Next Generation pH Measurement Removes the Need for Calibration

The measurement of pH is one of the most common analytical measurements used the world over in applications from process control in the food industry, to research in the pharmaceutical industry, through to effluent monitoring in the environmental sector. In 2002, the total pH measurement instrumentation market, including replacement sensors revenue, was estimated to be on the order of $500m.

The technology currently used for measuring pH is more than seven decades old and suffers from serious operational flaws. Specifically conventional glass electrodes: need constant re-calibration by suitably trained staff using expensive buffers, need careful wet storage and all too frequently break. More recent developments such as solid-state sensors and optical dye based systems all suffer serious limitations including limited pH measurement ranges and low sensitivity.

Researchers at the University of Oxford have developed a complete range of new pH sensors which are cheap and robust to manufacture, can be used over a broad pH range, are sensitive to small changes in pH, can be miniaturised and can be used at high temperatures and pressures; but, most important of all, the new sensors require no calibration.