Arfidyaninggar Septia RindaKanchana UraisinAkhmad SabarudinDuangjai NacaprichaPrapin WilairatBrawijaya UniversityMahidol UniversityFlow Innovation-Research for Science and Technology Laboratories (Firstlabs)2019-08-232019-08-232018-02-07IOP Conference Series: Materials Science and Engineering. Vol.299, No.1 (2018)1757899X175789812-s2.0-85046272472https://repository.li.mahidol.ac.th/handle/20.500.14594/45824© Published under licence by IOP Publishing Ltd. Cobalt has been reported for being abused as an illegal doping agent due to its ability as an erythropoiesis-stimulating agent for enhancing performance in racehorses. Since 2015, cobalt is listed as a prohibited substance by the International Federation of Horseracing Authorities (IFHA) with a urinary threshold of 0.1 μg cobalt per mL urine. To prevent the misuse of cobalt in racehorse, a simple method for detection of cobalt is desirable. In this work, the detection of cobalt is based on the spectrometric detection of the complex formation between cobalt(II) and 2-(5-bromo-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]aniline at pH 4. The absorbance of the complex is monitored at 602 nm. The metal:ligand ratio of the complex is 1:2. The calibration graph was linear in the range of 0 - 2.5 μM {Absorbance = (0.0825 ± 0.0013)[Co2+] + (0.0406 ± 0.0003), r2 = 0.999} and the detection limit (3 SD of intercept)/slope) was 0.044 μM. The proposed method has been successfully applied to horse urine samples with the recoveries in the range 91 - 98%.Mahidol UniversityEngineeringMaterials ScienceConference PaperSCOPUS10.1088/1757-899X/299/1/012006