Surface enhanced infrared absorption spectroscopy (SEIRA) as a green analytical chemistry approach: Coating of recycled aluminum TLC sheets with citrate capped silver nanoparticles for chemometric quantitative analysis of ternary mixtures as a green alternative to the traditional methods.

The past two decades have seen the full expansion of all fields of Nanotechnology, Chemometrics, Recycling, and Vibration spectroscopy into most of the research areas. The proposed method involves the harmonization of the previously mentioned fields as a vital tool to fulfill the concepts of sustainability and green analytical chemistry. This may reduce the negative impact of analytical laboratory activities on the surrounding environment and enables the implementation of sustainable development principles to analytical laboratories. This work compares the performance of surface enhanced infrared spectroscopy (SEIRA) with traditional chromatographic techniques for quantification of active pharmaceutical ingredients concerning the twelve principles of green analytical chemistry. The used aluminum TLC slides were recycled to be used as a SEIRA substrate. Citrate capped silver nanoparticles were synthesized via one step chemical reduction method, characterized, and deposited on the surface of the recycled aluminum TLC slides to be used as an active mid-infrared surface for quantification of the active pharmaceutical ingredient's combinations. SEIRA coupled with PLSR chemometric tool was developed, validated and successfully applied to mixtures having diverged concentration ranges (5, 30 and 500 μg ml-1) of Pholcodine, Pseudoephedrine and Paracetamol, respectively. Pholcodine is a synthetic or semi-synthetic opium alkaloid that derived from morphine. Pseudoephedrine is a sympathomimetic agent that is prohibited in sports competitions by the world antidoping agency at certain concentration levels. Paracetamol has analgesic and antipyretic actions. After optimization of the method parameters and number of latent factors, a good linear calibration model of the PLSR strategy was obtained as indicated by the lowest root mean square error of calibration and prediction obtained and the regression coefficients R2 of 0.9912, 0.9888, and 0.9992, respectively. The calibration ranges for the three drugs in their pharmaceutical combinations was 2.5-12.5, 15-75 and 200-600 μg ml-1, respectively. The method showed high resolving power for the three drugs in presence of excipients and good recoveries were obtained in a range of 97-102% with relative standard deviation < 2. The developed lab on a chip SEIRA analyzer in comparison to the traditional chromatographic techniques does not only fulfill the twelve principles of GAC but also it combines the merits of high throughput straightforward fingerprint analyzers, portable to measure samples on its place, cost effective, reduced sample volume and solvent consumption, coupled with intelligent chemometric tools to analyze multiple samples, reduced trials and time to get results.