恒电流库仑分析法测定乙烯基三乙氧基硅烷

建立了恒电流库仑分析法测定乙烯基三乙氧基硅烷(VTES)含量的方法. 探讨了电解液、反应时间、极化电位、溶剂等因素对测定的影响. 结果表明, 选用V(甲酸)∶V(KBr (2 mol/L))∶V(乙醇)＝6∶1∶3为电解液, 极化电位为200 mV, VTES与溴的四氯化碳溶液反应30 min, 甲醇为VTES的溶剂时测定结果最佳. 该方法用于样品VTES的测定, 加标回收率为98.4%～102.7%, 相对标准偏差为1.7%.     

手性固定相反相高效液相色谱法分析普萘洛尔对映体

建立了一种直接分析普萘洛尔对映体的RP-HPLC方法.采用ChiralPAKR AD-RH为色谱柱,以:V(20 mmmol/L H3BO3缓冲溶液(pH9.0)):V(乙腈):V(乙醇):V(四氢呋喃)=60:20:20:10为流动相,流速为0.5 mL/min,检测波长为230nm,建立了普萘洛尔对映体的反相高效液相色谱的方法,并用于实际样品盐酸普萘洛尔片的测定.实验证明:普茶洛尔两对映体完全分离(Rs=2.17),在0.448～6.72×10-5mg/mL浓度范围内线性关系良好,R-( )-普萘洛尔和S-(-)-普萘洛尔的平均回收率为97.50%和96.92%,可以作为实际样品含量测定的方法.     

姜黄中姜黄素的提取及电化学测定

姜黄中大约含有1%～3%的姜黄素,用95%乙醇从姜黄中浸取姜黄素,超声场介入下浸取的浸取速率最快.在0.2 mol/L磷酸盐缓冲溶液中（pH3.3）,姜黄素于玻碳电极上存在可逆的单电子转移过程,据此本实验首次建立了以线性扫描溶出伏安法检测姜黄素含量的新方法.在-0.2 V（vs SCE：饱和甘汞参比电极）电位下,含姜黄素的电解液于玻碳电极上经过富集,可得到一灵敏的氧化峰,峰电位Epa为＋0.464 V.在最佳条件下,氧化峰峰电流Ip与姜黄素浓度在8.0×10^-9～4.0×10^-7mol/L范围内呈线性关系,最低检出限为2.0×10^-9mol/L.本法操作简单、快速、灵敏、准确,可用于药物中姜黄素含量的直接测定.     

顶空气相色谱内标法测定香水中的乙醇

建立顶空气相色谱(HS–GC)内标法快速测定香水中的乙醇含量。香水用N,N-二甲基甲酰胺(DMF)溶解后,用强极性的DB–624毛细管色谱柱分离,FID检测器进行检测,内标法定量。香水中乙醇的质量浓度在40～80g/L范围内与其色谱峰面积呈良好的线性关系,相关系数为0.999 6,方法定量限为0.01 g/L。测定结果的相对标准偏差为3.1%(n=6),在5～20 g/L添加水平范围内,样品的平均加标回收率为99.4%～101.1%。该方法简单、快速,结果准确可靠,适用于香水中乙醇含量的测定。     

紫外分光光度法测定O/W型青蒿素脂肪乳剂中青蒿素的含量

建立了以紫外分光光度计法测定O/W型青蒿素脂肪乳剂中青蒿素的含量的方法.溶剂为V(乙醇):V(0.2%NaOH水溶液)=1:4,检测波长为290nm.青蒿素在10～60 μg/mL检测波长范围内与吸收度呈良好的线性关系(r=0.999166),平均回收率为100.72%(RSD=2.12).方法可用于青蒿素脂肪乳剂中青蒿素含量的测定.     

高效液相色谱法测定保健食品中大豆异黄酮含量

建立了高效液相色谱法(HPLC)测定保健食品中大豆异黄酮含量的方法,运用二极管阵列检测器(PDA)建立了4种大豆异黄酮D、G、De、Ge的光谱库,测定了D、G、Ge与De响应值之比.采用PDA检测,C18反相柱,以甲醇∶水∶醋酸(HAC)=55∶45∶1(V/V/V)为流动相测定了同一批保健食品美龄营养片中4种大豆异黄酮D、G、De、Ge的含量分别为2.24%、10.82%0、.085%、0.027%,变异系数小于5%,回收率为92.51%～99.30%.该方法快速,精密度及准确度在允许范围内,可作为保健食品中D,G,De,Ge的同时测定方法.     

示波极谱法烟丝中尼古丁含量测定及电极反应机理

研究了用示波极谱法直接测定烟丝中的尼古丁含量的新方法.在0.2mol/L草酸底液中(pH=4.0),于-1.22V处得到尼古丁的灵敏还原峰,峰电流与尼古丁浓度在1.5～31.5mg/L范围内呈良好的线性关系,检测下限达0.37mg/L.该方法用于烟丝中尼古丁含量的测定,简单快速,测定回收率在91%左右.     

2,4-二硝基氯苯衍生高效液相色谱法测定饮品中牛磺酸含量

建立了饮品中牛磺酸的高效液相色谱(HPLC)测定方法。采用2,4-二硝基氯苯90℃下衍生30 min,冷至室温后离心,取上清液10μL进样分析。以甲醇-KH2PO4为流动相梯度洗脱,360nm紫外检测,柱温20℃,流速1 mL/min。结果显示牛磺酸至少在0.02～200 mg/L范围内线性良好(r=0.999),回收率在97.5%～114.0%之间,保留时间和峰面积的相对标准偏差(RSD)(n=6)分别为0.40%和5.8%,方法已用于饮品中牛磺酸含量的测定。     

用反相高效液相色谱法测定人体血浆中盐酸氟桂利嗪含量

采用反相高效液相色谱法以桂利嗪为内标测定人体血浆中盐酸氟桂利嗪的含量.以V甲醇:V乙腈:V缓冲液=58:20:22的体系为流动相,用hypersilBDSC8不锈钢色谱柱、紫外检测器(检测波长254nm),血浆样品经乙酸乙酯萃取处理后进样测定.血浆中盐酸氟桂利嗪的含量在5～300μg/L范围内与盐酸氟桂利嗪的峰面积和桂利嗪的峰面积之比呈线性关系(r=0.9997),方法对盐酸氟桂利嗪的平均回收率为83.3%～85.0%,检出限为3μg/L(S/N=3).用该法测定了12名单次口服30mg西比灵(盐酸氟桂利嗪)胶囊的健康志愿者血浆中盐酸氟桂利嗪含量.结果表明,该药在血浆中含量平均达峰时间为(2.67±0.91)h,平均峰质量浓度为(154.9±66.0)μg/L.该法适用于盐酸氟桂利嗪药代动力学的临床监测和研究.     

发用防晒剂DDABDT的反相高效液相色谱法测定

建立了反相高效液相色谱法测定发用防晒剂二甲基对胺基苯甲酰胺丙基十二烷基二甲胺甲苯磺酸盐(简称DDABDT)的方法.采用的色谱条件为色谱柱Symmetry C8柱,流动相为V(乙腈):V(10 mmol/L NaAc)=65:35溶液(含体积分数0.02%三氟乙酸,pH5.04),流速1.0 mL/min;检测波长305 nm;进样量20μL.DDABDT质量浓度为0.05～1000 mg/L时,其浓度与峰面积呈良好的线性关系(R2＞0.999),检出限为0.02 mg/L(S/N=3).洗发水A中DDABDT的回收率在98.0%～102%之间,发样提取液中DDABDT的平均回收率在85%～108%之间.洗发水中DDABDT浓度测定日内和日间相对标准分别为1.2%,3.4%.头发吸附DDABDT含量测定日内和日间相对标准偏差(RSD)分别为9.1%,9.8%.同时以高效液相色谱-电喷雾离子化质谱对色谱法测定样品的DDABDT峰进行了验证.该方法已用于洗发水及头发吸附DDABDT的分析.     

Measuring Peak Capacity of Reversed-Phase Columns for Small Molecule Compounds Under Gradient Elution

The conventional approach to the measurement of peak capacity of reserved-phase columns under gradient elution assumes that all peaks have constant peak width, but this assumption can lead to inaccurate measurement of peak capacity. An integration approach employing a series of alkylphenones as model compounds was employed to more accurately measure the peak capacity for small molecule compounds under gradient elution. The base peak width of alkylphenones was plotted against retention time and a peak width function over retention time was established by polynomial regression. The peak capacity was then calculated by integrating the inverse of the peak width function over a gradient window. Compared to the conventional method, the integration method is not based on the assumption of equal peak width, thus providing a more accurate measurement of the peak capacity of reserved-phase columns, especially shorter ones packed with sub-2 μm particles under gradient elution.     

IR Spectrum Data Bank System

The infrared spectra of pure compounds of ninety thousands, poly compounds of twelve thousand, drugs of one thousand were included in the data bank. All of them can be searched out according to their serial number, chemical name, commercial name, amount of each atoms, or molecular formula, as well as their spectrum peak appearances. Program for spectrum information inputting, program for spectrum information search and program for spectrum peak appearance search were included in the system; in addition, spectrum information data bank, spectrum peak code data bank and spectrum figure data bank were attached to the system. System program was written by Visial Basic, and run under Windows system. The spectrum information data bank and spectrum figure data bank were administrated by Microsoft Access.The program for spectrum message inputting can be used to add message data and spectrum figure of some new compounds into the data banks by users themselves. The program for spectrum message search was designed to find out all the message data and spectrum figure of interested compound according to someone of the message data. The program for spectrum peak search was designed to find out some spectra most similar in peak shape with unknown spectrum by peak to peak comparison. When the wavenumbers and transmittances of main peaks in the spectrum of unknown sample were entered, the spectrum peak search was performed and several hits with higher similarity were reported including their similarity scores, spectrum serial numbers, sample's states,melt points, molecular formulas as well as spectrum images. If the search result was not satisfactory,some methods to modify spectrum parameters were reminded and search was performed again.     

Characterization of warfarin unusual peak profiles on oligoproline chiral high performance liquid chromatography columns

Unusual peak profiles of warfarin were characterized on two oligoproline chiral stationary phases (CSPs). The pattern of 1st peak (S(−)) broadening and the 2nd peak (R(+)) compression was observed under mobile phase of hexane (0.1% TFA)/2-propanol (IPA) on a triproline CSP 1, and with other alcohol modifier such as ethanol, 1-propanol, 1-butanol, 2-butanol, and tert-butanol as well. Through analyzing system peak of additives, the unusual peak profile was interpreted by perturbation of TFA additive system peak. The unusual peak profile was also found in enantioseparation of coumachlor and on a covalently bonded doubly tethered diproline CSP 2. The pattern of 1st peak (S(−)) broadening and the 2nd peak (R(+)) compression can change to pattern of 1st peak compression and the 2nd peak broadening from 15 to 50 °C. Chiral separation of warfarin created nonlinear van’t Hoff plots on CSP. No peak broadening/compression were observed with methyl tertiary butyl ether or ethyl acetate as the modifier. The peak shapes of the two warfarin enantiomers can thus be tuned by varying alcohol concentration and column temperature. High separation factor and resolution may be carried out to tune the peak profiles into Langmuir/anti-Langmuir band-shape composition. Using none hydrogen donor modifier may avoid interference of the TFA system peak.     

全反式球形烯的光敏异构化及异构体的光谱

从Rhodobacter sphaeroides 2.4.1提取了全反式球形烯, 用高压液相色谱(HPLC)分离了它的I2增感异构化产物: 9,13'-cis(峰A), 5,13-cis+13,9'-cis(峰B), 13-cis(峰C), 5,13'-cis(峰E1), 9-cis(峰E2), 13'-cis(峰F),5,9'-cis(峰G), 9'-cis(峰H), all-trans(峰I), 研究了异构体的结构对其电子吸收光谱及HPLC保留时间的影响, 从而确认峰E1为5,13'-cis。对全反式球形烯的光敏异构化机理也作了初步探讨。     

Tris(2-methyl-8-quinolinolato)gallium(III) as a fluorescent probe for sensitive silanol-testing.

The peak shape of tris(2-methyl-8-quinolinolato)gallium(III) by reversed-phase high-performance liquid chromatography was found to be very sensitive to trace amounts of silanol groups on the surface of octadecylsylanized silica gel (ODS silica gel). The variation of the peak of the gallium(III) complex can be used as a probe of the residual silanol groups in an ODS column. The chromatographic peak parameters of the complex were compared with the silanol activities output by some silanol-detecting tests using nitrogen-containing compounds as probes. The comparison was performed with several commercially available ODS columns and laboratory-packed columns in which the amount of silanol groups was controlled by mixing fully endcapped ODS materials and a non-endcapped ODS material. The peak height was the most effective parameter among the peak parameters, and much more sensitive than the silanol-detecting tests using nitrogen-containing compounds, in detecting a trace amount of silanol groups that could not be detected by other silanol-detecting tests.     

板蓝根颗粒中蔗糖含量的红外光谱法测定

A method for rapid quantitative determination of sucrose in isatis-root granules by Fourier Transform Infrared Spectrophotometry(FTIR) was developed. Potassium ferricyanide was chosen as an inside mark material because it has only one strong absorption peak at 2117cm-1 and the peak was chosen as its quantitative peak. The peak at 1283cm-1 is the characteristic absorption of sucrose and was chosen as the quantitative peak of sucrose. The ratio of the two absorbances is I=Ai/As.K3[Fe(CN)6] and sucrose were mixed according to a certain mass ratio m=mi/ms to prepare standard samples. The curve of m versus I is the quantitative working curve. The linear range for sucrose is 5.0～23.0mg/g,the recovery is in the range of 91%～103%,the relative standard deviation is less than 5%.     

博莱霉素与DNA在镍离子注入修饰电极上的相互作用 及其应用

博莱霉素(BLM)在0.1mol/LHOAc-NaOAc缓冲溶液(pH4.62)中,在Ni/GCE离子注入修饰电极上有一灵敏的还原峰,峰电位为-1.16V(vs.SCE),峰电流与BLM浓度有关。用线性扫描和循环伏安法研究体系的行为表明,体系为具有加速作用的不可逆过程,是注入的Ni加速BLM的还原。引入DNA后,BLM的峰电位为-1.15V(vs.SCE),与未加入DNA前几乎完全一致;只使峰电流降低,形成一种非电活性的结合物,求得该结合物的结合比为BLM：DNA=3：1,结合常数为β=3.16×10^16,用线性扫描和循环伏安法,并辅以紫外可见光谱法等手段研究表明,电极过程仍为不可逆过程,与未加入DNA时一样。加入DNA后,BLM的峰电流降低,可用于DNA的测定,回收率在96.8～103.9%之间.     

Consideration on peak shape in a batch-type chemiluminescence detection cell for capillary electrophoresis

Peak areas, peak heights, and apparent theoretical plate numbers were examined as a function of sample injection times by use of the batch-type CL detection cell. Comparing the experimental data with those obtained by absorption detector, some considerations were carried out about the peak shape. The peak shape in CL detection was influenced by not only concentration distribution of sample in a sample zone but also sample diffusion and CL reaction at the capillary outlet. The sample injection time of ca. 35 s was recommended for the present CE with CL detector. The injection time much influenced peak shape as well as sensitivity in the CL detection cell.     

Procedure for the quantification of rider peaks.

Rider peaks are small peaks which are not well resolved from a large and asymmetrical neighbour but sit on its trailing side. The usual case is a large, tailed peak which is eluted just in front of the small peak, although the opposite situation can also occur (a small peak in front of a large peak with fronting). The common integration techniques. i.e. separating the peaks by vertical drop or by a tangent and determining area or height, give erroneous results. We propose a method for their quantification with low error. It is necessary to set up a "two-dimensional" calibration by varying both concentrations, i.e. of the large peak and of the rider. This leads to a series of linear equations which describe the rider size, as found by the integrator, as a function of the size of the large peak. The y-axis intercepts i of these equations show a linear relationship with the concentration x of the rider analyte, whereas the slopes s follow a quadratic relationship. These equations can be used to solve the equation y = s(x) x z + i(x) for x (y and z are the integrated peak size of the rider and the large peak, respectively). The procedure was tested with computer-generated peak pairs as well as with HPLC separations of 2,3-dimethylaniline (large tailing peak) and 2,3-dimethylphenol (symmetrical rider peak).     

Nonphotosynthetic reduction of the intersystem electron transport chain of chloroplasts following heat stress. The pool size of stromal reductants

The properties of a negative transient signal (negative peak) observed during the first seconds of the induction of the photoacoustic (PA) signal in dark-adapted barley leaves treated with methyl viologen (MV) and diuron and then exposed to high temperatures have been examined. Under those conditions no electron donation from photosystem II (PSII) occurred, and electron flow through PSI could be supported only by soluble reductants located in the chloroplast stroma. The negative peak was observed only if the PA signal had been monitored at low, and not high, frequencies. The peak obviously originated from the oxygen consumption by PSI. The size of the peak increased as the temperature of preheating was raised from 39 to 45 degrees C. The size of the peak decreased exponentially with a half-time of 3.7 s during illumination under low light. This decrease was found to be much faster under strong light. The recovery of the peak during dark acclimation required several minutes. It is concluded that the negative peak reflects the oxygen consumption supported by stromal reductants, their pool being rapidly exhausted under light in the presence of MV. The maximal size of the pool was calculated as 140 eq: P700 in dark-adapated leaves.