Additional small variations (as described at the relevant location in the text) were made to this method to allow the effect of different experimental parameters to be tested. For completeness the standard method employed is summarised below. The glass pH electrode used was the ORION Ross Sure-Flow combination electrode (ORION Cat. Nilotinib Leukemia No. 8172BN). This was cleaned and re-hydrated before its first use and after the measurement of every ten samples by alternatively soaking several times in 1 M NaOH and 1 M H2SO4. The electrode was then rinsed and calibrated with pH 7.00 and pH 4.00 aqueous buffers, rinsing with deionised water between each solution. The electrode was then rinsed again and stored in the pH 7.00 buffer until use.

Inhibitors,Modulators,Libraries About 50 mL of sample was placed in a 100 mL beaker and the solution was stirred at a rate Inhibitors,Modulators,Libraries such as to produce a vortex in the solution between 6 and 8 mm deep. The electrode was removed from the pH 7.00 buffer, rinsed with deionised water, and blotted to remove the excess solution. The electrode was then placed into the sample and the voltage (or pHe) reading taken after 30 �� 1 s. Ethanol samples with a nominal water content 0.02 g/g were measured during experimentation, unless otherwise stated.3.?Results and DiscussionFigure 1 displays the average of 10 repeat measurements of an ethanol sample with a nominal water content 0.02 g/g. It is clear that upon starting the measurement the voltage exhibited by the glass electrode drops significantly. The rate of this decrease is highlighted by the plot of the gradient of this curve, also shown in Figure 1.

After the defined measurement Inhibitors,Modulators,Libraries time of 30 s the voltage recorded was still changing at a rate of 1.5 mV s?1. After about 50 s the rate of voltage decrease slowed significantly, and by 120 s a approximate steady state response had been achieved. Figure 1 additionally shows the repeatability of the responses as the standard deviation over ten separate measurements using the same electrode.Figure Inhibitors,Modulators,Libraries 1.Average voltage (V) over ten measurements (black line) exhibited by the glass electrode as a function of time when measuring ethanol containing 0.02 g/g of water using the ASTM D6423 method. The standard deviation of this measurement set (dashed grey …For comparison purposes, Figure 2 shows the average response Brefeldin_A for the same electrode in different compositions of water in ethanol mixtures.

This shows that the shape of the measured response is broadly similar, but that the voltage recorded after 30 Z-VAD-FMK clinical s may differ by up to 30 mV. This is to be expected given that changes in the composition of the mixture will result in changes in the autoprotolysis constant for the mixture [12], plus any additional effect there may be from small amounts of ionic content introduced following the addition of extra quantities of water.Figure 2.