LC-MS/MS Determination of Mono-Glutamate Folates and Folic Acid in Beer

Determination of Folic Acid Using Biosensors-A Short Review of Recent Progress

Folic acid (FA) is the synthetic surrogate of the essential B vitamin folate, alternatively named folacin, pteroylglutamic acid or vitamin B9. FA is an electroactive compound that helps our body to create and keep our cells healthy: it acts as the main character in a variety of synthetic biological reactions such as the synthesis of purines, pyrimidine (thus being indirectly implied in DNA synthesis), fixing and methylation of DNA. Therefore, physiological folate deficiency may be responsible for severe degenerative conditions, including neural tube defects in developing embryos and megaloblastic anaemia at any age. Moreover, being a water-soluble molecule, it is constantly lost and has to be reintegrated daily; for this reason, FA supplements and food fortification are, nowadays, extremely diffused and well-established practices. Consequently, accurate, reliable and precise analytical techniques are needed to exactly determine FA concentration in various media. Thus, the aim of this review is to report on research papers of the past 5 years (2016-2020) dealing with rapid and low-cost electrochemical determination of FA in food or biological fluid samples.

PtNPs-GNPs-MWCNTs-β-CD nanocomposite modified glassy carbon electrode for sensitive electrochemical detection of folic acid

A novel electrochemical sensor, platinum nanoparticles/graphene nanoplatelets/multi-walled carbon nanotubes/β-cyclodextrin composite (PtNPs-GNPs-MWCNTs-β-CD) modified carbon glass electrode (GCE), was fabricated and used for the sensitive detection of folic acid (FA). The PtNPs-GNPs-MWCNTs-β-CD nanocomposite was easily prepared with an ultrasound-assisted assembly method, and it was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical behavior of FA at PtNPs-GNPs-MWCNTs-β-CD/GCE was investigated in detail. Some key experimental parameters such as pH, amount of PtNPs-GNPs-MWCNTs-β-CD composite, and scan rate were optimized. A good linear relationship (R² = 0.9942) between peak current of cyclic voltammetry (CV) and FA concentration in the range 0.02-0.50 mmol L^-1 was observed at PtNPs-GNPs-MWCNTs-β-CD/GCE. The detection limit was 0.48 μmol L^-1 (signal-to-noise ratio = 3). A recovery of 97.55-102.96% was obtained for the determination of FA in FA pills (containing 0.4 mg FA per pill) at PtNPs-GNPs-MWCNTs-β-CD/GCE, indicating that the modified electrode possessed relatively high sensitivity and stability for the determination of FA in real samples.

Targeted healthy compounds in small and large-scale brewed beers

The determination of targeted healthy compounds in the most popular small and large-scale brewed beer sold in Italy was carried out. Nitrogen compounds, fermentable sugars, total phenolic content and antioxidant capacity, β-glucans, pyridoxine, folates and silicon were quantified. Further, amine content was determined since raw materials and brewing technology can affect their level. Significantly higher values for total phenolic content, antioxidant activity, nitrogen, folate and putrescine content were found for small scale beers. However, the statistical results were affected by the different beer styles in the small scale and large scale brewed beer groups, since the content of these components can vary between beer styles. Positive Pearson correlation was found between total phenolic content and EBC colour. Wide variations in pyridoxine, β-glucans and fermentable sugars levels were observed both for small and large scale beers, while average silicon content of two groups was similar.