Page 9 - Shimadzu Nexera Prep

Counter Ions Removal

In some cases, basic compounds can contain counter ions (such as tri uoroacetic acid, TFA) derived from both reagent and mobile
phase. These components may remain as impurities, affecting the nal purity. With Nexera UFPLC, the target component can be
recovered as a high-purity free base (free base type) by using a trap column.
Untreated Sample Treated Freebase Form

TFA / Hydrochloride
(0.13% / 0.08%)
Counter ion Cl −
derived from
reagent Hydrochloride TFA
(56%) (44%)
Freebase
(99.79%)

Counter ion TFA − Cl − TFA −
derived from
mobile phase

Structural Analysis without Preprocessing

The F NMR spectrum of a 0.1% TFA solution containing
19
propranolol after freebasing treatment is shown. Compared to Untreated Sample
the untreated sample, the TFA-derived peak in the fractionated
sample is signi cantly smaller, con rming that TFA is effectively Peaks from propranolol
+ TFA
removed in the puri cation process using Nexera UFPLC.

Treated Freebase Form

ppm
−72.0 −73.0 −74.0 −75.0
19 F NMR Spectra of Peaks from TFA Bonded to Propranolol

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