牛奶中抗生素的液相芯片检测方法研究

利用悬液芯片系统建立了一种快速、多成份、高灵敏、高通量的抗生素残留的检测方法.使用表面具有羧基的微球作为固相载体,将人工合成的抗生素全抗原键合到微球上作为捕获抗原,与样品中的抗生素竞争体系中抗生素的单克隆抗体,使用藻红蛋白标记的二抗作为荧光探针,构建间接竞争反应体系.反应体系经悬液芯片系统可对荧光探针进行测定并对包被不同抗原的不同型号微球进行分类识别,实现抗生素的高通量检测.以检测牛奶中头孢氨苄、卡那霉素为例,头孢氨苄、卡那霉素的检测限分别为13.98 ng/mL、23.44 ng/mL,50%抑制的质量浓度(IC50)分别为56.88 ng/mL、190.09 ng/mL.     

荧光法同时测定环境水中的As(Ⅲ)和As(V)

研究了一种快速、灵敏的同时测定水中的As(Ⅲ)和As(V)的荧光新方法。在pH=6.5~7.5的缓冲介质中,利用2’,7’-二氯荧光素(DCF)作为荧光试剂,激发波长λex=510nm,发射波长λem=528nm下,As(Ⅲ)和DCF竞争碘,引起荧光强度的增强,从而测定痕量As(Ⅲ)。同时利用L一半胱氨酸还原剂将水中的As(V)还原成As(Ⅲ),从而测定As(Ⅲ)和As(v)的总量,差减间接测定As(V)。As(Ⅲ)浓度在4~180ng/mL范围内,相对荧光强度差值与As(Ⅲ)浓度呈线性关系,线性方程△F=7.82C+0.76,相关系数为o.9991,本法快速、简便、灵敏度高,已用于检测自来水和池塘水中痕量的As(Ⅲ)和As(V),回收率在96%~105%,结果令人满意。     

前列腺特异性抗体电化学免疫传感器的研制

利用自组装的方法在金电极上制得巯基丁二胺铜(Ⅱ)/纳米金胶/前列腺特异性抗体(抗PSA)免疫修饰电极。用该修饰电极对PSA进行检测,发现其循环伏安图的氧化还原峰电流都随PSA浓度的增高而降低,峰电位没有变化。其最佳实验条件包括:pH5.2的0.1mol/L磷酸盐缓冲液作为底液,以及用示差脉冲方式进行定量测定。结果显示:该传感器的氧化峰电流减少值与PSA浓度在0.005-0.48μg/mL范围内成线性关系,检测下限为2ng/mL.在40 ng/mLPSA浓度下八次测量相对标准偏差为2.9%,该免疫传感器的稳定性和抗干扰性都较好。对血清中的PSA进行检测,获得满意的结果。     

饲料微生物添加剂中地衣芽孢杆菌实时荧光PCR检测

建立饲料添加剂中地衣芽孢杆菌实时荧光聚合酶链式反应(polymerase chain reaction,PCR)检测方法,评价此方法的特异性和灵敏度,并经实际样品检测。结果显示,该方法特异性良好,检测灵敏度均能达到103 CFU/mL,可用于饲料添加剂中地衣芽孢杆菌的快速检测。     

离子色谱法在饮用水溴酸盐分析中的应用

采用抑制电导离子色谱法(IC)检测饮用水中的痕量溴酸盐.对样品中高浓度的干扰组分氯离子进行了处理,避免其对测定的影响.溴酸盐浓度在5ng/mL～100ng/mL范围内具有良好的线性关系,相关系数为0.9999,方法的定量限为2ng/mL(S/N=10),样品加标回收率大于91.6%.该方法经试验,成功地试用于各种饮用水中溴酸盐含量的测定.     

GC-MS法测定食品包装材料印刷油墨中光引发剂二苯甲酮和4-甲基二苯甲酮

建立了气相色谱-质谱(GC-MS)检测食品包装材料表面印刷油墨中光引发剂二苯甲酮(BP)和4-甲基二苯甲酮(MBP)迁移量的方法。样品以正己烷为提取溶剂进行振荡提取和超声波辅助萃取,提取液用GC-MS分析检测。结果表明:该方法线性范围为0.02～0.1mg/mL,检测限为0.004～0.005mg/mL,在0.01,0.02,0.10mg/mL 3个添加水平下,2种光引发剂的平均回收率为88.2%～114.5%,相对标准偏差(n=6)为5.13%～7.95%。该方法简单快速,适用于食品包装材料的日常检测需要。     

三维荧光二阶校正法用于水样中培氟沙星和 氧氟沙星的同时测定

提出三维荧光二阶校正法,用于环境水样中氟喹诺酮类抗生素培氟沙星和氧氟沙星的同时定量分析.即在激发波长为230～400 nm,发射波长为360～580 nm范围内,测定样品(包含校正样、验证样、测试样)的三维荧光光谱,构建三维荧光响应数据阵;经数据处理后,采用交替三线性分解算法进行分解,得到与物质相关的相对激发、相对发射和相对浓度谱信息;通过对浓度信息进行单变量校正,获得校正曲线,进一步预测真实浓度.结果表明,培氟沙星和氧氟沙星的平均回收率分别为(101.1±5.3)％,(99.7±4.7)％,检测限分别为2.14,4.34 ng/mL,定量限分别为6.49,13.16 ng/mL.三维荧光二阶校正法可以在未知干扰物共存下,同时定量分析环境水样中培氟沙星和氧氟沙星,实现二阶优势.     

荧光法同时测定环境水中的As(Ⅲ)和As(Ⅴ)

研究了一种快速、灵敏的同时测定水中的As(Ⅲ)和As(Ⅴ)的荧光新方法。在pH=6．5～7．5的缓冲介质中，利用2’，7’-二氯荧光素(DCF)作为荧光试剂，激发波长λex=510nm，发射波长λem=528nm下，As(Ⅲ)和DCF竞争碘，引起荧光强度的增强，从而测定痕量As(Ⅲ)。同时利用L-半胱氨酸还原剂将水中的As(Ⅴ)还原成As(Ⅲ)，从而测定As(Ⅲ)和As(Ⅴ)的总量，差减间接测定As(Ⅴ)。As(Ⅲ)浓度在4～180ng／mL范围内，相对荧光强度差值与As(Ⅲ)浓度呈线性关系，线性方程△F=7．82C 0．76，相关系数为0．9991，本法快速、简便、灵敏度高，已用于检测自来水和池塘水中痕量的As(Ⅲ)和As(Ⅴ)，回收率在96％～105％，结果令人满意。     

苯基荧光酮分光光度法测定微量钼(Ⅵ)

研究了在表面活性剂CTMAB存在下,1.5～2.5moL/L硫酸介质中显色剂苯基荧光酮(苯芴酮)与钼(Ⅵ)的分光光度性质及反应条件,其最大吸收波长λmax=523nm,检测钼(Ⅵ)范围为0 ～20μg/25mL,符合朗伯-比尔定律,相关系数为R=0.9988.并试验了多种离子的干扰情况,建立了分光光度法测定微量钼的高灵...     

胶束增敏荧光光度法测定兔血样中阿霉素

基于阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)对蒽环类抗生素阿霉素的荧光强度有增敏作用,通过考察CTAB浓度、缓冲液pH及浓度、有机溶剂等对阿霉素荧光强度的影响,建立胶束增敏荧光光度法测定阿霉素的新方法。在体系为17mmol/L的硼酸缓冲液(pH 6.0)且含60%(v/v)乙醇、1.9mmol/L CTAB的条件下,阿霉素在0.5～120 ng/mL浓度范围内荧光强度呈良好的线性(r=0.999 2),检出限(3σ)为0.161 ng/mL。该方法用于测定兔血样中阿霉素时,回收率在93.7%～105.6%之间,相对标准偏差小于1.5%。结果表明该方法具有较好的准确度与灵敏度,可用于临床监测。     

Novel Mucoadhesive Oral Patch Containing Diazepam

The oral patch of diazepam (DZ) was developed to achieve a rapid absorption of DZ for the emergency treatment of epileptic seizure or anxiety disorder. The patch was composed of the outer mucoadhesive Carbopol 934 region, central drug region, and Tegaderm backing film. DZ (3 mg) was dissolved in propylene glycol (PG) alone or PG containing oleic acid (OA) at 5.6% (w/w), and used as the drug region. The patches with and without OA were attached to the mucosa of cheek in rats. The patch with OA exhibited the plasma level of more than 200 ng/mL at 10 min after administration, then the plasma concentration decreased gradually. The patch without OA displayed a plasma level of less than 30 ng/mL during 40 min after administration. To the contrary, in the in vitro drug permeation using a cellulose membrane, the patch without OA showed a three times faster permeation rate than the patch with OA, suggesting that the direct action of OA to mucosa might be associated with absorption enhancement. It was demonstrated that the patch with OA showed a good adhesion to oral mucosa and worked efficiently for rapid absorption of DZ.     

Novel mucoadhesive oral patch containing diazepam

The oral patch of diazepam (DZ) was developed to achieve a rapid absorption of DZ for the emergency treatment of epileptic seizure or anxiety disorder. The patch was composed of the outer mucoadhesive Carbopol 934 region, central drug region, and Tegaderm backing film. DZ (3 mg) was dissolved in propylene glycol (PG) alone or PG containing oleic acid (OA) at 5.6% (w/w), and used as the drug region. The patches with and without OA were attached to the mucosa of cheek in rats. The patch with OA exhibited the plasma level of more than 200 ng/mL at 10 min after administration, then the plasma concentration decreased gradually. The patch without OA displayed a plasma level of less than 30 ng/mL during 40 min after administration. To the contrary, in the in vitro drug permeation using a cellulose membrane, the patch without OA showed a three times faster permeation rate than the patch with OA, suggesting that the direct action of OA to mucosa might be associated with absorption enhancement. It was demonstrated that the patch with OA showed a good adhesion to oral mucosa and worked efficiently for rapid absorption of DZ.     

Clonazepam Oral Droplets for the Treatment of Acute Epileptic Seizures

Oral droplet formulations of clonazepam (CZ) were developed to examine their potentials as an alternative to i.v. administration for the treatment of acute epileptic seizures. Propylene glycol containing 2.5% (wt/wt) CZ with or without 5.0% (wt/wt) oleic acid (OA) was prepared as a solution by heating at 90°C and subsequently lowering the temperature to 30°C. The droplet (20 μL) was administered to the oral cavity between the lower gum and bottom lip before CZ precipitation started. With a droplet of propylene glycol loaded with 2.5% (wt/wt) CZ and 5.0% (wt/wt) OA, the plasma concentration reached 20 ng/mL (minimal effective concentration) within 10 min and was maintained between 20 and 60 ng/mL, less than a toxic level, for a period of 60 min. For a droplet of propylene glycol loaded only with CZ at 2.5% (wt/wt), it took more than 15 min for the plasma concentration to reach 20 ng/mL. It is suggested that a droplet of CZ/OA/propylene glycol (2.5:5.0:92.5, wt/wt) might be useful as an alternative to i.v. injection of CZ for the treatment of acute epileptic seizures.     

Clonazepam oral droplets for the treatment of acute epileptic seizures

Oral droplet formulations of clonazepam (CZ) were developed to examine their potentials as an alternative to i.v. administration for the treatment of acute epileptic seizures. Propylene glycol containing 2.5% (wt/wt) CZ with or without 5.0% (wt/wt) oleic acid (OA) was prepared as a solution by heating at 90 degrees C and subsequently lowering the temperature to 30 degrees C. The droplet (20 microL) was administered to the oral cavity between the lower gum and bottom lip before CZ precipitation started. With a droplet of propylene glycol loaded with 2.5% (wt/wt) CZ and 5.0% (wt/wt) OA, the plasma concentration reached 20 ng/mL (minimal effective concentration) within 10 min and was maintained between 20 and 60 ng/mL, less than a toxic level, for a period of 60 min. For a droplet of propylene glycol loaded only with CZ at 2.5% (wt/wt), it took more than 15 min for the plasma concentration to reach 20 ng/mL. It is suggested that a droplet of CZ/OA/propylene glycol (2.5:5.0:92.5, wt/wt) might be useful as an alternative to i.v. injection of CZ for the treatment of acute epileptic seizures.     

高效液相色谱-串联质谱法测定贻贝中腹泻性贝类毒素的含量

采用液相色谱-串联质谱法检测了贻贝中大田软海绵酸(OA)和鳍藻毒素-1(DTX-1)两种腹泻性贝类毒素的含量。样品经80%甲醇水溶液提取,Sep-pak silica固相萃取小柱净化,80%甲醇水溶液定容后供HPLC-MS/MS分析。采用电喷雾负离子模式多反应监测方式进行检测,OA和DTX-1的定量检测的离子对分别为m/z 803.5/255.1和m/z817.4/255.1。2种贝类毒素在20~800μg/L范围内线性良好;在4个添加水平下OA的回收率为79.5%～88.6%,RSD为8.43%～10.4%;DTX-1的回收率为83.8%～91.2%,RSD为4.22%～6.54%。方法灵敏度高,定量限为0.02mg/kg。来自市场和产地的45个贻贝样品残留分析发现,有4个样品检出腹泻性贝类毒素,检出率为8.9%。     

Analytical method for the determination of metolachlor,acetochlor, alachlor,dimethenamid, and their corresponding ethanesulfonic and oxanillic acid degradates in water using SPE and LC/ESI-MS/MS

A Good Laboratory Practices (GLP) validated, multiresidue analytical method is presented for the determination of the chloroacetanilide herbicides metolachlor, acetochlor, and alachlor, the chloroacetamide herbicide dimethenamid, and their respective ethanesulfonic (ESA) and oxanillic (OA) acid degradates in ground and surface water. A 50-mL water sample is subjected to purification using a C-18 SPE column. The four parent components and their eight ESA and OA degradates are isolated using 80/20 methanol/water (v/v) for elution. The eluate is reduced to < 1.0 mL and reconstituted in 10/90 acetonitrile/water (v/v) to the desired final fraction volume. Final analysis is accomplished using liquid chromatography/electrospray ionization-mass spectrometry/mass spectrometry in the + (parent compounds) and - (ESA and OA degradates) ion modes by monitoring appropriate precursor/product ion pairs for each of the 12 analytes. The method limit of quantification is 0.10 ppb and the limit of detection is 0.125 ng injected for each analyte. Average procedural recovery data range from 95 to 105% for fortification levels of 0.10-100 ppb. The method validation study was performed following GLP guidelines.     

Controlled release of drugs from gradient hydrogels for high-throughput analysis of cell-drug interactions

In this paper, we report a method to fabricate microengineered hydrogels that contain a concentration gradient of a drug for high-throughput analysis of cell-drug interactions. A microfluidic gradient generator was used to create a concentration gradient of okadaic acid (OA) as a model drug within poly(ethylene glycol) diacrylate hydrogels. These hydrogels were then incubated with MC3T3-E1 cell seeded glass slides to investigate the cell viability through the spatially controlled release of OA. The drug was released from the hydrogel in a gradient manner and induced a gradient of the cell viability. The drug concentration gradient containing hydrogels developed in this study have the potential to be used for drug discovery and diagnostics applications due to their ability to simultaneously test the effects of different concentrations of various chemicals.     

Magnetite-containing spherical silica nanoparticles for biocatalysis and bioseparations

The simultaneous entrapment of biological macromolecules and nanostructured silica-coated magnetite in sol-gel materials using a reverse-micelle technique leads to a bioactive, mechanically stable, nanometer-sized, and magnetically separable particles. These spherical particles have a typical diameter of 53 +/- 4 nm, a large surface area of 330 m(2)/g, an average pore diameter of 1.5 nm, a total pore volume of 1.427 cm(3)/g and a saturated magnetization (M(S)) of 3.2 emu/g. Peroxidase entrapped in these particles shows Michaelis-Mentan kinetics and high activity. The catalytic reaction will take place immediately after adding these particles to the reaction solution. These enzyme entrapping particles catalysts can be easily separated from the reaction mixture by simply using an external magnetic field. Experiments have proved that these catalysts have a long-term stability toward temperature and pH change, as compared to free enzyme molecules. To further prove the application of this novel magnetic biomaterial in analytical chemistry, a magnetic-separation immunoassay system was also developed for the quantitative determination of gentamicin. The calibration for gentamicin has a working range of 200-4000 ng/mL, with a detection limit of 160 ng/mL, which is close to that of the fluorescent polarization immunoassay (FPIA) using the same reactants.     

Synthesis spectrum properties of high-quality CdS quantum dots

High-quality CdS quantum dots with zinc-blende structure were prepared in noncoordinating solvent 1-octadence (ODE), using N-oleoyl-morpholine as an alternative solvent for sulfur powder, oleic acid (OA) as capping ligand. Sulfur powder could be dissolved in N-oleoyl-morpholine at room temperature. The kinetics of nucleation/growth was monitored via the temporal evolution of optical properties of the as-prepared CdS quantum dots. Various synthetic parameters were systematically investigated, such as growth temperature of 190 degrees C-260 degrees C, OA concentrations of 1.5 mL-2 mL, and the feed molar ratios of (0.5-3) Cd/1S. With increasing feed molar ratio of Cd/S, little trap emission could be observed. The feed molar ratio of 3Cd/1S was suggested to be the optimal synthetic window, together with the amount of OA 1.5 mL and the growth temperature of 210 degrees C. The quantum dots with growth periods ranging from 0 to 900 s at 210 degrees C exhibited their first excitonic absorption peak changing from 359 nm to 429 nm and the corresponding average size moved from 2.26 nm to 4.41 nm. The narrowest PL FWHM we obtained was 16 nm. Typical HRTEM images revealed that the as-prepared CdS quantum dots had narrow size distribution and high crystallinity.     

Effect of uncontrolled factors in a validated liquid chromatography-tandem mass spectrometry method question its use as a reference method for marine toxins: major causes for concern

Chromatographic techniques coupled to mass spectrometry is the method of choice to replace the mouse bioassay (MBA) to detect marine toxins. This paper evaluates the influence of different parameters such as toxin solvents, mass spectrometric detection method, mobile-phase-solvent brands and equipment on okadaic acid (OA), dinophysistoxin-1 (DTX-1), and dinophysistoxin-2 (DTX-2) quantification. In addition, the study compares the results obtained when a toxin is quantified against its own calibration curve and with the calibration curve of the other analogues. The experiments were performed by liquid chromatography (LC) and ultraperformance liquid chromatography (UPLC) with tandem mass spectrometry detection (MS/MS). Three acetonitrile brands and two toxin solvents were employed, and three mass spectrometry detection methods were checked. One method that contains the transitions for azaspiracid-1 (AZA-1), azaspiracid-2 (AZA-2), azaspiracid-3(AZA-3), gimnodimine (GYM), 13-desmethyl spirolide C (SPX-1), pectenotoxin-2 (PTX-2), OA, DTX-1, DTX-2, yessotoxin (YTX), homoYTX, and 45-OH-YTX was compared in both instruments. This method operated in simultaneous positive and negative ionization mode. The other two mass methods operated only in negative ionization mode, one contains transitions to detect DTX-1, OA DTX-2, YTX, homoYTX, and 45-OH-YTX and the other only the transitions for the toxins under study OA, DTX-1, and DTX-2. With dependence on the equipment and mobile phase used, the amount of toxin quantified can be overestimated or underestimated, up to 44% for OA, 46% for DTX-1, and 48% for DTX-2. In addition, when a toxin was quantified using the calibration curve of the other analogues, the toxin amount obtained is different. The maximum variability was obtained when DTX-2 was quantified using either OA or a DTX-1 calibration curve. In this case, the overestimation was up to 88% using the OA calibration curve and up to 204% using the DTX-1 calibration curve. In summary, the correct quantification of DSP toxins by MS detection depends on multiple factors. Since these factors are not taken into account in a validated protocol, these results question the convenience of having MS/MS as a reference method for protecting consumers of marine toxins, moreover if toxicity of each group is considered independently and total toxicity is not summed anymore as it is in the MBA.