| Oscillating chemical reaction is a typical phenomenon of non-equilibrium andnon-linear. With the continuous improvement and maturation of theory, the applicationoscillating chemical reaction in practical determination has attracted the attention of manyanalysts. In this paper, the effects of active methylene organic substrates on Br- in the B-oscillating chemical reaction were studied ; the perturbation of Ag+ ion on three differentsteady states were investigated; an non-equilibrium stationary state of an uncatalyzedoscillating chemical system involving m-phenylenediamine has been used to determinationcatechol; the non-equilibrium stationary state of sulfide modified B-Z oscillating chemicalsystem was studied and used to determinate Hg2+ ion.Part 1. IntroductionThe review summarized the classification and mechanism of B-Z oscillating chemicalreactions. Moreover, the application of oscillating chemical system to analytical chemistrywas introduced and the perspective was also discussed in brief.Part 2. Effects of active methylene organic substrates on the concentrationof bromide in B-Z oscillating chemical reactionThe effects of organic substrates containing active methylene on the periods of B-oscillating chemical reaction catalyzed by Fe(Ⅱ) and Ce(Ⅳ) were studied in this part. Theresults indicated that with the increasing of initial concentration of organic substrates in theoscillating chemical system, the oscillating periods varied regularly and it was consistentwith the change of f in Oregonator model. In addition, it was found that the concentrationBr– detected by using a bromide ion selective electrode was linearly proportional to theconcentration of added an organic substrates. It showed that the concentration of organicsubstrate containing active methylene was the key factor in controlling the change of Br– ionconcentration in B-Z oscillating chemical reaction.Part 3. Effects of Ag+ ion on the oscillating system consisting of oxalicacid-acetone-KBrO3-Ce(Ⅳ)-H2SO4 Three steady states, i.e., the regular oscillating, the non-equilibrium stationary state, andthe multistability phenomena were observed in the system of oxalicacid-acetone-KBrO3-Ce(Ⅳ)-H2SO4 by adjusting the control parameter. Base on theperturbation of Ag+ ion on the three steady states, the different detection limits were obtained,that is 2.50×10-6 mol/L for regular oscillator, 3.75×10-6 mol/L for non-equilibrium stationarystate and 2.50×10-8 mol/L for the multistability phenomena, respectively. A possible reactionmechanism was also discussed.Part 4. Determination of catechol by using non-equilibrium stationary stateof uncatalyzed oscillating chemical reactionBased on the perturbation of catechol on a non-equilibrium oscillating chemical systemconsisting of m-phenylenediamine-KBrO3-H2SO4 close to a bifurcation point, a new methodfor determination of catechol was proposed. The results showed that the change of thepotential (ΔE) was linearly proportional to the negative logarithm concentration of catechol(-lgC) in the range of 4.05×10-9 - 4.05×10-7 mol/L(r = 0.9948), with a lower detection limitof 1.62×10-9 mol/L. The proposed method had been successfully used to determine the traceamount of catechol in artificial wastewater with a well recovery from 97.5% to 101.2%.Part 5. Determination of trace amount of mercury ion in soil bysulfide-modified B-Z reaction at non-equilibrium stationary stateThe effects of Hg2+ ion on both the regular oscillating state and the non-equilibriumstationary state after bifurcation of sulfide modified B-Z oscillating chemical system (Mn2+-diacetone-KBrO3-H2SO4) were examined in this paper. The results showed that thenon-equilibrium stationary state was more sensitive to Hg2+ ion than the regular oscillatingstate. Thus, a method with high sensitivity for determination of Hg2+ ion in soil was proposed.The detection limit was down to 2.12×10-11 mol/L. |
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