The sensor arrangement includes: a least two sample chambers; at least two potentiometric FET-sensors, especially ISFET-sensors or ChemFET-sensors, having, in each case, a sensitive surface section, wherein each sensitive surface section lies in flow connection with its one of the sample chambers; and a reference cell having a reference medium for providing a reference potential, wherein the sample chambers are connected with the reference medium via an electrolyte bridge. The reference cell has, preferably, a potentiometric reference-FET-sensor for providing a reference potential, which is registered against the pseudo-reference-potential of a redox electrode. The potentials U.sub.diff1, U.sub.diff2, . . . U.sub.diffN of N FET-sensors in the sample chambers are determined against the pseudo-reference-potential, and the measured-variable-relevant, potential differences are determined, in each case, by difference formation between the pertinent potential and the reference potential--thus, in the case of pH, according to the formulas U.sub.pH1. . . N=U.sub.diff1. . . N-U.sub.diffref.