Dimethylformamide (DMF), which is still the most commonly used solvent for Fmoc-SPPS, has the potential for degradation over time on exposure to air (and water vapour) and storage, to give dimethylamine and formic acid impurities. In particular, dimethylamine can lead to unwanted deprotection of the fluorenylmethyloxycarbonyl (Fmoc) group during, for example, the initial loading of Fmoc amino acids in SPPS, which leads reduced calculated loading values. We have found that treatment of such aged DMF by simple sparging with an inert gas (N 2 ), or vacuum sonication, can regenerate the DMF in order to restore loading levels back to those found for newer, fresh, DMF samples.

The degree of resin swelling in a particular solvent system is one of the critical parameters for solid-phase peptide synthesis (SPPS) and for solid-phase synthesis in general. Methods used for measuring the degree of resin swelling include microscopy-based and volumetry-based methods. This study describes and compares the use of both methods for a number of commercially available resins commonly used in SPPS, with a range of solvents, which have been identified in the literature as 'greener' than DCM, DMF and NMP. The results were analysed by statistical methods, and a significant correlation between the two distinct methods has been demonstrated for the first time. The results will likely be used, in conjunction with other literature methods, to help in choosing both the resin and solvent system for greener SPPS, as well as for continuous flow SPPS, which is of growing importance. K E Y W O R D S continuous flow SPPS, green chemistry, green solid-phase peptide synthesis (GSPPS), resin swelling, solid-phase peptide synthesis (SPPS)

: A large percentage of a fish's weight is generally discarded during fish processing. Reducing waste in products of marine origin is a subject of great interest within the scientific community. Pelagic by-products such as the structural protein collagen, which can be generated during the processing of fish, has been proposed as an alternative to terrestrial, mammalian sources due to advantages including high availability and low risk of zoonotic disease transmission. Gelatine has multiple possible applications, ranging from nutraceutical applications to cosmetics and has the advantage of being generally regarded as safe. In this multidisciplinary review, the chemistry of gelatine and its parent protein collagen, the chemical reactions to generate their hydrolysates and studies on their biological activities using animal cell culture are discussed.