Flow-injection chemiluminescence determination of tryptophan using galangin-potassium permanganate–polyphosphoric acid system

A high sensitive flow-injection chemiluminescence （FI-CL） method for the determination of tryptophan has been developed. The method is based on the chemiluminescence reaction of galangin-potassium permanganate-tryptophan in polyphosphoric acid （PPA） media. Under the optimized conditions, tryptophan was determined in the range 0.05-10 μg/mL with the detection limit （3tr） of 5.0 × 10^-3 μg/mL. The relative standard deviation （RSD） was 1.0% for 11 replicate determinations of 1.0 μg/mL tryptophan. Three synthetic samples were determined selectively with recoveries in the range from 99.6% to 102.0% in the presence of other amino acids.     

萤石中钙的测定

萤石是简单氟化物的主要矿物。氟化物在自然界中分布不多，与氟组成化合物的元素数目虽可达15种左右，但其中只以钙起着独特的作用，形成较为常见的萤石CaF2。萤石由于其低熔点，大部分用于冶金工业作为熔剂；在化学工业，萤石是制取氢氟酸等氟的化合物的原料；无色的萤石晶体用于制作光学仪器；另外，在制陶工业萤石也有广泛应用。     

Determination of Baicalin in Traditional Chinese Preparation by High Performance Liquid Chromatography with Chemiluminescence Detection

Herbal medicine, a form of complementary and alternative medicine, is becoming increasingly popular in the world1. Scutellariae radix is the root of Scutellariabaica -lensis georgi. The primary active constituent includes baicalin as follows: Clinical studies showed that baicalin exhibited therapeutic functions of antifever, moistening aridity, anti-inflammatory and detoxifying 2 and it is also an anti-abortion agent as well as can scavenge free radicals and against oxidation3. So it is…     

金属电极上的中和滴定法:II. 不同预处理对Pt电极 pH响应的影响

本文讨论了不同的预处理对Pt电极 pH 响应的影响 。经阴极 极 化或火焰上红热后, Pt电极以Pt(OH)2+Ze-Pt+2OH响应溶液的pH。而经+1.5V(vs.SCE)阳极极化后, 由于Pt电极表面PtO2的快速分解,电极的电位值很快下降, 并逐渐达到稳定值, 稳定后的Pt电极仍以上式响应溶液的pH。用KMnO4溶液浸泡后, Pt电极表面有MnO~2沉积, 并以MnO2+4H^++Ze-Mn^2^++2H2O(PH2-7)ZMnO2+2H^++Ze-Mn2O3+H2O(PH8-12)响应溶液的pH。     

根据动力学-光谱数据解析高锰酸钾氧化草酸钠的反应过程

通过在线测量硫酸介质中高锰酸钾氧化草酸钠反应过程的光谱变化，获得了动力学—光谱二维数据。借助主成分分析法，确定了高锰酸钾的单信息区，并确认反应过程中产生了一种有吸收的中间体。根据最小二乘回归等化学计量学方法，结合相关组分间存在等吸收点这一光谱特征及质量平衡原理，成功地解折出反应体系中相关组分的实际动力学谱及纯光谱。根据Savitsky-Golay求导法，获得了各组分的速率曲线。对解析结果的进一步研究表明，该反应符合自催化模式。     

碘量滴定法测定过氧化氢溶液浓度的改进

研究了用碘量滴定法测定过氧化氢浓度时，试剂的加入顺序和放置时间对测定结果的影响。结果表明，在用碘量滴定法测定过氧化氢浓度的过程中，酸化条件下，I^-与H2O2反应的最佳时间为5～10min。与高锰酸钾氧化法相比，碘量法测定效果较好一些。     

基于油菜籽碳量子点荧光恢复测定盐酸米诺环素的研究

以油菜籽和水为原料,一步合成了强荧光碳量子点(CQDs)。基于KMnO_4能使该CQDs的荧光显著猝灭;而当有盐酸米诺环素(MINO)存在时,CQDs-KMnO_4体系的荧光恢复,使荧光信号重新"打开"的原理,提出了以油菜籽CQDs荧光信号的"关开"为荧光探针测定盐酸米诺环素的新方法。方法的线性范围为5.0×10~(-7)～1.0×10~(-5) mol/L,相关系数r=0.999 5,方法检出限为4.9×10~(-7) mol/L。方法用于样品中盐酸米诺环素的测定,回收率为99.6%～100%。通过紫外-可见吸收光谱的变化和荧光寿命的测定,确定CQDs与KMnO_4间的猝灭类型为动态猝灭。同时对体系的"关-开"机理进行了初步探讨。     

Determination of resveratrol in red wine by solid phase extraction-flow injection chemiluminescence method

A sensitive flow injection chemiluminescence method has been developed for the detection of resveratrol in red wine based on the fact that resveratrol can greatly enhance chemiluminescence reaction between KMnO_4 and HCHO in sulfuric acid medium. Analytes were pre-concentrated on solid sorbents (C_(18) solid-phase extraction cartridges).Under the optimum conditions,the proposed method allows the measurement of resveratrol over the range of 1.32×10~(-8) to 1.32×10~(-5) mol/L with a detection limit of 3.30×10~(-9) mol/L,and the relative standard deviation for 1.32×10~(-5) mol/L resveratrol (n=11) is 3.8%.This method has been successfully applied for the determination of the resveratrol in red wine.Furthermore,the possible reaction mechanism was also discussed.     

高锰酸钾引发魔芋粉/丙烯酰胺接枝共聚合及其增稠性研究

用KMnO4作引发刺对魔芋粉(KGM)与丙烯酰胺(AM)进行了接枝共聚反应．研究了引发剂浓度、接枝单体浓度、体系酸度、反应温度、反应时间以及KGM预氧化时间等条件对接枝效率的影响．结果表明：在适宜的条件下，接枝效率可达90％以上，并且接枝物的水溶性与增稠性得到较大的改善。     

高锰酸钾－抗坏血酸化学发光体系测定抗坏血酸

本文研究了高锰酸钾－抗坏血酸化学发光体系，建立了测定抗坏血酸的化学发光分析新方法。线性响应的浓度范围为５．０×１０￣（－７）ｍｏｌ／Ｌ～４．０×１０￣（－５）ｍｏｌ／Ｌ检出限为３．０×１０￣（－７）ｍｏｌ／Ｌ对２．５×１０￣（－６）ｍｏｌ／Ｌ抗坏血酸进行１０次平行测定，相对标准偏差为１．６％。考察了２２种物质的干扰情况。用于维生素Ｃ片剂及注射液中抗坏血酸含量测定，结果令人满意。