Dielectric Barrier Discharge Plasma-Assisted Preparation of Chitosan-Based Hydrogels.

Chitosan is widely used in the production of various hydrogels due to its non-biological toxicity, good biocompatibility, and strong biodegradability. However, chitosan-based hydrogels have not been widely used in tissue engineering due to their poor mechanical strength, poor stability and high biotoxicity of cross-linking agents. As a green technology, low temperature plasma is rich in active groups that can be involved in various chemical reactions, such as replacing the components on the chitosan chain, contributing to the cross-linking of chitosan. In this study, a plasma-assisted preparation method of chitosan-based hydrogels was developed and the properties, including mechanics, water absorption, and degradation (or stability), were characterized and analyzed. It is proved that plasma treatment plays a significant role in improving the mechanical strength and stability of hydrogels.

A Single-Laboratory Validation of a UPLC Method for Determination of Folic Acid in Various Dietary Supplement Dosage Forms.

BACKGROUND: Folic acid is an essential nutrient necessary for the synthesis of nucleic acids (DNA and RNA) and certain amino acids. There are no scientifically validated analytical methods for folic acid applicable to all dosage forms. OBJECTIVE: A single-laboratory method was validated for the determination of folic acid content in various dietary supplement dosage forms. This method used ultra-performance liquid chromatography/diode-array detector (UPLC/PDA) to determine the folic acid content in dietary supplements in the form of tablets, two-piece capsules, powder drinks, softgels, and gummies. METHOD: The ultra-performance liquid chromatography/diode-array detector method was evaluated for linearity, limit of detection (LOD), limit of quantification (LOQ), repeatability, recovery, specificity, and system suitability. RESULTS: Linearity of the folic acid standard was shown to be linear in the range of 0.45 µg/mL to 7.37 µg/mL. LOD and LOQ of folic acid were 0.089 and 0.268 µg/mL, respectively. The repeatability of nine samples from five matrixes resulted in 1.15-4.82% relative standard deviation (RSD). Five samples with five different matrixes spiked with 25, 50, and 100% of working standard concentration and had a recovery range of 95.48-104.72%. The chromatograms and spectra of the blank, standard, and sample solutions showed that the method was free of interference for folic acid. The system suitability results of different matrixes showed that the UPLC/PDA system is suitable for folic acid analysis. All the AOAC INTERNATIONAL SMPR® 2022.002 requirements were fulfilled. CONCLUSIONS: The ultra-performance liquid chromatography/diode-array detector method compares favorably with the requirements of AOAC SMPR 2022.002. HIGHLIGHTS: The UPLC/PDA method is fast and suitable for all dietary supplement matrixes studied. The method meets the requirements of SMPR 2022.002.

Life cycle assessment of microalgae-based aviation fuel: Influence of lipid content with specific productivity and nitrogen nutrient effects.

The aim of this work is to compare the life cycle assessments of low-N and normal culture conditions for a balance between the lipid content and specific productivity. In order to achieve the potential contribution of lipid content to the life cycle assessment, this study established relationships between lipid content (nitrogen effect) and specific productivity based on three microalgae strains including Chlorella, Isochrysis and Nannochloropsis. For microalgae-based aviation fuel, the effects of the lipid content on fossil fuel consumption and greenhouse gas (GHG) emissions are similar. The fossil fuel consumption (0.32-0.68MJ·MJ-1MBAF) and GHG emissions (17.23-51.04gCO2e·MJ-1MBAF) increase (59.70-192.22%) with the increased lipid content. The total energy input decreases (2.13-3.08MJ·MJ-1MBAF, 14.91-27.95%) with the increased lipid content. The LCA indicators increased (0-47.10%) with the decreased nitrogen recovery efficiency (75-50%).