Unlike odorants that mask odors, natural zeolite acts as a molecular sieve that captures and eliminates odors. Different treatment methods can be applied to influence the properties of the natural zeolites. To enhance the odor adsorption capacities of the natural zeolite two types of treatment methods were applied: chemical (acid, basic) and thermal. The initial natural zeolites and the activated one were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM-EDX). Two experiments were performed to establish the odor adsorption capacity of the activated natural zeolites. The best zeolite for the adsorption of humidity, ammonia and hydrogen sulfide was the 1–3 mm zeolite activated through thermal treatment. For the adsorption of PAHs, the best zeolite was the one activated through basic treatment, with an adsorption capacity of 89.6 ng/g.
The content and composition of dietary supplements is of great interest due to their increasing consumption and variety of available brand offered in the market. Accurate determination of vitamins is important for the improvement of dietary supplement quality and nutrition assessments. In this regard, the simultaneous determination of vitamin D3 (calcitriol—CT and cholecalciferol—CHL) and K2 (menaquinone-4—MK-4 and menaquinone-7—MK-7) in dietary supplements was developed by using ultra-high-pressure liquid chromatography (UHPLC). The overall runtime per sample was above 35 min, with the retention times of 2.40, 6.59, 7.06, and 32.6 min for vitamin D3 (CT and CHL) and vitamin K2 (MK-4 and MK-7), respectively. The limits of detection and limits of quantification for the target nutritional compounds ranged between 0.04–0.05 µg/mL, respectively. The validation results indicated that the method had reasonable linearity (R2 ≥ 0.9990), good recovery (>82%), satisfactory intra-day precision (≤1.9%) and inter-day precision (≤3.5%), and high selectivity and specificity. The validated UHPLC method was demonstrated to be precise, accurate, and robust for the simultaneous determination of vitamins D3 (CT and CHL) and K2 (MK-4 and MK-7) in dietary supplements.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.