Calibration Transfer Between near Infrared Reflectance Spectrophotometers¹

Abstract

The utilization of Near Infrared Reflectance (NIR) spectroscopy by the forage and feed industry has been limited by the requirement that each instrument be individually calibrated. One possible solution to the problem is the transfer of NIR calibrations by computer from one instrument to another. Computer programs have been developed by our laboratory to accomplish this objective. We conducted research to test this software with seven NIR scanning monochromators. Sixty sealed samples were used in the transfer process. One monochromator was chosen to be the master instrument. Calibration equations developed on it were transferred to six slave instruments. The standard errors of difference including bias (SED) among instruments for crude protein, acid detergent fiber, neutral detergent fiber, lignin, and in vitro dry matter disappearance were less than SED among laboratories for chemical analysis. Satisfactory transfer was accomplished with as few as 10 samples. Computerized transfer of equations promises to be a satisfactory alternative to individual instrument calibration.