Adsorption of Thiamin (Vitamin B1) on Soils and Clays

Abstract

Recent research suggests that thiamin applied to soils or coated onto seeds may stimulate plant growth. The behavior of thiamin in soils has not been investigated. Therefore, studies were carried out to determine how thiamin hydrochloride (3‐[(4‐amino‐2‐methyl‐pyrimidinyl)methyl]‐5‐(2‐hydroxyethyl)‐4‐methylthiazolium chloride hydrochloride) is adsorbed by 17 soils and three clays. The dominate mechanism in binding of thiamin is thought to be cation exchange with clay minerals and organic matter. In soils with low to medium organic matter content, thiamin adsorption occurred primarily on clay minerals and depended particularly on the amount and composition of the clay. Adsorption is species dependent (pKa1 [negative logarithm of the first dissociation constant] = 4.85) and takes place principally in the acidic pH range, probably with position 1′ of the pyrimidine ring. Adsorption equilibrium is attained in <30 min. Adsorption in all soils, and in kaolinite and illite clays, could be described by a one‐surface Langmuir isotherm at initial concentrations ranging from 16.3 to 995 µmol L−1. Adsorption by smectite in the same range was log‐linearly related to the equilibrium concentration. Extending the initial concentration range from 16.3 to 9890 µmol L−1 showed that a two‐surface Langmuir equation more adequately described adsorption in hydroxy‐interlayered vermiculitic and chloritic‐illitic soils, whereas a one‐surface Langmuir equation was found to be adequate in mixed layer‐smectitic soils. Only in the case of smectite clays is thiamin allowed to lie in a monolayer configuration parallel to the basal plane.

Competition for vitamin B1(thiamin) structures numerous ecological interactions

“…Under acidic conditions where thiamin is stable, thiamin is a cation with one or two positive charges. This leads thiamin to be adsorbed on clay mineral surfaces by ion exchange with cations under acidic conditions (pH 4-7) that are common in soil (Schmidhalter et al 1994). We have observed the pH-dependent release of thiamin from a cation exchange matrix in our efforts to concentrate thiamin from ambient water samples using solid phase extraction (in collaboration with K. Edwards, unpublished data), which lends support to two prior studies that examined thiamin availability in natural environments.…”

Potential adverse effects on animal health and performance caused by the addition of mineral adsorbents to feeds to reduce mycotoxin exposure

“…However, most researchers believe the process is physical adsorption by ion exchange reaction and electrostatic interaction (Thimm et al 2001;Deng et al 2010;Wang et al 2018). Similar mechanisms have also been proposed for the adsorption of nutritional content in animal diets including proteins (Ralla et al 2010;Alam and Deng 2017), micronutrients (Schmidhalter et al 1994;Barrientos-Velázquez et al 2016), as well as veterinary drugs (Devreese et al 2013). Furthermore, rate of adsorption is dependent on the origin and physicochemical properties of adsorbents and takes place predominantly in the acidic pH range (Deng et al 2010).…”

Pre-analytical challenges from adsorptive losses associated with thiamine analysis

“…This did not exclude thiamine retention onto the fibers, but thiamine potentially retained and recovered was below the instrumental limit of detection (8 nM). In addition, we cannot exclude the likelihood of thiamine sorption to particulates 68 smaller than the 0.7 μm membrane pores that would have been lost to the filtrate.…”

“…Aside from glass 28 , thiamine adsorption has been investigated in plastic particles of various compositions used in food packaging 70 , onto clays and soils 68 , and recognition of thiamine by charge-based interactions to various nanoparticles in the absence of a specific biorecognition event forms the basis of numerous reported biosensing technologies 20 . When adsorption experiments are carried out on particles, it is critical to consider the container and diluent used in the experiments and imperative to include a thiamine standard processed identically at all steps to account for losses that are independent of the particles.…”