Possible Clues:

• Bitter type of leaders caught in traffic going from old police force to a police department
• It's in lemons and limes
• Lime juice component
• It leaves a bitter taste in the mouth to almost name old police force with a criminal division
• Some lemon has HNO₃ containing carbon instead of nitrogen
• Critic scuffling with a hero leaves a sour taste in the mouth
• It's in oranges
• Tang provider
• C6 H8 O7 H2 O (lemon output)