Metrohm says its Aquatrode Plus are the most suitable electrodes for ethanol pH measurements according to ASTM D 6423
The pH value is an important quality criterion for bioethanol.
A combined pH glass electrode with ground-joint diaphragm is recommended for measuring the pH in organic solvents.
Because of the expected low conductivity of the sample, the electrode should be particularly well shielded in order to suppress electrostatic influences.
After preliminary tests with different electrodes, the Aquatrode Plus appears to be the best electrode for ethanol measurements says Metrohm.
With separable ground-joint diaphragm, the Aquatrode Plus is particularly suitable for measuring the pH of biofuels.
Ethanol samples were titrated according to the ASTM D 6423 norm.
Bioethanol is an alternative fuel that has similar properties to petrol.
However, it is obtained not from fossil oil but from starch plants and sugar plants.
Starch plants such as wheat, rye and maize as well as sugar cane and sugar beet are the most commonly used raw materials for the production of ethanol.
Sugar plants are fermented directly whereas in the case of corn, maize and potato the starch is first converted into sugar by means of enzymatic processes.
The development of suitable enzymatic processes will also allow wood, energy plants and straw to be fermented.
Intensive research is currently going on into these new approaches.
As of the 15 April 2008 all petrol which is sold at UK pumps now has to include at least 2.5% bioethanol.
The idea behind the Renewable Transport Fuels Obligation (RTFO) is to reduce climate change emissions from transport - which produced more than a quarter of overall greenhouse gases in the UK - by using renewable fuels instead of fossil fuels.
These renewable fuels have been added to fuel sold around the country.
The obligation extends to 3.75% biofuels content in 2009 and by 2010 the target will rise to 5%.
The move is aimed at making transport fuels increasingly environmentally friendly without changing how the vehicle engine works.
According to general opinion standard petrol engines run well with up to 10% addition of ethanol to petrol (E10).
Higher ratios of ethanol require modifications to the engine.
Bioethanol is also used in the production of ETBE.
ETBE (ethyl tertiary butyl ether) is a petrol mixture component that, in compliance with currently valid standards, can be added with up to a 15% ratio.
Furthermore, the fuel E85 (85% ethanol, 15% petrol) is continuously gaining in importance.
This requires ethanol engines or so-called flexible fuel vehicles (FFVs), that can run on any petrol/ethanol mixture.
Such vehicles are growing in importance on the North American, Brazilian and Swedish markets.
Since 2005 several vehicles suitable for use with E85 fuel have also been on offer in Germany.
