It is a simple, accurate and highly sensitive method for the chemical analysis and quality control of ginkgolic acids in G. biloba leaves and extracts.
    Extraction and ultra-performance liquid chromatographic analysis of adenosine phosphates in royal jelly
    CHEN Lanzhen, LI Guifen, XUE Xiaofeng, WU Liming, ZHAO Jing, HUANG Jingping, YUAN Hancheng
    2008, 26 (6):  736-739. 
    Abstract ( 2498 )   [Full Text(HTML)] () PDF (194KB) ( 852 )  
    Several different extraction procedures including perchloric acid extraction, boiling water extraction and boiling magnesium sulfate solution extraction were studied for the extraction of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) from the royal jelly. Among these methods, the extraction with 5% perchloric acid at below 4 ℃ was the optimum extraction method. A simple, fast and sensitive ultra-performance liquid chromatographic (UPLC) method was developed for the determination of ATP, ADP and AMP in royal jelly. The separation was achieved within 4 min using a BEH Shield RP18 column (100 mm×2.1 mm, 1.7 μm) with 50 mmol/L monoammonium phosphate solution (pH 6.5) and acetonitrile as the mobile phase. The spiked recoveries of ATP, ADP and AMP were 84.1%-94.3%、86.2%-93.7% and 91.0%-104.3%, respectively. The relative standard deviations were less than 10%. This method was successfully applied to the analysis of some royal jelly samples from beekeepers and markets for the investigation of distribution of ATP, ADP and AMP in royal jelly samples.
    Simultaneous determination of diflubenzuron and triflumuron residues in greasy wool using high performance liquid chromatography
    WANG Heng, ZHAO Jie, CHEN Zhiwei, HE Pingang, FANG Yuzhi
    2008, 26 (6):  740-743. 
    Abstract ( 2301 )   [Full Text(HTML)] () PDF (294KB) ( 708 )  
    new method has been developed for the simultaneous determination of diflubenzuron and triflumuron residues in greasy wool by reversed-phase high performance liquid chromatography (HPLC). The pesticides were extracted by hexane-ether from greasy wool and cleaned up with gel permeation chromatography (GPC) and solid phase extraction (SPE). The pesticides were analyzed by HPLC-diode array detector (DAD) and quantified by external standard method. The linear ranges of diflubenzuron and triflumuron were 0.41-41 mg/L and 0.38-38 mg/L, and the correlation coefficients were 0.9996 and 0.9999, respectively. The limits of detection were 0.22 mg/kg for diflubenzuron and 0.18 mg/kg for triflumuron; the limits of quantification were 0.73 mg/kg for diflubenzuron and 0.60 mg/kg for triflumuron. The average recoveries of pesticides spiked levels from 0.76 to 10.25 mg/kg in greasy wool samples were in the range of 86.3%-96.7%, and the relative standard deviations were 4.2%-8.7%. The method developed shows little interferences, good recovery and repeatability. It is suitable for the simultaneous determination of diflubenzuron and triflumuron in greasy wool samples.
    Application of solid-phase extraction and matrix solid-phase dispersion in orange sample preparation for organophosphorous pesticide residues analysis
    YANG Haiyu, YU Ying, ZHENG Xiuli
    2008, 26 (6):  744-748. 
    Abstract ( 2614 )   [Full Text(HTML)] () PDF (423KB) ( 799 )  
    A solid-phase extraction (SPE)-reversed-phase high performance liquid chromatographic (RP-HPLC) method for the determination of phoxim and diazinon in oranges has been developed. The analytical procedure involved in the ultrasonic extraction with methanol, the purification using a C18 SPE column, and the separation on a liquid chromatography column by the isocratic elution with acetonitrile-water (85∶15, v/v) at the flow rate of 0.7 mL/min and the ultraviolet wavelength of 254 nm. The results demonstrated that the linear ranges of phoxim and diazinon were 0.1-10.0 mg/L and 0.4-10.0 mg/L, and the detection limits of 4.1 and 6.7 μg/L, respectively. The average recoveries ranged from 87.3% to 102.7% with the relative standard deviations of 0.9%-4.9% at the spiking levels of 0.10 and 0.5 mg/kg in orange samples. The analytical results obtained by SPE were compared with those of the matrix solid-phase dispersion (MSPD) cleanup method. The recovery of diazinon using the SPE cleanup method was better, but the MSPD cleanup method was much suitable for phoxim. The lower background can be obtained via each cleanup method.
    Technical Notes
    Determination of melamine residue in foods using gas chromatography-tandem mass spectrometry
    LU Yeju, SHU Yong, ZHAO Chengshi
    2008, 26 (6):  749-751. 
    Abstract ( 2649 )   [Full Text(HTML)] () PDF (195KB) ( 1028 )  
    A method of gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for melamine residue in foods. The sample was extracted under ultrasonication with trichloroacelic acid (TCA), the protein in the sample was precipitated with zinc acetate solution. The extract was centrifuged, filtered, purified, derivatized and detected using GC-MS/MS in multiple-reaction monitoring mode. The limit of detection for melamine was 1 μg/kg. The good linearity in the range of 0.1-100 μg/L was obtained. The relative standard deviation (RSD) of peak area was less than 9%. This method has been applied to the analysis of melamine in milk powder, toffee, milk beverages, biscuits and other foods. It provides a method for the detection of abuse of melamine.
    Determination of melamine in milk powder and milk by high performance liquid chromatography
    HE Qiaosang, LIU Minfang, HUANG Liying, YANG Yuanyuan, LIAO Shangfu
    2008, 26 (6):  752-754. 
    Abstract ( 2706 )   [Full Text(HTML)] () PDF (187KB) ( 1644 )  
    The analytical method of melamine in milk and milk powder by high performance liquid chromatography (HPLC) was established. The sample was purified by a cation exchange solid-phase extraction column, separated on a Diamonsil C18 column (4.6 mm×200 mm, 5 μm) with acetonitrile-0.01 mol/L sodium heptanesulfonate (pH 3.3) (10∶90, v/v) as mobile phase at a flow rate of 1.0 mL/min, and determined by a photodiode array detector. A linear calibration curve was obtained in the concentration range of 1-500 mg/L. The qualification limit was 0.2 mg/kg, and the quantification limit was 1 mg/kg. The recovery was 81.4%-83.7%.
    Determination of melamine in milk and milk powder by high performance capillary electrophoresis
    RAO Qinxiong, TONG Jing, GUO Ping, LI Haiyan, LI Xiaowei, DING Shuangyang
    2008, 26 (6):  755-758. 
    Abstract ( 2740 )   [Full Text(HTML)] () PDF (261KB) ( 907 )  
    A high performance capillary electrophoresis (HPCE) method has been established for the separation of melamine in milk and milk powder. The separation was carried out on a fused-silica uncoated capillary column (58.5 cm×75 μm). The sample was injected by hydrodynamic injection (3.5 kPa (35 mbar)×8 s) at a temperature of 25 ℃. The analysis was completed in about 6 min in 40 mmol/L Na2HPO4-20 mmol/L citric acid buffer (pH 2.6) at 25 kV of separation voltage and 232 nm of detection wavelength. The linear range of melamine was 1-100 mg/kg, and the correlation coefficient was higher than 0.997. The limits of quantification (LOQs) in milk and milk powder were 0.5 mg/kg and 1.0 mg/kg, respectively. The average recoveries were in the range of 72.2%-97.3% in the spiked range of the concentration of LOQs and 50 mg/kg, and the relative standard deviations were between 2.1% and 3.9%.
    Determination of melamine residue in raw milk and dairy products using hydrophilic interaction chromatography-electrospray ionization tandem mass spectrometry
    YAN Lijuan, WU Min, ZHANG Zhigang, ZHOU Yu, LIN Liyi, FANG Enhua, XU Dunming, CHEN Luping
    2008, 26 (6):  759-762. 
    Abstract ( 2640 )   [Full Text(HTML)] () PDF (238KB) ( 966 )  
    A method for the determination of melamine residue in raw milk and dairy products was developed using hydrophilic interaction chromatography-electrospray ionization tandem mass spectrometry (HILIC-ESI-MS/MS). The melamine residue in the test sample was extracted with 1% trichloroacetic acid-acetonitrile (1∶1, v/v) solution. The homogenate was centrifuged and the supernatant was collected. The extract was cleaned up using a mixed-mode cation exchange (MCX) solid-phase extraction cartridge and then concentrated, and analyzed by HILIC-ESI-MS/MS. The gradient chromatographic separation was performed using a hydrophilic silica column (250mm×4.6 mm, 5 μm) with 10 mmol/L ammonium acetate buffer (pH 3.0) and acetonitrile as the mobile phases. Due to its hydrophilic property, melamine was well retained on the column and seperated from other compounds. It effectively reduced matrix effect. A triple quadruple mass spectrometer equipped with an electrospray ionization source was employed for the qualitative and quantitative measurement of melamine. The melamine was quantified using the fragments produced from the protonated melamine ion through multiple reaction monitoring (MRM) in positive ion mode. Two MRM transitions from the protonated melamine ion (m/z 127→85 and m/z 127→68) were monitored. The average recoveries were between 76.3% and 98.7% in the spiked range of 0.5 to 10 mg/kg in raw milk and dairy products, and the relative standard deviations were less than 6.8%. The linear range was from 0.05 to 10.0 mg/L. The limit of quantification (S/N>10) was 0.05 mg/kg. The method is highly selective and sensitive for the measurements of melamine and adequate for the analysis of melamine in raw milk and dairy products.
    Simultaneous determination of cefuroxime axetil and ornidazole in tablet dosage form using reversed-phase high
    RANJANE Poonam N, GANDHI Santosh V, KADUKAR Sayali S, RANHER Sandeep S
    2008, 26 (6):  763-765. 
    Abstract ( 2420 )   [Full Text(HTML)] () PDF (160KB) ( 664 )  
    A simple, accurate and sensitive reversed-phase high performance liquid chromatographic (RP-HPLC) method for the simultaneous determination of cefuroxime axetil and ornidazole in combined tablet dosage form has been developed. The method was performed with a HiQ-SiL C18 column (250 mm×4.6 mm) and photodiode array (PDA) detector, using 0.01 mol/L potassium dihydrogen orthophosphate-methanol (56∶44, v/v) as the mobile phase and tinidazole as the internal standard. Beer’s law obeys in the concentration ranges of 5-25 μg/mL and 10-50 μg/mL for cefuroxime axetil and ornidazole, respectively. The method has been successfully validated statistically and applied for the analysis of the drugs in pharmaceutical formulation.
    Chiral separation of bisoprolol using high performance liquid chromatography with amylose chiral stationary phase
    LI Fang, LI Jiayang, ZHANG Huayan, GUO Xingjie
    2008, 26 (6):  766-768. 
    Abstract ( 2402 )   [Full Text(HTML)] () PDF (197KB) ( 753 )  
    A high performance liquid chromatographic (HPLC) method using amylase chiral stationary phase for the separation of bisoprolol enantiomers has been developed. Tris(3,5-dimethylphenyl carbamate) amylase chiral stationary phase was used in the normal-phase mode. The effects of the concentration of organic solvents (iso-propanol and ethanol), flow rate and column temperature on the enantiomer separation were studied systematically. The best separation was obtained with hexane-ethanol-diethyl amine (88∶12∶0.1, v/v/v) as mobile phase at 20 ℃. The optimal flow rate was 0.6 mL/min. The detection wavelength was set at 270 nm.By using this method, the enantiomers of bisoprolol can be separated quickly and easily.
    Determination of polycyclic aromatic hydrocarbons in soil by ultra performance liquid chromatography
    CHEN Hao, LIU Ying, LIU Hailing, YUAN Yuan, XIAO Qianfen
    2008, 26 (6):  769-711. 
    Abstract ( 2365 )   [Full Text(HTML)] () PDF (229KB) ( 1075 )  
    An analytical method based on ultra performance liquid chromatography (UPLC) coupled with a photodiode array (PDA) detector has been developed for the simultaneous determination of 16 polycyclic aromatic hydrocarbons (PAHs). The comparison of UPLC and the conventional high performance liquid chromatography (HPLC) has been carried out. The major advantages of UPLC over HPLC include the faster analysis speed, considerably increased sensitivity and significantly improved detection limit. By UPLC, the whole analytical process can be performed in 13.5 min and the limits of detection for the 16 PAHs were between 2 pg and 20 pg
    Determination of residual monomers in polymer water treatment chemicals using high performance liquid chromatography
    FU Junfang, LIU Keqing, DING Yu, WANG Lei, HUANG Ruijuan, MA Zhengsheng
    2008, 26 (6):  772-774. 
    Abstract ( 3134 )   [Full Text(HTML)] () PDF (229KB) ( 866 )  
    A method was developed for the determination of residual monomers in polymer water treatment chemicals (sodium of polyepoxysuccinic acid (PESA), acrylic acid/maleic anhydride copolymer (AA/MA), polyacrylic acid (PAA), sodium of hydrolyzed polymaleic acid (HPMA), and maleic anhydride/acrylic acid/methyl acrylate copolymer(MA/AA/MAc) using high performance liquid chromatography. The separation was performed on a ZORBAX 300SB-C18 column (5 μm, 150 mm×4.6 mm). The mobile phase was 0.01 mol/L KH2PO4 (pH 2.3, adjusted by 5%H3PO4)-methanol (95∶5, v/v) with a flow rate of 0.6 mL/min. The detection wavelength was set at 210 nm and the column temperature was 30 ℃. The sample was diluted by the mobile phase and filtrated for analysis. The residual monomers of maleic acid, fumaric acid and acrylic acid were completely separated and determined in 10 min, and the limits of detection were 0.5, 0.5, and 0.2 mg/L, respectively. The average recoveries were 98.9%-103.7% with the relative standard deviations of 1.09%-1.69%. The correlation coefficients for the linear equations were 0.9996-0.9999. These results demonstrate that the proposed method is simple, sensitive and reliable for the determination of the residual monomers in five polymer water treatment chemicals.
    Determination of carbofuran residue in aquatic products by gas chromatography
    WANG Miao, LI Rong, ZOU Shiping
    2008, 26 (6):  775-777. 
    Abstract ( 2353 )   [Full Text(HTML)] () PDF (178KB) ( 908 )  
    A capillary gas chromatographic (GC) method was developed for the determination of carbofuran residue in aquatic products (Ctenopharyngodon idellus and Penaens vannamei). The sample was extracted with acetonitrile, defatted by hexane, re-extracted by acetoacetate and cleaned up with a Al2O3 column, and then determined by GC. The standard curve was linear in the investigated range of 0.1-10.0 mg/L. The correlation coefficients were more than 0.9995, the recoveries were 78%-90% with the relative standard deviations of 2.49%-9.59%at the spiking levels of 0.02-10.0 mg/kg. The detection limit of carbofuran was 0.02 mg/kg.