非水滴定测定烟叶中烟碱含量实验的微型化

研制了一种微型滴定装置,利用该装置(WD-COⅡ型微型滴定装置)对烟叶中烟碱含量进行非水滴定,通过数理统计方法将微型滴定管与常规滴定管的平行测定结果进行了比较,得到相同样品的一对非常接近的测定结果。证明新型微量滴定管具有较好的操作性能和精密度。     

介绍一种新型微型滴定管

阐述传统微型滴定管的优点及不足,对改造的微型滴定管装置部件的特征、性能进行剖析。并对改造的微型滴定管进行校正工作。     

电解法测定阿佛加德罗常数及气体常数

测量50毫升酸式滴定管顶端无刻度部分的体积。先取下酸式滴定管,洗净晾干,然后把管口向上正立,用碱式滴定管向酸式滴定管中加入一定量的水,使酸式滴定管中水面读数略小于50毫升即可,注意不要使液面以上的管壁沾有水,为此,可将碱式滴定管末端尖嘴玻璃管换一个长的尖嘴管,将长尖嘴玻璃管尽量伸入酸式滴定管内加水,第二次重复测量时,酸式滴定管中的水,应通过活塞放出,不宜从管口倒出。     

新型滴定管的研制与应用

介绍了一种新型滴定管的结构,特点是及使用方法,通过数理统计对新型滴定管与经典滴定管平行测定结果进行了比较。新型滴定管具有较好的精密度、准确度和操作性能,克服了经典滴定管活塞易渗漏、易产生气泡、装液困难、近终点液滴不易控制及酸碱不通用的缺点。     

环保型酸式自动滴定管的研制与应用

介绍了一种环保型酸式自动滴定管的结构、特点及使用方法。这种滴定管节省试剂,废液排放量极小,操作简单、省时,克服了常规微量滴定管精密度差、装液难、零点和滴定终点不易控制的缺点。通过数理统计方法,将环保型酸式自动滴定管与标称容量为50mL的常规酸式滴定管平行测定结果进行了比较,试验证明,该滴定分析的精密度、准确度不仅与50mL常规酸式滴定管相当,而且操作性还优于50mL常规酸式滴定管。     

微型滴定法在苯甲酸衍生物分析中的应用

本文报道WD—COⅡ微型滴定管在苯甲酸衍生物分析中的应用，所得结果与常规分析方法一致，并能有效地减少环境污染、节省试剂，具有推广应用价值。     

巧用碱式滴定管验证气体的状态

介绍了一套由2个碱式滴定管组成的简易装置，用来定量研究气体的状态，探究学习气体的压力、体积、温度间的关系，从而让学生更加深入地理解气体的性质。     

碱式滴定管的清洗方法

用铬酸洗液清洗碱式滴定管时,首先将其最下端的玻璃尖咀卸掉,然后将滴定管倒立,使上口插入盛有铬酸洗液(30gK_2Cr_2O_7 30ml热水 300ml浓H_2SO_4)的烧杯或锥形瓶中,并固定在滴定台的夹子上,接着象滴定操作时一样,左手的拇指与食指挤压乳胶管中的玻璃珠,与此同时,右手拿着洗耳球尖咀对准乳胶管口,右手再轻轻放松洗耳球,这时,随着滴定管内空气的抽出,洗液将由滴定管中缓缓上升.如果一次不能吸满,则先松开左手,后移开洗耳球,排出空气后     

微型氢气制备装置之设计

利用塑胶滴定管、塑胶注射筒、三通塑胶活栓、双通塑胶活栓、塑胶罐及一些小零件等,设计组合而成一套可兼制备氢气和测定摩尔体积的微型氢气制备器,在短时间内可以安全、快速、正确地制备氢气、收集氢气、检验氢气及求出摩尔体积。制备氢气体积在10mL以内只需要少於1分钟的时间,求出氢气的摩尔体积的平均值为2494(Lmol),平均误差仅为2044%。且能以极为安全及富有趣味性的点燃法和氢气枪法来检验氢气的性质,其效果明显又正确。本实验已将传统的氢气制备法加以改进成一套微型氢气制备器,此套装置经试验的结果颇符合微型化学实验的10大优点(小—体积小、省—时间省、快—反应快、好—效果好、易—操作易、安—很安全、多—动手多、高—趣味高、少—用药少、低—污染低),此套装置很值得提供给化学教育界专家及化学教师们参考。     

小型滴定管与小型滴定分析研究

微型化学实验 ( M.L)以其节约试剂经费、减少环境污染、提高实验教学质量等优点受到化学教育工作者的广泛重视 ,并在化学实验教学的某些学科中得到广泛应用。在滴定分析中 ,国内外有关的改革探索多是以微型方式进行的 [1 ]。我们认为有些微型化分析化学实验需要双管式微型滴定管和磁力搅拌器 ,初期投入较高 ,不符合通过微型化学实验节约教学经费的初衷。而用滴管、移液管、注射器改制的微量滴定管[2 ,3,4] 过于简陋 ,难以达到分析化学准确度、精密度的要求 ,基本操作方式改变较大 ,也难以达到师范院校的学生基本操作技能规范化的教学目标。…     

A simple automatic phototitrator for the determination of total carbonate and total alkalinity of sea water

An automatic photometric analyser based on the reversed use of a conventional motor syringe buret and modern optoelectronic components is described. The buret serves as a photometric titration vessel into which sample and reagents are selectively drawn through a set of solenoid valves. It has been applied to the photometric titration of total alkalinity and total carbonate concentration of sea water, giving precisions of 0.10% and 0.13%, respectively.     

一种微机控制的自动光度滴定系统

本文介绍了作者研制光度滴定传感器，它具有较小的工作电流，较高的灵敏度和较低的成本。     

An automatic titration control unit

A unit is described for the automatic termination of coulometric or volumetric titrations in conjunction with a suitable valve millivoltmeter and motorized buret or constant current generator. Two values of potential can be preset on the instrument, in either rising or falling sequence. On reaching the first potential, the end-point is approached by pulsed addition of the titrant ; the titration is terminated at the second potential, The on and off time cycles for the pulsing circuit are independently variable from 0.1 to 1.0 sec on and 3 to 15 sec off.     

Determination of iodine in organic compounds employing oxygen flask combustion and mercurimetric titration

Iodine in iodine-containing organic compounds is determined by oxygen flask combustion followed by mercurimetric titration. The method is the same as that used in a collaborative study on the determination of bromine and chlorine with the exception that hydrazine is used as the reducing agent instead of alkaline peroxide and the type of buret to be used for the titration is specified. Accuracy and precision are well within the acceptable limits.     

Systematic investigations of the photocatalytic alkyne-nitrile heterotrimerisation to pyridine

The photocatalytic heterocyclotrimerisation of ethyne and nitrile initiated by cobalt(I) complexes was studied. General mechanistic features as proposed for the ‘dark’ reaction were found to apply as well under photolytic conditions albeit with modifications. The results suggest that the irradiated light accelerates that stage of reaction, leading to the organometallic species which is believed to be the common intermediate for the formation of pyridine and benzene. The rate of pyridine production is linear dependent from nitrile concentration. Benzene formation may be minimised by keeping the ethyne concentration low. An alternative mechanism, based on the initial coordination of nitrile at cobalt is not confirmed. A novel gas buret system was used, which allowed automatic feed of ethyne under isobaric conditions and to monitor all reactants simultaneously on-line.     

微电喷雾与纳电喷雾装置的制作

研制了实验室可自制的多种微／纳电喷雾喷头。喷头制作简单且易于操作,并利用利血平标准样品测试了各种微／纳电喷雾喷头的性能,显示了其高灵敏、低消耗的显著特点。     

A Combined Thin-Layer Chromatography/Micro Infrared Method

Abstract

A method is described for the automatic elution of chromatographed compounds on thin-layer chromatography plates and their subsequent identification by micro infrared spectroscopy.

The method is simple, easy to perform in a few minutes, and requires 5 μg of material, 3 mg of KBr powder, and 150 μl of solvent.