3rd meeting of young researchers at UP 1 - IJUP - Universidade do ...

Automatic flow methodology for quinine determination in biological
samples
A.M. Vaz, A.R.T.S. Araujo, J.L.M. Santos, M.L.M.F.S. Saraiva and J.L.F.C. Lima
REQUIMTE, Department of Physical-Chemistry, Faculty of Pharmacy, University of Porto, Rua
Aníbal Cunha, 164, 4099-030 Porto, Portugal
E-mail: lsaraiva@ff.up.pt
Quinine is a natural occurring cinchona alkaloid that has been used in medicine for ages
as anti-malaria agent. However, quinine is also a potentially toxic drug and its overuse has
been determined to cause and complicate other health conditions. The typical syndrome of
quinine side effects is called cinchonism and it can be mild in usual therapeutic dosage or
severe in larger doses. The toxic effects of quinine appear to be related to plasma
concentrations.
D
In this sense the determination of
quinine in human biological fluids
is of utmost importance in the
clinical chemistry field. For this
purpose, several methods have
been reported based on HPLC
procedures. However, they are
time consuming and have a low
sampling throughput, requiring
sample pre-treatment (including
extraction with organic solvents).
Therefore the present work is
aimed to develop an automatic
analytical flow methodology for
the automatic, direct, rapid and
H2SO4 0.05 mol L-1 H2SO4 0.05 mol L-1 H2SO4 0.05 mol L-1 Sample
Fig. 1 Flow manifold for quinine determination in
biological samples: MP -10µL solenoid micropumps;
C – confluence point; D – Fluorimetric detector
(λexcitation=250 nm; λemission=450 nm); sv - solenoid
commutation valves; EC – extraction column; W –
waste.
reliable determination of quinine in urine and serum samples. The designed multimpumping
flow analysis system (MPFS) [1] comprises an in-line extraction column (filled with Amberlite
XAD-4 resin), where the quinine was retained using basic conditions and then eluted with
H2SO4, being finally propelled towards the fluorometric detector. The influence of parameters
such as eluent concentration, elution flow rate and volume, flow rate and volume of the
regeneration and cleanup steps as well as sample volume, etc., on the sensitivity and
performance of the MPFS system were studied and the optimum reaction conditions
subsequently selected.
The proposed automatic method is being applied to the urine and serum samples and high
relative extraction recoveries from these biological matrices were attained.
Acknowledgements: André R.T.S. Araujo thanks FCT and FSE (III Quadro Comunitário de Apoio) for
the Ph.D. grant SFRH/BD/23029/2005.
References:
[1] Lapa, R.A.S., Lima, J.L.F.C., Reis, B.F., Santos, J.L.M., and Zagatto, E.A.G. (2002), Multipumping
in flow analysis: Concepts, instrumentation, potentialities. Analytica Chimica Acta, 466, 125-
132.
MP 1
sv
3 rd meeting of young researchers at UP 331
W
EC
MP 2
sv
NaOH
0.1 mol L-1 NaOH
0.1 mol L-1 NaOH
0.1 mol L-1 sv
C
MP 3
W
W
MP 4
H 2 O