Influence of acid-base dissociation equilibria during electromembrane extraction
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Influence of acid-base dissociation equilibria during electromembrane extraction. / Restan, Magnus Saed; Ramsrud, Sindre Bergstrøm; Jensen, Henrik; Pedersen-Bjergaard, Stig.
I: Journal of Separation Science, Bind 43, Nr. 15, 2020, s. 3120-3128.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Influence of acid-base dissociation equilibria during electromembrane extraction
AU - Restan, Magnus Saed
AU - Ramsrud, Sindre Bergstrøm
AU - Jensen, Henrik
AU - Pedersen-Bjergaard, Stig
PY - 2020
Y1 - 2020
N2 - Electromembrane extraction is affected by acid–base equilibria of the extracted substances as well as coupled equilibria associated with the partitioning of neutral substances to the supported liquid membrane. A theoretical model for this was developed and verified experimentally in the current work using pure 2-nitrophenyl octyl ether as supported liquid membrane. From this model, extraction efficiency as a function of pH can be predicted. Substances with log P < 0–2 are generally extracted with low efficiency. Substances with log P > 2 are generally extracted with high efficiency when acceptor pH < pKaH − log P. Twelve basic drug substances (2.07 < log P < 6.57 and 6.03 < pKaH< 10.47) were extracted under different pH conditions with 2-nitrophenyl octyl ether as supported liquid membrane and fitted to the model. Seven of the drug substances behaved according to the model, while those with log P close to 2.0 deviated from prediction. The deviation was most probably caused by deprotonation and ion pairing within the supporting liquid membrane. Measured partition coefficients (log P) between 2-nitrophenyl octyl ether and water, were similar to traditional log P values between n-octanol and water. Thus, the latter have potential for pKaH − log P predictions.
AB - Electromembrane extraction is affected by acid–base equilibria of the extracted substances as well as coupled equilibria associated with the partitioning of neutral substances to the supported liquid membrane. A theoretical model for this was developed and verified experimentally in the current work using pure 2-nitrophenyl octyl ether as supported liquid membrane. From this model, extraction efficiency as a function of pH can be predicted. Substances with log P < 0–2 are generally extracted with low efficiency. Substances with log P > 2 are generally extracted with high efficiency when acceptor pH < pKaH − log P. Twelve basic drug substances (2.07 < log P < 6.57 and 6.03 < pKaH< 10.47) were extracted under different pH conditions with 2-nitrophenyl octyl ether as supported liquid membrane and fitted to the model. Seven of the drug substances behaved according to the model, while those with log P close to 2.0 deviated from prediction. The deviation was most probably caused by deprotonation and ion pairing within the supporting liquid membrane. Measured partition coefficients (log P) between 2-nitrophenyl octyl ether and water, were similar to traditional log P values between n-octanol and water. Thus, the latter have potential for pKaH − log P predictions.
KW - acid–base equilibria
KW - electromembrane extraction
KW - microextraction
KW - sample preparation
U2 - 10.1002/jssc.202000391
DO - 10.1002/jssc.202000391
M3 - Journal article
C2 - 32491271
AN - SCOPUS:85087176487
VL - 43
SP - 3120
EP - 3128
JO - HRC & CC, Journal of High Resolution Chromatography and Chromatography Communications
JF - HRC & CC, Journal of High Resolution Chromatography and Chromatography Communications
SN - 1615-9306
IS - 15
ER -
ID: 244914596