4th EucheMs chemistry congress

Poster Session 2
s1158
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - Analytical Chemistry
P - 0 5 9 2
eLeCtrooxidAtion of nA+/K+-AtPASe After
SoLuBiLizAtion By oCtAethyLene GLyCoL
MonododeCyL ether
M. zAtLouKALovA 1 , M. KuBALA 2 , J. vACeK 1
1 Palacky University, Department of Medical Chemistry and
Biochemistry, Olomouc, Czech Republic
2 Palacky University, Department of Biophysics, Olomouc,
Czech Republic
The present study is focused on oxidation and adsorption
behaviour of full-length transmembrane protein Na+/K+-ATPase
(NK) and its water-soluble isolated cytoplasmic loop connecting
transmembrane helices 4 and 5 (C45) using voltammetric
methods. Membrane proteins are substances that are poorly
soluble or insoluble in aqueous solution. The C45 is soluble in
water, the nonionic surfactant octaethylene glycol monododecyl
ether was used for NK solubilization [1] . Both proteins, NK and
C45, were studied using adsorptive transfer cyclic voltammetry
and square-wave voltammetry on basal-plane pyrolytic graphite
electrode. While NK gives two oxidation peaks (peak Y: +0.55 V
and peak W: +0.7 V) related to tyrosine (Y) and tryptophan (W)
oxidation, C45 is characterized by substantially lower anodic
responses (peak Y&W: +0.65 V). High anodic currents of Y and
W of NK are related to its transmembrane part, which are very
rich in Y and W residues. These experimental procedures allow
studying oxidation of NK and C45 at femtomole level without the
necessity to use derivatization, labeling by electroactive markers
or techniques based on protein immobilization within lipid bilayer
attached to the electrode surface.
Acknowledgments: The research was support by the internal
grant LF UP (LF_2012_010), MZ CR (NT11071) and GA CR
(303/09/H048).
references:
1. M. Huliciak et al., Biochem. Pharmacol., 83, 1507-1513,
2012.
4 th EucheMs chemistry congress
P - 0 5 9 3
the APPLiCAtion of hPLC with
eLeCtroCheMiCAL deteCtion for the
deterMinAtion of PeStiCide ChLorotoLuron
J. zAvAzALovA 1 , L. houSKovA 1 , J. ziMA 1 , J. BAreK 1 ,
h. deJMKovA 1
1 Charles University in Prague Faculty of Science, Department
of Analytical Chemistry UNESCO Laboratory of
Environmental Electrochemistry, Prague, Czech Republic
Many herbicides are used in agriculture all over the world.
Despite their benefits in increasing agricultural production,
herbicides can have a negative impact on the environment and can
pose a risk to animals and humans. For these reasons, there is a
growing demand for fast and reliable pesticide monitoring in
agriculture.
A method for the determination of phenylurea herbicide
chlorotoluron was developed using reversed-phase HPLC with
amperometric detection on carbon paste electrode in wall-jet
arrangement. Separation and detection conditions for the
determination were optimized, namely pH of mobile phase and
detection potential. The optimum conditions for the determination
are: LiChroCART ® 125-4 Purospher ® RP-18 (5 μm) column,
mobile phase consisting of methanol and ten times diluted
Britton-Robinson buffer pH 4.0 (60:40, v/v), and detection
potential +1.3 V. Concentration dependences are linear in the
range from 1.0·10 –7 mol L –1 to 1.0·10 –4 mol L –1 and the limit of
determination reaches value of 1.1·10 –7 mol L –1 . The method was
applied on model samples of river water, with the limit of
determination for amperometric detection 1.9·10 –7 mol L –1 .
Acknowledgement: The research was supported by
the Ministry of Education, Youth and Sports of the Czech
Republic (Project MSM 0021620857 and KONTAKT (AMVIS)
Project ME10004), Charles University in Prague (Project SVV
2012-265201), Grant Agency of the Czech Republic (Project
P206/12/G151), and Technology Agency of the Czech Republic
(project TA01020565). J. Zavazalova thanks to the Faculty of
Science, Charles University in Prague (project STARS) for
financial support.
Keywords: Electrochemistry; Environmental chemistry; Liquid
chromatography;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc