Cotinine (HRP)

May be stored at 4 °C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 °C. Aliquots are stable for at least 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Labeled with horseradish peroxidase (HRP). Sodium azide is a potent inhibitor of peroxidase and should not be added to HRP conjugates. HRP conjugates are sensitive to light.