在强酸与多元酸混合酸中影响各组分酸含量测定的因素及条件

在前文中曾提出，第一终点ＰＨ＞３．７的情况下，以多元酸标准溶液的半中和点为第一点，测定各组分酸含量的方法。在此基础上，本文在理论上明确了影响各组分酸含量测定的因素，从而提出第一终点ＰＨ不同的情况下，Ｋａ１／Ｋａ２倍数不同时可准确滴定的Ｖｅ２／Ｖ＾Ｔｅ值的计算方法。实验结果表明，在此条件下结果是可靠的。     

半中和点法测定两种一元弱酸混合酸中各组分酸含量

本文根据两种一元弱酸混合物测定各组分酸含量的标准曲线法，在理论上证明标准曲线的斜率（αＡ２－αａ１）值最大时，αＡ２＝１－αＡ１＝αＨＡ１，并提出此时溶液ｐＨ值的测量方法，从而根据Ｖｅ２／Ｖ＾Ｔｅ－１＋αＡ２－１）公式，求出混合酸中各组分酸含量的方法，方法简单，可靠。     

流动注射碳硅凝胶微柱预富集ICP—AFS法测定高纯氧化铕中的非…

利用自合成的碳硅凝胶为吸附材料，以铜试〔二乙基二硫代氨基甲酸钠（ＮａＤＤＴＣ）〕为衍生化试剂。柱前衍生的方法，在优化的实验条件下，于ｐＨ４．６的缓冲介质中在线预富集Ａｌ＾１２＋、Ｃｒ＾５＋、Ｃｕ＾２＋、Ｆｅ＾３＋、Ｐｂ＾２＋、Ｖ＾５＋、Ｚｎ＾２＋。采用停流技术洗脱，富集倍数可达８．１￣１２．６倍，检出限为ｎｇ／ｍｌ级。对高纯氧化铕（Ｅｕ２Ｏ３）中的非稀土杂质进行测定，可避免大量稀土基体对测定的干扰     

铍（Ⅱ）—均三溴偶氮胂配合物吸附波的研究

在ｐＨ９．２０的ＮＨ３．Ｈ２Ｏ－ＮＨ４Ｃｌ介质中，铍与均三溴偶氮胂（ＴＢＡ）的形成配合物，于－０．５５Ｖ（ｖｓ．ＳＣＥ）处产生一灵敏的配合物吸附波，峰电流与Ｂｅ浓度在８．０×１０＾－８～２．０×１０＾－６ｍｏｌ／Ｌ范围内呈线性关系。测得铍与均三溴偶氮胂的配合比为Ｂｅ（Ⅱ）：ＴＢＡ＝１：１，稳定常数β＝３．０×１０＾，电子转移数ｎ＝２，峰电流由配合物中配位体ＴＢＡ还原产生。可不经分离直接测定矿样中铍     

裉色光度法测定SO^2—3的研究

本文研究了ＳＯ＾２－３褪色碱蓝６Ｂ的反应，在ｐＨ５．２Ａｃ－ＮａＡｃ缓冲介质中，ＳＯ＾２－３浓度在０．３９－１２ｍｇ／Ｌ范围内符合比尔定律，仅Ｆｅ＾３＋，Ｎｉ＾２＋，Ｃｒ＾３＋干扰测定，用于食品中ＳＯ＾２－３的测定，结果令人满意。     

氢化物发生原子荧光光谱法测定临床样品微量砷和硒

研究了氢化物原子荧光法测定临床床样品全血，血清，胎盘，头发，指甲和尿液中微量Ａｓ和Ｓｅ的方法。线性范围为Ａｓ１．３＊１０＾－９－２．５＊１０＾－７ｇ／ｍＬ，Ｓｅ２．８＊１０＾１０－７．５＊１０＾－８ｇ／ｍＬ；相对标准偏差（ｎ＝１３）Ａｓ２．６－３．６％，Ｓｅ２．８－４．２％；Ａｓ、Ｓｅ的标准加入回收率为９６．７－１０４．２％，用于６种临床样品中Ａｓ、Ｓｅ测定，获得满意的结果。     

植酸在络合滴定铜时作为掩蔽剂的研究

研究了植酸在络合滴定铜时的掩蔽性能。发现在ｐＨ５．５或ｐＨ４．５以５－Ｂｒ－ＰＡＤＡＴ为指示剂,用ＥＤＴＡ滴定Ｃｕ＾２＋时,可以用植酸掩蔽Ｆｅ＾３＋、Ａｌ＾３＋,Ｓｎ＾４＋、Ｔｉ＾４＋、Ｔｈ＾４＋、Ｌａ＾３＋和Ｃｅ＾３＋。本法已用于测定锡青铜,磷青铜和铝青铜中的铜。     

间接紫外光度法测定食品添加剂乳酸亚铁中Fe^3^＋含量

基于Ｆｅ＾３＾＋能将抗坏血酸量氧化的特性，通过测定反庆前后体在紫外区２４５ｎｍ处吸光度值的差值，间接测定样品中Ｆｅ＾３＾＋的含量。试验结果表明，Ｆｅ＾３＾＋含量在０－２００μｇ／２５ｍＬ范围内服从比耳定律。应用于乳酸亚铁样品中Ｆｅ＾３＾＋含量的测定，回收率为９７．３％－１０１．７％，相对标准偏差为０．８％－２．７％。测定结果与标准方法基本一致。     

流动注射化学发光测定乙醛的研究

本文研究了应用Ｇａ（没食子酸）－Ｈ２Ｏ２－ＯＨ＾－化学发光体系，流动注射技术测定乙醛的条件，如反应介质及其ｐＨ值，Ｇａ及Ｈ２Ｏ２溶液的浓度，温度，试液混合次序与化学发光强度的关系等，选择了流动注射系统的若干参数，所拟定的方法测定乙醛的浓度范围为每ｍＬ１．７×１０＾－３～４．４×１０＾－７ｇ，相对标准偏差为１．８％（２×１０＾－５ｇ／ｍＬ，乙醛溶液进行１１次平行测定）检出限为每ｍＬ３．１×１０＾－８     

示波极谱滴定法测定显影液中米吐尔和对苯二酚含量

用１．５ｍｏｌ／Ｌ乙酸铵－氨（ｐＨ８．２）－无水乙醇（２：１，Ｖ／Ｖ）混合溶液为极谱底液，以Ｋ２ＣｒＯ４与米吐尔和对苯二酚的氧化还原反应为基础，用Ｋ２ＣｒＯ４作为滴定剂，以示波极谱图上ＣｒＯ４＾２－切口出现指示终点，测定显影液中米吐尔和对苯二酚的含量。本法简便易行，灵敏准确，终点直观，应用于Ｄ－７２和Ｄ－７６显影液中米吐尔和对苯二酚的测定，获得满意结果。     

电堆集富集非水毛细管电泳同时测定水杨酸、肉桂酸、阿魏酸和香草酸

建立了同时分离测定水杨酸、肉桂酸、阿魏酸和香草酸的电堆集富集-非水毛细管电泳(NACE)的新方法。运行缓冲溶液为40mmol/L乙酸钠-2.5mmol/L氢氧化钠甲醇溶液,电压-25kV,在225nm波长下紫外检测。对电压、乙酸钠浓度、氢氧化钠浓度、进样时间、样品溶液等因素对电堆集及分离的影响做了系统的研究。水杨酸、肉桂酸、阿魏酸和香草酸分别在1.4~28mg/L、0.40~8.0mg/L、0.7~18mg/L和0.7~30mg/L范围内线性关系良好(r=0.9999、r=0.9997、r=0.9994、r=0.9997);回收率分别为95.8~99.6%、96.2~98·2%、95.7~105%和98.9~103%,基于3倍信噪比(S/N=3),4种有机酸的检出限分别为0.069、0.051、0.107和0.089mg/L。     

离子色谱法测定乙醛酸中的顺丁烯二酸和乙二酸

采用抑制电导离子色谱法测定高浓度乙醛酸基体中痕量的顺丁烯二酸和乙二酸。将乙醛酸样品稀释至1 000倍体积后,采用高浓度的淋洗液,以高容量色谱柱对样品进行分析。实验结果表明,顺丁烯二酸和乙二酸最低检出限分别为12.7,19.6μg/L,重现性(n=5)分别为1.13%,1.11%,回收率分别为97.9%,94.7%。该方法具有较高的灵敏度,适用于乙醛酸的例行检测。     

对氨基苯甲酸的合成研究进展

综述了以对硝基苯甲酸为原料合成对氨基苯甲酸的近期研究进展。并从技术和经济角度讨论了各种合成方法的优点与不足。     

Determination of Cyanuric Acid or Trichloroisocyanuric Acid in Air

Abstract

An analytical procedure for measurement of cyanuric acid or trichlor oisocyanuric acid in air has been developed. The procedure involves air sampling with a 37-mm PVC membrane filter, recovery with a phosphate buffer, and analysis by high performance liquid chromatography with a UV detector at 225 nm. The interior surface of the front piece of the cassette filter holder also is analyzed. Average recoveries were 0.98 to 1.00 after fortification of PVC filters with 12- to 412-μg quantities of cyanuric acid. Average recoveries of trichloroisocyanuric acid were 0.83 to 0.98 after fortification of glass surfaces with 12- to 424-μg quantities (these are reasonable approximations for recoveries of trichloroisocyanuric acid from PVC filters). The analyst should ascertain which analyte is present at the sampling site because trichloroisocyanuric acid reacts with water in the phosphate buffer to form cyanuric acid in high yield.     

Surface Functionalization of Magnetite Nanoparticles with Sulfonic Acid and Heteropoly Acid: Efficient Magnetically Recoverable Solid Acid Catalysts

New magnetically recoverable solid acid catalysts for acid‐catalyzed reactions were designed via the surface chemical functionalization of silica‐coated magnetite nanoparticles (SCMNPs) with sulfonic acid groups. First, the SCMNPs were covalently functionalized with 3‐aminopropyl groups to achieve Amp‐SCMNPs. Then, reaction of the Amp‐SCMNPs with 1,4‐butane sultone followed by acidification with phosphotungstic acid (HPW) or diluted sulfuric acid produced magnetically recoverable solid acid catalysts, HPW‐ampsul‐SCMNPs and H‐ampsul‐SCMNPs, respectively. Both catalysts were characterized by various physicochemical analyses such as Fourier transform infrared (FT‐IR) and inductively coupled plasma‐optical emission (ICP‐OES) spectroscopies, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), and energy‐dispersive X‐ray (EDX) analyses. Finally, the catalytic activities of the prepared catalysts were examined in the esterification of acetic acid with butanol and acetalization of benzaldehyde with ethylene glycol. Excellent catalytic efficiencies were obtained in both cases. The catalysts were consecutively recovered and reused five times without significant loss of their activities.     

以对甲基苯磺酸作为淋洗液用离子色谱法测定酸雨中的有机酸

本文研究了用对甲基苯磺酸作为淋洗液测定液相中HCOO~-和CH_3COO~-的离子色谱条件,该方法对HCOO~-和CH_3COO~-的最低检出限分别为48ppb和93ppb。该方法与用进口的辛磺酸作为淋洗液的方法进行了对比实验,并用于两广实际酸雨样品中甲酸和乙酸的测量。     

Mechanochemical Complexation between Deoxycholic Acid and Salicylic Acid

A complex between deoxycholic acid (DCA) and salicylic acid (SA) was prepared by grinding and coprecipitation methods. The resultant complex was characterized by means of powder X-ray diffractometry, IR spectroscopy and thermal analysis. The stoichiometry (DCA : SA 1 : 1) of the complex obtained by grinding was identical to that obtained by coprecipitation. The powder X-ray diffraction pattern of the DCA–SA complex differed from the typical pattern of DCA–guest complexes such as DCA–camphor and DCA–phenanthrene complexes. IR spectra suggested that a different kind of hydrogen bonding was formed in the crystal of the DCA–SA complex, compared with the other DCA–guest complexes. This was in good agreement with data from the crystal structure.     

硝酸氧解法提高泥炭中黄腐酸的产率

硝酸氧解法提高泥炭中黄腐酸的产率;腐植酸;硝酸氧化降解     

Determination of Monochloroacetic Acid and Dichloroacetic Acid for Quality Control of Acetic Acid Chlorination Industry by Ion Chromatography

An ion chromatographic method is described for the purpose of quality control in the process of monochloroacetic acid production. Using 2.5 mM NaOH–10% methanol as eluent, the simultaneous determination of acetic acid, monochloroacetic acid, dichloroacetic acid, and Cl⁻ was obtained in a single run. Monochloroacetic acid and dichloroacetic acid showed good linearity in the range 0.1–20 and 0.15–20 μg/ml and correlation coefficients were 0.9999 and 0.9998, respectively. The detection limits (signal-to-noise ratio 3:1) of monochloroacetic acid and dichloroacetic acid were 17 and 25 ng/ml. This simple, sensitive, and time-saving method can be applied for composition analysis in acetic acid chlorination production.