Investigation of formaldehyde pollution of tap water and rain water using a novel visual colorimetry.

The pollution of tap water and rain water with formaldehyde in Toyama Pref., Japan was investigated by means of a simple, rapid and cost-effective visual colorimetry developed by us. The levels of formaldehyde in three tap waters from different sources of dams on mountainside and a well-water pumped in urban area in Toyama Pref. were lower than 0.01 mg L(-1) that was the detection limit of the colorimetry. On the other hand, rain waters were seriously polluted with formaldehyde. Rain waters were sampled from three different sites (urban area, top of hill and industrial area) in Toyama Pref. from autumn to winter in 2006. The levels of formaldehyde in the rain waters ranged from 0.07 to 0.30 mg L(-1). The analytical results by the visual colorimetry were in good agreement with those obtained by GC-MS method. It was confirmed that the colorimetry is excellent for practical use for the determination of formaldehyde. It must be concerned about the pollution of rainwater with formaldehyde, when rain water is applied for tap water and miscellaneous purpose.

Electrochemical oxidation of bisphenol A. Application to the removal of bisphenol A using a carbon fiber electrode.

The electrochemical behavior of bisphenol A was investigated by voltammetric techniques. The electrochemical oxidation of bisphenol A led to the inactivation of the glassy carbon electrode as the result of the deposition of the electropolymerized films. Although phenolate is oxidized more easily than the neutral phenol, an electropolymerized film of bisphenol A was formed in neutral media rather than in alkaline media. The fouling of the electrode surface by the electropolymerized film was evaluated by monitoring the electrode response of ferrocyanide ion as the redox marker. The electrochemical removal of bisphenol A based on the formation of the electropolymerized film on an anode surface was also attempted using a carbon fiber electrode with a very large surface area. The high removal efficiency for bisphenol A was obtained in a dilute solution of bisphenol A. The maximum surface coverage (gamma) of electropolymerized bisphenol A on the carbon fiber was about 2 x 10(-9) mol/cm2.

Voltammetric detection of lectin using sugar labeled with electroactive substance.

The voltammetric detection of soybean agglutinin (SBA) was investigated on the basis of an interaction between the lectin and a sugar. Because galactose and lactose combined with SBA, the sugars were labeled by a Schiff base with an electroactive daunomycin. After the labeled sugar and SBA were mixed, measurements were carried out by voltammetry. When SBA-sugar binding occurs, a part of daunomycin of the labeled sugar is taken to the binding sites. As a result, SBA is detected by a change in the peak current of daunomycin, and the SBA-sugar interaction is evaluated. The length of the alkyl chain between daunomycin and the sugar was also considered. The electrode response to the concentration of SBA was linear over the range of 0.04-0.8 microg min(-1). The merits of this procedure are the convenient preparation of labeled sugar and a rapid measurement without separation. On the other hand, the detection of sugar at the 10(-9) mol dm(-3) level was achieved by a competitive reaction to limited binding sites of the lectin between the sugar and the labeled sugar.