• Measurement task — total VOC screening and leak detection, or identification and quantification of several gases at once.
• Detection principle — FID for hydrocarbons, PID for many VOCs at low levels (3050: 0.2 ppm detection limit), FTIR for multi-component gas analysis.
• Spectral range and path — the 1680 covers 600–4500 cm⁻¹ with a 5 m or 10 m optical path for low concentrations.
• Portability — handheld or transportable, battery operation and data logging for field campaigns.
• Regulations — measurement according to the emission or workplace method that applies to your site.

A handheld FID/PID gives a fast total VOC reading and is the tool for leak surveys and screening. Portable FTIR identifies and quantifies many gases simultaneously, which matters for emission measurements and unknown releases. Many users combine both: screening with FID/PID, confirmation with FTIR.