Construction of anthraquinone functional zinc phthalocyanine sensor platform for ultra-trace amount of water determination in tetrahydrofuran and N,N-Dimethylformamide

Anthraquinone functional zinc phthalocyanine sensor platform was utilized for ultra-trace amount of water determination in THF and DMF. Using the fluorometric method, the water content in THF was determined with a LOD of 2.27 × 10⁻⁴ M and a response time of 1 s. The sensor is based on the mechanism of aggregation depended on quenching of emission. Although the aggregation is known as an undesirable property in the application of phthalocyanine, this property has been successfully applied in the quantification of water content in THF. By using the shift of the third reduction wave of the sensor, the water content in DMF was measured with a LOD value of 5.64 × 10⁻⁷ M. The voltammetric response mechanism is based on the hydrogen bonding depended shifting of the reduction potential of quinone moiety on phthalocyanine. Redox potentials of phthalocyanine are used as a calibrant for accurate quantification of water content in DMF. Water molecules (n and m) and equilibrium constants (K¹ and K²) for the formation of hydrogen bonding for the first and third reduction processes were calculated as 1.18 (n), 10.4 (m) and 19.3 (K¹), 1.6 × 10¹¹ (K²) M^−(m-n), which demonstrated why the third reduction process was chosen to set the calibration plots.