Refine
Document Type
Language
- English (2)
Has Fulltext
- no (2)
Is part of the Bibliography
- yes (2)
Keywords
- Diode-array detector (1)
- Dünnschichtchromatographie (1)
- Fluorescence measurements (1)
- Flupirtine (1)
- Flüssigkeit (1)
- Kubelka-Munk theory (1)
- Methadon (1)
Institute
Open Access
- Closed (1)
- Closed Access (1)
We present a videodensitometric quantification method for methadone in syrup, separated by thin-layer chromatography (TLC). The quantification is based on a derivation reaction with Dragendorf reagent. Measurements were carried out using a 16-bit flatbed scanner. The range of linearity covers two magnitudes of power using the Kubelka-Munk expression for data transformation. The separation method is inexpensive, fast, and reliable.
A new formula is presented for transforming fluorescence measurements in accordance with Kubelka-Munk theory. The fluorescence signals, the absorption signals, and data from a selected reference are combined in one expression. Only diode-array techniques can measure all the required data simultaneously to linearize fluorescence data correctly. To prove the new theory HPTLC quantification of the analgesic flupirtine was performed over the mass range 300 to 5000 ng per spot. The fluorescence calibration curve was linear over the whole range. The transformation of fluorescence measurements into linear mass-dependent data extends the technique of in-situ fluorescence analysis to the high concentration range. It also extends Kubelka-Munk theory from absorption to fluorescence analysis. The results presented also emphasize the importance of Kubelka-Munk theory for in-situ measurements in scattering media, especially in planar chromatography.