Superabsorbent polymer particles, consisting of partly neutralized, slightly crosslinked poly(acrylic acid), have been surface-crosslinked photochemically. Surface crosslinking is required for many applications of superabsorbent polymers, such as disposable diapers, to control the flow and absorption of liquids in the gel bed. Photoinduced surface crosslinking has been achieved under UV irradiation (200-300 nm) with (NH 4 ) 2 S 2 O 8 as a photoactivated crosslinking agent. In comparison with the currently used thermal ester bridging method for surface crosslinking, the new photochemical method generates superabsorbent particles with superior properties, such as an improved flow of liquid through the gel bed, which utilizes the entire gel bed. These improved properties have been shown by water absorption capacity studies, fluid flow dynamics, environmental scanning electron microscopy, and low-energy ion-scattering studies.

Expanded oligo(l-leucine)s, containing an alternate arrangement of a bis(terpyridine)ruthenium(II) moiety and a l-leucine residue, were synthesized and characterized by 1H NMR, UV, CD, and electrochemical properties. The intensity of CD spectra per ruthenium unit increased with the elongation of the peptide chain. 1H NMR analysis of a tetramer indicated the right-handed helical structure in acetonitrile.

A novel N-terminal-labeling reagent [(tpy)Ru II-(tpyCONSu)] 2þ (=-COONSu) provides an efficient and effective N-terminal sequencing of peptides and proteins in MALDI-TOF-MS/MS (PSD) analysis, which shows a n fragments predominantly without any C-terminal-fragment ions.

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