毛细管区带电泳法分离发酵液中的木糖和木糖醇

 建立了利用毛细管区带电泳分离发酵液中木糖和木糖醇的新方法。研究表明 :采用硼砂缓冲溶液时 ,木糖和木糖醇的分离度随硼砂浓度的增高而加大 ,在室温下硼砂最高浓度为 130mmol/L ;分离度还与溶液的 pH有关 ,在pH 9 5 5处分离度有最大值 ;缓冲液中十六烷基三甲基溴化铵的浓度为 4× 10 -6mmol/L～ 8× 10 -4 mmol/L时对分离度无显著影响 ;在优化的分离条件下 ,木糖和木糖醇可在 6min内基线分离。测定了发酵过程中样品各组分的含量和加标回收率 ,5次测定木糖的相对标准偏差 (RSD)为 1 42 %～ 3 11% ,回收率为 96 0 %～ 10 8 0 % 。     

褶合光谱法测定复方苯甲酸醇溶液中的苯甲酸和水杨酸

利用褶合光谱法不经分离同时测定复方苯甲酸醇溶液中苯甲酸和水杨酸的含量，苯甲酸和水杨酸的平均回收率分别为100.15%、100.02%，测定结果的相对标准偏差分别为1.40%、0.58%。     

高效液相色谱法测定防晒化妆品中水杨酸酯类紫外线吸收剂的含量

采用高效液相色谱法同时测定防晒化妆品中8种水杨酸酯类紫外线吸收剂(水杨酸乙基己酯、水杨酸三甲环己酯、水杨酸辛酯、水杨酸苯酯、水杨酸异十六酯、水杨酸己酯、水杨酸乙二醇酯和水杨酸苄酯)的含量。1.000 0g样品经5mL乙酸乙酯于20℃超声萃取10min,萃取液在Agilent ZORBAX Eclipse XDB-C_(18)色谱柱上分离,以甲醇-四氢呋喃-0.1%(质量分数)甲酸溶液为流动相进行梯度洗脱,紫外检测波长为340nm。8种水杨酸酯类紫外线吸收剂质量浓度在5.0~100.0mg·L~(-1)内与峰面积呈线性关系,检出限(3S/N)在0.5~2.5mg·kg~(-1)之间;加标回收率在90.6%~98.8%之间,测定值的相对标准偏差(n=6)在1.4%~3.6%之间。     

紫外多波长光谱法监测阿司匹林合成过程的水杨酸和阿司匹林

建立测定阿司匹林合成过程中水杨酸、阿司匹林含量和转化率的分析模型。采用紫外多波长扫描乙醇溶液中阿司匹林和水杨酸的紫外光谱,建立水杨酸和阿司匹林紫外光谱的向量长度与其质量浓度的标准曲线,通过斜投影算法分离出待测样本中阿司匹林和水杨酸的紫外光谱。计算光谱向量长度,代入标准曲线得到待测样本中阿司匹林和水杨酸的含量。实验结果表明,水杨酸、阿司匹林的质量浓度与其紫外光谱的向量长度呈良好的线性关系,线性范围分别为2.00~40.00,10.00~200.00μg/m L。水杨酸和阿司匹林测定结果的相对标准偏差为0.16%~2.19%(n=5),加标回收率在93.3%~106.9%之间。该方法快速简便、准确可靠,可满足阿司匹林和水杨酸的同时测定及反应过程中水杨酸转化率监测要求。     

羟乙基纤维素中毛细管电泳DNA分离特性研究

本实验以羟乙基纤维素(HEC)为筛分介质,以100～1500 bp DNA ladder为分离对象,系统地研究了直流电场下毛细管电泳时DNA分离特性.论文考察了DNA迁移淌度及分离度随HEC溶液浓度和分子量、毛细管两端电场强度(E)、毛细管有效长度(le)及其内径形状、背景电解液(BGE)温度等因素变化规律.研究发现:(1)当筛分介质HEC浓度高于其阈值浓度c*时,HEC分子量越大,相邻DNA片段之间淌度差越大,HEC浓度越高,其迁移淌度越低;(2)对于相邻的DNA片段,le在一定范围内,其分离度随le增大而线性升高;(3)毛细管有效长度一定时,DNA淌度随毛细管侧面积与截面积之比R增大而升高,分离效率提高;(4)BGE温度升高,DNA在筛分介质中扩散效应增强,迁移淌度变大,相邻DNA片段间分离度减小.根据以上结论,在直流电场下毛细管电泳φ×174-Hirc II限制性酶切片段,并实现了其高分离度、快速分离.     

比值导数紫外吸收光谱法测定阿司匹林中的微量水杨酸

本文应用比值导数吸收光谱法于药物阿司匹林中微量水杨酸含量的测定,在０．０１￣０．１２％浓度范围内比值导数光谱峰高与水杨酸浓度成正比。线性相关系数为０．９９９４,检出限为０．００５％,样品测定回收率为９５．０％￣１０２．５％。将其用于阿司匹林原料中微量水杨酸杂质含量的测定,乙酰水杨酸含量在９０．０％￣９９．０％范围内,不干扰微量水杨酸的测定。     

大型液相色谱分离甘露醇和山梨醇的热力学及动力学参数辨识

本文研究了液相色谱分离过程的吸附平衡常数、传质系数参数的估值模型，用色谱技术和以惰性物示踪的扰动应答实验技术测定甘露醇和山梨醇在钙型吸附剂上的吸附相平衡常数和总传质系数以及床层中的轴向扩展系数，结果表明：吸附平衡常数和吸附剂的选择性随温度的升高而下降；液固相间的总传质系数随温度的升高而增大；轴向扩散系数随流速的增大而增大，参数灵敏度分析的结果表明，相平衡关系，尤其是吸附选择性，对色谱分离的影响有较     

水杨酸分子印迹膜电化学传感器的制备

以水杨酸为模板分子,采用循环伏安法电聚合形成聚吡咯膜,以固定电位过氧化法去除印迹分子,制备了水杨酸分子印迹膜电极.本印迹电极能促进水杨酸电氧化过程,有效地避免结构类似物(如苯甲酸)对其测定的干扰.循环伏安法用于电化学检测,当富集时间为10 min,磷酸盐缓冲溶液的pH=6.86 时,在1.0×10-6～2.0×10-3 mol/L浓度范围内,水杨酸氧化峰电流与其浓度呈良好的线性关系,检出限为0.8 μmol/L, 用分子印迹膜电极对加标样品进行分析,回收率为94.6%～103.4%.     

紫外差示分光光度法同时测定含苯系物废水中苯胺和苯酚

苯胺、苯酚在不同酸度的水溶液中具有不同的结构和紫外吸收光谱。以苯胺水溶液为测定液,以等浓度的苯胺酸溶液为参比液;以苯酚碱溶液为测定液,以等浓度的苯酚水溶液为参比液,分别测定其吸光度。结果表明:在280 nm处,当苯胺质量浓度为1~100 mg/L时;在287 nm处,当苯酚质量浓度为1~30 mg/L时,苯胺、苯酚的吸光度与浓度之间存在良好的线性关系,据此建立了紫外差示分光光度法。用此法不需分离直接测定了含苯系物废水中的苯胺和苯酚,回收率分别大于94.6%和96.7%。     

三波长校正光度法测定水果蔬菜中多菌灵残留量

研究了三波长光度法测定水果蔬菜中多菌灵残留量的最佳测定条件，在pH8．3的条件下，测定278，281和290nm波长处的吸光度，计算出校正吸光度，校正吸光度与多茵灵含量在0～50μg范围内呈线性关系，相关系数为0．9991，方法检出量为0．773μg；样品的加标回收率在93．5％～101．0％范围内，测定结果满意。     

亚/超临界乙醇中羟基和氢自由基作用下的纤维素液化行为

以水杨酸为羟基自由基(HO·)捕捉剂、四氯化碳为氢自由基(H·)捕捉剂,采用间歇高压反应釜对玉米秸秆纤维素在亚/超临界乙醇中的液化行为进行了研究,通过考察自由基捕捉剂用量、反应温度和反应时间对纤维素液化行为的影响,研究亚/超临界乙醇产生的HO·和H·自由基对纤维素的液化作用。结果表明,随着水杨酸用量增加(0-4mL),HO·浓度升高,生物油收率由29.3%提高至47.9%,固体残渣收率从26.7%降低至24.3%;反应温度从250℃升高至320℃,HO·活性随之增强,生物油收率由35.9%升高至58.2%,固体残渣收率由51.8%降低至20.4%;随着四氯化碳用量由0增加为2mL时,H·浓度降低,生物油收率由24.7%降低至20.7%,固体残渣收率由54.1%增加至59.1%;反应时间从0到30min,液化作用不断增强,生物油收率从8.7%升高至28.5%,固体残渣收率由86.3%下降至60.9%;30min之后,四氯化碳对H·活性的抑制加强,导致液化作用减弱,生物油收率有所下降。实验结果表明,乙醇在亚/超临界状态下能够产生HO·和H·,且HO·和H·浓度和活性与反应条件相关,对纤维素液化产物的收率及其分布具有明显的影响。     

SINGLE AND BINARY ADSORPTION PERFORMANCE OF SALICYLIC ACID AND 5-SULFOSALICYLIC ACID ONTO HYPERCROSSLINKED POLYMERIC ADSORBENTS

Single and binary adsorption behaviors of salicylic acid and 5-sulfosalicylic acid onto hypercrosslinked polymeric adsorbents, i.e. NDA-101 and NDA-99 were investigated. The Freundlich model can successfully describe all the adsorption isotherms tested, which indicates a favorable and exothermic adsorption process. The adsorption of salicylic acid relies on π-π interaction, while the electrostatic interaction further influences the adsorption of 5-sulfosalicylic acid onto NDA-99. The adsorptive capacity of salicylic acid on NDA-99 decreases but increases on NDA-101 with 5-sulfosalicylic acid as the background component in a binary solute system. The amount of 5-sulfosalicylic acid adsorbed was decreased with the increase in initial concentration of salicylic acid on both adsorbents. The competition for the adsorption sites is considered to be predominant in the solid-to-liquid interaction process. The adsorption selectivity of salicylic acid onto NDA-101 is higher than onto NDA-99 by more than an order of magnitude. Thus, combination technique involving NDA-101 followed by NDA-99 can be effectively applied to separate and recover salicylic acid and 5-sulfosalicylic acid from wastewater.     

A reinvestigation of the reaction between titanium(iv) and salicylic acid in concentrated sulphuric acid

It is shown that the coloured species formed between TiO(2+) and salicylic acid in concentrated sulphuric acid may be a pi-complex rather than a chelate. Similar species are formed by other hydroxybenzoic acids where chelating sites for TiO(2+) are not available. The ultraviolet and NMR spectral characteristics of hydroxybenzoic acids in water, concentrated sulphuric acid and deuterochloroform are presented as evidence for the pi-complex formation. The reaction of VO(2+) with salicylic acid in concentrated sulphuric acid is shown to be due to increasing electron-donation in the pi-component of the V-O bond of VO(H(2)O)(5)(2+) as the concentration of sulphuric acid is increased, and not to the presence of salicylic acid.     

The acetylsalicylic acid–bromine system for multicomponent kinetic determinations

When acetylsalicylic acid (ASA) is added to a bromine solution, slow decay of the bromine concentration occurs. Hydrolysis of ASA yields salicylic acid (SA) slowly, and bromine reacts rapidly with SA but not with ASA. Simulated reaction profiles based on a two-step reaction scheme agree closely with the experimental profiles. This behaviour can be used to develop kinetic methods for resolution of mixtures of ASA and a second component that reacts rapidly with bromine. A remarkable practical feature of these methods is that the faster the reaction between bromine and the second component, the simpler and easier the analytical method. The reaction between hydroquinone (HQ) and bromine is rapid and a very simple analytical method is proposed. Mean validation errors of 2.8% for HQ and 7.2% for ASA have been found with concentration ratios [ASA]:[HQ] ranging between 0.32 and 19.4. The reaction between paracetamol (AAP) and bromine is not so fast and more complicated calibration methods are required. After use of a calibration plane mean validation errors of 2.7% for AAP and 8.1% for ASA have been found with concentration ratios ranging between 1.28 and 77.5. Similar kinetic approaches should be possible with many other mixtures of ASA and a second fast-reacting component, because bromine reacts with many inorganic and organic species by oxidation-reduction, substitution, and addition reactions.     

Rapid direct determination of trace amounts of salicylic acid in deproteinized serum by means of high-pressure liquid--liquid chromatography

A simple method for the quantitative analysis of salicylic acid in blood serum is described. A liquid--liquid chromatographic system, consisting of a long-chain aliphatic amine as the stationary phase and dilute aqueous perchloric acid as the mobile phase, enables the direct injection of deproteinized serum into the system. No change in the chromatographic properties of the system was noticed after 2000 injections of deproteinized serum. Quantitative analysis is possible using peak area or peak height measurements. The method has a high precision: relative standard deviations of 0.4% and 5% are found for samples containing 10 micrograms and 10 ng injected salicylic acid respectively. The detection limit is found to be about 1 ng slicylic acid, corresponding to 40 ppb salicylic acid in serum. Simultaneously administered drugs such as indomethacin, acetylsalicylic acid, caffeine and phenacetin, and metabolites of salicylic acid do not interfere with the analysis. The time course of the concentration of salicylic acid in serum is demonstrated after oral administration of 1 g sodium-salicylate. The phase system was also found to be suitable for the analysis of salicylic acid in urine.     

Towards an integrated microfluidic device for spaceflight clinical diagnostics Microchip-based solid-phase extraction of hydroxyl radical markers

A microchip-based solid-phase extraction method for biological fluid small molecule analysis has been developed. Using a commercially available copolymer packed into a microchip channel, extraction and preconcentration of 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA from saliva was achieved. The metabolites, formed from salicylic acid by reactive oxygen species, can be used as markers of oxidative stress. The results show high recovery of both metabolites (>90+/-15% for spiked saliva) with an 80-fold concentration enhancement possible. The eluent is directly analyzed using capillary electrophoresis, with good resolution for the two metabolites. This study demonstrates the feasibility of future integrated microdevices for spaceflight small molecule biomarker analysis.     

基于子空间夹角判据监测阿司匹林合成体系中的水杨酸和阿司匹林

利用水杨酸、阿司匹林、乙酸酐和乙酸的多波长紫外光谱作为本底光谱库和样本光谱库,建立一种基于子空间夹角判据的快速定量分析阿司匹林合成体系中水杨酸和阿司匹林的方法。水杨酸、阿司匹林质量浓度范围分别在1.16～34.684,9.84～188.928μg/mL内,所测得水杨酸和阿司匹林检验集的R分别为0.999 7和0.999 1,RMSE分别为0.509 5,2.624 0μg/mL,效果优于普通波峰点最小二乘法和偏最小二乘法。水杨酸和阿司匹林的加标回收率在94.01%～106.44%之间,测定结果的相对标准偏差分别为3.45%和4.80%(n=7)。该方法可用于监测阿司匹林合成体系中的水杨酸和阿司匹林。     

Percutaneous penetration, melanin activation and toxicity evaluation of a phytotherapic formulation for vitiligo therapeutic

The aim of this work was to apply photoacoustic spectroscopy for the ex vivo determination of the penetration rate of a phytotherapic formulation for vitiligo therapeutic, with or without salicylic acid as the promoter agent. In addition, the compound toxicity and morphophysiology effects were evaluated for different concentrations of salicylic acid. The experiments were performed as a function of the period of time of treatment in a well-controlled group of rabbits. Toxic effects were not observed with any of the tested products. All formulations containing salicylic acid induced cutaneous reaction which was dose dependent. The histological analysis showed that the use of the medication was associated with an increased comedogenic effect in relation to the control group, regardless of salicylic acid concentration. Inflammatory reactions and acanthosis were observed only in the animals treated with formulations containing higher concentrations of salicylic acid, while none of these effects were detected with the use of the formulation containing 2.5% (wt/vol) of salicylic acid. Photoacoustic depth monitoring showed that both formulations, with or without salicylic acid, propagated through the skin up to the melanocytes region, suggesting that the transport of the active agent may occur through the epithelial structure without the need of using queratinolitic substances, which are known to induce side effects in the animals.     

Analysis of salicylic acid based on the fluorescence enhancement of the As(III)-salicylic acid system

A new, simple and sensitive spectrofluorimetric method for the determination of salicylic acid (λ_ex = 315 nm, λ_em = 408 nm) using As(III) as a sensitizing reagent has been investigated by measuring the increase of fluorescence intensity of salicylic acid due to the complexation of As(III)-salicylic acid in presence of sodium dodecyl sulfate (SDS) 10⁻³ M. Under optimum conditions, a significant relationship was obtained between the fluorescence intensity and salicylic acid concentration. A linear calibration curve was obtained in the range 13.8-13812 μg l⁻¹ with product-moment correlation coefficient (R) 0.99985 and detection limit 4.2 μg l⁻¹. The R.S.D. is 2.35% (n = 5).The method was applied successfully to the determination of salicylic acid in human serum.