An Umeclidinium membrane sensor; Two-step optimization strategy for improved responses

Publication date: 1 September 2017
Source:Talanta, Volume 172
Author(s): Ali M. Yehia, Hany H. Monir
In the scientific context of membrane sensors and improved experimentation, we devised an experimentally designed protocol for sensor optimization. Two-step strategy was implemented for Umeclidinium bromide (UMEC) analysis which is a novel quinuclidine-based muscarinic antagonist used for maintenance treatment of symptoms accompanied with chronic obstructive pulmonary disease. In the first place, membrane components were screened for ideal ion exchanger, ionophore and plasticizer using three categorical factors at three levels in Taguchi design. Secondly, experimentally designed optimization was followed in order to tune the sensor up for finest responses. Twelve experiments were randomly carried out in a continuous factor design. Nernstian response, detection limit and selectivity were assigned as responses in these designs. The optimized membrane sensor contained tetrakis-[3,5-bis(trifluoro- methyl)phenyl] borate (0.44wt%) and calix[6]arene (0.43wt%) in 50.00% PVC plasticized with 49.13wt% 2-ni­tro­phenyl octylether. This sensor, along with an optimum concentration of inner filling solution (2×10⁻⁴molL⁻¹ UMEC) and 2h of soaking time, attained the design objectives. Nernstian response approached 59.7mV/decade and detection limit decreased by about two order of magnitude (8×10⁻⁸mol L⁻¹) through this optimization protocol. The proposed sensor was validated for UMEC determination in its linear range (3.16×10⁻⁷ −1×10⁻³mol L⁻¹) and challenged for selective discrimination of other congeners and inorganic cations. Results of INCRUSE ELLIPTA^® inhalation powder analyses obtained from the proposed sensor and manufacturer's UPLC were statistically compared. Moreover the proposed sensor was successfully used for the determination of UMEC in plasma samples.

Graphical abstract

http://ift.tt/2rcsEk8