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The accurate determination of antimony in steel is important to the steel industry, because grain boundary segregation of antimony causes the decrease in toughness of steel owing to the temper embrittlement. Spectrometric methods 1,2 are commonly used for the determination of antimony in iron and steel, but they require a preconcentration procedure, which generally involves much skill, labor or time, and the use of toxic organic solvents such as toluene, 1 to avoid any interference from iron matrix. Furthermore, the methods exhibit poor sensitivity.Stripping voltammetry is a powerful electroanalytical technique for the determination of trace antimony and has been extensively applied in studying antimony in various samples. It includes anodic stripping voltammetry (ASV) at mercury, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Only a few papers have been published to date on the stripping voltammetric determination of antimony in steels. [33][34][35] Wang et al. 33 and Hofbauerova et al. 34 used ASV at mercurybased electrodes in a hydrochloric acid-alcohol medium for the determination of antimony in steels. Zhou et al. 35 developed 1.5th-order derivative linear-sweep adsorptive stripping voltammetry of antimony(III) complexed with morin (2′,3,4′,5,7-pentahydroxyflavone) at a static mercury drop electrode. However, those methods involve a troublesome procedure such as filtration or require a time-consuming and laborious standard additions method because of removing interferences from coexisting elements. Furthermore, mercury, which is toxic and difficult to use, is employed exclusively as the working electrode.The present paper describes a simple, rapid and accurate method for the direct determination of antimony at trace levels in steel based on ASV of antimony(III) at a gold film electrode without any preconcentration step. Experimental ApparatusVoltammetric determinations were performed using a BAS-50W electrochemical analyzer with an RDE-1 rotating disk electrode (Bioanalytical Systems, West Lafayette, IN, USA) and a BJC-240J printer (Canon, Tokyo, Japan). A platinum wire was used as a counter electrode. A saturated calomel reference electrode (SCE) was connected to a glass voltammetric cell (25 mm×22 mmφ) by a 4% agar-saturated potassium nitrate bridge. ReagentsKanto Chemicals "Ultrapure" grade mineral acids were used throughout, and other chemicals were of analytical-grade without further purification. Water was distilled from a vitreous silica sub-boiling still. An acid mixture solution was prepared by mixing one volume of 10 mol dm -3 nitric acid and one volume of 10 mol dm -3 sulfuric acid. Standard antimony(III) solutions were prepared daily by diluting a commercially available stock standard solution (1 mg cm -3 of animony(III) in 2.5 mol dm -3 hydrochloric acid) to the desired concentration with the acid mixture solution. Preparation of gold plated glassy-carbon electrodeThe surface (7 mm 2 area) of a glassy carbon disk electrode (Bioanalytical Systems) was polished to a mirror fin...

We started our home hemodialysis (HHD) program in July 2005 and have been promoting overnight HHD. As more than 6 years have passed since we started our HHD program, we review our HHD program and 8 overnight HHD patients (5 males and 3 females). Their underlying disease differs in each and none have diabetic nephropathy. Their average age was 49.2 ± 6.0 years (mean ± SD). Average duration of dialysis treatment, HHD, and overnight HHD was 9.4 ± 4.4, 3.5 ± 2.4, and 2.2 ± 1.7 years, respectively. Average treatment time per dialysis session was 6.9 ± 0.8 h/treatment, average treatment days weekly was 4.5 ± 0.8 days/week, and average treatment time weekly was 31.2 ± 7.0 h/week. Laboratory data were good and their blood pressure was well controlled without any antihypertensive drugs excluding a patient who was recently introduced to dialysis with some residual kidney function. Severe problems did not occur in these 6 years except for blood access infection twice, slipping out of a needle during dialysis with small blood loss once, and a drop in blood pressure at the end of dialysis once, which was recovered by her assistant's help. According to our HHD training program, the average training duration for HHD was 106 ± 42 days. The shortest was 60 days and longest 198 days. These differences among training durations might be because of the frequency of training and having a better hand of puncturing. We did not instruct any additional issues and points for overnight HHD, because performing overnight HHD is similar to standard HHD. Some patients moved to overnight HHD slowly starting with once weekly and the others started overnight HHD several days after they had started HHD.

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