Excited state interaction between Hydrochlorothiazide and europium ion in PMMA polymer and its application as optical sensor for Hydrochlorothiazide in tablet and serum samples

► HCT was determined by europium sensitized by HCT in PMMA polymer. ► Band at 617 nm of Eu3+ ion (5D0→7F2) is sensitive to HCT concentration. ► Recovery and R.S.D for tablets serum samples in proposed method were calculated. ► Method is verified for HCT determination in real samples with no interferences.