生物素-亲和素放大酶联免疫吸附法测定双酚A

建立了可用于快速、灵敏地检测双酚A的生物素-亲和素放大酶联免疫吸附测定法,测得最佳实验条件为包被抗原浓度为13.8mg/L、抗体稀释为2.4×105倍,生物素化二抗和酶标亲和素的最佳稀释倍数分别为2000倍和500倍。在优化条件下,方法的线性范围0.2~1000μg/L;最低检出限0.05μg/L。所建立的方法用于食品和唾液中双酚A含量的测定,样品处理简单,结果满意。     

荧光免疫法测定生物样品中的氯胺酮

制备了氯胺酮的多克隆抗体,以间接酶联免疫吸附法为基础,异硫氰酸荧光素为荧光探针,建立了检测氯胺酮的荧光免疫法。在优化的反应条件下,方法的线性范围为1～1000μg/L,检出限为0.48μg/L。不同浓度的氯胺酮在人体血清和尿液样品中的加标回收率在99%～107%。方法适用于生物样品中氯胺酮的检测。     

卡那霉素A酶联适配体检测方法研究

通过EDC法偶联辣根过氧化物酶(HRP)和卡那霉素A(Kanamycin,KaA)分子制备酶标记物,采用棋盘滴定法确定链霉亲和素(Streptavidin,SA)的包被浓度为8 mg/L,通过单因素实验优化了检测条件,建立了卡那霉素A酶联适配体检测(Enzyme-linked aptamer assay,ELAA)方法。本方法半抑制浓度(IC50)为2.2"g/L,检出限(LOD)为0.04"g/L,检测范围(IC20～IC80)为0.07～71.5"g/L,与结构类似物无明显交叉反应;对牛奶、猪肉、猪肝、鸡肉、蜂蜜样品加标回收率在78%～100%之间,平均相对标准偏差小于11.1%。本方法特异性强、灵敏度高,适用于食品中卡那霉素A的快速检测。     

生物素-亲和素放大酶联免疫吸附法测定二乙基磷酸酯类有机磷农药

基于生物素和亲和素之间发生特异性反应,形成多酶系统,建立了二乙基磷酸酯类有机磷农药的竞争酶联免疫分析技术和生物素-亲和素放大酶联免疫分析技术.在优化条件下,二乙基磷酸酯类有机磷农药浓度在1×10-1～1×104 μg/L范围内与抑制率线性关系良好,其线性回归方程为y＝0.1168x+0.6259(r＝0.9889),半...     

PSA分散固相萃取和高效液相色谱-质谱法测定蔬菜中多杀菌素的残留量

建立了用高效液相色谱-质谱联用(HPLC-MS)技术测定蔬菜中多杀菌素残留量的方法。样品经乙腈提取并用无水硫酸镁和氯化钠混合盐盐析后,上层乙腈经分散固相萃取净化,采用HPLC-MS测定。结果表明:多杀菌素A在0.1μg/L～1 mg/L范围内线性良好,相关系数达0.9999;多杀菌素D在1μg/L～5 mg/L范围内线性良好,相关系数为0.9996;在青椒、萝卜、甘蓝等样品中4个加标水平的平均回收率(n=6)为83.2%～111.9%,相对标准偏差为0.6%～9.1%;多杀菌素A和多杀菌素D的方法检测限分别为0.04μg/L和0.2μg/L。     

直接竞争酶联免疫吸附法测定饲料中沙丁胺醇

应用本实验室制备的对沙丁胺醇(SAL)具有高亲和力的多克隆抗体和酶标半抗原,采用包被抗体-酶标半抗原直接竞争模式建立沙丁胺醇的酶联免疫吸附分析(ELISA)法。在优化实验条件下,ELISA法检测沙丁胺醇的线性浓度范围为0.1~1.0×10~3μg/L,沙丁胺醇对抗体-酶标半抗原结合反应的抑制中浓度(Ic50)为14μg/L,相对标准偏差(RSD)为8.6%(n=5),定量检测下限(Ic_(10))为0.29μg/L。在猪饲料中分别添加沙丁胺醇标样10、50、250μg/kg,ELISA法检测的回收率分别为85%~108%、81%~92%和81%~102%,RSD(n=5)分别为9.1%、5.6%和8.9%,对饲料中沙丁胺醇的最低定量检测浓度为4.23μg/kg。利用高效液相色谱-紫外检测(HPLC-UV)法同步测定饲料中添加250μg/kg沙丁胺醇的平均回收率为89%(n=3),相对标准偏差为3.9%。     

基于双核酸适配体的夹心试纸条法在多菌灵检测中的应用研究

建立了一种胶体金标记核酸适配体的试纸条用于多菌灵的快速检测。将核酸适配体CZ13与AuNPs结合作为信号探针，生物素标记的核酸适配体CZ12固定在链霉亲和素包被膜上作为捕获探针。优化了影响灵敏度的实验条件，如信号探针制备中使用的NaCl和适配体的浓度，检测线上链霉亲和素与生物素标记的核酸适配体的摩尔比等。在最佳实验条件下，多菌灵检测范围为0.5～40μg/mL,检测限为0.45μg/mL。该方法可用于实际样品检测，检测时间为15 min,与果蔬中常见农残不存在交叉反应，方法准确、可靠、使用简便，适合样品的现场快速检测。     

磁珠表面核酸探针的固定及电化学方法检测

报道了用戊二醛将氨基修饰的寡核苷酸探针固定于氨基磁珠表面制成核酸传感器，传感器与生物素标记的DNA杂交，再利用亲和素－生物素偶合系统，偶联上亲和素标记的碱性磷酸酶。碱性磷酸酶催化底物α-萘酚磷酸酯（α－NATP）水解形成具有电化学活性的α-萘酚，用示差脉冲伏安法测定杂交结果，本法测得短链DNA片断的浓度线性范围为10－1000μg/L；最低检测限为3μg/L。作者优化了相关的检测条件，并成功测定了乙型肝炎病毒HBV－DNA的片段。     

离心式微固相萃取与液相色谱-质谱联用测定生物样品中新型合成大麻素

建立了离心式微固相萃取与液相色谱-质谱(LC-MS)联用，同步测定尿样和血样中5种新型合成大麻素的分析方法。尿样和血样稀释后在离心条件下通过C18离心式固相萃取柱，甲醇洗脱后LC-MS检测。结果显示，尿液基质中，5种合成大麻素在0.1～10μg/L浓度范围内线性关系良好，相关系数(R²)大于0.994，检出限(LODs)为0.01～0.02μg/L，定量限(LOQs)为0.05～0.08μg/L。全血基质中，5种合成大麻素在0.5～10μg/L浓度范围内线性关系良好，R²大于0.992, LODs为0.05～0.15μg/L, LOQs为0.18～0.50μg/L。在尿样和全血中分别添加0.5, 2, 10μg/L 3个浓度水平的合成大麻素，回收率分别为81.9%～108.3%和75.0%～95.5%，相对标准偏差(RSDs)低于10%。该方法可以满足生物样品中新型合成大麻素的分析需求。     

喷射式流动注射电化学发光免疫检测禽流感H9亚型

利用磁分离和生物素亲和素技术,形成亲和素化磁微球-生物素化抗体-抗原-钌标抗体的免疫夹心复合物,初步建立了体外免疫诊断试剂的制备方法,并利用喷射式流动注射电化学发光体系对制备出的禽流感病毒H9免疫复合物进行检测。实验选择最适的包被抗体,检测抗体和封闭剂,优化Ru标抗体的最佳稀释度。在生物素化的兔抗H9多抗作为亲和素化的磁微球的结合抗体,鼠抗H9单抗作为Ru(bpy)32+标记抗体,2%BSA作为封闭剂,1:50倍稀释的Ru-鼠抗H9单抗条件下,非特异性吸附最低。测定不同浓度的H9抗原,发现抗原浓度在3.125～100μg/mL范围内与电化学发光强度呈较好的线性关系。实验还测定了不同亚型的禽流感病毒、不同来源的毒株和鸡的棉拭子样品。     

双波长叠加吸收光谱法测定药物中的酒石酸美托洛尔

建立了快速、准确测定药物中酒石酸美托洛尔的双波长叠加可见吸收光谱法。在pH 4.55的酸性Tris-盐酸介质及586~740 nm波长范围内,偶氮氯膦Ⅲ与酒石酸美托洛尔反应生成具有两个明显正吸收峰的离子缔合物,最大正吸收波长位于614 nm,次大正吸收波长位于664 nm,表观摩尔吸光系数(κ)分别为6.03×10~4L/(mol·cm)(614 nm)和5.37×10~4L/(mol·cm)(664 nm),酒石酸美托洛尔的质量浓度在0.2~8.6 mg/L范围内服从朗伯-比尔定律,检出限为0.13 mg/L(614 nm)和0.15 mg/L(664 nm)。当采用双波长叠加法测定时,其表观摩尔吸光系数(κ)可达1.14×10~5L/(mol·cm),检出限为0.072 mg/L。该文同时探讨了显色反应的适宜条件、共存物质的影响及吸收光谱特征。实验发现,该反应体系的单波长及双波长叠加吸收光谱法的表观摩尔吸光系数可达5.37×10~4~1.14×10~5L/(mol·cm),方法可用于市售药物中酒石酸美托洛尔含量的测定,加标回收率为98.0%~101%,相对标准偏差(n=6)为1.8%~2.3%。     

Enhancement of palmarumycin C12 and C13 production in liquid culture of the endophytic fungus Berkleasmium sp. Dzf12 by oligosaccharides from its host plant Dioscorea zingiberensis

Three crude oligosaccharides were respectively prepared by acid hydrolysis of three polysaccharides, which were water-extracted polysaccharide (WEP), sodium hydroxide-extracted polysaccharide (SEP) and acid-extracted polysaccharide (AEP) from the rhizomes of Dioscorea zingiberensis. Among the three oligosaccharides, the crude oligosaccharide prepared by acid hydrolysis of WEP was found to be the most efficient elicitor to enhance the production of palmarumycins C(12) and C(13) in liquid culture of endophytic fungus Berkleasmium sp. Dzf12. When OW was applied to the medium at 300 mg/L on day 3 of culture, the maximal yields of palmarumycin C(12) (87.96 mg/L) and palmarumycin C(13) (422.28 mg/L) were achieved on day 15 of culture, which were 9.83 and 3.24-fold in comparison with those (8.95 and 130.43 mg/L) of control, respectively. The results indicate that addition of the oligosaccharides from the host plant D. zingiberensis should be an effective strategy for enhancing production of palmarumycins C(12) and C(13) in liquid culture of endophytic fungus Berkleasmium sp. Dzf12.     

Production of ginseng saponin and polysaccharide by cell cultures ofPanax notoginseng andPanax ginseng

The effects of various combinations of the two kinds of phytohormones, auxin and cytokinin, on cell growth and production of ginseng saponin and polysaccharide were investigated in suspension cultures ofPanax notoginseng. It was found that a high concentration of kinetin (KT) (7 mg/L) seriously inhibited cell growth, but that of benzyl adenine (BA) did not. Under 0.7 mg/L of cytokinin (i.e., KT and BA), 2,4-dichlorophenoxy acetic acid (2,4-D) at 0.2 mg/L was better for the cell cultures than that at 2 or 20 mg/L; and for both naphthalene acetic acid (NAA) and indole acetic acid (IAA), 20 mg/L was their best level for the cell cultures. The highest cell concentration of 11.9 g/L (by dry wt) was obtained with the combination of 0.2 mg/L of 2,4-D and 0.7 mg/L of BA. The highest saponin content of 13.9% was achieved under 2.0 mg/L IAA and 0.07 mg/L KT; its highest production, i.e., 1.13 g/L, was obtained at 0.2 mg/L of 2,4-D and 0.7 mg/L of KT. Under 20 mg/L NAA and 0.7 mg/L KT, the highest polysaccharide content and production were reached, i.e., 16.4% and 1.86 g/L, respectively. In this work, the effects of phytohormones onP. ginseng cell cultures were also studied. A high saponin production of 1.78 g/L was observed at 10 mg/L of indole butyric acid and 0.1 mg/L of BA, and the highest production of polysaccharide (1.95 g/L) was reached with the combination of 10 mg/L NAA and 0.1 mg/L KT.     

反相高效液相色谱法同时测定川芎中的四种内酯类化合物

用反相高效液相色谱法同时测定了川芎中的4种主要内酯类成分(洋川芎内酯-H、洋川芎内酯-I、瑟丹酸内酯和蒿本内酯)。采用XDB-C8柱,以甲醇-1%乙酸水溶液为流动相进行梯度洗脱,甲醇-1%乙酸水溶液的体积比在15 min内从55∶45线性变化至100∶0,流速0.8 mL/min,紫外检测波长280 nm。4种内酯类化合物的检测限为0.011～0.027 μg,回收率为96%～108%。该方法操作简单,结果准确,重现性好,可用于川芎药材及饮片中4种内酯类化合物的同时测定,具有很高的实用价值。     

Uncertainty of the concentration of a copper calibration solution

The postulated uncertainty of many commercially available standard solutions is estimated on the basis of uncertainties of individual preparation steps. The declared concentration of Cu standard solution (1000 ± 2) mg/L was verified by gravimetric analysis (found (1000.7 ± 0.4) mg/L), isotope dilution with commercial and laboratory-prepared isotope-enriched solutions (found (1000.6 ± 16.8) mg/L and (1002.4 ± 3.6) mg/L, respectively), and by atomic absorption spectrometry (found (1001.4 ± 5.3) mg/L). Uncertainty budgets of all used methods are given and the procedures of uncertainty estimation are fully documented.     

Biosorbent for tungsten species removal from water: effects of co-occurring inorganic species

The effect of co-occurring inorganic species on the removal of tungsten from water was investigated using biosorbent (i.e., chitosan coated montmorillonite clay). Simulated natural water and well water from Fallon, NV were used for this study. The concentrations of tungsten (21-541 mg/L) and inorganic species ([H(2)CO(3)]=0-4.2 mg/L, [H(4)SiO(4)]=0-90 mg/L, and [SO(2-)(4)]=0-400 mg/L) in simulated feed water were varied. The concentration of tungsten in the well water was 26 microg/L. The pH level of simulated feed water and well water was adjusted to 4 since this pH was found to be the most effective pH for the tungsten removal using chitosan coated clay. Tungsten removal without the existence of co-occurring inorganic species decreases from 99.8 to 87.1% with an increase in initial tungsten concentration from 21 to 541 mg/L. It reduces further as the co-occurring inorganic species concentration increases. The percentage of the tungsten removal ranges between 68.2-93.8%, 66.7-94.2%, and 53.6-93.7% for simulated natural water containing varied amount of H(2)CO(3), H(4)SiO(4), and SO(2-)(4), respectively. The adsorption kinetic data could be best described by the pseudo second order expression. The adsorption equilibrium data was modeled with the Langmuir, Temkin, and Freundlich equations and was found to be represented well by the Langmuir equation. The essential characteristics of the Langmuir isotherm indicate that the adsorption of tungsten on chitosan coated clay is favorable regardless of the presence of interfering species. Compared to natural clay, chitosan coated clay has about 116 times larger adsorption capacity per gram of chitosan, which makes it a superior adsorbent. However, the maximum tungsten adsorption capacity decreases in the presence of co-occurring species since the co-occurring species suppress the adsorption. For the well water treated with biosorbent, the tungsten concentration in the product water was found to be lower than the detection limit (1 microg/L) of the inductively coupled plasma mass spectrometer (ICP-MS). The repeatable results obtained from the treatment of both simulated and well water suggest that using chitosan coated clay can be an efficient adsorbent for tungsten removal from contaminated sites.     

Optical fibre chemical sensor for trace vanadium(V) determination based on newly synthesized palm based fatty hydroxamic acid immobilized in polyvinyl chloride membrane

Fatty hydroxamic acid (FHA) immobilized in polyvinyl chloride (PVC) has been studied as a sensor element of an optical fibre chemical sensor for V(V). By using this instrument, V(V) in solution has been determined in the log concentration range of 0-2.5 (i.e. 1.0-300 mg/L). The detection limit was 1.0 mg/L. The relative standard deviation (R.S.D.) of the method for the reproducibility study at V(V) concentration of 200 mg/L and 300 mg/L were calculated to be 2.9% and 2.0%, respectively. Interference from foreign ions was also studied at 1:1 mole ratio of V(V):foreign ions. It was found that, Fe(III) ion interfered most in the determination of vanadium(V). Excellent agreement with ICP-AES method was achieved when the proposed method was applied towards determination of V(V).     

三种植物对铀耐性及土壤中铀吸收积累差异的研究

采用溶液培养结合土壤培养的方法,研究了小白菜、冬苋菜和菠菜对铀的耐性及土壤中铀吸收积累的差异.结果表明:水培条件下(U 50mg/L),与小白菜和冬苋菜相比,菠菜对铀具有较强的耐性;在100mg/kg 土U的条件下,菠菜表现出比小白菜和冬苋菜更高吸收和积累铀的能力,其地上部分铀含量为232mg/kg DW(Dry Weight 干重),而根部铀含量达433mh/kg DW(Dry Weight 干重).菠菜可能对铀污染土壤的植物修复具有潜在的应用价值.     

Determination of fluoride in drinking water and in urine of adolescents living in three counties in Northern Chihuahua Mexico using a fluoride ion selective electrode

This study was carried out to determine fluoride in drinking water and in urine of adolescents, ages 15-20 years, living in Northern Chihuahua Mexico. Participants are from a cross-sectional study on health effects of chronic fluoride exposure from drinking water. A total of 201 participants (106 female and 95 male) in the study were recruited from three counties. Samples of drinking water of each county were collected and analyzed using the U.S. EPA Fluoride Ion-Selective Method. Statistically significant difference of fluoride content in water was found among the three counties of recruitment (Cd. Juarez; 0.3 mg/L, Samalayuca, 1.0 mg/L, and Villa Ahumada, 5.3 mg/L). Fluoride content in wells and tap water samples of Villa Ahumada ranged from 5.0 to 5.7 mg/L. Fluoride content of these samples was above the level permitted by Mexican regulations. The fluoride content in bottled water obtained from local stores in Villa Ahumada ranged from 0.3 to 3.7 mg/l.Fluoride in urine samples of each participant was also analyzed using the U.S. EPA Ion-Selective Method. The mean fluoride urine concentration (reported in mg/g creatinine) in adolescents living in these counties was 0.792±0.39, 1.33±0.67 and 2.22±1.16 (Cd. Juarez, Samalayuca and Villa Ahumada), respectively. The high fluoride urinary levels found in participants from Villa Ahumada may be associated to the high fluoride level (5.3 mg/L) in dinking water.The accuracy of measurements was assessed with reference materials in water and in urine. Mean fluoride recovery was 99.0% and 99.6% in water and in urine, respectively. The levels obtained were within the assayed 5% confidence levels.     

Rapid spectrophotometric method to resolve ternary mixtures of Tartrazine, Quinoline Yellow and Patent Blue V in commercial products

A very simple spectrophotometric method is described for resolving ternary mixtures of the food dyes Tartrazine (E-102), Quinoline Yellow (E-104) and Patent Blue V (E-131) by using the second derivative of the spectra with measurements at zero-crossing wavelengths. Calibration graphs are linear up to 20.0 mg/L of Tartrazine, up to 20.0 mg/L of Quinoline Yellow and up to 6.4 mg/L of Patent Blue V. Repeatability and reproducibility studies (with the Students’s and F tests) were achieved for two series of nine standards for each dye showing no significant differences at the 95% confidence level. Detection limits of 0.0526, 0.0164 and 0.0034 mg/L were obtained for Tartrazine, Quinoline Yellow and Patent Blue V, respectively. This method was used for determining synthetic mixtures of these colorants in different ratios and it was successfully applied to four commercial products without previous separation step. The results found in commercial products were compared with those obtained by an HPLC method and very similar values were found for both methods.