Kromoscopic analysis in two- and three-component aqueous solutions of blood constituents

The selectivity of a four-channel Kromoscopic analysis is demonstrated for the measurement of glucose in separate binary and tertiary matrices. A novel virtual search procedure is used to identify three different sets of four, overlapping transmission filters. The first filter set includes filters centered at 900, 1300, 1410, and 1538 nm and is selected to differentiate glucose and urea in a series of binary mixtures. These binary mixtures were prepared with independent levels of 1-10 mM glucose and 9- 213 mM urea dissolved in an aqueous phosphate buffer solution. A second filter set contains filters centered at 1064, 1100, 1224, and 1290 nm and is used to measure glucose in a series of tertiary mixtures composed of glucose, urea and bovine serum albumin. This tertiary matrix consists of 2-13 mM glucose, 13-129 mM urea and 0.05-0.46 g/L bovine serum albumin dissolved in the same type of buffer. Multilinear regression is used to relate the relative Kromoscopic responses to the concentration of glucose in these sample solutions. In both cases, the prediction errors are on the order of 0.6-0.8 mM. The impact of solution temperature is also investigated by examining glucose responses obtained from solutions maintained at temperatures ranging from 35 to 39 degree(s)C. The filter set used in this experiment is composed of filters centered at 1100, 1150, 1254, and 1300 nm. Results from this particular filter set indicate that the directionality and magnitude of the glucose responses are independent of solution temperature. Finally, accurate glucose measurements are demonstrated when a same-temperature blank is used to generate the relative channel response.