Nitrocefin is a chromogenic β-lactamase substrate that undergoes colour change from yellow to red as the amide bond in the β-Lactam ring is hydrolyzed by β-lactamase. Nitrocefin undergoes colour changes induced by lactamases produced by Gram-positive and Gram-negative bacteria. Several studies have utilized the colour changing properties of Nitrocefin for the detection of β-lactamase activity from bacterial cell extracts by isoelectric focusing and spectroscopy. Nitrocefin has also been used in studies involving β-lactamase resistant antibiotics.