分光光度法测定水中微量氯

本文研究了氯与碘酸银反应放出碘酸根,并使碘酸根在酸性条件下与碘离子反应产生碘,以可溶性淀粉显色,分光光度法测定水中微量氯的新方法,本法检出下限为2.0×10~(-5)molL~(-1)线性范围0.5～5×10~(-4)mol·L~(-1).应用于水中微量氯的测定,结果满意.     

小蓟抗氧化作用的研究

采用H2O2/Fe2+体系,通过Fenton反应产生羟自由基(HFR),用邻苯三酚自氧化体系产生超氧阴离子自由基(SAFR),用分光光度法(波长为536nm)监测小蓟冠毛部分提取物对HFR和SAFR的清除作用.结果表明:60%乙醇,50%甲醇,丙酮,蒸馏水浸提物,对HFR和SAFR均有明显的清除作用,其中对HFR清除率;水>60%乙醇>50%甲醇>丙酮;对SAFR清除率;50%甲醇>60%乙醇>水>丙酮.     

银-过硫酸钾-藏红T体系催化光度法测定痕量银

本文研究了在pH-4.5的HAc-NaAc介质中,以2,2'-联吡啶为活化剂,过硫酸钾氧化藏红T催化动力学光度法测定痕量银的新方法.本法检测限为7.0×10-4mg/L;相对标准偏差为3.0%(n=9);线性范围为0.004～0.018mg/L.可用于测定氯化银的溶度积.     

Application of derivative ratio spectrophotometry for determination of β-carotene and astaxanthin from Phaffia rhodozyma extract

A derivative ratio spectrophotometric method was used for the simultaneous determination of β-carotene and astaxanthin produced from Phaffia rhodozyma. Absorbencies of a series of the standard carotenoids in the range of 441 nm to 490nm demonstrated that their absorptive spectra accorded with Beer's law and that the additivity when the concentrations of β-carotene and astaxanthin and their mixture were within the range of 0 to 5 μg/ml, 0 to 6 μg/ml, and 0 to 6 μg/ml, respectively.When the wavelength interval (△λ) at 2 nm was selected to calculate the first derivative ratio spectra values, the first derivative amplitudes at 461 nm and 466 nm were suitable for quantitatively determining β-carotene and astaxanthin, respectively. Effect of divisor on derivative ratio spectra could be neglected; any concentration used as divisor in range of 1.0 to 4.0 μg/ml is ideal for calculating the derivative ratio spectra values of the two carotenoids. Calibration graphs were established for β-carotene within 0-6.0 μg/ml and for astaxanthin within 0-5.0 μg/ml with their corresponding regressive equations in: y=-0.0082x-0.0002 and y=0.0146x-0.0006, respectively. R-square values in excess of 0.999 indicated the good linearity of the calibration graphs. Sample recovery rates were found satisfactory (＞99%) with relative standard deviations (RSD) of less than 5%. This method was successfully applied to simultaneous determination of β-carotene and astaxanthin in the laboratory-prepared mixtures and the extract from the Phaffia rhodozyma culture.     

PC-1500袖珍机在分光光度法条件试验中的应用

本文介绍了使用PC——1500袖珍机处理分光光度法条件试验的结果,设计的程序可完成六项条件试验的数据处理,并能作出相应的曲线图形。     

分光光度法测定水中微量氯

本文研究了氯与碘酸银反应放出碘酸根，并使碘酸根在酸性条件下与碘离子反应产生碘，以可溶性淀粉显色，分光光度法测定水中微量氯的新方法，本法检出了限为2．0×10-5mol·L-1，线性范围0.5～5×10-4mol·L-1．应用于水中微量氯的测定，结果满意．     

南、北五味子中五味子酯甲含量的测定

目的：建立南、北五味子中五味子酯甲的测定方法并比较其在南、北五味子中含量的差异。方法：采用超声提取法提取南、北五味子中五味子酯甲,利用紫外可见分光光度法测定五味子酯甲的含量。结果：五味子酯甲在220nm处有最大吸收,其在0．15～0．65mg·mL^-1（r=0．9996）范围内线性关系良好;南五味子中五味子酯甲平均回收率为96．54％,RSD为1．67％（n=5）;北五味子中五味子酯甲平均回收率为97．77％,RSD为2．87％（n=5）。结论：该方法用于测定五味子药材中五味子酯甲的含量具有简单快捷,重复性好的优点,可用于五味子药材中五味子酯甲的质量控制。     

活性炭吸附酸性铬蓝 K 的研究简

以小麦秸秆为原料。通过复合物理活化法制备高比表面积活性炭．用所得活性炭为吸附剂,研究了其对酸性铬蓝K的吸附行为,考察了吸附剂用量、pH值、初始浓度、温度与吸附时间对酸性铬蓝K的吸附容量与脱除效果的影响．结果表明。酸性铬蓝K在浓度50g／m^3、pH为2．02、温度320K、吸附剂用量0．1g与吸附时间40min时去除率达到99．9％．     

钨合金中铁元素含量的邻二氮菲分光光度测定方法研究

根据郎伯-比尔定律,以氢氟酸和硝酸溶解钨合金,邻二氮菲为络合剂（显色剂）,盐酸羟胺为还原剂,在波长为511 nm,pH为6的条件下,采用分光光度法测得其中的铁含量为0.3374%（质量百分含量）,测试的相对平均偏差为0.1037%.对反应条件进行了系统的研究,该方法测定速度快,灵敏度高,干扰小,结果准确可靠.     

First experiments for the use of microblasting technique with powdered cellulose as a new tool for dry cleaning artworks on paper

This research evaluates the use of microblasting technique with powdered cellulose as a new tool for dry cleaning documents. Different cleaning tests were conducted on three documents with different properties following this new approach and the results were compared to those obtained with traditional dry cleaning with erasers. In order to assess changes caused to the supports, the treated documents were examined both before and after cleaning with optical and 3D stereomicroscopy, SEM-EDS and spectrophotometry. The results allow the conclusion that microblasting with powdered cellulose is a feasible technique to remove surface dirt or grime on paper documents. This research proves that the new use of the technique does not entail changes to the surface properties of the treated supports. Moreover, powdered cellulose is chemically stable and compatible with paper documents, preventing negative long-term effects derived from the presence of rubber residues that may remain in paper fibres when using erasers in dry cleaning treatments.