Classification and quantification of sucrose from sugar beet and sugarcane using optical spectroscopy and chemometrics.

Sucrose, obtained from either sugar beet or sugarcane, is one of the main ingredients used in the food industry. Due to the same molecular structure, chemical methods cannot distinguish sucrose from both sources. More practical and affordable methods would be valuable. Sucrose samples (cane and beet) were collected from nine countries, 25% (w/w) aqueous solutions were prepared and their absorbances recorded from 200 to 1380 nm. Spectral differences were observable in the ultraviolet-visible (UV-Vis) region from 200 to 600 nm due to impurities in sugar. Linear discriminant analysis (LDA), classification and regression trees, and soft independent modeling of class analogy were tested for the UV-Vis region. All methods showed high performance accuracies. LDA, after selection of five wavelengths, gave 100% correct classification with a simple interpretation. In addition, binary mixtures of the sugar samples were prepared for quantitative analysis by means of partial least squares regression and multiple linear regression (MLR). MLR with first derivative Savitzky-Golay were most acceptable with root mean square error of cross-validation, prediction, and the ratio of (standard error of) prediction to (standard) deviation values of 3.92%, 3.28%, and 9.46, respectively. Using UV-Vis spectra and chemometrics, the results show promise to distinguish between the two different sources of sucrose. An affordable and quick analysis method to differentiate between sugars, produced from either sugar beet or sugarcane, is suggested. This method does not involve complex chemical analysis or high-level experts and can be used in research or by industry to detect the source of the sugar which is important for some countries' agricultural policies.

The design, synthesis, and evaluation of two universal doxorubicin-linkers: preparation of conjugates that retain topoisomerase II activity.

The design, synthesis, and evaluation of two N-alkylmaleimide aldehydes have been achieved, which upon reductive alkylation with the C3'-amino group of doxorubicin (DOX) permits the preparation of DOX conjugates via Michael addition of thiol-containing vectors. This method enables the mild, facile, and high-throughput preparation of DOX conjugates that retain the basic C3'-nitrogen, a pre-requisite for topoisomerase II inhibition. Seven DOX-amino acid conjugates were prepared, each displaying similar inhibitory activity as the parent drug.