Investigation of proton dynamics and the proton transport pathway in choline dihydrogen phosphate using solid-state NMR

Choline dihydrogen phosphate has previously been shown to be a good ionic conductor as well as an excellent host for acid doping, leading to high proton conductivities required for e.g., electrochemical devices including proton membrane fuel cells and sensors. A combination of variable-temperature ¹H solid-state NMR and 2D NMR pulse sequences, including ³¹P and ¹³C CODEX and ¹H BaBa, show that the proton conduction mechanism primarily involves assisted transport via a restricted three-site motion of the phosphate unit around the P–O bond that is hydrogen bonded to the choline and exchange of protons between these anions. In other words, proton transport at ambient temperatures appears to occur most favorably along the crystallographic b axis, from phosphate dimer to dimer. At elevated temperatures exchange between the protons of the hydroxyl group on the choline cation and the hydrogen-bonded dihydrogen phosphate groups also contributes to the structural diffusion of the protons in this solid state conductor.

Profiling national mandatory folic acid fortification policy around the world

Mandatory food fortification “occurs when governments legally oblige food producers to fortify particular foods or categories of foods with specified micronutrients” [1]. Because mandatory food fortification exposes everyone in the population who consumes the fortified food(s) to raised levels of the specified micronutrient, it is one of the most powerful policy instruments available to influence dietary intake and population health outcomes. Many national food regulatory authorities have established policy guidance on mandatory food fortification. From an international perspective, the Codex Alimentarius Commission (Codex) provides principles for the addition of essential nutrients to foods [2]. According to these Codex principles, mandatory food fortification with additional vitamins and minerals is recommended where there is proven public health and nutrition need (Note: these principles are under review at the time of writing).