Solubility analysis of homologous series of amino acids and solvation energetics in aqueous potassium sulfate solution

Abstract

In this study we estimated the solubilities of glycine, D,L-alanine, D,L-nor-valine and D,L-serine in aqueous mixtures of potassium sulfate (K 2 SO 4 ) at 298.15 K using analytical ‘gravimetric method’. The experimental solubilities of homologous series of amino acids in aqueous K 2 SO 4 mixture were discussed in terms of relative solubility, salting-in and salting-out effect by evaluating the influential constants. The effect of physicochemical and chemical factors on solubility were discussed briefly and correlated with the thermodynamics. Initially, the study of solvation energetics such as transfer Gibbs energies were evaluated based on the calculations from solubility data and relative stability of the experimental molecules was discussed under the experimental condition.

Electrolyte Effects on the Amino Acid Solubility in Water: Solubilities of Glycine, l-Leucine, l-Phenylalanine, and l-Aspartic Acid in Salt Solutions of (Na+, K+, NH4+)/(Cl–, NO3–)

“…Ion effects on the relative solubility of dl -alanine in aqueous salt solutions containing the K + , Na + , and NH 4 + cations at 298.2 K. Lines are a guide to the eyes. ,,,,,,− …”

Improvement of dissolved organic nitrogen extraction accuracy in unsaturated zones

“…In contrast, the extractable DON concentration of Soil Q was elevated and then decreased with increases in extract salinity ( p < 0.05). Previous studies of the effects of salinity on protein solubility have shown that salting‐out effects can affect the solubility of organic matter in saline solutions, and several studies have demonstrated that these effects could even be significant at low concentrations (<0.01 M) of neutral salts (Asrami & Saien, 2018; Hossain et al, 2019). Therefore, when DON is extracted from soils using a saline solution, its solubility in the extract may also be affected by the salting‐out effect.…”

“…Dissolved amino acids, peptides, proteins, chitin, lignin, and amino sugars constitute a large proportion of DON, and each compound has specific functional groups and different relationships with the solid phase of soil (Awad et al, 2019; Quan et al, 2018; Zhang et al, 2018). Therefore, salt‐out effects can affect DON structure and induce coagulation/precipitation, which could seriously impact the DON extraction accuracy (Asrami & Saien, 2018; Hossain et al, 2019). The application of conventional extraction methods to evaluate the content of DON in unsaturated zones can be problematic.…”

“…Traditionally, soil is pre‐treated to quantify its bioavailable mineral nutrients by shaking with a soil extractant (e.g., KCl, K 2 SO 4 , CaCl 2 , or NaOH) at an appropriate solution volume:soil weight ratio (such as 5:1 v/w) for a specific duration (0.5–2 h), followed by separation of the solution‐phase by filtration (or centrifugation) (Kachurina et al, 2000). As the importance of DON was increasingly recognized, a standardized extraction procedure for DON was proposed by Jones and Willett (2006), and this has become the basis for investigations of DON (Hossain et al, 2019; Liu et al, 2018; Moore et al, 2019). However, over the past decade, researchers have improved our understanding of the components and nature of DON (Carrillo‐Gonzalez et al, 2013; Chikuvire et al, 2018), and recent studies have shown that extraction conditions seriously influence the recovery of DON (e.g., amino acids and proteins) (Inselsbacher, 2014).…”

“…Therefore, salt-out effects can affect DON structure and induce coagulation/precipitation, which could seriously impact the DON extraction accuracy (Asrami & Saien, 2018;Hossain et al, 2019). The…”