High flow-rate cells for continuous monitoring of low concentrations of electroactive species by polarography and stripping voltammetry at the static mercury drop electrode

Use of mercury drop electrodes for polarographic measurements in flowing solutions

“…Pulse amperometric techniques have been widely applied in flow analysis [35,[46][47][48][49]. For flow systems, the improvement in the detection limit is not as drastic as for quiescent solutions; some studies reported similar detection limits for pulse and dc detection.…”

“…In some applications, the requirements may be quite different. Industrial applications, for example, usually require robust, high-volume detectors [46]. A model study for flow-velocity dependence requires detector designs that give a well-defined, measurable flow velocity around the electrode [51].…”

“…Substances commonly used for this purpose are sulfite (in basic and neutral solutions) and ascorbic acid (in acidic solutions). Sulfite is used by adding it t o the carrier solution [77] or in the form o f a sulfite bed [46]. MacCrehan and May (85) proposed using zinc-mesh columns as an oxygen scrubber.…”

“…Among the inorganic ions determined were cadmium [45,46,52,87,88], cobalt (661, copper [40, 52, 60, 66, 881, iron [88], manganese [66], nickel [66, 681, lead [37,45,46], thallium [ 271, zinc [37,45,46, 581, and the anions iodide, bromide, chloride, and thiocyanide [89], sulfide and cyanide [90], and pertechnetate [47]. The determined organic compounds included nitrocompounds such a s nitrobenzene [35, 74, 75, 80, 871, ni- trophenols [56, 75, 80, 87, 911, nitrotoluenes [92, 931, nitronaphtalenes [94], nitropyridine derivatives [95], nitrofuran derivatives [96], nitrobenzoic acids [ Table 3.…”

Studies of reverse pulse amperometry at mercury electrodes and its application for cation-exchange chromatography

“…A number of other approaches for oxygen removal from the eluent stream have also been reported including use of a compressed bed of sodium sulfite (22), a continuous-flow deaeration chamber (23), and a nitrogen-activated glass nebulizer (24). However, the large dead volume associated with these devices makes them incompatible with HPLC.…”