The process analytical instrument is distinct from other so-called process instruments that measure parameters such as power, temperature, pressure, level, and flow. Rather, the categories covered cover more sophisticated measurements, usually involving the quantification or identification of chemical components in a process or waste stream. These reports cover on-line and in-line process analytical instruments. In-line instruments refers to devices that are a part of the process pipeline while on-line instruments are additional devices that are fixed into the process flow for monitoring purposes. Both on-line and in-line measurements provide a continuous process monitoring with near real-time analysis power while off-line (lab sample) or at-line (portable) devices require more time to isolate and analyze the sample.