Effects of amino acid ionic liquids with different cations ([N2Py], [N2222], [P2222], and [C2mim]) on wheat seedlings

The ecotoxicity of four ionic liquids with different cations (N-ethyl-pyridine alanine [N2Py][Ala], tetraethyl phosphine L-α-amino propionic acid salt [P2222][Ala], 1-ethyl-3-methyl-imidazolium alanine [C2mim][Ala], and tetraethyl ammonium L-α-amino propionic acid salt [N2222][Ala]) was assessed in hydroponically-grown wheat seedlings at concentrations from 200–1200 mg L−1. The results showed that type of cation has a significant influence on the growth, chlorophyll and nutrient uptake of wheat seedlings (P [N2222][Ala] > [P2222][Ala] > [C2mim][Ala]. In this work, the relatively stronger toxicity of [N2Py][Ala] was likely contributed by ethanol, which was used to dissolve [N2Py][Ala]. Therefore, it is not recommended to use N-ethyl-pyridine alanine ([N2Py][Ala]) widely in practical applications.