Determination Of Lead,Arsenic,Selenium And Tin By Differential Potentiometric Stripping Analysis & Preparation And Application Of An Ion-selective Electrode Of Atomoxetine

Metals such as lead,arsenic and tin,are very poisonous to human's health .They can enter into human body through drinking water, eating food, breathing. Trace elements such as selenium are related to our health closely. For this reason, the determination of lead,arsenic, tin and selenium is necessary. This paper studied the quantitive analysis of trace lead, arsenic, tin and selenium in foods and traditional Chinese medicine samples using potential stripping analysis method.1. A method of determination of lead in vinegar by DPSA was reported. Determination was carried out in medium of 0.1 mol/L HCl solution. Experimental results showed that the method has a good linearity of peak height vs concentration in the range of 2-100 ng/mL for Pb²⁺. The method has been used to determine lead in vinegar with satisfactory results.2. A constant current potentiometric stripping method for the determination of trace selenium in mineral water with gold membrane electrode was presented. The optimum conditions of the method include a supporting electrolyte of 0.2 mol/L HClO₄-0.05 mol/L KNO₃, an deposition potential of -0.50 V, the peak potential is at +0.80 V (vs SCE).The peak height is linear to the Se(IV) of concentrations between 0.5-2.5 ng/mL.The method has been used to determine Se(IV) in mineral water with satisfactory results.3. Discussed the determination of arsenic content in traditional Chinese medicine by the method of constant current potential stripping analysis(ccPSA). Arsenic deposited on the working electrode (gold-film electrode) was oxidized by constant current which is contained in a base liquid composed of 2.5 mol/LHNO₃. There is a sensitive two-step derivative peak of As at Ep(the peak potential)=+0.13V (vsSCE) . A good linear connection exists between the height of this peak (Hp) and the concentration of arsenic when the latter is between 2-10 ng/mL. The method has been used to determine this element in some Chinese traditional herbs with satisfactory results.4. In the solution containing 0.09 mol/L oxalic acid,7.5×10^-5mol/L neutral red,thesimultaneous determination of lead and tin is reported by differential potentiometric stripping analysis. The peak potentials are at -0.62 and -0.52 V(vs SCE) for Sn⁴⁺ and Pb²⁺ respectively. The method has been used to determine these elements in some foods with satisfactory results.Tomoxetine hydrochloride is a nonstimulant that was approved for the treatment of ADHD in both children and adults by the US Food and Drug Administration (FDA) in November 2002. The low cost and ease of operation of potentiometric instrumentation make the potentiometric determination of tomoxetine hydrochloride a highly desirable method. In the present work, an Ion-selective electrode of tomoxetine hydrochloride has been prepared and applied.1. A PVC membrane selective electrode of tomoxetine hydrochloride is prepared based on tomoxetine-tetraphenylboron ion-associate. The electrode exhibits Nernst response for tomoxetine hydrochloride with a slop of 55.53 mV/pC over the concentration range of 1×10^-5-1×10^-2mol·L^-1.The detection limit is 3.18×10^-6 mol·L^-1. The electrode has the advantages of fast response and good repeatability.It displays a good selectivity for tomoxetine hydrochloride in the presence of a number of inorganic cations and organic substances. The content of tomoxetine hydrochloride in capsules has been determined by potentiometry and potentiometric titration with satisfactory results.