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Poly(vinylpyrrolidone) (PVP), as the low-cost and commercial material, exhibits superior phosphoric acid doping capability due to the presence of heterocycle and carbonyl groups in the repeat unit. However, it can’t be used as the high temperature polymer electrolyte membrane (HT-PEM) alone because of its significant hydrophilicity and poor mechanical stability. In the present work, polyethersulfone (PES), polysulfone (PSU), polyetherketone-cardo (PEK-c), polyvinylidene fluoride (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PHFP), five kinds of engineering thermoplastics with excellent mechanical properties and chemical inertness, are chosen to prepare a series of PVP blend membranes by the polymer blending method in order to enhance the dimensional and mechanical stabilities of PVP based membranes. The influence of structures of enhanced polymers on properties of HT-PEMs was investigated systematically. PVP blend membranes with aromatic polymers (i.e. PES, PSU and PEK-c) exhibited decreased volume swellings, increased acid doping contents, superior conductivities and improved mechanical strengths, which determined that they are more suitable for electrolytes of fuel cell applications comparing with PVP/PVDF and PVP/PHFP membranes blended with aliphatic polymers.

The acid doping behavior of poly(2,2′-(m-phenylene)-5,5′-bibenzimidazole) (PBI) membranes in aqueous phosphoric acid was studied at room temperature. It was found that doping phosphoric acid in the membrane obeyed a multimolecular layer absorption mechanism proposed in this work. Equation, i.e., 1/[LT]B=(1 − C0/17.5)/2.1, was presented to describe the relationship of the acid doping level of membranes and the concentration of the doping acid in a range of 2–14 mol L−1. The acid doping kinetics as well as the influence of the doped acids on the conductivity and mechanical strength of the PBI membranes was investigated.

A concentration-jump chemical relaxation catalytic procedure by using stopped flow injection is described with detection by spectrophotometry. The photoreduction of the Fe(III)-bipyridyl complex to Fe(II)-bipyridyl is pre-equilibrated at dark for at least 12 h. This solution is afterwards delivered by a peristaltic pump and mixed up with a stream of Co2+ solution as a catalyst. The mixture is confluenced down-stream with a flow of Fe(III) solution from a second pump, the concentration of which is about 30% of the pre-equilibrated Fe(III)-bipyridyl solution and acts as the perturbation (concentration-jump). The chemical relaxation process was monitored under thermodynamically non-equilibrium state, and the characteristic parameter of the relaxation process, relaxation time τ, is derived. The calibration graph between 1/τ and cobalt concentration is linear within 0.1–2.5 µg mL−1. The detection limit (LOD) and precision (RSD) are 9 ng mL−1 and 1.6%, respectively, both have been improved as compared to 12 ng mL−1 and 3.6% with a former reported manually operated procedure. The present procedure has been applied to the determination of cobalt in a certified reference material and a soil sample.

A novel catalytic procedure for zirconium was proposed based on Zr(IV) catalyzed oxidation of gallocyanine by hydrogen peroxide in hexamethylene tetramine-hydrochloric acid buffer medium. The calibration graph is linear for 0–110 ngċml−1, and the detection limit is 0.4 ngċml−1 Zr(IV). Most foreign ions do not interfere with the determination, except for Cu2+, Fe3+ and Cr(VI). The interferences of Cu2+ and Fe3+ could be eliminated by masking with EDTA and mannitol, and that of Cr(VI) by reducing to Cr(III) with ascorbic acid. The typical features of this procedure are that it is sensitive for zirconium, and the determination could be carried out at room temperature. It had been used to the determination of zirconium in zirconium bronze, simulated samples and a certified reference material. The recoveries were 98.6 ∼ 102%, and relative standard deviations (R.S.D.) were 0.9 ∼ 1.5%, respectively.

A kinetic dual standard additions method for determination of two mutually interfering analytes is proposed. The deviations of absorbance from additivity in kinetic systems, caused by synergistic effects of catalysts, are compensated with the defined synergistic catalytic coefficient. The hydrogen peroxide-iodide kinetic reaction catalysed by molybdate and tungstate was studied with the stopped-flow injection technique and the conditions for simultaneous determination of Mo and W established. The molybdenum and tungsten contents in different samples were determined with recoveries of 97.6 ∼ 102.1% and 96.9 ∼ 98.6%, and relative standard deviations of 2.3 ∼ 3.4% and 1.6 ∼ 2.6%, respectively.

A kinetic method is proposed for the simultaneous determination of europium(II) and cerium(III), based on their inductive action on the Cr(VI)-iodide redox reaction in weak acidic medium. The reaction rate was followed by the stopped-flow spectrophotometric technique using starch-iodine complex as indicator. The method can be used for the determination of europium and cerium after reduction with zinc metal powder in the concentration ranges 0–2.1 and 0–1.8 μg/ml, respectively. The detection limits are 0.015 μg/ml Eu and 0.010 μg/ml Ce. 100 to 1000 times higher concentrations of other rare earth metal ions and Th4+, Al3+, Mn2+, Hg2+, Co2+, Ni2+, Cu2+, Pb2+ do not interfere. The method is applied to the determination of europium and cerium in a synthetic sample and in barium yttrium fluoride fluorescent material, with relative standard deviation of about 4%.