荧光法检测油田注水示踪剂的含量

荧光素和钙黄绿素可作为油田注水示踪剂使用,通过试验确定检测出油田水样中荧光素和钙黄绿含量的方法,为获得油藏信息提供依据.该方法较为简便、快速和具有较高的精密度和准确度,在荧光素和钙黄绿素的检测分别为0～0.35mg/L,0～0.89mg/L的范围内,检测误差均在2.5%以内.     

钙黄绿素荧光光度法测定粉煤灰中痕量钪

研究了钙黄绿素与钪的荧光反应。实验表明,在pH 8.5 NH₃·H₂O-NH₄Cl缓冲溶液和表面活性剂Triton X-100的存在下,痕量钪能和钙黄绿素反应生成络合物,使体系的荧光强度显著增强,激发波长和发射波长分别为495 nm和520 nm,钪的质量浓度在0.021~1.80 μg/mL范围内与荧光强度差值(ΔF)的线性关系良好,线性回归方程为:ΔF=3.431+2.473 ρ(μg/mL),相关系数r=0.998 1,检出限为0.021 μg/mL。干扰试验表明:粉煤灰样品中的钪经1-苯基-3-甲基-4-苯甲酰-5-砒唑酮(PMBP)-甲苯萃取分离后,大多数常见离子不干扰测定。方法应用于粉煤灰中痕量钪的测定,结果与电感耦合等离子体原子发射光谱法(ICP-AES)相符,相对标准偏差(RSD,n=6)为0.57%~1.0%,加标回收率在98%~105%之间。     

钇-钙黄绿素-吐温80体系荧光光度法测定痕量钇

在硼酸-硼砂缓冲溶液介质中,表面活性剂吐温80的存在下,痕量钇离子能显著提高钙黄绿素的荧光强度,据此建立了一种测定痕量钇的新体系。考察了荧光体系的光谱特征,研究了试剂用量、酸度、温度、时间及共存离子对测定的影响。结果表明,体系的最大激发波长（λ_ex）和发射波长(λ_em)分别为492和512 nm,钇的含量在0.04~2.0 μg/mL范围内与△F呈良好的线性关系,其回归方程为△F=2.384ρ+3.264 8,相关系数为0.996 1,检出限为0.023 μg/mL。此法用于醋酸铈中钇的测定,测定结果与电感耦合原子发射光谱法一致,相对标准偏差(RSD,n=6)为1.4%~2.1%。     

改性大豆磷脂在脂质体制备中的应用研究

以大豆磷脂和聚乙二醇单甲醚2000为原料,制备了大豆磷脂酰乙醇胺-聚乙二醇单甲醚2000(SPE-MPEG2000),产物结构经1H NMR和IR进行了表征。采用薄膜分散法制备了含SPEMPEG2000的空间稳定脂质体(SSL),同时制备不含SPE-MPEG2000的普通脂质体(CLs)。通过TEM考察了两种脂质体的形态及粒度分布,测定了粒径及Zeta电位变化,采用紫外分光光度法测定了脂质体加乙醇后的吸光度变化及包封钙黄绿素后的包封率。结果表明:SSL粒子呈类球形,粒径分布较CLs均一且分散性较好;放置前后SSL的粒径及吸光度变化较小,包封率高于CLs,从而说明SPE-MPEG2000对脂质体有良好的稳定作用。     

氧化钙黄绿素光度法测定酒中的微量锰

建立测定酒中微量锰的新方法-氧化钙黄绿素光度法。在硫酸介质中,钙黄绿素能够被锰(Ⅶ)氧化而褪色,且褪色程度和高锰酸钾的质量浓度呈线性关系。用铋酸钠将样品中的锰元素全部转化为锰(Ⅶ),从而采用分光光度法对锰进行测定。在最大吸收波长480nm处,锰的质量浓度在0～2.7μg/mL范围内符合朗伯比尔定律,方法的检出限为0.014μg/mL,表观摩尔吸光系数为1.74×104L/(mol ·cm)。将此方法用于几种酒中锰的测定,结果与原子吸收分光光度法(AAS)的测定结果一致,加标回收率在97.0%～102.7%之间。     

Preparation and Characterization of pH-Sensitive Vesicles Made of Cholesteryl Hemisuccinate

pH-sensitive vesicles are designed to promote efficient release of entrapped agents in response to low pH. In this study, such vesicles were prepared from cholesteryl hemisuccinate (CHEMS) in Tris-HCl buffer. Vesicles prepared by this direct hydration method had a small particle size of 74.1 nm based on intensity of Gaussian and a size of 65.8 nm based on volume of Gaussian. The mean zeta potential was about –73mV, indicating that the vesicle system was stable. Entrapment efficiency for calcein by these vesicles was measured at 37 ± 2.36%, which is higher than that by phospholipid MLVs. These calcein loaded vesicles exhibited excellent stability at pH 7.4 and underwent rapid destabilization upon acidification as showed by calcein release. However these vesicles were unstable in Fetal Bovine Serum (FBS). Optimization of formulation might improve their stability in serum.     

钙黄绿素荧光猝灭法测定痕量钯(Ⅱ)

在pH 6.4 KH2PO4缓冲溶液中,痕量钯(Ⅱ)能显著猝灭钙黄绿素的荧光,基于钯(Ⅱ)对钙黄绿素的荧光猝灭效果,建立测定痕量钯(Ⅱ)的新方法。考察了它们的光谱特征,影响因素和适宜的反应条件。结果表明,在λex/λem=496/515 nm处,Pd的量在0.047~1.25μg/mL范围内与ΔF呈良好的线性关系,其线性回归方程为:ΔF=29.1ρ(μg/mL)+8.62,相关系数为0.9990,检出限为0.014μg/mL。方法用于银矿样中钯(Ⅱ)的分析,相对标准偏差为2.9%~3.7%,样品加标回收率     

Preparation and characterization of pH-sensitive vesicles made of cholesteryl hemisuccinate

pH-sensitive vesicles are designed to promote efficient release of entrapped agents in response to low pH. In this study, such vesicles were prepared from cholesteryl hemisuccinate (CHEMS) in Tris-HCl buffer. Vesicles prepared by this direct hydration method had a small particle size of 74.1 nm based on intensity of Gaussian and a size of 65.8 nm based on volume of Gaussian. The mean zeta potential was about -73mV, indicating that the vesicle system was stable. Entrapment efficiency for calcein by these vesicles was measured at 37 ± 2.36%, which is higher than that by phospholipid MLVs. These calcein loaded vesicles exhibited excellent stability at pH 7.4 and underwent rapid destabilization upon acidification as showed by calcein release. However these vesicles were unstable in Fetal Bovine Serum (FBS). Optimization of formulation might improve their stability in serum.     

发酵液乳酸含量测定法中EDTA络合滴定钙指示剂的改进

乳酸是三大有机酸之一,其生产主要是生物发酵法和化学合成法。当前,乳酸的生产以生物发酵法为主。发酵生产过程中,乳酸含量的检测是个关键问题。乳酸含量的测定方法较多,其中EDTA定钙法因具有高灵敏性和易操作等优点而得以广泛应用。EDTA定钙法主要是通过钙黄绿素指示剂的黄绿色荧光在滴定前后的有和无进行乳酸测定。但该指示剂变色欠佳,滴定终点难以判断。本研究对EDTA定钙法的指示剂进行改进,即在钙黄绿素指示剂中添加入茜素溶液为衬色剂。改进的指示剂可提高显色反应的对比度,由滴定前的黄绿色荧光变为滴定后的红色,这使终点易于观察和判断,这将提高实验结果的准确度和精密度。实验确定了茜素作为钙黄绿素衬色剂的比例,即钙黄绿素和茜素的较佳混合比例为1∶0.275～1∶0.3(g∶g)。