The local critical coalescence concentration l-CCC presents a relationship between frother concentration and the gas flow rate Q(g)' at which coalescence starts to occur at a capillary tube. Such a relationship is used in this work to determine frother concentration. The solution with unknown frother concentration is tested to determine Qg' and the concentration is determined from a reference l-CCC curve that has been previously determined for the frother to be tested. The technique is simple, and easy to implement. The determination of the reference l-CCC curve takes 1 h or less, after which the measurements are very quick, taking no more than 5 min per sample. The technique was validated against the total organic carbon (TOC) method for a series of samples of unknown frother concentration, for three different frothers, with a correlation coefficient R-2 equal to 0.997. The measurements are not affected by the presence of xanthate in the system, when using MIBC as a frother, which suggests the possibility of using it, combined with TOC analysis to determine both frother and xanthate concentration by mass balancing. (C) 2016 Elsevier Ltd. All rights reserved.