Distribution ratio

phase, HFTA may show faster kinetics than HTTA.
apparatus. The experiment in Fig. 1 was conducted at anaction kinetics and mechanism for Zr and Hf withincreased temperature (45°C) because the acceleration of
ere investigated by the batch method. In addition,
the extraction reaction by using the FIA apparatus at 25°C
ction experimentusing theFIAChemistry
apparatus waswas insufficient. The result
extraction
Ⅲ-3. Radiochemistry& Nuclear
RIKENshowedAccel. Prog. thatRep. 51the(2018)d.
equilibrium of Zr and Hf with HFTA using the FIA88
Solvent
extraction
behaviorofZrand Hfwaswith
2-furoyltrifluoroacetone
g-lived radionuclides of Zr ( 1/2 = 83.4 d) andapparatus
attainedin 30–40 s. This is a promising result
89
88=70d)wereproducedintheY(,3)Zr
andfortheextraction
experimentof the 104)
short-lived 261Rf ( 1/2 =/2
as model experiments for rutherfordium (element)175Hf reactions, respectively, by using the68 s) isotope. In the future, an on-line extraction experiment∗1,∗2∗1∗1K. Ooe,
S. Kusakari,
S. Goto,ofH.
Komori,and H.
Kudo∗4 coupled to a gas-jet
K70 AVF cyclotron. These
producedradiotracers
ZrHaba,and ∗3HfY.withthe∗3FIAapparatus
parated and purified by an anion exchange and atransport system will be conducted.
Our
group
has
been
investigating
thesolvent
ex100
extraction method. In the batch extraction
88Zr
Aq: 1 M HNO3
traction behavior of zirconium (Zr) and hafnium(Hf)containing 88Zr
ent, 600 Lof 1 M HNO3 solution
Org: 0.018 M
175Hf
with chelating agents
such as 2-thenoyltriﬂuoroacetone
HFTA/toluene
Hf tracers (HTTA)
was mixedwith the same volume
10
and di-2-ethylhexylphosphoricacid of(HDEHP)
Zr batch (45°C)
as model experiments
for thehomolog,
021 M HFTA/toluene
solution.
Theheavier
mixturewas ruther1–3)
fordium(Rf).
In
ourpreviousstudy,
wecally shaken at 25°C and then centrifuged. After theextracted
1and Hf (extractant: HDEHP) with a rapid extracn of eachZrphase,
the samples of aqueous andHf batch (45°C)
tion apparatus by using a ﬂow injection analysis (FIA)3)
phases weresubjectedAlthoughto γ-ray thespectrometry
a of Zr
technique.
distribution using
ratio (D)0.1
Hf experiment,
increased moreaqueous
rapidly thanin 3the) batch
ctor. In theandFIA(1 MthoseHNO
020
406080method,it
took
morethanseveralminutestoreachthenic (0.018 M HFTA/toluene) phases were pumped
Contact time / s
equilibrium of Zr and Hf with the apparatus.
Fig.
1. Dependenceofofthe
the DZr and
Hf onHfcontactnge pumpsextraction
at the same
flow rate of 30–100 L/min.
Fig. 1.
Dependence
D values
valuesof ofZr andon contact
An experiment with HTTA using the apparatus showedtimeintheextraction
coil(innerdiameter:0.017mm)
of of thewo phases almost
were mixed
inanextraction
coil(Teflon
time in the extraction coil (innerdiameter: 0.017 mm)
the same result; therefore, we planned to employ
the FIA apparatus at 45◦ C.
) with an anotherinner diameterof 0.17 mm
anda length
FIA apparatus at 45°C.
chelate extractant
havingfasterextraction kiseparated by pipetting into other sample tubes. Thenetics
fortheshort-lived
Rfexperiment.
Inthisstudy,m. The aqueous and organic solutions eluting from
References
samples were then subjected to γ-ray spectrometry uswe used 2-furoyltriﬂuoroacetone (HFTA), which is a β1) A. Tanaka, RIKEN Accel. Prog. Rep. , 288 (2015).
ction coil werecollected in a sample tube. Aftering a Ge detector. The D values of Zr and Hf were
diketone like HTTA, for extraction experiments of Zr2) R. Yamada, RIKEN
Accel.equation:
Prog. Rep. , 241 (2016).
calculated fromthe followingand Hf. This extractant has lower distribution constante of Science (Kand )Technology,
NiigataUniversity3) R. Yamada, RIKEN Accel. Prog. Rep. , 251 (2017).
d and acid dissociation constant (pKa ) values thanD = Ao /Aa ,ment of Nuclear
Medicineand Tracer
4)
HTTA.
BecauselowerKinetics,
Kd andOsakapKa values lead to 4)
a T. Sekine, J. Inorg. Nucl. Chem. , 3968 (1973).
sity Graduatehigher
Schoolconcentrationof Medicine of the coordinating anion, FTA− ,88whereAdenotes
radioactivityof either
Zr or 175 Hf P31,5) K. Ooe, thethe61stSymposiumon Radiochemistry,
N Nishina Centerin the aqueous phase, HFTA may show faster kinetics
and the subscripts a and o refer to the aqueous andIbaraki, Japan (2017).
y of Science, thanNiigata
UniversityHTTA.
The extraction kinetics and mechanism for Tsukuba,organic phase, respectively.
Zr and Hf with HFTA were investigated by the batch
In the batch extraction experiment, the extraction
method. In addition, an extraction experiment using
equilibrium of Zr and Hf with HFTA was attained inthe FIA apparatus was conducted.
3–4 min, showing faster kinetics than HTTA which reLong-lived radionuclides of 88 Zr (T1/2 = 83.4 d) andquired approximately 1 h for attaining equilibrium.5)
175Hf (T1/2 = 70 d) were produced in the 89 Y(d, 3n)88 Zr
The plots of log D of Zr and Hf against log [HFTA]
and nat Lu(d, xn)175 Hf reactions, respectively, by using
showed linear relations with slopes of approximately 4
the RIKEN K70 AVF cyclotron. These produced rafor both Zr and Hf. The slope indicates the number
diotracers were separated and puriﬁed by an anion exof HFTA molecules involved in the extraction reaction,change and a solvent extraction method. In the batch
and therefore, the extracted species would be Zr(FTA)4extraction experiment, 600 µL of 1 M HNO3 solutionand Hf(FTA)4 .
containing 88 Zr and 175 Hf tracers was mixed with theFigure 1 shows the dependence of the D values of Zr
same volume of 0.008–0.021 M HFTA/toluene solution.
and Hf on contact time in the extraction coil of the FIA
The mixture was mechanically shaken at 25◦ C andapparatus. The experiment in Fig. 1 was conducted atthen centrifuged. After the separation of each phase,
an increased temperature (45◦ C) because the accelerathe samples of aqueous and organic phases were subtion of the extraction reaction by using the FIA appajected to γ-ray spectrometry using a Ge detector. Inratus at 25◦ C was insuﬃcient. The result showed that
the FIA experiment, aqueous (1 M HNO3 ) and organic
the extraction equilibrium of Zr and Hf with HFTA us(0.018 M HFTA/toluene) phases were pumped with sying the FIA apparatus was attained in 30–40 s. This isringe pumps at the same ﬂow rate of 30–100 µL/min.
a promising result for the extraction experiment of theThese two phases were mixed in an extraction coilshort-lived 261 Rf (T1/2 = 68 s) isotope. In the future, an(Teﬂon capillary) with an inner diameter of 0.17 mm
on-line extraction experiment of Zr and Hf with the FIAand a length of 1–10 m. The aqueous and organic soluapparatus coupled to a gas-jet transport system will betions eluting from the extraction coil were collected inconducted.
a sample tube. After centrifugation, both phases wereReferences∗1∗2∗3∗4Institute of Science and Technology, Niigata University
Department of Nuclear Medicine and Tracer Kinetics, Osaka
University Graduate School of Medicine
RIKEN Nishina Center
Faculty of Science, Niigata University

1) A. Tanaka et al., RIKEN Accel. Prog. Rep. 48, 288 (2015).
2) R. Yamada et al., RIKEN Accel. Prog. Rep. 49, 241 (2016).
3) R. Yamada et al., RIKEN Accel. Prog. Rep. 50, 251 (2017).
4) T. Sekine et al., J. Inorg. Nucl. Chem. 35, 3968 (1973).
5) K. Ooe et al., the 61st Symposium on Radiochemistry,(Tsukuba, Ibaraki, Japan, 2017), p. 31.

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