Page 18 - PR 2014 2016 07 Nuclear Science and Technology

160 Nuclear Science and Technology | Progress Report

reproducible and traceable. Aiming to stan- Quantitative analysis of light elements
dardize the antigen obtained from different (Z<26) in serum and whole blood
regions, its elemental composition was inves- using compact XRF spectrometers
tigated using Neutron Activation Analyses
technique (NAA). The measurements were The use of analytical techniques to investigate
performed in the IEA-R1 nuclear reactor (IPEN/ specific ions in body fluids has increase in last
CNEN-SP, Brazil). The elements Cl and Na were year’s presenting significant progress in clinical
identified as majorities while the presence of tests. This motivated us to check the perfor-
As, Ca, Cr, Fe and S were also observed, but in mance of two compacts XRF spectrometers,
small concentration (μg/L). These data can be consisting of Ag and Au X-ray mini-tubes asso-
used to standardize a specific antilonomic se- ciated with a Si Drift detector with Be window
rum for caterpillars (L. obliqua) coming from (12.5μm) for this clinical finality. Using the En-
different regions of Brazil. ergy Dispersive X-Ray Fluorescence technique
(EDXRF), specific ions of clinical relevance, such
Characterization of inorganic elements as, Ca, Cl, Fe and K were investigated using
in coxal fluid of Ornithodoros standards (certified solutions). The perfor-
brasiliensis (Acari: Arrgasidae) mance of these spectrometers were checked
by evaluation of several parameter (linearity,
Ornithodoros brasiliensis tick has distribution reproducibility, accuracy, precision, sensitivity
restricted to the State of Rio Grande do Sul and detection limit) usually considered for
(São Francisco de Paula). Due to its quick en- validation procedures on analytical methods,
gorgement, hydrostatic balance is maintained according to ISO 17025 and EURACHEM/CITAC
through the secretion of excess body fluids norms. The method was proved to give reliable
and ions in the coxal liquid (CL) by coxal gland, results with limits of detection at levels of 0.23
during and after feeding. The biochemical to 0.58 mgL . Considering that the ranges of
−1
and ionic compositions are unknown; more- the body fluids, such as: blood, saliva, serum
over, recent investigations suggest that there and urine, are in the order of hundreds of mg
are some molecules able to help the tick in L , this procedure is very promising for ions
-1
anti-haemostatic strategies. The aim of this dosage requiring a small amount of sample
study was to determine the elemental com- (50μL, 10 times less comparatively to the con-
position of the coxal liquid of this tick using ventional tests), simultaneous analysis, short
NAA. The liquid was collected during and after time of analysis (minutes) and simple sample
tick feeding; the ticks feed on rabbits (Oryc- preparation. In addition, this procedure offers
tolagus cuniculus). The NAA measurements a non-destructive alternative for clinical usage.
were performed in the IEA-R1 nuclear reactor
at IPEN/CNEN-SP (3-4.5MW, pool type). These These compact spectrometers have also poten-
measurements revealed high concentrations tial use when the biological material is scarce,
of Na, Cl and S suggesting the association case of the pediatric practice in newborns and
with osmotic pressure regulation mechanisms premature infants (blood collection is the main
during tick feeding and the presence of Br, Mg, cause of transfusions) and in vivo tests, in small
K, P and Ca as trace. The data are crucial for size animal model (mice and rats), in order to
appropriate purification and characterization evaluate the safety of new drugs, vaccines and
of the relevant proteins in this secretion. others medical supplies.

Instituto de Pesquisas Energéticas e Nucleares