Rapid isolation of angiotensin peptides from plasma by electromembrane extraction

Rapid and simple pretreatment of human body fluids using electromembrane extraction across supported liquid membrane for capillary electrophoretic determination of lithium

“…The liquid membrane thickness may decrease for longer extraction times and may not fully separate the two aqueous phases. Similar behavior was previously described by Balchen et al [19] for EME of peptides using 1-octanolbased SLM. We have therefore prolonged the impregnation Electrophoresis 2011Electrophoresis , 32, 1182Electrophoresis -1189 time (defined as time in seconds for which the HF was dipped into organic solvent) of the HF and have looked at the EME stability for longer extraction times.…”

“…After a short extraction period (usually 5-10 min), EME equilibrium was reached and the analyte-enriched acceptor solution was analyzed by LC or CE. EME is well suitable for the pretreatment of organic compounds due to their favourable distribution coefficients between aqueous and organic phase [14][15][16]; however, it has been shown that EME can also be optimized for the pretreatment of biochemical [17][18][19] and inorganic compounds [20,21]. Complete overview of EME applications can be found in two recent review articles [12,13].…”

Electromembrane Extraction from Biological Fluids

“…27 In a subsequent paper, angiotensin peptides were extracted by EME from human plasma for the first time. 28 In this case, the extraction voltage was 15 V, and the SLM consisted of 1-octanol and 8% DEHP (w/w). Both the voltage and the content of DEHP were reduced as compared to the first paper, to avoid excessive current in the system which may result in electrolysis and formation of small bubbles in the aqueous compartments.…”

“…[27][28][29][30] In the first paper, small model peptides were extracted as net-cationic species from acidic sample (pH 3), through a SLM of 1-octanol and 15% DEHP (w/w), and into 25 μl of 100 mM HCl as acceptor phase using 50 V. DEHP in the SLM was found to be crucial for the transfer of peptides into the SLM. During 5 min of operation, the peptides were enriched by a factor of up to 11 by EME.…”

“…18 Several of the developed EME methods have been validated, and have provided acceptable results from human plasma, whole blood, urine, saliva, and breast milk. 10,[17][18][19][20][21][22][23][24][25]28,31,32 Typically, the EME methods have provided linear calibration curves over 2 decades (r 2 > 0.99) 22,24 and with repeatability values in the range 2 -10% RSD. 22,24 One example of validation results are reported in Table 1 for naltrexone and nalmefene in human plasma and urine.…”