芦荟中多糖的光度测定新方法

利用正交试验考察了芦荟多糖与刚果红显色反应的最佳条件；研究了麦芽糖糊精等多糖、蔗糖等低聚糖和葡萄糖等单糖对显色反应的影响；建立了简便快速、常见糖类基本无干扰的测定芦荟多糖含量的吸光光度法。对芦荟鲜叶和芦荟制品中的多糖进行分析，加标回收率在92％～96％范围内，相对标准偏差≤5％。     

气相色谱法测定芦荟及芦荟干粉中的多糖

提取芦荟及芦荟干粉样品中的多糖，将多糖水解为单糖之后衍生化反应，用气相色谱法进行分析，实验选择了最佳分离条件，以木糖醇为内标物，用OV-225与OS-138为色谱柱固定液，使衍生物得到了很好的分离，结果表明：未经水解的芦荟中含有少量的单糖以葡萄糖的形式存在，水解后的单糖主要为甘露糖和葡萄糖，这与用乙醇沉淀多糖后测定结果一致，即芦荟及芦荟干粉中的多糖主要为甘露聚糖和甘露葡聚糖。     

气相色谱法测定芦荟及芦荟干粉中的多糖

用气相色谱法测定了芦荟及芦荟干粉样品中的多糖。实验以木糖醇为内标物,采用以OV-225与OS-138为固定液的色谱柱,使多糖水解为单糖后的衍生物得到了分离。结果表明:未经水解的芦荟中含有少量的单糖,主要为葡萄糖;水解后的单糖主要为甘露糖和葡萄糖。这与用乙醇沉淀多糖后的测定结果(即芦荟及芦荟干粉中的多糖主要为甘露聚糖和葡甘露聚糖)是一致的。     

四工作曲线法同时测定芦荟甙和芦荟大黄素

利用芦荟甙和芦荟大黄素吸光度的良好加和性,提出了一种同时测定芦荟甙和芦荟大黄素的方法。在只加入氨水的情况下,分别作芦荟甙和芦荟大黄素的工作曲线;在加入氨水和高碘酸钠溶液的情况下,作芦荟甙和芦荟大黄素的另外两条工作曲线。样品在同样的两条件下,分别测出吸光度,由四条工作曲线联立方程组求解,即可同时求出芦荟甙和芦荟大黄素的量。芦荟甙的测定下限为0．0024mg/mLL;芦荟大黄素的测定下限为0．0006mg/ML。样品分析结果相对标准偏差小于7％,加标回收率99％～101％。     

壳聚糖的光度测定新方法

研究了以刚果红分光光度法测定壳聚糖,探讨了最佳实验条件及干扰因素的影响。在pH9．7时,刚果红和壳聚糖形成有色物质,检测波长为543．5nm,线性方程为：A=0．0200ρ＋0．0156,R^2=0．9978。在0～20．00μg／mL范围内呈现良好的线性关系,平均回收率为99．20％。采用该方法测定了两种复方样品中的壳聚糖,方法的选择性和灵敏度良好。该方法可用于检测复方样品中少量的壳聚糖。     

分光光度法测定莼菜多糖中的葡萄糖醛酸

１引言莼菜多糖是莼菜的主要有效成分，准确测定莼菜多糖中的葡萄糖醛酸是该多塘生产中质量控制所必需的。目前报道测定葡萄糖醛酸的方法有气相色谱法、紫外分光光度法和咔唑比色法。气相色谱法要求试样具有良好的挥发性和热稳定性，因多糖是含有大量羟基的大分子，不能在高温下直接挥发，而需对其进行衍生化处理，导致操作手续繁琐，测定时影响因素较多，结果重现性差。紫外分光光度法用于多糖测定其选择性差。已报道的咔唑比色法费时，检测范围窄。在原咔唑比色法基础上，本方法改变了硫酸浓度，加热方式，并加入适当浓度的硼酸盐。相比之…     

分光光度法测定玉竹药材中多糖

建立分光光度法测定玉竹药材中玉竹多糖含量。玉竹药材经加热回流提取,多糖经80%乙醇溶液沉淀12h,采用苯酚-硫酸法进行比色测定。葡萄糖的质量在0～120μg范围内与490 nm波长处的吸光度成正比,线性回归方程为y=0.006 42x-0.007 53,相关系数为0.999 6,检出限为0.91μg。显色后溶液在6 h内保持稳定,样品加标回收率为95.9%～98.6%,平行测定结果的相对标准偏差为1.13%(n=6)。该方法可用于玉竹药材中多糖含量的测定。     

蔗糖测定的紫外分光光度新方法研究及应用

方法基于在酸性条件下,蔗糖水解生成果糖和葡萄糖,果糖受热破坏后,其产物在285nm处有较大的紫外吸收。通过试验,确定了最佳条件,并建立了测定蔗糖的新紫外分光光度法;其线性范围为0.27～31.2μg/mL,摩尔吸光系数ε为9.63×103L·mol-1·cm-1。该法简单、快速,准确度高,用于甘蔗汁中蔗糖含量的测定,结果满意。对蔗糖水解的机理进行了初步探讨。     

测定可见光区分光光度系组成的新方法

本文报道一种测定二元分光光度系组成的新方法,原理新颖,为作者首创,采用双波长分光光度技术消除显色产物的影响,直接测定与显色剂平衡浓度相对应的吸光度,通过简单的计算即可求得产物组成。     

A new photometric method for the determination of chymotrypsin in stool

Conclusions The proposed method offers the following advantages:a) high reactivity of the enzyme; b) need for small sample volume, thus absorption from suspended particles does not interfere and c) nearly complete solubilization of particle bound enzyme thus allowing automated analysis with the supernatant after centrifugation.

---

Neue photometrische Methode zur Chymotrypsinbestimmung im Stuhl

     

A new spectrophotometric method for the determination of promethazine-HCl from pure and pharmaceutical preparations

Promethazine-HCl reacts with potassium persulphate to give a pinkish red color complex exhibiting maximum absorbance at 515 nm. The reaction is selective for promethazine-HCl, with 1 μg/mL as visual limit of identification and provides a basis for a new spectrophotometric determination method. The color forming reaction obeys Beer's Law from 0.001 to 0.125 mg/mL of promethazine-HCl. The relative standard deviation does not exceed 0.005 mg/mL. The method is successfully applied to pure and pharmaceutical formulations of promethazine-HCl. The quantitative assessment of tolerable amounts of possible interferants was also studied. The results are reproducible within ±1% and in good agreement with those obtained by the standard procedure.     

A photometric method for the determination of oxalic acid

Summary A method for the quantitative determination of oxalic acid based onEegriwe's color test for glycolic acid is described. The principle of the method is the reduction of oxalic to glycolic acid by nascent hydrogen from magnesium powder and dilute sulfuric acid. By heating with a solution of 2,7-dihydroxynaphthalene in concentrated sulfuric acid formaldehyde splitt off from glycolic acid condensates with the reagent, tetrahydroxydinaphthylmethane forms and is oxidized to a deep colored dye-stuff by atmospheric oxygen.A study of interfering substances and the way of avoiding their influence was made.The color system, under the conditions of the method, follows theLambert-Beer's law. With the exception of a photoelectric colorimeter, no special equipment is required. The procedure is very simple, possesses great sensitivity, and may be applied with minor variations to a wide variety of materials.

---

Zusammenfassung Es wird ein Verfahren zur quantitativen Bestimmung der Oxalsäure beschrieben, das auf der Farbreaktion nachEegriwe für Glykolsäure beruht. Das Prinzip der Methode beruht auf der Reduktion der Oxalsäure zu Glykolsäure durch nascierenden Wasserstoff aus Magnesiumpulver und verd. Schwefelsäure. Durch Erhitzen mit einer Lösung von 2,7-Dioxynaphthalin in konz. Schwefelsäure wird der abgespaltene Formaldehyd mit dem Reagens kondensiert. Es bildet sich Tetraoxydinaphthylmethan, welches durch den Luftsauerstoff zu einem intensiv gefärbten Produkt oxydiert wird. Der Einfluß störender Substanzen und dessen Vermeidung werden untersucht. Die Farbreaktion folgt unter den geschilderten Versuchsbedingungen demLambert-Beerschen Gesetz. Mit Ausnahme eines photoelektrischen Kolorimeters ist kein besonderer Aufwand erforderlich. Die Methode ist sehr einfach und von großer Empfindlichkeit. Sie kann mit geringfügigen Abänderungen für verschiedenartiges Untersuchungsmaterial angewendet werden.

---

Résumé On décrit une méthode pour le dosage quantitatif de l'acide oxalique, basé sur le test coloré d'Eegriwe pour l'acide glycolique. Le principe de la méthode repose sur la réduction de l'acide oxalique en acide glycolique par l'hydrogène naissant produit avec le magnésium en poudre et l'acide sulfurique dilué. En chauffant avec une solution de dihydroxy-2,7 naphtalène dans l'acide sulfurique concentré, le formaldéhyde se libère du produit de condensation entre l'acide glycolique et le réactif; le tétrahydroxydinaphtylméthane se forme et s'oxyde en une matière colorante foncée sous l'action de l'oxygène atmosphérique.On a fait une étude des substances interférentes et de la manière d'éviter leur influence.Le système coloré, dans les conditions de la méthode, suit la loi deLambert-Beer. A l'exception d'un colorimètre photoélectrique, aucun équipement spécial n'est nécessaire. Le mode opératoire est très simple, possède une grande sensibilité et peut être appliqué avec de minimes variations à un grand nombre de substances.

     

A new kinetic photometric method for the simultaneous determination of metals based on catalytic and activating effects

Summary The potential use of the activating effect of Pb(II) on the Mn(II)-catalysed oxidation of Tiron by hydrogen peroxide in the presence of 1,10-phenanthroline for the simultaneous determination of the two metals was investigated. The results obtained allowed the development of a new kinetic photometric method for the simultaneous determination of Pb(II) and Mn(II). The catalysed reaction was monitored by the initial rate method, which was applied to absorbance-time curves. Different Mn(II) concentrations were used to construct calibration graphs by plotting the slopes of the photometric curves obtained against the Mn(II) concentration at each Pb(II) concentration assayed. A new calibration graph was obtained in terms of the Pb(II) concentration from the slopes of such graphs. By applying the standard-addition method to the sample to be assayed a third graph was obtained, the slope and intercept of which provided the analytical concentration of Pb(II) and Mn(II), respectively. The optimized values of the different variables involved were used to determine Mn(II) and Pb(II) over the concentration ranges 1–5 and 200–800 ng/ml, respectively.     

A sensitive flow-injection method for determination of trace amounts of nitrite

A new sensitive colour reaction for nitrite determination is presented. In acidic medium, nitrite was reacted with safranine to form a diazonium salt which caused the reddish-orange dye colour of the solution to change to blue. The carrier stream, into which the sample solution was injected, was doubly distilled water. The reagent solution stream, which contained safranine dye, hydrochloric acid and potassium chloride, was mixed with the carrier in a 3-m length of silicon tubing (bore 0.5 mm) maintained at 30°C in a thermostatic bath. The absorbance intensity was measured at 520 nm. The detection limit was 20 ng ml⁻¹ and the RSD% of 20 injections of 1 μg ml⁻¹ of nitrite was 0.65%. Analysis can be done at a rate of up to 30 h⁻¹. Under the optimum conditions in the concentration range of 30–4000 ng ml⁻¹ of nitrite ion, a linear calibration graph was obtained (r=0.9999). The method was applied successfully to the determination of nitrite in sausages.     

Vanadox--a new reagent for the photometric determination of vanadium

A new reagent, 2,2-dicarboxydiphenylamine, vanadox, is proposed for the photometric determination of vanadium in steels, high temperature alloys and ferrotitanium ores. In strongly acidic medium the reagent is selective for vanadium(V) and only eerium(IV) interferes.     

离子色谱-脉冲安培法测定芦荟多糖中7种单糖的含量

采用水提醇沉法提取芦荟鲜叶中的多糖，经三氟乙酸水解，利用Dionex CarboPac PA10高效阴离子色谱柱分离，氢氧化钠梯度淋洗，积分脉冲安培检测，建立了芦荟多糖中岩藻糖、鼠李糖、阿拉伯糖、半乳糖、葡萄糖、甘露糖和木糖7种常见单糖的测定方法。结果表明：7种单糖在线性范围内的相关系数（R²）均高于0.997，检出限为0.007~0.024 mg/L，加标回收率为97.5%~102.5%，相对标准偏差（RSD）为0.1%~4.8%。该法简单、快速、灵敏、准确，可用于芦荟多糖中单糖含量的测定和多糖组成的研究。     

A novel method for the spectrophotometric determination of nitrite in water

A rapid, simple, selective and sensitive method for the spectrophotometric determination of nitrite in water has been developed and optimum reaction conditions along with other analytical parameters have been evaluated. Nitrite reacts with barbituric acid in acidic solution to give the nitroso derivative, violuric acid. At analytical wavelength of 310 nm, Beer's law is obeyed over the concentration range 0.00–3.22 ppm of nitrite. The molar absorptivity is 15330 ± 259.7 (95%) with pooled standard deviation of 355.57 and R.S.D. of 2.32%. As well as the method is sensitive (2.99 × 10⁻³ μg NO₂ cm⁻²) and selective, it tolerates most of the potential interferents. It has been successfully applied to nitrite determination in natural waters by use of a calibration graph with determination limit of 1.66 μg NO₂ in 100 mL working solution corresponding to minimum 9.5 ppb NO₂–N in water samples. Lower concentrations of nitrite (3.0 μg NO₂/L sample) is precisely analyzed by using the method of dilution with sample, with R.S.D. of lower than 0.5%. The results were compared with standard N-(1-naphtyl)ethylenediamine dihydrochloride method and very good agreement between the data was observed. The method can easily be applied in the field.     

Downscaling a multicommuted flow injection analysis system for the photometric determination of iodate in table salt

In this work a downscaled multicommuted flow injection analysis setup for photometric determination is described. The setup consists of a flow system module and a LED based photometer, with a total internal volume of about 170 μL. The system was tested by developing an analytical procedure for the photometric determination of iodate in table salt using N,N-diethyl-henylenediamine (DPD) as the chromogenic reagent. Accuracy was accessed by applying the paired t-test between results obtained using the proposed procedure and a reference method, and no significant difference at the 95% confidence level was observed. Other profitable features, such as a low reagent consumption of 7.3 μg DPD per determination; a linear response ranging from 0.1 up to 3.0 m IO₃⁻, a relative standard deviation of 0.9% (n = 11) for samples containing 0.5 m IO₃⁻, a detection limit of 17 μg L⁻¹ IO₃⁻, a sampling throughput of 117 determination per hour, and a waste generation 600 μL per determination, were also achieved.