Definition of niggling for English Language Learners. : causing you to feel a slight pain or to be worried or annoyed for a long time.
What is PPAP? The Production Part Approval Process (PPAP) is a standardized process in the automotive and aerospace industries that helps manufacturers and suppliers communicate and approve production designs and processes before, during, and after manufacture.
Thermo Scientific Pierce PNPP (p-nitrophenyl phosphate) is a colorimetric, soluble substrate of alkaline phosphatase for use in ELISA applications. Features of PNPP (p-nitrophenyl phosphate): â¢ One-component alkaline phosphatase (AP) substrate. â¢ Absorbance maximum of 405nm.