BS ISO 21543:2020 pdf free.Milk and milk products一Guidelines for the application of near infrared spectrometry. BS ISO 21543 NIR instruments are based on diffuse reflectance, transmittance or transflectance measurement principle by NIR spectroscopy in the whole NIR wavelength region of 780 nm to 2 500 nm (12 800 cm-1 to 4 000 cm-1) or segments of this or at selected...