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Abstract: A modified molybdenum blue method for fast and accurate measurement of arsenate and phosphate in aqueous solution at concentrations below 10μmoll−1 is reported. The modification consists of optimizing the composition of the molybdenum-containing solution (potassium antimony tartrate, ammonium molybdate, sulfuric acid). Selective reduction of arsenate by sodium dithionite is used to determine phosphate concentrations, and for the speciation of arsenate and arsenite, in an aqueous mixture according to the scheme developed by Johnston and Pilson. Sodium dithionite is used for the first time to achieve complete, fast (<10min), and selective reduction of arsenate in neutral solution. These two significant improvements afforded a colorimetric limit for As detection near 1ppb, which easily meets the requirements imposed by the revised EPA threshold levels for As in drinking water. [Copyright &y& Elsevier]

Thoracic sympathectomy is a commonly performed surgical procedure for the treatment of palmar hyperhidrosis. However, one major complication of such a procedure is compensatory truncal hyperhidrosis. We describe an extreme case of compensatory truncal hyperhidrosis and anhidrosis over the head and neck region which led to a heatstroke. Bilateral reoperative needlescopic video-assisted thoracic surgery was performed for the reversal of thoracic sympathectomy with an interposition intercostal nerve graft. The patient's truncal hyperhidrosis resolved gradually over 1 month following the reversal procedure.