Determination of stimulants and narcotics as well as their in vitro metabolites by online CE-ESI-MS

A simple, rapid and sensitive CE-ESI-MS method for the simultaneous analysis of seven stimulants and narcotics (amphetamine, ephedrine, methadone, pethidine, tetracaine, codeine and heroin) was developed. The CE-ESI-MS experimental conditions were optimized as follows: 20?mmol/L ammonium acetate with pH 9.0 as running buffer, the separation voltage of 22?kV and the sheath liquid of isopropanol/water (1:1 v/v) containing 7.5?mmol/L acetic acid with 3.0?μL/min flow rate. Under the optimized conditions, the stimulants and narcotics were well separated within 4.6?min using a 70-cm length fused-silica capillary (50?μm id). The detection limits (S/N=3) of the CE-ESI-MS analysis were in the range of 0.40-1.0?ng/mL. Method repeatability of intra-day and inter-day was satisfactory. The recoveries obtained from the analysis of spiked urine samples were between 84.1 and 108%. The developed method was successfully applied for the simultaneous analysis of methadone, pethidine and codeine and their in vitro metabolites.     

A new method for screening and determination of diuretics by on-line CE-ESI-MS

A rapid, high-resolution and effective new method for analyzing 12 diuretics by CE-ESI-MS was established in this paper. Ten diuretics (except two neutral compounds) could be fast separated by CE with a DAD at 214 nm with a 20 kV voltage within 6 min, using a 50 microm id and 48.5 cm effective length uncoated fused-silica capillary in a 40 mM ammonium formate buffer (pH 9.40). CE was coupled to the mass spectrometer applying an orthogonal electrospray interface with a triple-tube sheath liquid arrangement. The sheath liquid was composed of isopropanol-water (1:1 v/v) containing 30 mM acetic acid with a flow rate of 4 microL/min. Mass spectrum was employed in the positive mode and both full scan mode and SIM scan mode were utilized. All 12 diuretics could be detected and confirmed by MS in a single analysis. Under optimized conditions, LODs for the 12 diuretics were in the range of 0.13-2.7 micromol/L at an S/N of 3, and the correlation coefficients R(2 )were between 0.9921 and 0.9978. The RDSs (n = 5) of the method was 0.24-0.94 % for migration times and 1.6-8.8 % for peak areas. The recoveries of spiked samples of 12 diuretics were between 72.4% and 118%. The real urine samples were injected directly for analysis, with only simple filtration through a 0.22 microm membrane filter in order to remove solid particles, which may cause capillary blockage. Based on the migration times and characteristic ions, the diuretics in urine samples were detected successfully. This CE-ESI-MS method for analyzing diuretics will hopefully be applied to doping control.     

橡胶及橡胶制品中4种酚类防霉剂的高效液相色谱法测定

建立了橡胶及其制品中硝基苯酚(PNP)、2,3,5,6-四氯苯酚(TeCP)、五氯苯酚(PCP)、邻苯基苯酚(OPP)4种酚类防腐剂的高效液相色谱测定方法。样品冷冻粉碎后,经甲醇超声提取,在Venusil-XBP C18色谱柱(250 mm×4.6 mm,5μm)上以10 mmol/L醋酸铵和甲醇为流动相梯度洗脱,采用二极管阵列检测器,PCP、TeCP、OPP的检测波长为220 nm,PNP的检测波长为320 nm。4种酚类防霉剂的质量浓度在0.5~250mg/L范围内与峰面积呈良好的线性关系,相关系数大于0.999 4。丁苯橡胶、硅橡胶基体的加标回收实验结果表明:TeCP、PCP、OPP、PNP在不同基质中的平均加标回收率分别为82%~95%、68%~90%、85%~98%、87%~98%,相对标准偏差小于5%。     

Positional and geometrical anionic isomer separations by capillary electrophoresis-electrospray ionization-mass spectrometry

Capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) was applied to the analysis of polar positional and geometrical anionic isomers. Since the investigated positional and geometrical anionic isomers have different pK(a) values, they could be separated by CE-ESI-MS under simple analytical conditions using a bare fused-silica capillary and volatile ammonium acetate buffer after optimizing buffer pH. Ortho-, meta-, para-hydroxybenzoate positional isomers were completely separated on a fused-silica capillary with 20 mM ammonium acetate buffer at pH 10.0, and cis-, trans-cyclohexane dicarboxylate geometrical isomers could be also separated with 20 mM ammonium acetate buffer at pH 4.0. Several analytical parameters affecting ESI-MS sensitivity were also investigated. It was found that both running buffer pH and sheath liquid pH had significant effects on the selectivity and the sensitivity on CE-ESI-MS analysis while sheath flow rate and other parameters had little influence. Under optimized conditions, linearity, detection limit, and repeatability of the analysis of hydroxybenzoate isomers were examined, and good results were obtained. It was found that the method presented in this paper is a simple, robust, and cost-effective method for simultaneous analysis of positional and geometrical anionic isomers as well as of other small anionic compounds.     

Design of a sheathless capillary eletrophoresis-mass spectrometry probe for operation with a Z-spray ionization source

The construction of a sheathless interface for capillary electrophoresis-electrospray ionization mass spectrometry (CE-ESI-MS), for operation with a Z-Spray source on a Micromass Quattro-LC triple quadrupole mass spectrometer is described. Designing the interface involved machining a probe compatible with the setup already in place on the mass spectrometer, i.e., MegaFlow-Z ESI. The probe was made of Lexan with the same dimensions as the ESI probe supplied with the instrument. The electrical connection at the electrospray end of the CE capillary was made possible by gold-coating (sheathless CE-ESI-MS). The probe design as well as the electrical and power supply requirements are described in detail. Experiments were performed using this interface, and CE separations of mixtures containing pmole and sub-pmole amounts of peptides were monitored by on-line MS. For a standard peptide mixture (10(-4) M), separation efficiency was typically characterized by N > 10(4) theoretical plates with S/N > 400. Using the same experimental setup, it was also possible to conduct on-line CE-ESI-tandem MS (MS/MS) experiments on the same peptide mixture, and to determine the sequence of the peptides. MS/MS scan functions for different precursor ions were used either alternately or sequentially and the results from both methods were compared. The possibility of peptide mass mapping was explored, and CE-ESI-MS results were obtained for the digestion products of equine myoglobin. Separation efficiencies and S/N values were similar to those obtained for standard peptides. A complete map of the digestion products was obtained.     

Metabolite profiling of human urine by CE-ESI-MS using separation electrolytes at low pH

We investigated the potential of CE coupled to electrospray MS (CE-ESI-MS) in metabolite profiling of human urine without any sample prefractionation step. A heterogeneous mixture of biologically relevant compounds covering a broad range of physicochemical properties was used to optimize separation conditions in fused-silica capillaries. A running electrolyte containing 50 mM of acetic acid and 50 mM of formic acid at pH 2.5 was used for the CE separations. A sheath-flow electrospray interface was employed for CE-ESI-MS analysis. Sheath liquids containing 80:20 v/v methanol/water with 0.1% v/v of acetic acid or 60:40 v/v isopropanol/water with 0.5% v/v of ammonia were selected for optimum detection in positive and negative ESI modes, respectively. Reproducibility and sensitivity were studied, and strategies for identification of the separated urinary compounds are suggested. We report major advantages and disadvantages of CE-ESI-MS for metabolite profiling of human body fluids. This work may be regarded as a first step in the use of CE-ESI-MS for reliable differential analysis of body fluids from healthy and diseased individuals.     

Experimental and computational exploration of the dynamic behavior of (PNP)BF2, a boron compound supported by an amido/bis(phosphine) pincer ligand

The diarylamido/bis(phosphine) PNP pincer ligand (2-(i)Pr(2)P-4-MeC(6)H(3))(2)N has been evaluated as a scaffold for supporting a BF(2) fragment. Compound (PNP)BF(2) (6) was prepared by simple metathesis of (PNP)Li (5) with Me(2)SBF(3). NMR spectra of 6 in solution are of apparent C(2) symmetry, suggestive of a symmetric environment about boron. However, a combination of X-ray structural studies, low-temperature NMR investigations, and DFT calculations consistently establish that the ground state of this molecule contains a classical four-coordinate boron with a PNBF(2) coordination environment, with one phosphine donor in PNP remaining "free". Fortuitous formation of a single crystal of (PNP)BF(2)·HBF(4) (7), in which the "free" phosphine is protonated, furnished another structure containing the same PNBF(2) environment about boron for comparison and the two PNBF(2) environments in 6 and 7 are virtually identical. DFT studies on several other diarylamido/bis(phosphine) pincer (PNP)BF(2) systems were carried out and all displayed a similar four coordinate PNBF(2) environment in the ground state structures. The symmetric appearance of the room-temperature NMR spectra is explained by the rapid interconversion between two degenerate four-coordinate, C(1)-symmetric ground-state forms. Lineshape analysis of the (1)H and (19)F NMR spectra over a temperature range of 180-243 K yielded the activation parameters ΔH(?) = 8.1(3) kcal mol(-1) and ΔS(?) = -6.0(15) eu, which are broadly consistent with the calculated values. Calculations indicate that the exchange of phosphine donors at the boron center proceeds by an intrinsically dissociative mechanism.     

气相色谱-负化学源质谱法测定蜂蜜和王浆中4种杀虫剂的残留

建立了气相色谱-负化学源质谱（GC-NCI/MS）测定蜂蜜和王浆中4种杀虫剂残留量的方法。蜂蜜样品由乙酸乙酯提取、乙二胺-N-丙基硅烷（PSA）净化,而王浆样品经乙腈-水（1：1,v/v）提取、C18固相萃取柱净化,采用GC-NCI/MS测定,外标法定量。结果表明：在50~500 μg/L范围内4种农药的线性良好;所有农药的LOD在0.12~5.0 μg/kg之间,LOQ在0.40~16.5 μg/kg之间;在10、15、20 μg/kg 3个添加水平下,4种农药的平均回收率在78.2%~110.0%之间,且RSD均小于14%。所有农药的测定均没有出现干扰峰。该方法简单、快速,准确度、精密度和选择性高,抗干扰能力强,可用于蜂蜜和王浆中这4种农药的快速检测。     

Fast determination of calcium, magnesium and zinc in honey using continuous flow flame atomic absorption spectrometry

A procedure is described for the rapid determination of calcium, magnesium and zinc in honey with no previous mineralization stage. The samples are dissolved in a solution containing dilute hydrochloric acid and a lanthanum salt, and then directly introduced into the flame atomic absorption spectrometer by means of a simple continuous-flow manifold. The computer-controlled system performs an automatic on-line dilution of the solutions, in this way decreasing matrix effects due to the organic matter content and allowing analytical signals within the linear response range to be obtained. Calibration is carried out against aqueous standards. Reproducibilities for calcium and magnesium measurements in the honey samples are close to +/-3%. The detection limit for zinc is 0.2 mug g(-1), the reproducibility obtained for a honey sample containing 1.7 mug g(-1) zinc being +/-5.2%. The results agree with those obtained by means of a lengthy mineralization-based procedure, the main advantages of the non-conventional methodology reported being automation, saving of time and a decrease in the contamination risk.     

Core-shell magnetic porous organic polymer for magnetic solid-phase extraction of fluoroquinolone antibiotics in honey samples followed by high-performance liquid chromatography with fluorescence detection

By monomer-mediated in-situ growth synthesis strategy, with hydroquinone and 1,3,5-tris(4-aminophenyl)benzene as monomers, a core-shell magnetic porous organic polymer was synthesized through a simple azo reaction. Based on this, a magnetic solid-phase extraction–high-performance liquid chromatography–fluorescence detection method was proposed for the analysis of fluoroquinolones in a honey sample. With ofloxacin, ciprofloxacin, enrofloxacin, lomefloxacin, and difloxacin as target analytes, factors affecting the extraction efficiency had been optimized. The LODs were 1.5–5.4 ng/L (corresponding to 0.23–0.81 μg/kg in honey). The linear range was 0.005–20 μg/L for difloxacin, 0.01–20 μg/L for ofloxacin, ciprofloxacin and lomefloxacin, and 0.02–20 μg/L for enrofloxacin. The enrichment factor was 84.4–91.7-fold with a high extraction efficiency of 84.4–91.7%. The method was assessed by the analysis of target fluoroquinolones in honey samples, and the recoveries for the spiked samples were 79.3–95.8%. The results indicated that the established magnetic solid-phase extraction–high-performance liquid chromatography–fluorescence detection method is efficient for the analysis of trace fluoroquinolones in honey.     

A New Strategy for Rapid Classification of Honeys by Simple Cluster Analysis Method Based on Combination of Various Physicochemical Parameters

An array of real honey samples from 3 difl^rent botanical origins and 4 provinces of China, as well as two honeys with common adulterantsfwhite sugar and high fructose com syrup(HFCS)], were analyzed with a new strategy of “simple cluster analysis" based on physicochemical parameters of honey. The results showed that the physicochemical parameters varied greatly for different honey samples. For example, the minimum conductivity of honey samples was less than 1/17 of the maximum value. Therefore, the physicochemical parameters could be used to distinguish different types of honey. The results are promising, as different kinds of testing honey were successfully discriminated into different groups, allowing us to verify the authenticity of honeys. Furthermore, this approach was followed to successfully analyze two honeys with common adulterants, which are difficult to be identified when they are mixed with true honeys. The results indicated the accuracy and reliability of the proposed strategy, and provided more references for the quality classification of honeys.     

Rapid and sensitive determination of two degradation products of flumethrin in honey by ultrasonically assisted extraction and gas chromatography with electron capture detection

A rapid and sensitive method for the determination of 4-fluoro-3-phenoxybenzaldehyde cyanohydrin (FPBC) and 4-fluoro-3-phenoxy-benzaldehyde (FPB) in honey samples using ultrasonically assisted extraction and gas chromatography with electron capture detection (GC-ECD) has been developed. The different factors affecting the efficiency of the extraction were carefully optimized. The honey sample was extracted with a mixture of hexane and dichloromethane (v/v, 1:1) utilizing the ultrasonically assisted technique and cleaned up by solid-phase extraction on Oasis HLB cartridges. The eluate was evaporated to dryness and residues were reconstituted to 1.0 mL with hexane and determined by GC-ECD. The calibration curves of fortified samples showed acceptable linear response (R(2) >0.99) over a range of 3-100 ng/g for FPBC and FPB in seven replicate determinations of six concentrations, respectively, and analysis of variance (ANOVA) with a lack-of-fit test was performed to validate the regression data. Overall average recoveries ranged from 90.9 to 106.2% for honey samples. The detection limits were 0.9 ng/g for FPBC and 1.0 ng/g for FPB, respectively. This method can be successfully applied to routine determination of two degradation products of flumethrin in honey samples.     

化学计量学二阶校正方法结合高效液相色谱用于蜂蜜中10种酚酸类物质的快速定量分析

利用化学计量学二阶校正方法结合高效液相色谱对枣花蜜中10种酚酸类物质的快速定量分析进行了研究。首先通过验证样本研究了所建立模型的准确性。结果显示：10种酚酸类物质的线性相关系数（R）为0.9982~0.9999,平均回收率为97.6%~101.1%,说明所建立的模型稳定可靠。其次,通过模拟蜂蜜试验,确定了固相萃取柱的种类及操作条件（HLB柱,酸化水淋洗,甲醇洗脱）。最后,利用模拟蜂蜜得到的最优条件结合化学计量学二阶校正方法,测定了枣花蜜中10种酚酸类物质的含量,并测得其加标回收率为62.1%~93.8%,考虑到目标分析物的种类较多,且蜂蜜基质极为复杂,该结果基本满足要求。另外,还利用统计与品质因子验证了试验方法的可靠性,结果令人满意。该方法具有简单、快速等优点,可用于复杂基质中多种目标分析物的同时定量分析。     

A polyamine coating for enhanced capillary electrophoresis-electrospray ionization-mass spectrometry of proteins and peptides

A procedure for enhanced capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) of proteins is presented. The use of a newly presented capillary coating, PolyE-323, provided fast separations of typically a few minutes with high efficiency, good deactivation, and no bleeding into the mass spectrometer. Capillaries coated with PolyE-323 showed high stability over a range of pH 2-10, and tolerance towards methanol and acetonitrile, two modifiers commonly used in CE-ESI-MS. Due to the speed and simplicity of the coating procedure, the polymeric surface could, if necessary, easily be regenerated. This capability is especially valuable when working with samples of complex matrix, where a capillary surface cleaning step might be desired in order to eliminate possible memory effects. The potential of PolyE-323-coated capillaries in bioanalysis using CE-ESI-MS was demonstrated by analyzing peptides and proteins up to 66 kDa using time of flight (TOF)-MS. Due to the stable, anodal electroosmotic flow generated by the coating, the use of a sheathless ESI interface was enabled, demonstrated in peptide analysis with attomole sensitivity. The fast on-line CE-ESI-TOF system using PolyE-323-coated capillaries provided efficient separation and detection of a large number of peaks in a short time, exemplified by the analysis of a tryptic digest of bovine serum albumin (BSA). The capability of the developed capillary surface coating was demonstrated by the separation of human plasma and cerebrospinal fluid (CSF).     

混合型离子交换液相色谱-串联质谱法测定蜂蜜中5种氨基糖苷类抗生素残留

建立了混合型离子交换液相色谱-串联质谱测定蜂蜜中链霉素、双氢链霉素、壮观霉素、卡那霉素和阿米卡星等5种氨基糖苷类抗生素的方法。蜂蜜样品采用磷酸盐缓冲溶液提取，分子印迹固相萃取柱富集净化，Obelisc R色谱柱分离，以0.1%（v/v）甲酸水溶液和乙腈为流动相进行梯度洗脱，采用电喷雾电离、正离子模式扫描，多反应监测模式检测，外标法定量。实验结果表明，链霉素和双氢链霉素在5~100 μg/L范围内呈现良好的线性关系，定量限为5 μg/kg；壮观霉素、卡那霉素和阿米卡星在20~500 μg/L范围内呈现良好的线性关系，定量限为20 μg/kg。在空白蜂蜜样品中添加1倍、2倍和5倍定量限水平的5种氨基糖苷类药物，其平均回收率为75.1%~92.3%，相对标准偏差为4.5%~10.7%。该法不添加离子对试剂，可减少对质谱仪的污染，并具有较高的灵敏度，适用于蜂蜜中5种氨基糖苷类抗生素的同时检测。     

Electrospray mass spectrometry of a series of mixed nitrido 99gTc- heterocomplexes conjugated with bioactive molecules

Electrospray ionization mass spectrometry (ESI-MS) was successfully employed for the identification of six nitrido technetium mixed ligand complexes with a general formula of [99gTc(N)(O,S-BID)(PNP)], where PNP represents a heterodiphosphine and O,S-BID represents a simple dianionic bidentate ligand (compounds 1-3) or a more sophisticated N-substituted O,S-cysteine framework conjugated with a bio- active molecule (BAM) (compounds 4-6). In spite of similar coordination spheres exhibited by all the complexes investigated, simple co-ordination compounds 1-3 displayed collisionally-induced fragmentation processes (MSn) different from those observed in biomolecule-containing compounds 4-6. In the latter, more decomposition channels were observed. This behavior is likely to be associated with some additional intramolecular contacts of the biomolecule (or part of the biomolecule) with pendant group(s) incorporated in the PNP-co-ligand. This view is further supported by the observations arising from both in vitro binding affinity experiments and nuclear magnetic resonance investigations. The presence of cationized forms for all compounds 1-6 and the practical lack of the [2M + Na]+ species for biomolecule-containing compounds 4-6 provided further evidence of a subtly different structural conformation.     

Metallosupramolecular chemistry with bis(benzene-o-dithiolato) ligands

The bis(benzene-o-dithiol) ligands H(4)-1, H(4)-2, and H(4)-3 react with [Ti(OC(2)H(5))(4)] to give dinuclear triple-stranded helicates [Ti(2)L(3)](4)(-) (L = 1(4)(-), 2(4)(-), 3(4)(-)). NMR spectroscopic investigations revealed that the complex anions possess C(3) symmetry in solution. A crystal structure analysis for (PNP)(4)[Ti(2)(2)(3)] ((PNP)(4)[14]) confirmed the C(3) symmetry for the complex anion in the solid state. The complex anion in Li(PNP)(3)[Ti(2)(1)(3)] (Li(PNP)(3)[13]) does not exhibit C(3) symmetry in the solid state due to the formation of polymeric chains of lithium bridged complex anions. Complexes [13](4)(-) and [14](4)(-) were obtained as racemic mixtures of the Delta,Delta and Lambda,Lambda isomers. In contrast to that, complex (PNP)(4)[Ti(2)(3)(3)] ((PNP)(4)[15]) with the enantiomerically pure chiral ligand 3(4)(-) shows a strong Cotton effect in the CD spectrum, indicating that the chirality of the ligands leads to the formation of chiral metal centers. The o-phenylene diamine bridged bis(benzene-o-dithiol) ligand H(4)-4 reacts with Ti(4+) to give the dinuclear double-stranded complex Li(2)[Ti(2)(4)(2)(mu-OCH(3))(2)] containing two bridging methoxy ligands between the metal centers. The crystal structure analysis and the (1)H NMR spectrum of (Ph(4)As)(2)[Ti(2)(4)(2)(mu-OCH(3))(2)] ((Ph(4)As)(2)[(16]) reveal C(2) symmetry for the anion [Ti(2)(4)(2)(mu-OCH(3))(2)](2)(-). For a comparative study the dicatechol ligand H(4)-5, containing the same o-phenylene diamine bridging group as the bis(benzene-o-dithiol) ligands H(4)-4, was prepared and reacted with [TiO(acac)(2)] to give the dinuclear complex anion [Ti(2)(5)(2)(mu-OCH(3))(2)](2)(-). The molecular structure of (PNP)(2)[Ti(2)(5)(2)(mu-OCH(3))(2)] ((PNP)(2)[17]) contains a complex anion which is similar to [16](2)(-), with the exception that strong N-H...O hydrogen bonds are formed in complex anion [17](2)(-), while N-H...S hydrogen bonds are absent in complex anion [16](2)(-).     

A comparison of liquid chromatography, capillary electrophoresis, and mass spectrometry methods to determine xyloglucan structures in black currants

Different separation (HPAEC, RP-HPLC, CE) and identification (MALDI-TOF-MS, ESI-MS(n)) techniques were compared to analyse oligosaccharides obtained after incubation of xyloglucan with endo-glucanase. It was possible to analyse xyloglucan oligosaccharides with each technique. Several techniques, including off line (HPAEC-MALDI-TOF-MS) or online (CE-ESI-MS(n), RP-HPLC-ESI-MS(n)) connection provided complementary information on xyloglucan structure. Online CE-MS and RP-HPLC-MS are described for the first time in xyloglucan analysis. Advantages and disadvantages of the techniques for different purposes such as structural characterisation of oligosaccharides or oligosaccharide profiling are discussed. Black currant xyloglucans had a rather simple XXXG-type structure with galactose and fucose containing side chains.     

MOF assisted synthesis of new porous nickel phosphate nanorods as an advanced electrode material for energy storage application

Journal of Solid State Electrochemistry - A highly uniform porous 1-D nickel pyrophosphate (PNP) nanorods have been developed by a simple and green approach for the first time and served as...     

高效液相色谱法检测新西兰Manuka蜂蜜中的甲基乙二醛

建立了高效液相色谱法用于检测新西兰Manuka蜂蜜中的甲基乙二醛。将蜂蜜溶于水后加入邻苯二胺水溶液,在室温、避光条件下衍生化反应8 h以上,产物过0.22 μm滤膜后用HPLC检测。以Kromasil反相色谱柱为分析柱;甲醇和0.1%(v/v)乙酸水溶液为流动相,梯度洗脱;检测波长为318 nm;外标法定量。甲基乙二醛在1~50 mg/L范围内线性良好,相关系数为0.9999;检出限(S/N=3)为0.02 mg/L,定量限(S/N=10)为0.06 mg/L;在50、100、200 mg/kg添加水平下的回收率为98.3%~101.5%,相对标准偏差(n=5)小于5%;衍生化产物在24 h内稳定。实验结果表明,该方法前处理过程简单,具有良好的灵敏度、回收率和重复性,可用于新西兰Manuka蜂蜜的质量控制。该方法也适用于中国蜂蜜中甲基乙二醛的检测。