Use of Cucurbit [6] Uril as a Modifier in the Electrochemical Determination of Antitumor Platinum (II) Complex: <i>Trans</i>-[PtCl₂(Dimethylamine) (Isopropylamine)]. Application to Biological Samples

A square wave voltammetry (DPV) method for trans-Pt[Cl2(Dimethylamine)(isopropylamine)] determination is developed. To this end, all the chemical and instrumental variables affecting the determination of trans-Pt[Cl2(Dimethylamine) (isopropylamine)] are optimized. From studies of the mechanisms governing the electrochemical response of trans-Pt[Cl2(Dimethylamine)(isopropylamine)], it was concluded that it was an electrochemically reversible system with an adsorptive oxidation phenomenon. Under optimal conditions, the variation of analytical signal (Ip) with trans-Pt[Cl2(Dimethylamine)(isopropylamine)] concentration was linear in the 0.05 μg·mL-1 to 10 μg·mL-1 range, with a LOD 91 μg·mL-1 of and a LOQ of 303 μg·mL-1, a RSD 1.10% and Er 0.72%. The optimized method was applied to the determination of trans-Pt[Cl2(Dimethylamine)(isopropylamine)] in biological fluids, in human urine and synthetic urine.

Factors influencing the photodegradation of Nnitrosodimethylamine in drinking water

In order to provide basic data for practical application,photodegradation experiment of Nnitrosodimethylamine(NDMA)in aqueous solution was carried out with a low-pressure Hg lamp.Effects of the initial concentration of NDMA,solution pH,dissolved oxygen,and the presence of humic acid on NDMA photodegradation were investigated.NDMA at various initial concentrations selected in this study was almost completely photodegraded by UV irradiation within 20 min,except that at 1.07 mmol/L,NDMA could be photodegraded almost completely in the acidic and neutral solutions,while the removal efficiency decreased remarkably in the alkaline solution.Dissolved oxygen enhanced the NDMA photodegradation,and the presence of humic acid inhibited the degradation of NDMA.Depending on the initial concentration of NDMA,NDMA photodegradation by UV obeyed the pseudo-first-order kinetics.Dimethylamine,nitrite,and nitrate were detected as the photodegradation products of NDMA.^(1)O_(2) was found to be the reactive oxygen species present in the NDMA photodegradation process by UV,based on the inhibiting experiments using tert-butanol and sodium azide.

Cationized Melamine-formaldehyde Resin for Improving the Wet Strength of Paper

In this work, melamine-formaldehyde resin was cationized by adding modifiers so that the fibers closely bonded to improve their usability and the wet strength of paper was greatly improved. Triethanolamine and dimethylamine were added to modify the melamine-formaldehyde resin,respectively.The mechanism of the cationized resin was explored and the possible chemical reactions were deduced. It was concluded that,with the use of triethanolamine,the most optimum product was obtained by hydroxymethylation for 30 min with a temperature of 85℃ and p H of 9. 0 where n( melamine) ∶ n( formaldehyde) ∶ n( methanol) ∶ n( triethanolamine) was 100 ∶ 330 ∶ 450 ∶ 15. With the combined use of dimethylamine and methanol,the optimal product was acquired by condensation for 30 min at a temperature of 50℃ and p H of 2. 0 at melamine, formaldehyde, methanol, and dimethylamine molar ratio of100∶ 330∶ 350∶ 20. With the only use of dimethylamine,the optimal product was obtained by condensation at melamine,formaldehyde,dimethylamine molar ratio of 100∶ 330∶ 10. The wet tensile strength of fruit-bagging paper was improved by adding cationized melamine-formaldehyde resin. The zeta potential,charge density,and conductivity of the melamine-formaldehyde resin were also studied.

Adsorptive Removal of Heavy Metals from Aqueous Solution with Environmental Friendly Material—Exhausted Tea Leaves

In this study adsorptive removal of Pb(II) and Cu(II) from aqueous solution by using environmental friendly natural polymers present in exhausted tea leaves has been studied. The biosorbent was modified with dimethylamine to introduce N-functional groups on the surface of adsorbent. The modified adsorbent was characterized by elemental analysis, zeta potential analysis, SEM, DRFTIR, XRD and TG/DTA analysis to conform the modification. Adsorption capacity of the adsorbent was determined as the function of pH of the solution, initial concentration of the solution and contact time. The adsorption experiments were performed using batch experiments. The maximum adsorption capacities of the adsorbent were found to be 91.68 and 71.20 mg/g for Pb(II) and Cu(II), respectively. To minimize the process cost, regeneration of the biosorbent and recovery of metal ions was explored by desorption study. The results indicate that the adsorbent holds great potential for the sequestration of Pb(II) and Cu(II) from their aqueous solution. Hence the modified exhausted tea leaves (MTL) have been investigated as a new cost effective and efficient biosorbent for removal of Pb(II) and Cu(II) from their aqueous solution.