聚亚甲基蓝/碳纳米管修饰电极阳极溶出伏安法测定痕量锡

研究了聚亚甲基蓝/碳纳米管修饰电极通过阳极溶出伏安法测定痕量Sn2+的电分析方法。Sn2+通过与电极表面的亚甲基蓝吩噻嗪环上S和N原子发生螯合作用而富集在电极表面,同时在-1.20 V(vs.SCE)还原成Sn0,当电极电势从-1.20 V向-0.30 V扫描时,被还原的Sn0从电极表面溶出。碳纳米管与亚甲基蓝的协同作用,使得Sn2+在该修饰电极上有良好的响应。Sn2+的溶出峰电流与其浓度在0.2×10-3~0.1 mmol/L浓度范围内呈良好的线性关系,检测限为0.1×10-3mmol/L。     

双硫腙修饰电极超声波溶出伏安法测定痕量汞

制备了双硫腙修饰的玻碳电极,利用阳极溶出伏安法并通过超声波富集测定痕量重金属离子Hg~(2+)。Hg~(2+)与电极表面的双硫腙通过螯合作用而被富集在电极表面,在-1.20 V时还原成Hg0,当电极电势从-0.50 V到0.70 V扫描时,被还原为单质的Hg0从电极表面溶出,在0.20 V左右形成灵敏的阳极溶出峰。选择0.1 mol/L的Na Cl溶液为支持电解质并对pH、富集时间、富集电位、双硫腙的修饰量等参数进行优化。在优化条件下,Hg~(2+)浓度为5.0×10~(-8)~2.0×10~(-4)mol/L时与溶出峰电流呈现良好的线性关系,检出限为1.1×10~(-8)mol/L,重现性良好,可用于水样中痕量重金属离子Hg~(2+)的快速检测。     

铋膜电极吸附溶出伏安法测定铅的研究

建立了采用铋膜电极应用吸附溶出伏安法测定痕量铅的方法。在含有Pb(II)的0.1 mol·L-1柠檬酸-柠檬酸钠缓冲溶液(pH 6.7)中,于-0.1V搅拌富集,Pb(II)与茜素紫形成络合物而富集于电极表面,然后交换介质至空白底液中,于-0.85 V还原后再进行阳极化扫描,于-0.60 V左右获得一灵敏的铅氧化溶出峰,溶出峰电流与Pb(II)的浓度在1.2×10-8~2.4×10-6 mol·L-1范围内呈良好的线性关系,检出限达6.2×10-9 mol·L-1。方法应用于皮蛋中铅的测定,其加标回收率达到98.0%~122.0%,结果较满意。     

阴极溶出伏安法测定黄原酸盐

提出了一种测定微量有机硫化合物的方法一阴极溶出伏安法测定黄原酸盐，研究了它的溶出伏安性质和测试条件，此化合物在酸性溶液中，在电位-0．45V附近出现溶出峰。溶出峰高度与浓度在10^-6-10^-8mol／L范围内具有良好的线性关系。     

纳米二氧化钛膜电极测定痕量锌

以nano-TiO2膜修饰玻碳电极作为工作电极,采用线性扫描溶出伏安法测定饮料样中的痕量Zn2+。在pH值4.5的磷酸盐缓冲溶液中,Zn2+在-1.2 V电位下富集7min,再静置60s后阳极化扫描,于-0.72 V处出现一个灵敏而尖锐的阳极溶出峰。Zn2+溶出峰电流与其浓度在1.0×10-8~5.0×10-6mol.L-1范围内呈良好的线性关系,富集12 min,检出限(S/N=3)为2.5×10-9mol.L-1。方法用于实际饮料样中Zn2+的检测,结果令人满意。     

方波溶出伏安法同时测定水体中的重金属

应用方波溶出伏安法同时测定水体中几种微量重金属离子浓度,在浓度为8.0g/L的氯化铵底液中,合适的条件和参数下,Mn2+、Zn2+、Hg2+均灵敏地产生溶出峰。峰电位分别为:-1.94V、-1.05V、1.31V。此方法灵敏度高,检测限低,重现性好,适合进行微量重金属离子的快速同时检测。     

计时电位溶出法测定天麻中的痕量砷

以镀金玻碳电极为工作电极,计时电位溶出法测定天麻中的痕量砷。选择富集电位为-0.45V,溶出低液为3.0 mol/L的硝酸,在+0.14V电位处获得一灵敏的砷(Ⅲ)的二次微分电位溶出峰,且该溶出峰的峰高与砷的质量浓度在2.0～12.0μg/L范围内呈线性关系,方法的检出限(3S/N)为0.96μg/L。方法用于测定天麻中痕量砷的回收率为97.6%～102.4%,RSD为2.7%～3.1%。     

ABS树脂中痕迹量铜和铅的连续测定

本文介绍一种采用2.5次微分阳极溶出伏安法同时连续测定ABS树脂中痕迹量铜和铅的方法。试验表明:在含有0.04M HCl的支持电介质中,铜和铅有很好的溶出峰,其蜂电位分别为—0.20V和—0.42V,检测下限为1×10~(-9)g/ml,回收率为95～105%。     

金电极阳极溶出方波伏安法测定痕量铬

研究了金电极阳极溶出方波伏安法测定痕量铬的新方法。SCN-在金电极表面特异性吸附,三价铬离子与其发生配合作用,从而富集在金电极表面。预富集时在-1.2 V(vs.)还原成零价的铬,当电极从-1.4 V向0.5 V扫描时,铬原子则从电极表面溶出,于-0.70 V左右形成灵敏的阳极溶出峰。本文优化了支持电解质pH、富集电位及富集时间等实验参数。方法测定铬的线性范围0.1 pg/L到0.6 pg/L,相关系数为0.9935,检测限为0.03 pg/L。     

阴极吸附溶出方波伏安法测定微量镉

研究了阴极吸附溶出方波伏安法测定微量镉的方法,该法不受共存离子镍、锌等的干扰。详细研究了阴极吸附溶出方波伏安法测定微量镉的最佳条件。在pH=4.50的0.2 mol.L-1HAc—NaAc缓冲体系中,Cd2 —XO配合物在汞膜电极上于-0.68 V(Vs.Ag/AgCl)处产生一灵敏的阴极吸附溶出方波伏安峰,灵敏度高,波形好。峰电流Ip与Cd2 浓度在1.5×10-7~5.0×10-6mol.L-1范围内呈良好的线性关系,相关系数为0.997 6,其检测下限为5.0×10-8mol.L-1。将该法用于水中微量镉的测定,结果较好。     

In situ bismuth-film electrode for square-wave anodic stripping voltammetric determination of tin in biodiesel

A bismuth-film electrode (BiFE) was applied in square-wave anodic stripping voltammetry (SWASV) in order to determine Sn (IV) in biodiesel samples. In situ simultaneous deposition of tin and bismuth at −1.2 V for 90 s was carried out in a supporting electrolyte containing 0.1 mol L⁻¹ acetate buffer (pH 4.5) and 1.73 mmol L⁻¹ caffeic acid as the complexing agent. A single well-defined anodic stripping peak was observed at −0.58 V for the oxidation of Sn to Sn (II), which was used as the analytical signal. The calibration curve was obtained in the concentration range of 0.17–7.83 μmol L⁻¹ with the detection limit being 0.14 μmol L⁻¹ (r = 0.9990). Repeatability and reproducibility for the measurement of the current peak were characterized by relative standard deviations of 3.6% and 4.1%, respectively, for a 5.0 μmol L⁻¹ Sn (IV) solution (n = 10). The method was validated by comparing the results obtained with those provided by application of the atomic absorption spectroscopy technique.     

EXTRACTION OF NEPTUNIUM AND PLUTONIUM NITRATES WITH n-OCTYL(PHENYL)-N,N-DIISOBUTYL-CARBAMOYLMETHYLPHOSPHINE OXIDE∗

Distribution equilibria of Np and Pu in various valence states and stripping of Np(V) were studied in a system involving 0.20 M n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide + 1.2 M tributyl phosphate in dodecane as a solvent. Np(V) is weakly extractable at <2 M nitric acid but more effectively extractable at >3 M nitric acid, due to the disproportionation of Np(V) to Np(IV) and Np(VI). Addition of nitrous acid to solutions containing Np(V) increases the over-all extractabllity of Np, due to its partial oxidation to Np(VI). This is also the case In the presence of oxalic acid, both at room temperature and at 40^°C. Both Np(IV) and Np(VI) are highly extractable, but the reduction of Np(V,VI) to Np(IV) is slow even with a reductant as strong as sodium formaldehyde sulfoxylate. Pu(IV) is highly extractable and its reduction to Pu(III) with sulfoxylate Is incomplete in the two-phase system if the aqueous phase contains >0.5 M nitric acid. Extracted Np(VI) can be stripped by reduction to Np(V). The stripping rate is, however, slow with nitrous acid as the reductant at low nitric acid concentration. The reduction of Np(VI) by hydrogen peroxide is fast, but is followed by further reduction to Np(IV). Sulfurous acid reduces Np(VI) rapidly and, if no iron is present, only to Np(V), but Fe(II) induces further reduction to Np(IV).     

微分脉冲阳极溶出伏安法测定氢溴酸右美沙芬

应用循环伏安法和微分脉冲阳极溶出伏安法在玻碳电极上对氢溴酸右美沙芬的伏安行为进行了研究。实验结果表明,在pH6.5的B-R(Britton-Robinson)缓冲底液中,氢溴酸右美沙芬在+1.01 V(vs.Ag/AgCl)处有一明显的氧化峰,在4.0×10-6~8.0×10-5mol/L范围内与峰电流呈良好的线性关系(r=0.995 1),检出限为5.6×10-7mol/L。用该方法对氢溴酸右美沙芬片进行了测定,回收率为98.6%~102.9%,结果令人满意,还对其电极反应机理进行了初步探讨。     

DL-精氨酸/石墨烯修饰电极测定铅

用循环伏安法制备DL-精氨酸/石墨烯修饰玻碳电极,研究金属铅在修饰电极上的电化学行为。在0.1 mol/L pH=4.5的NaAc-HAc缓冲液中,以DL-精氨酸/石墨烯修饰电极作为工作电极,用循环伏安法测定-1.0~1.0 V处的溶出峰电流。实验结果显示:铅的浓度与溶出峰电流具有良好的线性关系,范围是3.0×10-9~9.0×10-7mol/L,检测限为1.0×10-10mol/L,用于测定金属结果满意。     

Vanadium Extraction using Pseudo-Emulsion Based Hollow-Fiber with Strip Dispersion Technique

The present work investigated the removal rates of vanadium (V) from aqueous solution using PEHFSD technology. A pseudo-emulsion was prepared by dispersing hydrochloric acid (stripping) solution into an organic phase constituted of kerosene, Aliquat 336(carrier), and 1-decanol. Within 60 min, typical results with continuous recycling of both the feed and the pseudo-emulsion employing carrier concentration of 0.025 M and feed pH 5 showed that extraction was nearly 99% whereas maximum recovery in the HCl solution achieved was over 85%. Mathematical analysis suggested that the removal rates are controlled by mass transfer resistance from extraction and stripping reactions.     

鸟粪石法回收磷过程的耗碱量及其变化规律

从分析磷回收过程中的各种耗碱因素入手,推导出耗碱量的理论计算公式,计算出不同工艺条件下的理论耗碱量,并与小型套管式空气脱气填料层磷回收过程的实测值进行比较。结果表明：耗碱量的理论计算值与实验测定值的平均相对误差为18.73%,说明计算方法可用于耗碱量的工程估算;在套管式空气脱气填料层磷回收装置中,由于填料和空气对二氧化碳和氨气的脱气作用,耗碱量可节省约20%;耗碱量随出水pH值的增大而急剧增加,随废水中氨氮含量和磷初始浓度的增加都近似于线性增加,但随镁磷比的增加基本不变。因此,从节约处理成本的角度看,磷回收过程中pH值应控制在9.20～9.30,氮磷比控制在3.0～5.0,镁磷比控制在1.1～1.2为宜。磷回收过程的药剂消耗量与废水中磷的浓度和工艺条件有关,以磷初始浓度为77.5 mg·L^-1,N∶Mg∶P=5∶1.2∶1,出水pH值为9.20的回收过程为例,处理毎吨废水需消耗片碱0.3315 kg,成本约为0.828元,需消耗氯化镁（含6个结晶水）0.6099 kg,成本约为0.396元。因此,处理每吨废水的药剂成本约为1.224元,其中耗碱约占67.6%。     

丁香酚在活化玻碳电极上的电化学行为

用循环伏安法和差分脉冲溶出伏安法研究了丁香酚在活化玻碳电极于醋酸-醋酸钠（pH=6．0）缓冲溶液中的电化学行为。结果表明,丁香酚在该电极上于0．188V、0．485V有一对氧化还原峰,表明该电极对丁香酚有催化作用。在pH=6．0的醋酸-醋酸钠缓冲液中,用差分脉冲溶出伏安法在该电极上测定了丁香酚,线性范围为4．00×10^-6-2．58×10^-4mol／L。检测限为1．96×10^-6mol／L。成功用于样品的测定。     

Development of an adsorptive catalytic stripping voltammetric method for the determination of an endocrine disruptor pesticide chlorpyrifos and its application to the wine samples

A very sensitive voltammetric method for the determination of an endocrine disruptor Chlorpyrifos (CP) insecticide at ng mL⁻¹ level was described. The pesticide was accumulated at a hanging mercury drop electrode (HMDE) and a well-resolved reduction peak was observed at −1.2 V (vs. Ag/AgCl) in pH: 2.0 media containing 5% aqueous ethanol solution. A systematic investigation of the solution parameters and operational parameters which affect the stripping response were carried out with differential pulse voltammetry. With an accumulation potential of −0.5 V and an accumulation time of 60 s, the detection and quantification limits were found to be 0.14 and 0.45 ng mL⁻¹, respectively. The remarkable sensitivity of the method was attributed to a catalytic process as concluded from cyclic voltammetry. The degree of interference from diverse ions and some other pesticides on the differential pulse stripping signal for CP was evaluated. The method developed was adapted for wine samples. The matrix effect of red wine was eliminated by means of liquid–liquid extraction (LLE) followed by solid-phase extraction (SPE) with satisfactory recovery values. This method offers a very sensitive and inexpensive way for determining CP residues in red wines.     

Solvent Extraction of Gold(I) from Alkaline Cyanide Solution with Furfuryl Thioalcohol

A facile approach was designed to extract gold(I) from alkaline cyanide solution via a hydrometallurgy method. The performances of gold(I) extraction with furfuryl thioalcohol were investigated. The results revealed that gold(I) extraction increased with increasing extractant concentration and phase ratio but decreased with increase of pH value and god(I) concentration. The transfer speed of gold(I) between two phases was rather fast, and the extraction equilibrium could be established within 2 min. The extraction of gold(I) reached 92.7% with 15% (V/V) extractant. Gold(I) loaded in organic phase was stripped by NaOH solution, and stripping of gold(I) reached 90.2% with 0.08 mol · L^?1.