首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 312 毫秒
1.
高效液相色谱法对吗啡、杜冷丁、安定的同步测定   总被引:6,自引:0,他引:6  
王越  田薇  黄锋 《色谱》1999,17(4):399-400
利用高效液相色谱法同时分析测定了血液中吗啡、杜冷丁、安定的质量浓度。分析柱为C18,流动相为V(甲醇):V(25mmol/LKH2PO4)=90:10,检测波长为285nm。样品血液pH8.5~9.4时,用V(氯仿):V(异丙醇)=9:1溶液提取,以氮气吹干有机溶剂后用流动相溶解残渣进样分析。线性范围为0.05~50mg/L,最小检出质量浓度为0.05mg/L,日内与日间精密度CV<6%。  相似文献   

2.
取过20 目筛黄筋泥(浙江龙游县, 桔园表层土,pHH20 为5.1,有机质含量为2.35% , 每100 g 土的阳离子交换量为10.50 mmol, 每1 kg 土的可溶态稀土总量为11.44 mg) 风干土若干, 以0,10,50,100,200,350 mg·kg-1的浓度水平分别加入混合稀土及单一稀土元素Pr,Sm ,Eu 等, 混合稀土的配比为La∶Ce∶Pr∶Nd∶Sm∶Eu∶Gd∶Y=4∶4∶2∶2∶2∶1∶1∶4, 并对土样加蒸馏水至田间持水量的50% , 保持100% 的湿度在生化培养箱中于25 ℃下恒温培养一周后进行微生物量的测定, 每个样重复3 次, 土壤样品微生物量碳的测定方法采用氯仿熏蒸,0.5 mol·L-1 K2SO4 提取法, 提取液中的有机碳浓度用自动定碳仪(TOC)测定, 并由下式计算微生物量:SMBC= (cECt- cECO)/0.45, 式中,SMBC为土壤微生物量碳,cECO,cECt分别为氯仿熏蒸前后提取液中有机碳的浓度。测定结果表明, 不同稀土元素对土壤熏蒸前后的有机碳含量及其微生物量碳变化的影响规律基本相似, 随着稀土浓度的升高,熏蒸前后有机碳的含量都有不同程度的升高, 而且两者在量值上有逐渐  相似文献   

3.
掺铂二氧化钛纤维光催化降解氯仿的研究   总被引:19,自引:2,他引:19  
 TiO2纤维作为一种微米级光催化剂应用于废水处理时,不但克服了TiO2纳米颗粒不易分离回收的困难,而且对其进行贵金属掺杂,可使其光催化活性大大提高.用光还原沉积法制备了掺铂的二氧化钛纤维催化剂(Pt/TiO2(F)),并将其作为光催化剂用于光催化降解氯仿反应,考察了掺铂量、氧及pH值等条件对降解氯仿反应的影响,并与掺铂的二氧化钛颗催化剂粒(Pt/TiO2(G))的光催化活性进行了比较.结果表明,当掺铂量w(Pt)=0.5%,催化剂用量为0.5g/L,预先溶氧至饱和状态,c0(CHCl3)=1mmol/L,pH=5,用300W中压汞灯光照120min时,Pt/TiO2(F)上氯仿的降解率可达98.44%,而Pt/TiO2(G)上氯仿的降解率仅为72.03%.  相似文献   

4.
薄层色谱溶剂系统的优化设计   总被引:2,自引:0,他引:2  
靳颖华  班允东  孙毓庆 《色谱》1997,15(3):263-265
采用复合形法,根据色谱优化函数对肾上腺皮质激素类、磺胺类药物及银杏粉针剂的薄层溶剂系统进行了最优化设计。肾上腺皮质激素类药物的最佳溶剂系统为1,2-二氯乙烷-苯-甲醇(4.814.420.78);磺胺类药物的最佳溶剂系统为甲苯-无水乙醇-二氯乙烷-氯仿(2.301.463.322.92);银杏粉针剂的最佳溶剂系统为氯仿-甲醇-乙酸乙酯(3.303.293.41),实验结果与计算结果一致。  相似文献   

5.
研究了在不同稀释剂如苯,甲苯,正己烷,环己烷,四氧化碳,氯仿中萃取剂浓度,水相酸度以及温度对二(2-乙基己基)磷酸萃取Ni(Ⅱ)的平衡的影响,借助萃合物红外光谱,确定了萃合物组成和萃取反应机理。  相似文献   

6.
研究了Nd(ClO4)3·nH2O-bphsm[双(苯基亚砜)甲烷1体系(甲醇-氯仿1:2)和Er(ClO4)3·nH2O-bphsm体系(甲醇-氯仿1:2)的电子光谱。分析了在可见光区内,f一f跃迁的强度和强度参数,并从Nd3+和Er3+的超灵敏跃迁的振子强度和强度参数T2与配体bphsm浓度的关系,指出了体系中Nd与bphsm形成1:2.5的物种和Er3+与bphsm形成1:2的物种。  相似文献   

7.
甲壳胺接枝聚合反应的研究   总被引:18,自引:1,他引:18  
本文是以过硫酸钾为引发剂,研究甲基丙烯酸甲酯(MMA)与甲壳胺的接枝聚合反应.通过对不同脱乙酰度(da)甲壳胺(CTS)的接枝聚合反应条件实验,研究了反应时间,温度,引发剂浓度和单体浓度对接枝聚合反应的影响,从中得到优选的反应条件.在相同条件下,比较不同脱乙酰度甲壳胺及N-取代甲壳胺的接枝聚合反应结果,表明:甲壳胺中氨基参与了接枝聚合反应的引发过程.  相似文献   

8.
呼吸尘埃中游离晶态α-石英的X射线衍射外标法测定   总被引:1,自引:0,他引:1  
本实验用X射线衍射外标法测定了极微量(0.1~5mg)呼吸尘埃中游离晶态α-SiO_2的含量。其精确度(相对偏差)小于10%,达到常规微量(5~10mg)样品的分析精确度。  相似文献   

9.
研究了酸性、中性、碱性范嗣内丙酮酸在悬汞电极上的电化学行为.对实验条件进行了优化.在最佳条件下丙酮酸的还原峰电流和浓度有良好的线性关系。同时在不同pH值条件下研究了AI(Ⅲ)和丙酮酸的相互作用,结果表明,不同pH值范围内AI(Ⅲ)和丙酮酸的相互作用均为弱作用,弱作用强度为酸性〉碱性〉中性。这种作用强度的差别可能来自于不同条件下AI(Ⅲ)的存在形态不同.  相似文献   

10.
单分散SiO2体系制备中TEOS水解动力学研究   总被引:7,自引:1,他引:7  
采用一种与他人不同的萃取-冷冻分离-气相色谱法,跟踪形成单分散二氧化硅体系条件下正硅酯乙酯(TEOS)的水解过程,考察了温度(25~45℃)、氨浓度(0.5~0.2mol•L-1)、水浓度(6.0~15.0mol•L-1)等实验条件范围内,以上实验参数对TEOS水解速度的影响;并回归得到目前适用于在乙醇介质中氨催化下,形成单分散二氧化硅微粒常用实验条件范围内,唯一的较完整的水解动力学方程式.  相似文献   

11.
涂布溶剂对涂敷型手性固定相手性识别能力的影响   总被引:2,自引:0,他引:2  
陈小明  杨利  邹汉法 《分析化学》2000,28(7):879-882
以微晶纤维素为原料,在非均相乙酰化条件下反应合成了微晶纤维素三醋酸酯。分别以二氯甲烷、三氯甲烷作涂布溶剂,采用减压蒸发溶剂法将其涂布在硅胶上制备成适宜于高效液相色谱上用的涂敷型手性固定相,得到的CSPs对反-2,3-二苯基环氧乙烷和吡喹酮均具有较好的手性识别能力。  相似文献   

12.
A chiral stationary phase has been prepared from the 3,5-dimethylphenylcarbamate of cellulose chemically bonded to 3-aminopropylsilica gel at the 6-positions of the glucose units. The phase has been used to study direct liquid chromatographic enantioselective separation of five racemates. The effects on resolution of modifiers (alcohols, THF, and chloroform), flow rate, and temperature were investigated. It was found that the concentration and structure of the alcohol modifier can affect the separation; enantiomer separations were improved to different extents by addition of THF or chloroform to the mobile phase. Flow rate and temperature can also effect the resolution of racemates. In the range 10–40°C there was a linear relationship between ln k (or ln α) and 1/T (r > 0.98) for four of the compounds. These results indicate retention mechanism does not change as a function of temperature.  相似文献   

13.
用NaOH-吡啶比色法可以测定水或某些废水中的微量CHCl3浓度,但测定N,N-二甲基甲酰胺(DMF)废水经CHCl3萃取DMF后的萃余液中CHCl3浓度时,DMF对显色的有严重的干扰。采用蒸馏预处理后,再用比色法测定蒸馏所得的馏液中CHCl3浓度的方法,可以消除废水中DMF对显色的干扰。研究了水样中DMF浓度、蒸馏汽化率等因素对比色时显色的影响,建立了蒸馏-比色法测定DMF废水萃余液中微量或大量CHCl3浓度的分析方法。对含10g/LDMF水样的测定,CHCl3的线性范围为0~0.75g/L;与顶空色谱法测定结果对比,测定CHCl3浓度为5g/L和0.16g/L水样的相对误差分别为2.1%和1.2%;对CHCl3浓度为0.575g/L的水样进行7次平行测定,相对标准偏差为6.6%。对含DMF<15g/L水样的分析,结果令人满意。  相似文献   

14.
We investigate the effects of interfacial energy between water and solvent as well as polymer concentration on the formation of porous structures of polymer films prepared by spin coating of cellulose acetate butyrate (CAB) in mixed solvent of tetrahydrofuran (THF) and chloroform under humid condition. The interfacial energy between water and the solvent was gradually changed by the addition of chloroform to the solvent. At a high polymer concentration (0.15 g/cm3 in THF), porous structures were limited only at the top surfaces of CAB films, regardless of interfacial energies, due to the high viscosity of the solution. At a medium concentration (approximately 0.08 g/cm3 in THF), CAB film had relatively uniform pores at the top surface and very small pores inside the film because of the mixing of the water droplets with THF solution. When chloroform was added to THF, pores at the inner CAB film had a comparable size with those at the top surface because of the reduced degree of the mixing between the water droplets and the mixed solvent. A further decrease in polymer concentration (0.05 g/cm3 in THF) caused the final films to have a two-layer porous structure, and the size of pores at each layer was almost the same.  相似文献   

15.
采用两性离子型的催化剂Rh+[η-C6H5(nbd)B-(C6H5)3]实现了含手征性中心和硫代乙酸酯基的苯乙炔单体的聚合,用红外光谱、核磁共振氢谱和紫外-可见吸收光谱表征了聚合物的结构,证实得到了预期产物.聚合物的重均分子量达到了73200,在氯仿、四氢呋喃、二氯甲烷等有机溶剂中有良好的溶解性能.聚合物热稳定性高,在氮气氛围下热分解温度为336℃,在900℃的高温下有31%的重量残留.用扫描电子显微镜观察发现,在浓度为5.0mg/mL的聚合物氯仿溶液形成的薄膜中有微米长度的棒状有序结构;由浓度为0.5mg/mL的聚合物氯仿稀溶液形成的薄膜表面有晶体析出.用透射电子显微镜观察聚合物在氯仿溶液中缓慢形成的微结构,发现当浓度高于1.0mg/mL时,聚合物在碳膜上形成铺展的薄膜,薄膜由纳米尺寸的丝带状结构取向排列而成;当浓度低于0.5mg/mL时,聚合物形成具有规则几何形态的微晶体.在聚合物热稳定性的显著提高和有序微结构的形成过程中,聚苯乙炔侧链中的手征性中心发挥了关键的作用.  相似文献   

16.
Single-base resolution in the separation of DNA markers V and VI was achieved in the presence of electroosmotic flow (EOF), using poly(ethylene oxide) (PEO) solutions containing ethidium bromide (EtB) under isocratic conditions. Furthermore, a new approach called stepwise capillary electrophoresis (SCE) has been developed for DNA analysis, including stepwise changes in PEO concentration, EtB concentration as well as both PEO and EtB concentrations, wherein the EOF was used to introduce different PEO solutions into the capillary during the separation. DNA fragments smaller than 80 bp were both detected under isocratic conditions using 20 micrograms/ml EtB, and SCE using 1 and 20 micrograms/ml EtB, but not under isocratic conditions using 1 microgram/ml EtB. Resolution and speed of the DNA separation in SCE were different from those obtained from isocratic means, indicating that DNA underwent different concentrations of PEO and EtB in SCE. For example, DNA fragments with 458 and 504 base pairs (bp) were partially resolved in SCE, but not under isocratic conditions. The results further suggest that it is worth developing gradient techniques for widening the separation range and enhancing resolution in DNA analysis.  相似文献   

17.
Teflon AF 2400 films are known to imbibe solvents, making films in the presence of solvents less fluorous than they might otherwise be. Herein, we demonstrate that doping films with perfluorotripentylamine (Fluorinert FC-70) maintains the fluorous nature of Teflon AF 2400 and improves transport selectivity for fluorine-containing organic compounds. Density measurements on the FC-70-doped films reveal that free volume decreases dramatically as the dopant concentration increases (0-12 wt %) and then increases to approach that of pure FC-70. Remarkably, films from 0 to 12 wt % FC-70 have the same w/v concentration of Teflon AF 2400, indicating that FC-70 fills the free volume of Teflon AF 2400. This is consistent with the observed increased storage modulus and significant decrease (compared to undoped films) of solute diffusion coefficients in the same range of FC-70 concentrations. In contrast, FC-70 at concentrations greater than 12 wt % dilutes Teflon AF 2400, leading to a decrease of storage modulus and dramatic increase in solute diffusion coefficients. Sorption of chloroform decreases from 11.8 g of chloroform/100 g of film (pure Teflon film) to 3.8 g of chloroform/100 g of film (27 wt % FC-70-doped Teflon film), less than the solubility of chloroform in pure FC-70 (4.06 g of chloroform/100 g of FC-70). Solute partition coefficients from chloroform to FC-70-doped films generally decrease with increased dopant concentration. However, within a series of toluenes and nitrobenzenes, selectivity for F-containing solutes over analogous H-containing solutes increases as dopant concentration increases if the substitution is on the aromatic ring but not if it is on the methyl group (toluene). Transport (partitioning × diffusion) rates, as they involve both thermodynamic and kinetic factors, are not simply related to composition.  相似文献   

18.
疏亿万  刘晓亚  陈道勇 《化学学报》2006,64(18):1937-1939
全氟辛酸(PFOA)与聚苯乙烯-b-聚-4-乙烯吡啶(PS-b-P4VP)的配合能诱导嵌段共聚物在其共同溶剂氯仿中胶束化. 胶束化不仅能形成棒状聚集体, 还能得到椭球形胶束. 当嵌段共聚物PS-b-P4VP浓度为1.0 g/L时, 使用光散射和扫描电镜研究了MR值(全氟辛酸与聚合物中吡啶环的物质的量比)在1/30到1/10之间的聚集行为及形态. 发现即使当MR值小到1/30时仍然形成稳定的聚集体. 通过扫描电镜观察发现: 改变MR值可以获得不同形态的聚集体.  相似文献   

19.
王永华 《分析化学》2002,30(1):53-55
推导了改变气液相比/顶空气相色谱法的基本关系式。测定了20℃时氯仿在纯水中的液气分配常数为8.04,与文献值一致,测定标准水样品的浓度是97.83μg/L,相对误差0.68%,实测在实验室旋转一周的氯化消毒饮用水中氯仿含量为119.62μg/L,实验方法是测定3个具有不同相比的顶空浓度,然后通过回归分析建立的线性方程来计算。  相似文献   

20.
反相高效液相色谱法测定乳品及乳制品中的黄曲霉毒素M_1   总被引:1,自引:0,他引:1  
采用反相高效液相色谱测定乳品及乳制品中黄曲霉毒素M_1(AFM_1)的含量。样品经氯仿提取,过硅胶固相萃取柱净化,用氯仿-丙酮(1+1)混合溶液将黄曲霉毒素M_1从固相萃取柱上洗脱下来。以ZORBAX SB C_(18)色谱柱为分离柱,水和乙腈为流动相梯度淋洗,用荧光检测器检测,外标法定量。黄曲霉毒素M_1在1.0~25μg·L~(-1)质量浓度范围内与其峰面积呈线性关系,检出限(3S/N)为0.05μg·kg~(-1)。应用此法测定了牛奶和乳粉中AFM_1的含量,并测得其平均回收率分别在76.0%~80.0%和76.7%~90.8%之间,相对标准偏差(n=6)均小于7.0%。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号