Methinium colorimetric sensors for the determination of cholesterol sulfate in an aqueous medium

Methinium colorimetric sensors 1 and 2 were studied for the determination of cholesterol sulfate by UV-Vis spectroscopy in 0.001 M NaCl (H2O:MeOH; 7:3), pH = 7.34. Both of the tested sensors displayed high affinity, excellent selectivity and sensitivity for cholesterol sulfate against other steroids (estrone sulfate, pregnenolone sulfate, cholesterol, cholic acid and taurocholic acid). The determined values of conditional binding constants, linear ranges and detection limits demonstrated the high usability of these sensors for the determination of cholesterol sulfate. For example, the detection limits of tested sensors I and 2 for the detection of cholesterol sulfate were 0.16 mu M (0.07 mg/L; R-2 = 0.9966) and 1.3 mu M (0.59 mg/L; R-2 = 0.9872), respectively. Our detection limit strongly indicates the potential usability of these sensors for the determination of biologically important levels of cholesterol sulfate. (C) 2017 Elsevier B.V. All rights reserved.