The colorful world of sulfonephthaleins: Current applications in analytical chemistry for “old but gold” molecules

Magnaghi, Lisa Rita; Zanoni, Camilla; Alberti, Giancarla; Biesuz, Raffaela

doi:10.1016/j.aca.2023.341807

Cited by 7 publications

(1 citation statement)

References 232 publications

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“…However, UV–vis detection of piperidine would be possible in the presence of a piperidine indicator dye with a fast UV–vis response. Although several indicators such as the sulfonephthalein dyes, are potentially applicable, this work focuses on the scope and limitations of applying Oxyma Pure (Oxyma) as a piperidine indicator dye in either an in- or online detection mode. The principle of utilizing a visibly colored indicator for monitoring the presence of free amines on the resin in SPPS has previously been reported using bromophenol blue, , but to the best of our knowledge, no one has reported the application of such an indicator for direct in- or online monitoring of residual piperidine in the waste stream during SPPS.…”

Section: Resultsmentioning

confidence: 99%

Green Solid-Phase Peptide Synthesis: Oxyma-Triggered Spectrophotometric Monitoring of Residual Piperidine

Broman,

Rosenberg,

Wojcik

et al. 2024

Org. Process Res. Dev.

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Solid-phase peptide synthesis (SPPS) is an efficient platform technology for synthesizing synthetic peptides but has an environmental downside due to the use of vast amounts of toxic solvents. In recent years, a big effort has been made to replace these solvents with more environmentally benign alternatives; however, this work has not had a significant effect on reducing the PMI and carbon footprint of SPPS. Herein, we demonstrate that by adding a low concentration of Oxyma Pure to the waste stream after Fmoc-removal, a simple real-time online UV−vis monitoring system can quantify piperidine with the needed sensitivity. In addition to the potential for reducing washing volumes after Fmoc-removal, this inexpensive and easy-to-implement process analytical tool allows the determination of completed washing by visual inspection due to the yellow color of Oxyma Pure in the presence of piperidine. Moreover, manual sampling of the waste stream is not needed, which reduces the overall process time. Importantly, the methodology was found to be compatible with green SPPS performed in 10−50% DMSO in the EtOAc mixtures.

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Section: Resultsmentioning

confidence: 99%