Serotonin is a key neurotransmitter, present in the brain, blood and gastrointestinal tract. Due to the interest in measuring this important biogenic amine in these various environments, electrochemical recordings were carried out in PBS buffer, 0.5 % w/v mucin and 5 % w/v albumin on Screen Printed Gold Electrodes (SPAuEs) bare and modified with gold nanoparticles (AuNps), for better understanding the influence of the matrix on the stability of recordings The results suggest that the proteins resulted protective against electrode fouling, compared to PBS buffer, which enhanced the rate of such a fouling.