Fast-Scan Cyclic Voltammetry (FSCV) is frequently used to monitor the concentrations of neurotransmitters in real-time. However, few studies have examined the issue of monitoring the concentration of multiple neurotransmitters at the same time, despite their coexistence at brain synapses. This stems from the fact that some neurotransmitters have relatively similar electrochemical profiles. In this work we use Factor Spaces to analyze the current signals obtained using FSCV for both individual and mixed solutions of neurotransmitters. It is shown that the behavior of the current signals during the interaction between the neurotransmitter species approaches the principle of superposition. This potentially results in a significant simplification in the way combined voltammetric data is interpreted. The performance of Principal Component Analysis in extracting suitable Factor Spaces is evaluated.