ORIGINAL PAPER Voltammetric determination of nitric oxide using a glassy carbon electrode modified with a nanohybrid consisting of myoglobin, gold nanorods, and reduced graphene oxide Ab Rahman Marlinda 1 & Alagarsamy Pandikumar 2 & Subramaniam Jayabal 1 & Norazriena Yusoff 1 & Abu Bakar Suriani 3 & Nay Ming Huang 1 Received: 14 April 2016 /Accepted: 28 July 2016 # Springer-Verlag Wien 2016 Abstract Myoglobin-modified gold nanorods incorporating reduced graphene oxide (rGO) were fabricated and deposited on a glassy carbon electrode (GCE) to obtain a sensor for nitric oxide (NO). The Mb-AuNR/rGO nanohybrid showed a transverse localized surface plasmon resonance (LSPR) band with a peak at 508 nm, and a longitudinal LSPR band at 724 nm. The AuNRs have an average length of 38 ± 3 nm and a width of 11 ± 1 nm. The GCE modified with the nanohybrid is shown to be a viable sensor for the determina- tion of NO by linear sweep voltammetry. Its electrocatalytic response toward the oxidation of NO is distinctly enhanced compared to other electrodes. The sensor, best operated at a working voltage of 0.85 V (vs. SCE), showed two linear re- sponse ranges (from 10 to100 μM, and from 100 to 1000 μM), with a detection limit of 5.5 μM. Furthermore, it exhibits ex- cellent selectivity for NO over common interferents such as NaNO 3 , and also over electroactive species such as ascorbate, dopamine, glucose, and uric acid. These properties make it a promising tool for the detection of NO in situations such as capillary and pulmonary hypertension and embolism, and during vasodilation. Keywords Electroanalysis . Biosensor . Nanocomposite . Localized surface plasmon resonance . LSPR . Linear sweep voltammetry . X-ray diffractometry . X-ray photoelectron spectroscopy . Capillary dilatator Introduction Nitric oxide (NO) has been shown to be involved in regulating neuronal excitability, synaptic transmission, neuronal net- works functioning, learning, and memory mechanisms [1, 2]. An excess or a deficiency of NO results in various patholog- ical conditions such as tumor angiogenesis [3], atherosclerosis [4], Parkinson’ s disease [5], and diabetes [6]. Therefore, the accurate measurement of NO is very important to unravel the action of this key compound. Because NO levels may become useful markers of inflammation and disease pathogenesis, the development of reliable and sensitive analytical techniques is of interest for the quantitation of NO production. Several analytical techniques are used for the detection of NO, including spectroscopic [7], chemiluminescence [8], chro- matographic [9], capillary electrophoresis [10], and electro- chemical methods [11]. However, those methods often have complicated operating procedures, and are time con- suming, high cost, and occupy larger space. Hence, there is an urgent need to develop a cost-effective, easy-to-perform, rapid-response detection method for NO. In this respect, an electrochemical sensor has recently been adopted for the detection of nitric oxide, and it has several advantages over conventional detection methods, including a rapid response, robustness, high sensitivity and selectivity, low cost, Electronic supplementary material The online version of this article (doi:10.1007/s00604-016-1922-4) contains supplementary material, which is available to authorized users. * Alagarsamy Pandikumar pandikumarinbox@gmail.com * Nay Ming Huang huangnayming@gmail.com 1 Low Dimensional Materials Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia 2 Research Institute & Department of Chemistry, SRM University, SRM Nagar, Kattankulathur, Chennai 603 203, India 3 Nanotechnology Research Centre, Faculty of Science and Mathematics, University Pendidikan Sultan Idris, 35900 Tanjong Malim, Perak, Malaysia Microchim Acta DOI 10.1007/s00604-016-1922-4