催化分光光度法测定地质样品中微量镓

在25mL反应体系中加入3.0mL硫酸(1.0mol/L)-盐酸(5.0mol/L)混合酸,3.0mL碘酸钾溶液(0.05mol/L),1.5mL胭脂红溶液(0.50g/L),微量镓对碘酸钾氧化胭脂红的褪色反应有良好的催化作用,为此建立了测定地质样品中微量镓的催化分光光度法。方法的线性范围在0~100μg/L,工作曲线的线性方程ΔA=2.369CGa+0.223 6(相关系数r=0.999 6),检出限(3S/N)为1.0×10~(-3)μg/mL。方法应用于地质标准样品中微量镓的测定(分别是岩石标准样品GBW07120和水系沉积物标准样品GBW07301a),测定值与认定值相符,测定值相对标准偏差(n=6)均小于5%,结果满意。     

光催化剂Sm2FeSbO7的制备及光物理和光催化性能表征

首次采用固相反应法制备了新型光催化剂Sm₂FeSbO₇,有效地降解了水中有机污染物。利用X射线衍射、扫描电镜、X射线光电子能谱、傅里叶变换红外光谱、透射电子显微镜和紫外-可见光谱仪对Sm₂FeSbO₇的结构和光催化性能进行了表征。Sm₂FeSbO₇为烧绿石型结构,立方晶系和空间群Fd3m结晶。Sm₂FeSbO₇的晶格参数a为1.035 434 nm。Sm₂FeSbO₇的带隙经估算为2.46 eV。用Sm₂FeSbO₇作为光催化剂在可见光照射下降解靛蓝胭脂红,并与氮掺杂TiO₂对比。结果表明,与掺氮TiO₂相比,Sm₂FeSbO₇在可见光照射下光催化降解靛蓝胭脂红显示出较高的光催化活性。总有机碳的减少,无机产物的逐渐形成,SO₄^2-和NO₃^-以及CO₂的演变揭示了在光催化过程中靛蓝胭脂红的连续矿化。检测了一些来自光催化降解靛蓝胭脂红的中间体,如邻硝基苯甲酸和邻硝基苯甲醛,并获得了可能的靛蓝胭脂红光催化降解路径。     

“牛仔”很忙——牛仔裤中的化学

Known as the "timeless classic", jeans have been deeply integrated into people's lives. In order to give readers a more comprehensive and profound understanding of jeans, this paper introduces the development of indigo dye and the principles of jeans dyeing and aging process from the perspective of chemistry.     

活性炭的zeta电位对各种染料吸附的影响3.活性炭对阴离子染料洋红的…

测定了在不同ｐｈ下活性炭吸附阴离子染料洋红的变化规律，发现活性炭表面的电位（ξ）对洋红吸附量的影响起着重要作用。当溶液ＰＧＨ小于活性炭的零电位ＰＨ（ＰＨｚｐｃ＝６．２）时，活性炭表面带正电，这绎洋红阴离子具有静电引力，而当ＰＨ增大时活性炭的ξ电位下降，静电引力减弱，使得吸附量下降；另一方面由于洋红变色（ＰＨ３．５橙色，－ＰＨ６．８玫瑰红后），洋红我溶解度增大，所以导致吸附量很快下降并趋于零， 通过     

Catalytic spectrophotometric determination of trace aluminium with indigo carmine

A new catalytic spectrophotometric method is described for the determination of trace amounts of Al(III). The methods based on catalytic action of Al(III) on the oxidation of indigo carmine (IC) by ammonium persulfate in hexamethylene tetramine-hydrochloric acid ((CH2)6N4-HCl) buffer medium (pH 5.4) and in the presence of surfactant-TritonX-100. The effects of some factors on the reaction speed were investigated. Aluminium concentration is linear for 0-1.2x10(-7) g/ml in this method. The detection limit of the proposed method is 1.96x10(-8) g/ml. Most of the foreign ions except for Cu(II), Fe(III) do not interfere with the determination, and the interference of Cu(II) and Fe(III) in this method can be removed by extraction with sodium diethyldithiocarbamate-carbon tetrachloride (DDTC-CCl4). This system is a quasi-zero-order reaction for Al(III), but it is a quasi-first-order reaction for IC. The apparent rate constant is 2.62x10(-5) s-1 and the apparent activation energy is 6.60 kJ/mol in the system. The proposed method was applied to the determination of trace aluminium(III) in real samples with satisfactory results.     

用靛蓝胭脂红-H_2O_2流动注射化学发光法测定水样中的铜(Ⅱ)

在Na2CO3-NaHCO3缓冲溶液中,铜(Ⅱ)对H2O2氧化靛蓝胭脂红的反应具有明显的催化作用.基于此,结合流动注射技术,建立了测定铜(Ⅱ)的化学发光新方法;研究了影响化学发光强度的各种因素.结果表明,在最佳试验条件下,铜(Ⅱ)浓度在1.0×10-8"1.0×10-5 mol·L-1范围内与发光强度呈线性关系,检出限为4.1×10-10 mol·L-1.将该方法用于水样中铜(Ⅱ)的测定,结果满意.     

Utilization of bromination reactions for the determination of carbamazepine using bromate–bromide mixture as a green brominating agent

One titrimetric and two spectrophotometric procedures have been developed for the assay of carbamazepine (CBZ) in bulk drug, formulations and spiked human urine. The methods are based on the bromination of CBZ by the bromine generated in situ by the action of the acid on the bromate–bromide mixture. The twin advantages of avoiding liquid bromine and analysis in a cost-effective manner are realized. In titrimetry, the drug was treated with a known excess of bromate–bromide mixture in hydrochloric acid medium followed by the determination of unreacted bromine iodometrically. Spectrophotometry involves the addition of a measured excess of bromate–bromide reagent in acid medium to CBZ, and after the reaction is ensured to be complete, the residual bromine was determined by reacting with a fixed amount of either methyl orange and measuring the absorbance at 510 nm (method A) or indigo carmine and measuring the absorbance at 610 nm (method B). Titrimetric procedure is applicable over the range of 1.00–7.50 mg CBZ, and the calculations are based on a 1:1 reaction stoichiometry (CBZ:KBrO₃). In spectrophotometric methods, Beer’s law is valid within concentration ranges of 0.25–1.50 and 0.50–6.00 μg ml⁻¹ CBZ for methods A and B, respectively. The proposed methods were successfully applied to the determination of CBZ in tablets and syrup, in addition to spiked human urine by the spectrophotometric methods, with mean recoveries of 95.50–104.0% and the results were statistically compared with those of an official method by applying Student’s t-test and F-test.     

ZnO-Bi2O3/graphitic carbon nitride photocatalytic system with H2O2-assisted enhanced degradation of Indigo carmine under visible light

Indigo carmine in aqueous solution was effectively degraded using ZnO-Bi₂O₃/Graphitic Carbon Nitride heterojunction structure by visible light/H₂O₂ system. The mechanism of photocatalytic degradation of Indigo carmine shows the responsible species for the degradation of Indigo carmine in the ZnO-Bi₂O₃-xC₃N₄/H₂O₂/visible light system (x = 0, 1, 2, and 3) is the hydroxyl radicals which were generated from the reaction of e⁻ and h⁺ with H₂O₂. Under optimal conditions, ZnO-Bi₂O₃-2C₃N₄/H₂O₂/Vis system degraded more than 93% of Indigo carmine in 180 min. Besides, the kinetic of the photocatalytic process was detailed. These results demonstrate that the ZnO-Bi₂O₃-2C₃N₄/H₂O₂/visible light system may become a promising approach to achieve efficient environmental remediation as an environmentally friendly oxidant.     

Chitosan‐Based Hydrothermal Nanocarbon: Core‐Shell Characteristics and Composite Electrodes

Low cost sustainable hydrothermal nanocarbon from chitosan is investigated for anion binding and electrochemical sensing. Raman analysis suggests amorphous carbon core components but film electrodes show insulator characteristics due to incomplete “core‐shell carbonisation”. Anion adsorption capability is exploited in a composite with negatively charged carbon nanoparticles. The accessible positive surface charge is estimated as 14, 70, 20 C g^?1 for hydrothermal nanocarbon obtained at 180 °C, 200 °C, 230 °C, respectively (Langmuirian binding constant ca. 10⁵ mol^?1 dm³), which suggests that up to 15 % of nitrogen can be present in the form of accessible surface or shell ammonium functionalities.     

超高效液相色谱-串联四极杆质谱法筛查青黛中非法掺入的染色物质

建立了超高效液相色谱-质谱联用法测定青黛中非法掺入的染色物质孔雀石绿、隐色孔雀石绿、天青A、天青B、天青C和亚甲基蓝的检测方法.样品经乙腈溶液(含5%甲酸)提取,采用超高效液相色谱-串联三重四极杆质谱(UPLC-MS/MS)的多反应监测模式(MRM)进行定性和定量检测,其中孔雀石绿、隐色孔雀石绿内标法定量,天青A、天青B、天青C、亚甲基蓝外标法定量.6种染色物质测定的线性范围在1～30 ng/m L之间,孔雀石绿、隐色孔雀石绿、天青A、天青B、天青C、亚甲基蓝的检出限分别为0.5、0.5、1.0、1.0、1.0、1.0 ng/g,定量限分别为1.0、1.0、2.0、2.0、2.0、2.0 ng/g,3个水平的回收率在79.7%～119.7%之间,精密度的RSD%在0.7%～1.8%之间.方法前处理简单,灵敏度高,适用青黛中非法掺入的染色物质孔雀石绿、隐色孔雀石绿、天青A、天青B、天青C和亚甲基蓝的快速检测.