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Gold nanorods (AuNRs) stabilized by cetyltrimethylammonium bromide (CTAB) were synthesized and an interaction of catecholamines (CAs) with silver ions in the presence of the obtained AuNRs was studied. The reaction results into formation of core-shell Au@Ag nanorods (Au@AgNRs) and leads to a hypsochromic shift of the long-wave surface plasmon resonance (SPR) band in the absorption spectrum of AuNRs. The influence of a CA structure, excess of CTAB, interaction time, pH, concentration of AuNRs, silver ions and CAs on this interaction was studied. Based on correlation of the NRs spectral characteristics with the concentration of CAs, a method for spectrophotometric determination of dobutamine, epinephrine, norepinephrine and dopamine with detection limits 27, 18, 16 and 13 μg L(-1), respectively, has been developed. The method can be applied to the analysis of medicines., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The use of hypercrosslinked polystyrene for the group sorption preconcentration of catecholamines is proposed. The conditions for the preconcentration of noradrenaline, adrenaline, and dopamine are optimized: a microcolumn (10 × 6 mm), mass of adsorbent 0.03 g, 25 mL of solution (pH ~ 8.5), and transmission rate of the solution 1.0 mL/min. Compounds were desorbed with 1 mL of 6 M acetic acid and determined in the eluate by reversed-phase HPLC with an amperometric detector (E = 0.8 V). Adsorption preconcentration ensures the reduction of the limits of detection for catecholamines by more than 20 times. The limits of detection were 0.7 ng/mL for dopamine and 1 ng/mL for noradrenaline and adrenaline. The procedure was applied to the analysis of model mixtures based on urine. [ABSTRACT FROM AUTHOR]