Despite their outstanding performance for the stripping voltammetric detection of trace metals, bismuth electrodes show poor sensitivity for the cathodic detection of organic compounds. Moreover, oxygen removal from samples is recommended to lower the background signal, which limits their application to on-site analysis. Herein, we propose recently introduced sparked-bismuth oxide screen printed electrodes for the cathodic detection of riboflavin, a reducible organic compound. The ultra-sensitive determination of riboflavin in the sub-nanomolar range in the presence of dissolved oxygen is demonstrated. After electroless preconcentration for 60 s, electrodes showed a linear response over the concentration range 1-100 nmol L-1 riboflavin, while the limit of detection (S/N = 3) was found to be 0.7 nmol L-1 riboflavin, ca. 140-fold lower than that has been achieved with electroplated bismuth electrodes. Excellent interelectrode reproducibility and application to a pharmaceutical sample are also demonstrated. (C) 2015 Elsevier Ltd. All rights reserved.