Determination of Nitrite in Food Samples by Kinetic Spectrophotometric Data and Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS)

Current Applications of Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) in Pharmaceutical Analysis: Review

The present review encompasses various applications of multivariate curve resolution- alternating least squares (MCR-ALS) as a promising data handling, which is issued by analytical techniques in pharmaceutics. It involves different sections starting from a concise theory of MCR-ALS and four detailed applications in drugs analysis. Dissolution, stability, polymorphism, and quantification are the main four detailed applications. The data generated by analytical techniques associated with MCR-ALS deals accurately with different challenges compared to other chemometric tools. For each reviewed purpose, it was explained how MCR-ALS was applied and detailed information was given. Different approaches were introduced to overcome challenges that limit the use of MCR-ALS efficiently in pharmaceutical mixture were also discussed.

Application of ultrasonic-assisted inclusion complex formation with α-cyclodextrin for simultaneous spectrophotometric determination of gallic acid and vanillic acids in fruit samples

There are various methodologies to generate second-order data. Spectrophotometric method owing to its high sensitivity continues to be of wide interest to analytical chemists. Spectra recording at different interval time while the reaction is proceeded, or at different pHs, or at different concentrations of complexing agent are examples of strategies by which one can generate second-order data by the spectrophotometric method. In this work, for the first time, we employed α-CD as an inclusion complexing agent under ultrasonic irradiation for simultaneous determination of gallic acid (GA) and vanillic acid (VA). UV spectra of a mixture of two analytes were recorded as a function of α-CD concentration. A calibration set containing 9 reference samples was used to construct model using bilinear least squares/residual bilinearization (BLLS/RBL) as second-order calibration method. The predictive ability of the resulting model was validated by a test set including 5 samples. Finally, the proposed model was successfully applied to simultaneously determine the content of GA and VA in five fruit juice samples. Satisfactory results in terms of the recovery yields were obtained. In a word, UV-spectroscopy coupled with a strategy to yield a second-order data in combination to second-order calibration methods has high potential to be a simple, quick and accurate analysis procedure for the determination of various types of chemical structures in practice.

Multivariate curve resolution applied to kinetic-spectroscopic data matrices: Dye determination in foods by means of enzymatic oxidation

In this work, the combination of chemometric techniques with kinetic-spectroscopic data allowed quantifying two dyes (tartrazine and carminic acid) in complex matrices as mustard, ketchup, asparagus soup powder, pumpkin soup powder, plum jam and orange-strawberry juice. Quantitative analysis was performed without the use of tedious sample pretreatment, due to the achievement of the second-order advantage. The results obtained showed an improvement in simplicity, speed and cost with respect to usual separation techniques, allowing to properly quantifying these dyes obtaining limits of detection below 0.6mgL^-1. In addition, to the best of our knowledge, is the first time that kinetic-spectroscopic data are obtained from the action of laccase for analytical purposes.