The balance gas of the T�CVOC test gas was nitrogen. The total concentration of the T�CVOC gas was 10.29 ppm, i.e., 3.66 �� 104 ��g/m3 [7].Table 1.Concentrations of each component www.selleckchem.com/products/BIBF1120.html in the T�CVOC test gas [7].The gas sensing properties of the elements were measured using a flow-type gas sensing measurement apparatus, as shown in Figure 1. The apparatus was equipped with temperature-controlled water bubbler. Synthetic air was flowed into water bubbler before flowing into the apparatus. The relative humidity of the synthetic air was set at 25, 50, and 75% at 20 ��C by controlling the temperature of water bubbler. The elements were placed into quartz tube with internal diameter and length of 4 and 25 cm. The elements were heated at 300 ��C using an electric furnace. The Inhibitors,Modulators,Libraries original T�CVOC test gas (3.

66 �� 104 ��g/m3) was diluted with humid air to below 1,000 ��g/m3 by using mass flow controllers. The heating temperature, 300 ��C, was discovered to be the most suitable condition for the Pt,Pd,Au/SnO2 and the Pt/SnO2 as T�CVOC test gas sensors in previous tests. The total flow rate was kept at 200 mL/min. The sensor response (S) is defined Inhibitors,Modulators,Libraries as Equation (1),S=RaRg(1)where Ra, and Rg are the electrical resistance in synthetic air and T�CVOC test gas, respectively.Figure 1.Schematic diagram of a flow-type gas sensing measurement apparatus.3.?ResultsFigure 2 shows the dynamic resistance responses of high-humidity aged Pt,Pd,Au/SnO2 and Pt/SnO2 and non-aged Pt,Pd,Au/SnO2 thick film elements to the T�CVOC test gas at 25, 50, and 75%RH.

The resistance of the elements is normalized at the initial change of gas flow from synthetic air to test gas. It can be seen that all elements exhibit distinct responses to the T�CVOC test gas. The resistance of all the elements Inhibitors,Modulators,Libraries decreased and increased relative to the T�CVOC test gas concentration. The resistance changes are almost saturated within 10 min for each step of the gas concentration change. For the aged Pt,Pd,Au/SnO2, the decrease in normalized resistance by the T�CVOC test gas does not change significantly when the humidity is increased. Thus, the profiles of the aged Pt,Pd,Au/SnO2 in Figure 2a are almost identical. For the non-aged Pt,Pd,Au/SnO2 (Figure 2b), the response to the T�CVOC test gas is almost identical at 25 and 50%RH, whereas it is reduced significantly at 75%RH.

However, the drop in resistance of the non-aged Pt,Pd,Au/SnO2 to the T�CVOC test gas was less severe at 75%RH. It should be noted that the high-humidity aging treated Pt/SnO2 element exhibits a lager humidity dependence of the resistance Inhibitors,Modulators,Libraries change compared with Carfilzomib that of the non-aged Pt, Pd, Au/SnO2 elements.Figure 2.Normalized resistance profiles of (a) selleckchem Imatinib Mesylate high-humidity aged Pt,Pd,Au/SnO2, (b) non-aged Pt,Pd,Au/SnO2, and (c) high-humidity aged Pt/SnO2 in humid air with several concentrations of T�CVOC test gas at 300 ��C. The black, gray-dashed, and gray …