镓(Ⅲ)-茜素红体系的吸附伏安法

本文对镓(Ⅲ)与茜素红络合物在悬汞电极上的吸附伏安法作了研究,确定了电极过程.在HAc-NH_4Ac(pH4.06)缓冲溶液中茜素红存在下,用1.5阶微分吸附伏安法测定镓,其线性范围是1×10~(-10)～1×10~(-7)mol/L,其检测限为1×10~(-10)mol/L,并用此法测定了中草药中的痕量镓.     

碘化物-结晶紫-聚乙烯醇体系分光光度法测定自来水中痕量二氧化氯

在稀磷酸介质中，二氧化氯（ＣｌＯ２）氧化Ｉ离子形成 Ｉ３配阴离子，Ｉ３进一步与结晶紫（ＣＶ）阳离子形成离子缔合物［ＣＶ］［Ｉ３」。在聚乙烯醇存在下，该离子缔合物最大吸收波长λｍａｘ位于５５２ ｎｍ处，摩尔吸光系数ε＝２５ × １０５Ｌ·ｍｏｌ－１·ｃｍ－１，对 ＣｌＯ２的检出限为 ０．６ μｇ／Ｌ，线性范围是 ０．６～２８０μｇ／Ｌ。加入适量 ＫＦ溶液可消除自来水中Ｆｅ（Ⅲ）的干扰。方法对μｇ／Ｌ级ＣｌＯ２ 的测定有较好的选择性，可成功地用于自来水样品分析。     

Determination of proteins with Alizarin Red S by Rayleigh light scattering technique

A new protein determination method by enhanced Rayleigh light scattering (RLS) technique has been developed. In acid condition (pH=3.60), RLS of 1,2-dihydroxyanthraquinone-3-sulfonate (Alizarin Red S) can be greatly enhanced by addition of proteins, resulting in two characteristic peaks, 360 and 505 nm, respectively. The new protein assay is based on the RLS enhancement and spectrum change. The optimum condition for the reaction was investigated. The linear range is 0.20-24.9 μg ml⁻¹ for BSA and 0.20-15.5 μg ml⁻¹ for HSA. The detection limits (S/N=3) are 9.59 ng ml⁻¹ for BSA and 9.51 ng ml⁻¹ for HSA. The results of determination for human serum samples were comparable to those obtained by Bradford method. The binding stoichiometry was determined.     

A Sensitive Spectrophotometric Determination of Nitrite in Water and Soil

A highly sensitive spectrophotometric method for the determination of nitrite in water and soil has been developed. The reaction of nitrite with acidified potassium iodide to liberate iodine which oxidizes leuco‐crystal violet (LCV) to form crystal violet having absorption maxima at 590 nm forms the bases of this method. In aqueous medium the system obeys Beer's law in the range of 0.1 to 1.0 μg per 25 mL (0.004–0.04 ppm), while in an extractive system the range is 0.025–0.25 μg in 100 mL (0.00025–0.0025 ppm). The molar absorptivity and Sandell's sensitivity were found to be 1.54 × 10⁶ 1 mol^?1 cm^?1 and 44 pg cm^?2, respectively.     

Resonance Rayleigh scattering, frequency doubling scattering and second-order scattering spectra of the heparin-crystal violet system and their analytical application

In pH 6.0-11.2 Britton-Robinson buffer solution, binding of heparin with crystal violet (CV) can result in a significant enhancement of resonance Rayleigh scattering (RRS) and resonance non-linear scattering, such as frequency doubling scattering (FDS) and second-order scattering (SOS). Their maximum scattering wavelengths, λ_ex/λ_em, appear at 492 nm/492 nm for RRS, 984 nm/492 nm for FDS and 492 nm/984 nm for SOS, respectively. The optimum conditions of the reaction, the influencing factors and the relationship between the three scattering intensities and the concentration of heparin have been investigated. New methods for the determination of trace amounts of heparin based on the RRS, FDS and SOS methods have been developed. The methods exhibit high sensitivities, the detection limit for heparin is 2.9 ng ml⁻¹ for the RRS method, 3.5 ng ml⁻¹ for the FDS method and 3.3 ng ml⁻¹ for the SOS method. The methods have good selectivity and were applied to the determination of heparin in heparin sodium injection samples with satisfactory results.     

Preparation,characterization and photocatalytic performance of polyoxometalate / polyaniline / titania ternary composite

A new CoW₁₁Mn/PANI/TiO₂ ternary composite was synthesized with K₈[Co(H₂O)MnW₁₁O₃₉] (CoW₁₁Mn) and PANI/TiO₂ by electrostatic self-assembly. These catalysts were characterized using infrared (IR) spectroscopy, X-ray diffraction, scanning electron microscopy, ultraviolet–visible spectroscopy, and N₂ adsorption–desorption. CoW₁₁Mn/PANI/TiO₂ was used to photodegradate the example contaminant, gentian violet (GV). Under the optimum photodegradation conditions, 92.63% degradation was achieved, indicating that the introduction of polyoxometalate and polyaniline greatly enhanced the photocatalytic performance of the catalyst. Moreover, CoW₁₁Mn/PANI/TiO₂ exhibits stable performance with little loss in activity after three successive runs. Thus, CoW₁₁Mn/PANI/TiO₂ ternary composite could be a promising photocatalyst in photodegradation of organic pollutants.     

Optimization of solid phase dispersive field‐assisted ultrasonication for the extraction of auramine O and crystal violet dyes using central composite design

Simultaneous preconcentration and determination of auramine o (AO) and crystal violet (CV) dyes from aqueous solution was conducted by ultrasound assisted (dispersive) solid phase microextraction (UASPME) based on SnO₂/SnS composite loaded activated carbon (SnO₂/SnS‐NCs‐AC). The prepared of SnO₂/SnS‐NCs‐AC was characterized by FESEM and XRD analysis. Main and interaction influences of operational parameters such as pH, sonication time, amounts of sorbent, and type of eluent on extraction efficiency were investigated by central composite design and optimized with desirability function approach (DFA). ANOVA was conducted and shows that optimized values were found at 15.33 min sonication time, 0.019 g SnO₂/SnS‐NCs‐AC mass, pH 5.46 and among different solvents, dimethyl formamide was selected as an efficient eluent. Under this conditions recoverees percentage were obtained 82.85% and 86.70% for AO and CV, respectively. Based on F‐test under ANOVA all main effect and interaction effect of understudy parameters has the significant effect on the responses. At optimum conditions, limit of detection (0.0015 and 0.001 mg/l), limit of quantitation (0.4 and 0.4 mg/l), limit of linearity (9.0 and 9.0 mg/l), enrichment factor (33.48 and 83.71) and percent relative standard deviation (3.44 and 4.20) were found to be for auramine o and crystal violet dyes, respectively. Finally, the method was successfully applied for the preconcentration and determination of AO and CV in water samples and ER% of 89.0‐97.0 and 96.2–98.0% as acceptable range were found to be for AO and CV samples, respectively.     

Efficient removal of crystal violet and methylene blue from wastewater by ultrasound nanoparticles Cu-MOF in comparison with mechanosynthesis method

The present investigation reports the synthesis of CuBTC (BTC = 1,3,5-benzenetricarboxylate) metal–organic frameworks (MOFs) under solid-state conditions and ultrasound irradiation. Herein, we study uptake and release properties of crystal violet (CV) and methylene blue (MB) from ultrasound nano-CuBTC MOF in comparison with mechanosynthesis method (bulk structure). The ultrasound-assisted methods give a decrease in the surface area as calculated from the reduced nitrogen adsorption capability. In comparison, the uptake of guest molecules on ultrasound nano-CuBTC is remarkable and clearly exceeds that of bulk structure in the aqueous solution of guests. In bulk compound the channel length is increased so that the amount of adsorption is decreased a little. The small guest enters and leaves the cavity rapidly, whereas larger guests enter slowly due to their size relative to the size of the gaps in the capsule. As a result, the uptake and release of MB from CuBTC is faster than that of CV.     

Hydrogen production and photocatalytic activity of g-C3N4/Co-MOF (ZIF-67) nanocomposite under visible light irradiation

Herein, cobalt (Co)-based metal–organic zeolitic imidazole frameworks (ZIF-67) coupled with g-C₃N₄ nanosheets synthesized via a simple microwave irradiation method. SEM, TEM and HR-TEM results showed that ZIF-67 were uniformly dispersed on g-C₃N₄ surfaces and had a rhombic dodecahedron shape. The photocatalytic properties of g-C₃N₄/ZIF-67 nanocomposite were evaluated by photocatalytic dye degradation of crystal violet (CV), 4-chlorophenol (4-CP) and photocatalytic hydrogen (H₂) production. In presence of visible light illumination, the photocatalytic dye results showed that 95% CV degradation and 53% 4-CP degradation within 80 min. The H₂ production of the g-C₃N₄/ZIF-67 composite was 2084 μmol g⁻¹, which is 3.84 folds greater than that of bare g-C₃N₄ (541 μmol g⁻¹).     

Unpredictable adsorption and visible light induced decolorization of nano rutile for the treatment of crystal violet

Photocatalysts containing different ratios of anatase and rutile are prepared via heat treatment of Degussa P-25 titania. X-ray diffraction (XRD), Bruuauer-Emmett-Teller (BET), ultraviolet–visible light diffuse reflectance spectra (DRS), Raman spectra (Raman), positron annihilation lifetime spectra (PAL) and temperature-programmed desorption (TPD) are applied to investigate the phase composition of the synthesized catalysts. Using crystal violet (CV) as the target pollutant, the unexpected visible light decolorization of rutile is observed. Despite the decreased specific surface area, the as-synthesized rutile samples exhibit much higher adsorption capability of CV than P-25 does, which in turn leads to improved photoreaction efficiency. Since the rutile samples can't absorb the visible light, the degradation under visible light irradiation is attributed to self-sensitization of CV on the surface of rutile.