Rapid LC-MS/MS Method in Quantitation of N-Nitroso Amlodipine. A sensitive, reliable LC-MS/MS assayhasbeen created in order to identify the cancer-causative N-nitroso amlodipine contamination in amlodipine drugproducts. Separations were done using a Phenomenex Kinetex(r) C18 150x3 mm, 2.6um UPLC column by usingagradient programmed with Mobile Phase A: 0.1 percent formic acid in water and Mobile Phase B: 0.1 percent formic acid in methanol. Detection has been done by the use of a triple quadrupole mass spectrometer (in positiveelectrospray ionisation mode), which monitored MRM (multiple reaction monitoring) transitions characteristic of N- nitroso amlodipine. This procedure is a rapid and inexpensive risk assessment procedure in risk assessment studiesof N-nitroso amlodipine in amlodipine manufacturers in the pharma industry to allow routine analysis and regulatorycompliance. It has been demonstrated to comply with ICH Q2(R2) and USP <1225> guidelines, and therefore with: - Linearity: r > 0.99 over the calibrated range - Accuracy (recovery):89.2 percent-113.8 percent.