A potentiometric pH sensor made of graphite, solid paraffin and quinhy
drone is described to behave near to reversibility. The slope of the p
otential versus pH plot is - 53.06 mV, the standard deviation of measu
rements is 0.05 to 0.06 pH units. Unlike the usual glass electrode thi
s new pH sensor does not need calibration before use. The sensor can b
e made of any shape and size.