Development of a portable analyzer with polymer lab-on-a-chip (LOC) for continuous sampling and monitoring of Pb(II).

A new portable analyzer with polymer lab-on-a-chip (LOC) has been designed, fabricated and fully characterized for continuous sampling and monitoring of lead (Pb(II)) in this work. As the working electrodes of the sensor, bismuth (Bi (III)) which allowed the advantage of being more environmentally friendly than traditional mercury drop electrodes was used, while maintaining similar sensitivity and other desirable characteristics. The size of a portable analyzer was 30 cmx23 cmx7 cm, and the weight was around 3 kg. The small size gives the advantage of being portable for field use while not sacrificing portability for accuracy of measurement. Furthermore, the autonomous system developed in coordination with the development of new polymer LOC integrated with electrochemical sensors can provide an innovative way to monitor surface waters in an efficient, cost-effective and sustainable manner.

Oxidation of aminopyrine by hypochlorite to a reactive dication: possible implications for aminopyrine-induced agranulocytosis.

Aminopyrine is associated with a high incidence of agranulocytosis. It is known to be oxidized by peroxidases and hypochlorous acid to a blue cation radical. It has been proposed that the mechanism by which hypochlorous acid oxidizes aminopyrine to a cation radical involves N-chlorination followed by loss of a chlorine radical. Another possible mechanism is loss of HCl to form an iminium ion and subsequent reaction with another molecule of aminopyrine and a hydrogen ion to form two radical cations. This mechanism would lead to incorporation of a hydrogen from water; however, using a deuterated analog, we found no hydrogen incorporation, thus providing strong evidence against this mechanism. Using a stopped-flow diode array spectrophotometer to study the reaction between aminopyrine and hypochlorous acid, an intermediate with a lambda max at approximately 420 nm was observed in the formation of the cation radical. We propose that this represents a dication formed by the loss of chloride ion from N-chloroaminopyrine. This intermediate is very reactive, with a half-life of approximately 15 ms, and in addition to being the precursor of the cation radical, it also appears to react with two molecules of water to form several other products that were observed and are consistent with the proposed dication intermediate. Similar stable products were formed when amino-pyrine was oxidized by the combination of myeloperoxidase, hydrogen peroxide, and chloride or activated neutrophils. The reactive dication formed by neutrophil-derived hypochlorous acid could be responsible for aminopyrine-induced agranulocytosis.