Dados do Trabalho

Título

COMPARISON BETWEEN DIGESTION METHODS APPLIED TO COMPLEX MATRICES FOR MICROPLASTIC ANALYSIS

Introdução

Despite the growth of research related to the presence of microplastics in food matrices, standardized experimental protocols have not been attained. Biological matrices of all natures were digested and removed from samples using various pretreatment methods. Food matrices processed from animal viscera or fish-based, added with additives, with various purposes, such as cat foods, present a very expressive degree of difficulty in the pre-treatment stage.

Material e Métodos

Various pretreatment methods were employed to isolate microplastics, including potassium hydroxide (KOH), sodium hydroxide (NaOH), hydrogen-peroxide (H2O2), Fenton's reagent (Fe2+ ion with H2O2, nitric acid (HNO3), perchloric acid (HCLO4), and digestive enzymes. The objective of the present study was to compare the use of different concentrations of KOH solution available in the literature, comparing the 10, 30 and 40% solutions, with different resting times and use of ambient temperatures and 60 oC, to properly separate microplastic particles. To separate the microplastic particles, we compare the use of an alkaline digestion solution of 10% potassium hydroxide (KOH) described by Hamdhani et al (2024), in a becker covered by aluminium foil, followed by agitation using a magnetic spinner for 2 h, digestion solution of 30% potassium hydroxide and digestion solution of 40% potassium hydroxide. Digestion temperatures and times ranged from ambient temperature (25 oC) to 70 ◦C and time varying from 12 to 96 h.

Resultados e Discussão

The processes were compared taking into account the observation of the material, the difficulty in the vacuum filtration step and the visualization of the particles observing the effectiveness in destroying proteins and other soft tissues under a stereomicroscope. The most effective solution was 10%, with a resting time of 72 hours and a temperature of 60°C.

Conclusão

It is important to consider that, for each food matrix, depending on the degree of processing and lipid content, a different situation in the pre-treatment should be considered.