Transfer of near-infrared monochromator calibrations for tobacco constituents to tilting-filter instruments
✍ Scribed by Robert A. Heckman; John T. Diffee; L.Arthur Milhous Jr.
- Publisher
- Elsevier Science
- Year
- 1987
- Tongue
- English
- Weight
- 491 KB
- Volume
- 192
- Category
- Article
- ISSN
- 0003-2670
No coin nor oath required. For personal study only.
✦ Synopsis
Near-infrared calibrations for water, reducing sugar, glycerin, propylene glycol, nicotine, and menthol in tobacco blends were first obtained with a monochromator instrument. Transfer of calibrations to a tilting-filter instrument for factory trials is shown to be facilitated greatly by the computer-assisted scheme MTRAN. By means of this software, calibration equations were established for a Neotec 51A instrument that is sufficiently rugged for factory use. The predictive capabilities of the transferred calibrations are similar to those of the research monochromator. The use of diffuse-reflectance measurements in the near-infrared (i.r.) region (1100-2500 nm) for routine determinations of major components in agricultural commodities dates from the late 1960s. More recently, this. technique was extended to the analysis of ground tobacco by McClure and co-workers [l-3].
The chief advantages of this instrumental method are its speed and potential for real-time process monitoring.
Most near-i.r. instruments are committed to measurement of moisture, oil, protein and starch in grain and forage crops. There seems to be a paucity of published reports where near-i.r. spectrometry has been utilized for inplant monitoring of other constituents and products. Even rarer are explicit, published protocols whereby an analytical method developed on a scanning instrument in a laboratory can be transferred to one or more slave instruments. The scheme described herein requires a normalization set of ca. 20 samples. In contrast, recalibration for several of the tobacco constituent: would have required >lOO samples, including replicate analyses of these samples by independent laboratory methods.
Research in this laboratory generally begins with calibration work using a grating monochromator equipped with capabilities for derivative mathematics, graphics and statistics. This requires the availability of analytical data from a primary or referee laboratory method that is accurate and precise. For the past five years, investigators in this laboratory [4] have developed near-i.r.