双波长紫外吸收法测定L-苯丙氨酸含量

采用双波长紫外吸收法测定转化液中L 苯丙氨酸含量 ,测定波长为 2 5 8nm ,参比波长为 2 78nm。由Acr2 78=138.18C+0 .0 0 85γ =0 .9995得到肉桂酸浓度Cr ,再由A2 58=ACr2 58+Acp2 5 8=76 .5 31Cr +.94 4 6Cp +0 .0 36 6 ,计算出L 苯丙氨酸含量Cp。此方法快速、简便、准确度高、除杂效果好 ,适用于生产过程控制。     

双波长薄层扫描法测定不同来源枸杞子中甜菜碱的含量

通过对枸杞子样品提取、脱色时间等前处理条件的优化,建立不同来源枸杞子中甜菜碱含量测定的双波长薄层扫描法(TLCS法)。使用快速溶剂萃取仪(ASE 350)用80%甲醇提取出枸杞子中的甜菜碱,经活性炭脱色、雷氏盐沉淀、丙酮溶解沉淀,采用改进的薄层扫描法在检测波长为530 nm,参比波长为625 nm条件下对枸杞子中的甜菜碱进行含量测定。得到清晰的薄层色谱斑点,无干扰;甜菜碱点样量在3.84~38.40μg范围内线性关系良好,r=0.9995;平均加样回收率为98.30%,RSD=2.55%(n=9)。该方法简便、准确,重现性好,适用于测定枸杞子中甜菜碱的含量测定,可为枸杞的质量控制提供依据。     

用双波长薄层层析扫描法测定中药黄柏中小檗碱等生物碱含量的研究

本文以乙酸异戊酯—无水乙醇—甲酸(7:1:2)作展开剂,用双波长薄层扫描法测定了三种不同来源以及同种来源而产地不同黄柏药材中小檗碱及巴马汀含量,并评价黄柏质量。     

双波长微孔板赖氏法检测人血浆丙氨酸氨基转移酶含量的方法学验证

目的采用双波长(492 nm/630 nm)微孔板赖氏法检测人血浆中丙氨酸氨基转移酶(alanine aminotransferase, ALT)的含量,并对该方法进行系统性的评价。方法按照ALT测定试剂盒的要求加样,应用双波长(492 nm/630 nm)微孔板赖氏法测定人血浆中的ALT含量,并对检测系统的专属性、线性范围、准确度和精密度进行验证。结果专属性分析结果显示,血浆样品与不同比例的抗凝剂混合,其中的ALT均能有效被检出,回收率分别为100%、95%和90%;对28和150个单位丙酮酸钠标准溶液进行倍比稀释5个梯度以制作标准曲线,采用多项式对标准曲线进行拟合,结果显示丙酮酸钠标准溶液分别在9.375～150、1.75～28和1.75～150个单位范围内线性关系均良好,相关系数r均达到0.99以上;准确度检测结果显示,已知含量的厂家质控血清和国家能力验证样品的实测值和理论值相比,回收率均在90%～110%之间;同一样品,重复加样18孔,重复性检测结果变异系数(CV)为5.29%;两位试验人员在不同日期对同一样品重复测定6次,中间精密度检测结果变异系数为5.49%。结论该检测方法专属性强、检测结果稳定可靠、线性良好、重复性好、检测通量大,可以有效降低成本,提高工作效率,适用于大规模检测人血浆中ALT的含量。     

双波长/双光束分光光度计数据处理系统的改进

通过加入计算机和设计新软件,双波长/双光束分光光度计数据处理能力得到大大增强.仪器原来依靠绘图仪输出,手量手算,数据处理能力弱,限制了它的使用,尤其是在动力学测定上.现在由计算机控制数据采集,显示多条曲线,显示数值,在曲线上自动寻峰,光滑曲线,任意缩放图形,并用激光打印机输出.介绍了升级后的系统结构,及其在关于磷脂酰乙醇(PE)对Ca²⁺-ATPase的Ca²⁺转运能力影响的研究中的应用.     

双酶偶联转化果糖制备含有稀少糖的混合糖液

酶转化法是功能性稀少糖生产的重要途径,但单一稀少糖转化酶的转化率普遍较低。文中提出构建双酶偶联转化系统提高转化效率的思路,即利用D-阿洛酮糖3-差向异构酶(D-psicose 3-epimerase,DPE)和L-鼠李糖异构酶(L-rhamnose isomerase,L-RhI)双酶偶联反应,催化D-果糖生成D-阿洛酮糖和D-阿洛糖等功能性稀少糖。DPE和L-RhI加酶量的比例为1∶10,其中DPE的浓度为0.05 mg/mL;转化反应的最佳温度为60℃,最适pH为9.0。当D-果糖浓度为2%时,反应10 h达到平衡,此时D-阿洛酮糖和D-阿洛糖的产量分别为5.12和2.04 g/L。利用文中提出的双酶偶联系统可以将果葡糖浆等富含果糖的低附加值原料转化为含有功能性稀少糖的高附加值混合糖液。     

HPLC法测定植物中乌索酸的含量

采用HPLC法测定6种植物中乌索酸的含量,为扩大植物中乌索酸药物资源的开发利用提供分离测定方法。色谱柱为SyrmnetryShieldRP18,流动相甲醇-水-磷酸(88：12：0．1),流速1．0mL／min,检测波长210m,柱温2．5℃。该方法的线性范围为0．192-3．072μg,R=0．9999,平均回收率为98．12％,RSD=1．7％(n=5)。HPLC法测定乌索酸含量灵敏、准确、重现性好。     

不同方法整枝后的南瓜果实成熟过程中果胶、戊糖和铬(Cr3+)含量的变化

单干、双干和三干3种整枝方式下的南瓜‘龙圆栗香’果实成熟过程中果胶含量在总体上均呈现先高后低的变化趋势。其中,单干和双干整枝的果实中,果胶含量先是急剧升高,30d后急剧下降,而三干整枝的变化趋势比较平缓。果实成熟过程中的戊糖和铬(Cr3 )含量变化趋势大体一致,都呈上升趋势。其中,双干和单干整枝的上升趋势明显。双干整枝的果实中果胶、戊糖和铬(Cr3 )含量都一直是最高。     

HPLC法测定卷柏及其炮制品中穗花杉双黄酮的含量

采用HPLC方法测定卷柏及炮制品中穗花杉双黄酮的含量。方法:Shim-pack VP-ODS柱(4.6 mm×250mm,5μm);流动相:甲醇-0.1%磷酸水(65∶35);流速:0.8 mL/min;检测波长:337 nm;柱温:25℃。实验结果表明,卷柏生品中穗花杉双黄酮的含量为0.84%,焦卷柏为1.07%,卷柏炭为0.53%。不同的炮制方法对穗花杉双黄酮的含量产生不同的影响。     

薄层扫描法测定产妇定胶囊中盐酸水苏碱的含量

为建立一种控制产妇定胶囊质量的方法,本文采用薄层扫描法测定处方中君药益母草中所含的主要有效成分盐酸水苏碱的含量.结果表明盐酸水苏碱在3.090～30.900μg范围内线性关系良好,平均回收率为99.06%,RSD=2.57%(n=5).该方法灵敏、准确,分辨率高,可用于产妇定胶囊的质量控制.     

Quantitative Detection of Pharmaceuticals Using a Combination of Paper Microfluidics and Wavelength Modulated Raman Spectroscopy

Raman spectroscopy has proven to be an indispensable technique for the identification of various types of analytes due to the fingerprint vibration spectrum obtained. Paper microfluidics has also emerged as a low cost, easy to fabricate and portable approach for point of care testing. However, due to inherent background fluorescence, combining Raman spectroscopy with paper microfluidics is to date an unmet challenge in the absence of using surface enhanced mechanisms. We describe the first use of wavelength modulated Raman spectroscopy (WMRS) for analysis on a paper microfluidics platform. This study demonstrates the ability to suppress the background fluorescence of the paper using WMRS and the subsequent implementation of this technique for pharmaceutical analysis. The results of this study demonstrate that it is possible to discriminate between both paracetamol and ibuprofen, whilst, also being able to detect the presence of each analyte quantitatively at nanomolar concentrations.     

Quantitative Method for Colorimetric Determination of Formate in Fermentation Media

The effects of fermentation products and media supplements on a colorimetric assay for formate were evaluated. Formate was detected at concentrations as low as 0.5 mM in fermentation media.     

A New Method for Quantitative Determination of Steroid Metabolites of Cytochrome P450-Dependent Reactions Using Fluorescent Spectroscopy

A method for determination of hydroxylase activity of cytochrome P450 3A4 (CYP3A4) towards its substrate hydrocortisone using fluorescent analysis of the product was developed. 6β-hydroxycortisol, formed during CYP3A4-dependent electrocatalysis, has a characteristic fluorescent peak at λ = 427 ± 2 nm after treating with the sulfuric acid : ethanol (3 : 1) mixture and excitation at λ = 365 nm, which is different from the substrate (hydrocortisone) fluorescence (λ = 525 ± 2 nm). The limit of detection of 6β-hydroxycortisol was 0.32 μM. The developed analytical approach was used to determine the kinetic parameters of CYP3A4-dependent hydrocortisone hydroxylation.     

基于比浊法的杆菌肽定量测定方法优化

杆菌肽在研究应用过程中,定量测定方法不统一,结果缺乏参考性。为规范其测定方法,拟通过建立杆菌肽浓度对数值与OD600之间的线性关系,以重复性和精密度为指标,优化指示菌初始浓度、杆菌肽溶液与菌悬液的比例、培养时间等因素,确定比浊法测定杆菌肽抑菌活性的方法。结果显示,比浊法的最适测定条件为:指示菌初始浓度107 CFU/mL,杆菌肽溶液与菌悬液比例1∶9,培养时间4 h,在此条件下,线性关系良好,R2达到0.99以上,且具有良好的重复性。进一步选用大肠杆菌和金黄色葡萄球菌验证方法的可行性,方法重复性好,精密度高。研究结果将为比浊法的进一步应用以及杆菌肽在试验和生产过程中的定量测定提供参考和依据。     

A Convenient Method for the Quantitative Determination of Pipecolic Acid

The quantitative determination of pipecolic acid was examined.

The reaction of 3% ninhydrin solution in n-butanol, saturated with citrate buffer (pH 4.2), with pipecolic acid in boiling water for 3 min yielded the colored products showing λ_max at 570 mμ, but with proline hardly yielded those products. By the colorimetry proposed, it is possible to determine the amount of pipecolic acid in the sample containing proline no more than 50 times the amount of the pipecolic acid, directly from the calibration curve using pipecolic acid.

The method for removal of amino acids from the sample containing pipecolic acid and proline was examined and discussed.     

Wavelength Optimization for Quantitative Spectral Imaging of Breast Tumor Margins

A wavelength selection method that combines an inverse Monte Carlo model of reflectance and a genetic algorithm for global optimization was developed for the application of spectral imaging of breast tumor margins. The selection of wavelengths impacts system design in cost, size, and accuracy of tissue quantitation. The minimum number of wavelengths required for the accurate quantitation of tissue optical properties is 8, with diminishing gains for additional wavelengths. The resulting wavelength choices for the specific probe geometry used for the breast tumor margin spectral imaging application were tested in an independent pathology-confirmed ex vivo breast tissue data set and in tissue-mimicking phantoms. In breast tissue, the optical endpoints (hemoglobin, β-carotene, and scattering) that provide the contrast between normal and malignant tissue specimens are extracted with the optimized 8-wavelength set with <9% error compared to the full spectrum (450–600 nm). A multi-absorber liquid phantom study was also performed to show the improved extraction accuracy with optimization and without optimization. This technique for selecting wavelengths can be used for designing spectral imaging systems for other clinical applications.     

Quantitative Ultrastructural Immunocytochemistry Using a Computerized Image Analysis System

Secretory granules in human pituitary adenoma cells have been examined indirectly for hormone epitopes by immunogold labelling of resin-embedded ultra thin sections. The specific binding of different immunoglobulin-gold complexes to the antigrowth hormone antibodies over the secretory granules was measured using a computerized image analysis system. This facilitated the assessment of the preferential binding to the target granules of gold particles with three different average particle diameters (Au₇, Au₁₁, Au₁₇). The time of pretreatment of sections with H₂0₂ or a buffer was found to influence the staining considerably. The scanning electron microscopic findings of protruded secretory granules with a mountain-like surface might be relevant to the uneven distribution of immunolabels seen over the secretory granules in the adenohypophysis.     

Determination of Benzalkonium Chloride Partition in Micelle Solutions Using Ultrafiltration Method

The objectives of this study were to determine the concentrations of free benzalkonium chloride (BAC) and apparent partitions coefficients (K _m) in micelle solutions and to explore its application in formulation development. Ultrafiltration (UF) was carried out using 10K Nanosep® devices and centrifugation at 5,000 rpm for 5 min. The separation of free BAC from micellar solutions was also conducted using ultracentrifugation (UC) method for the comparison with UF method. Capillary electrophoresis method was used for the identification of micelles. Results showed that a UF method was applicable for quantitatively evaluating BAC–micelle interaction in micellar solutions. Unlike UF, UC could not completely separate free BAC from the micelles. The free BAC concentrations in the micelle solutions decreased with increasing surfactant concentrations. Among polysorbate 80, cremophor EL, and tyloxapol, BAC had the highest K _m in polysorbate 80 solutions. The K _m was significantly lower in non-buffered aqueous solutions than that in citric buffers. Moreover, increasing surfactant concentrations led to reducing antimicrobial activity. The UF is a rapid and accurate method that minimally alters the micellar equilibrium for the determination of free BAC and K _m in micellar solutions. In conclusion, free BAC concentration, which is a function of surfactant type, surfactant concentration, and ion strength of solution, is likely associated with the antimicrobial activity.     

一种定量分析水稻细胞过敏反应的方法

在定量分析水稻细胞过敏反应(HR)方法中,溴酚蓝染色法的效果明显优于伊文氏蓝染色法。线形回归分析显示,在0.625￣20ΜG·ML-1范围内的溴酚蓝最大光吸收值与其浓度间的相关系数为0.9994。溴酚蓝染色法优化的测定条件为:0.03%溴酚蓝染色15MIN,水洗去除未结合染料,再在50℃下用含50%甲醇和1%SDS抽提液抽提与死亡细胞结合的染料30MIN,测定抽提液光吸收值(OD595),以甲醇处理15MIN的细胞作为全杀死细胞参照。用优化方法测定的水稻细胞死亡率与实际死亡率一致。     

Turbidimetric Method for Quantitative Determination of Triton X-100 with Silicotungstic Acid

The formation of Triton X-100–silicotungstic acid complex was studied. Quantitative turbidimetric determination of the detergent based on this process was suggested. This method allows us to determine the complex formation at any wavelength in the range from 350 (₃₅₀ =15600 cm^–1 M^–1) to 600 nm (₆₀₀ = 9090 cm^–1 M^–1). The calibration curve for Triton X-100 recorded at 350 nm is linear in the concentration range of 0 to 30 g/ml. A sigmoid calibration curve was observed at longer wavelengths. A linear fragment of the calibration curve recorded at 600 nm was found at a concentration of Triton X-100 of about 5 g/ml. The complex nature of calibration curves can be explained by the heterogeneity of the complex dispersion.