Investigation of 2-[(<Emphasis Type="Italic">E</Emphasis>)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3H-indolium as a new highly sensitive reagent for the spectrophotometric determination of nitrophenols

A new, simple, rapid, and sensitive spectrophotometric method has been developed for the determination of nitrophenols [picric acid (PA); dinitrophenols (DNP)] in wastewater samples. The method is based on the reaction of nitrophenols with 2-[(E)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3 H-indolium chloride reagent to form the colored ion associates, which are extracted by organic solvents. The molar absorptivity of the ion associates of PA with the investigated reagent ranges from 8.3×10⁴ to 11.3×10⁴ L mol^–1 cm^–1, depending on the extractant. Because only PA is extracted in an acidic medium with the investigated reagent, but both PA and DNP are extracted in an alkaline medium, it is possible to determine both substances in a mixture. Appropriate reaction conditions have been established. The absorbance of the colored extracts obeys Beers law in the range of 0.04–4.58 mg L^–1 PA, 1.0–18.4 mg L^–1 2,4-DNP and 1.2–14.7 mg L^–1 2,6-DNP, respectively. The limit of detections, calculated from a blank test (n=10; P=0.95), are 0.05 mg L^–1 PA, 0.9 mg L^–1 (2,4-DNP), and 1.1 mg L^–1 (2,6-DNP), respectively.     

铑（Ⅲ）－钼酸盐－罗丹明B显色体系的研究和应用

在聚乙烯醇（ＰＶＡ）存在下，铑（Ⅲ）与钼酸盐和罗丹明Ｂ（ＲＢ）形成离子缔合物，缔合物的最大吸收位于５８０ｎｍ，摩尔吸光系数ε值１．６８×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，服从比耳定律范围０～１０μｇＲｈ／２５ｍＬ，方法用于催化剂和冶金产品中铑的测定，结果满意     

碱性二苯基萘基甲烷染料褪色分光光度法测定肝素

肝素(Heparin, Hep)由葡萄糖胺磺酸、葡萄糖醛酸和艾杜糖醛酸组成, 在水溶液中由于其酸性基团的离解而成为带多个负电荷的大阴离子[1].肝素具有广泛的生物学功能, 在人体内由肥大细胞分泌而自然存在于血液中, 在体内外均有延缓或阻止血液凝固的作用. 肝素或其衍生物还可用于调血脂、抗血栓、改善血液流变学指标、抗炎、抗过敏及免疫调节等, 是重要的生化药物之一 [2]. 对不同的疾病, 肝素有不同的最适剂量, 临床上常采用生物方法 [3]来进行监控. 但由于受生物个体的影响较大, 故使其应用受到限制. 此外, 分光光度法 [1,4,5]、荧光法[6]、HPLC法[7]、细管电泳法[8]及电化学传感器[9]已用于肝素的测定, 其中分光光度法由于操作简便、快速、仪器价廉和灵敏度较高等优点而得到重视.     

Kinetic Spectrophotometric Determination of Trace Amounts of Nitrite by Catalytic Reaction between Methylthymol Blue and Bromate

A kinetic spectrophotometric method for determination of trace nitrite in two dynamic ranges (2–100 and 100–500 ng/mL) based on its catalytic effect on the reaction between methylthymol blue and potassium bromate in acidic (sulfuric acid) media is described. The reaction was monitored spectrophotometrically by measuring the decreasing color of methylthymol blue at 437 nm by the fixed‐time method of 4.0 min at 30°C. The detection limit is 0.6 ng/mL, and the relative standard deviations for 50.0 and 250.0 ng/mL nitrite are 1.6% and 1.3%, respectively. The method was used for the determination of nitrite in water samples.     

Synthesis, spectroscopic and thermal studies of the copper(II) aspartame chloride complex

Aspartame adduct of copper(II) chloride Cu(Asp)₂Cl₂·2H₂O (Asp=aspartame) is synthesized and characterized by elemental analysis, FT IR, UV/vis, ESR spectroscopies, TG, DTG, DTA measurements and molecular mechanics calculations. Aqueous solution of the green solid absorbs strongly at 774 and 367 nm. According to the FT IR spectra, the aspartame moiety coordinates to the copper(II) ion via its carboxylate ends, whereas the ammonium terminal groups give rise to hydrogen bonding network with the water, the chloride ions or neighboring carboxylate groups. The results suggest tetragonally distorted octahedral environment of the copper ions.     

锌试剂分光光度法测定壳聚糖含量

利用锌试剂与壳聚糖在一定酸度条件下的特异性显色反应，即其复合物在465nm处吸光度与壳聚糖含量在0～O．04g／L范围内呈现良好的线性关系(R=0．996)，基于此建立了一种简便快速的分光光度法。平均回收率为99．68％。