| Author | Message | ||
     David Russell (russell) Senior Member Username: russell Post Number: 57 Registered: 2-2001 |
The biggest success factor in the selection of a filter based instrument is the selection of the filters themselves. If the "feed" that you're analyzing is well understood and the instrument has been applied successfully elsewhere then the filters have been chosen and are known to produce a useful result. If that work has not been done, then access to an application development laboratory would be required. However, as Howard already mentioned, this would be necessary for any type of instrument. | ||
| venkatarman (venkynir) Senior Member Username: venkynir Post Number: 143 Registered: 3-2004 |
Hi Howard Mark ! It is accepted that sensivity in filter type is good.General remark is tedious in calibartion in filter type . Slowly the DAS type started moving in to measuremnt . Now LVF with minature NIRS in the market . | ||
| Howard Mark (hlmark) Senior Member Username: hlmark Post Number: 461 Registered: 9-2001 |
Venky - I'm sure you know this, but the wording or your response may be misleading to some. It is true that Dickey-John instruments are based on the use of interference filters. It is also true, however, that ALL kinds of instruments, regardless of the technology used (filters, gratings, FTIR, diode arrays, etc.) require a goodly number of samples for calibration, but your wording seems to limit the requirement to filters, whereas it is always true. This is because the largest source of error in calibration data turns out to be the samples themselves (see Appl. Spect., 64(9), p.995-1006 (2010)). This error is due to inherent non-linear relationships between the way analyte concentrations are expressed and the way light "sees" the samples. An exception is if concentrations are expressed in molarity or other volume-based units. Howard \o/ /_\ | ||
| venkatarman (venkynir) Senior Member Username: venkynir Post Number: 142 Registered: 3-2004 |
I understood that Dicky John NIRS analyser is filter type and Calibrations requires good number of training sets ? Think off. | ||
| David W. Hopkins (dhopkins) Senior Member Username: dhopkins Post Number: 208 Registered: 10-2002 |
Hi Marijana, I used to work for DICKEY-john many years ago, maybe I can help you. What model are you considering? What kind of samples do you want to measure, and what constituents are you interested in? Where are you located? That may be a factor, should you ever need repairs or maintenance. Best regards, Dave | ||
| Marijana Maslovaric (vidra) Junior Member Username: vidra Post Number: 10 Registered: 5-2011 |
Hello to you all! Can anyone, please, tell me something about Dickey John NIR analyser? Is it a good choice for feed analysis? Marijana |