REASSESSMENT OF
239
PU ON PLANCHETS FROM HUMAN
URINE SAMPLES AT ULTRA-TRACE LEVELS USING
ARIDUS-ICP-SFMS AND AMS
He
´c o He na
´ndez-Mendoza1, Elena Chamizo2,*, An onio Delgado1, Manuel Ga cı
´a-Leo
´n3
and Abel Ylle a1
1
Cen o de In es igaciones Ene ge
´ icas, Medioambien ales y Tecnolo
´gicas (CIEMAT), A . Complu ense 22,
28040 Mad id, Spain
2
Cen o Nacional de Acele ado es (CNA), A . Thomas Alba Edison, 41092 Se illa, Spain
3
Depa amen o de Fı
´sica A o
´mica, Molecula y Nuclea , Uni e sidad de Se illa, 41012 Se ille, Spain
*Co esponding au ho : [email protected]
Recei ed Oc obe 17 2011, e ised Ap il 11 2012, accep ed Ap il 25 2012
New analy ical me hods de eloped a he acili ies he e, based on wo ul a-sensi i e mass spec ome y (MS) echniques, in-
duc i ely coupled plasma sec o ield mass spec ome e wi h a desol a o sys em (A idus-ICP-SFMS) and accele a o MS
(AMS), ha e been applied in his wo k o he eassessmen o
239
Pu in alpha spec ome y (AS) planche s co esponding o
spiked human u ine samples. The ob ained
239
Pu minimum de ec able ac i i ies (MDAs) alues by A idus-ICP-SFMS and
AMS we e 3 g (∼6.92 mBq) and 0.4 g (∼0.92 mBq), espec i ely, pe sample, which a e much be e han hose a ainable
by AS [50 g (∼115.3 mBq) o
239
Pu pe sample, app oxima ely]. The e o e, i is demons a ed ha he MS echniques
employed in his wo k a e e y powe ul ools o in e nal dosime y s udies in human u ine samples, gi ing excellen esul s
when he eassessmen o AS planche s is needed (samples wi h a Pu concen a ion below o a he MDA le els measu able
by AS). This wo k is he con inua ion o an a icle published in J. Anal. A . Spec om. 25 (1410–1415) 2010.
INTRODUCTION
The success ul measu emen and assessmen o in-
e nal exposu e o adioac i i y in dosime y s udies
a e highly dependen on he ins umen al capabili ies
o measu ing adionuclides in biological samples
(u ine, eces, blood o o he sec e ions)
(1,2)
.
No mally, du ing he Pu bioassay o human u ine
samples, i is manda o y o p econcen a e and
pu i y he Pu ac ion. In he case o mass spec om-
e y (MS) echniques, i is usually impo an o
p e en he p esence o
238
U in he sample, because
i can in e e e wi h he signal o he majo Pu
iso ope
39
Pu (T
1/2
¼24 110 y), and also o a oid
ma ix e ec s. Fo hese pu poses, ion-exchange o
solid-phase ex ac ion ch oma og aphy is ex ensi ely
used in wo ldwide labo a o ies
(3–8)
.
Alpha spec ome y (AS) is he mos commonly
used adioanaly ical echnique o he de e mina ion
o Pu in ou ine bioassay s udies, due o i s simpli-
ci y and low cos . Howe e , his me hod is e y
ime-consuming and i canno esol e he
239
Pu and
240
Pu peaks because o hei e y simila ene gies
(5.15 and 5.16 MeV). Analy ical esul s om AS a e
he e o e exp essed as he sum o he
239
Pu and
240
Pu
ac i i y concen a ion (i.e.
239þ240
Pu). Addi ionally,
his echnique shows some sensi i i y sho comings
when he in ol ed
239þ240
Pu ac i i y le els a e below
0.3 mBq pe sample (1.3 pg o
239
Pu pe sample),
due o he noise associa ed wi h he de ec o and
he poo s a is ics
(9)
. On he o he hand, se e al
pa ame e s, such as coun ing e iciency, chemical
yield, sample coun ing ime, ace ac i i y used and
backg ound condi ion he p ecision and accu acy o
he esul s o low-le el samples and, he e o e,
he minimum de ec able ac i i y (MDA) o AS
(10–12)
.
Because o i s excellen de ec ion sensi i i y, MS
echniques a e use ul ools o measu ing
239
Pu a
sub- g le els, and also
240
Pu/
239
Pu a omic a ios,
which would be impossible o measu e using con en-
ional adioac i e decay coun ing echniques. Due o
he equi emen s imposed by he In e na ional
Commission on Radiological P o ec ion (ICRP),
echniques capable o measu ing
239/240/241
Pu iso-
opes a concen a ions o 1 gl
21
in u ine
samples a e becoming manda o y
(13,14)
.
Di e en MS echniques, such as induc i ely coupled
plasma (ICP) MS
(3–6)
, The mal ionisa ion MS
(TIMS)
(15,16)
and accele a o MS (AMS)
(14,17,18)
,a e
good candida es o he dosime ic con ol o he popu-
la ion exposed o ionising adia ion, opening up he
possibili y o iden i ying and quan i ying small
amoun s o di e en adionuclides in a sample, and
also o e ing iso opic composi ion una ainable by
adioac i e coun ing echniques
(19 –22)
.
ICP-MS is one o he mos sui able me hods o
he analysis o ac inides a ul a ace le els, in pa -
icula
239
Pu, due o i s high sensi i i y, good
#The Au ho 2012. Published by Ox o d Uni e si y P ess. All igh s ese ed. Fo Pe missions, please email: jou nals.pe [email protected]
Radia ion P o ec ion Dosime y (2012), Vol. 152, No. 4, pp. 296–303 doi:10.1093/ pd/ncs078
Ad ance Access publica ion 23 May 2012
accu acy and p ecision and gene ally simple sample
p epa a ion p ocedu e e sus AS
(3)
. Howe e , he ac-
cu a e de e mina ion o Pu iso opes by ICP-MS is
hampe ed by bo h spec al and non-spec al in e e -
ences. Fo he analysis o Pu, he mos common
in e e ences a e
238
UH
þ
and
238
UH
2
þ
, which in e -
e e wi h he
239
Pu and
240
Pu iso opes, espec i ely,
due o he p esence o U. To a oid hese p oblems,
wo complemen a y solu ions a e usually applied:
he p econcen a ion and pu i ica ion o he Pu ac-
ion using ion-ch oma og aphy esins
(4,5)
, and/o
he educ ion o u anium hyd ide o ma ion using
special sample in oduc ion sys ems, such as mic o-
nebulize s wi h desol a o sys em
(6)
.
On he o he hand, AMS has ecen ly been
demons a ed o be a compe i i e echnique o he
p ecise and accu a e de e mina ion o Pu a sub- g
le els in u ine bioassay samples. I ea u es a high
sensi i i y wi h i ually no ma ix e ec s (high e-
jec ion o molecula isoba ic in e e ences), allowing
he iden i ica ion o abno mal ac i i ies o Pu wi h
no special chemical equi emen s
(7)
.
The aim o his s udy was o de elop and alida e
an analy ical me hod o he eassessmen o
239
Pu
in AS planche s con aining small amoun s o
239
Pu
( om 8 o 40 g pe sample), using he A idus deso-
l a o coupled wi h an ICP-SFMS, and a 1-MV
compac AMS sys em. This is specially in e es ing
o he au ho s’ esea ch cen e, CIEMAT (Resea ch
Cen e o En i onmen and Ene gy and Technology),
whe e he e is a big s ock o Pu elec odeposi s om
human u ine samples om he popula ion o
Paloma es (Alme ia, Spain), a ec ed by a nuclea ac-
ciden in 1966, and om p o essionally exposed
people.
MATERIALS AND REAGENTS
Ins umen a ion
Spec opho ome y and AS
C ea inine de e mina ion was ca ied ou by using a
spec opho ome e Zuzi, Model 4211/20 (Auxilab
S.L., Spain). AS measu emen s we e pe o med wi h
an Alpha Analys In eg a ed Alpha Spec ome e
(Canbe a, TECNASA S.L., Spain) equipped wi h
Passi a ed Implan ed Plana Silicon de ec o s. These
de ec o s ha e an ac i e a ea o 450 mm
2
and hei
nominal alpha-peak ene gy esolu ion, exp essed as
ull-wid h a hal -maximum, is 18 keV. The plan-
che s (Pu sou ces) we e placed a 1.5 mm om he
de ec o su ace. Fo he e alua ion o he da a, he
Genie 2000 .2.2 so wa e (Canbe a) was used.
HR-ICP-MS ins umen a ion
Pu quan i ica ion was ca ied ou wi h an Elemen
XR Mass Spec ome e (The mo Fishe Scien i ic,
B emen, Ge many). The sample in oduc ion sys em
employed was an A idus desol a o (CETAC
Technologies, Inc., USA) wi h a Mic o low nebulize
PFA-100 (Elemen al Scien i ic Inc., USA). Aqueous
samples we e in oduced o he desol a o in he
con inuous low mode by using an au o sample
CETAC ASX-520 (CETAC Technologies, Inc.,
USA). The ICP o ch was shielded wi h a g ounded
pla inum elec ode (Gua dElec odeTM, The mo
Scien i ic, Ge many).
Accele a o MS
The measu emen s o
239
Pu we e pe o med using
he 1-MV compac AMS sys em se up a he
Cen o Nacional de Acele ado es (CNA, Se ille,
Spain). The sys em was designed and manu ac u ed
by High Vol age Enginee ing Eu opa (HVEE,
Ame s oo , Holland).
Ma e ials and eagen s
239
Pu and
242
Pu s anda ds we e ob ained om
Na ional Physical Labo a o y (NPL, UK).
S anda ds we e dilu ed wi h 2 M HNO
3
o ob ain
s ock solu ions wi h a concen a ion o 20.3 mBq
ml
21
(140.4 ng l
21
)o
242
Pu and 7.9 mBq ml
21
(3.4
ng l
21
)o
239
Pu.
237
Np (chosen as ex e nal s anda d
o ICP-SFMS measu emen s) was ob ained om
Ame sham In e na ional plc (UK). This s anda d
was dilu ed wi h 0.1 M HCl o ob ain a s ock solu-
ion wi h a concen a ion o 3.256 mBq ml
21
(123
ng l
21
). Fo ICP-SFMS mass calib a ion, a ce i ied
mul i-elemen solu ion XXIII (Ba, B, Co, Fe, Ga,
In, K, Li, Lu, Na, Rh, Sc, Y, Tl and U) om Me ck
(Ge many) was used. The es o he sal s and solu-
ions we e p epa ed using analy ical g ade eagen s
om Me ck. High-pu i y wa e (.18 MVcm
21
)
was ob ained om a Milli-Q Elemen A10 Cen u y
(Millipo e Ibe
´ ica, Spain). Ni ic acid was pu i ied
by sub-boiling dis illa ion (Duopu , Miles one S. .l.,
I aly). Ce i ied A gas (99.999 %) was supplied by
Ai Liquide (Spain). Ce ipu
w
i on ICP s anda d
(Me ck, Ge many) and 500-mesh pu e aluminium
powde (Al a-Aesa , UK) we e employed o p epa -
a ion o he AMS ca hodes. AG1X2 anion-exchange
ch oma og aphy esins (Bio-Rad Labo a o ies S.A.,
Spain) we e used o Pu pu i ica ion. The ICP-
SFMS measu emen s we e ca ied ou in a clean
oom (ISO 6 class) a 24+18C.
Expe imen al
The di e en ea u es o he me hod o he ex ac-
ion and pu i ica ion o
239
Pu in human u ine
samples and he eassessmen o AS planche s o
ICP-SFMS and AMS de e mina ions a e shown in
he diag am in Figu e 1.
REASSESSMENT OF
239
PU BY ARIDUS-ICP-SFMS AND AMS
297
Figu e 1. Schema ic diag am o he p epa a ion p ocedu e o u ine samples and measu emen s o Pu by AS, A idus-ICP-
SFMS and AMS: (1) collec ion o sample ( ime: 24 h); (2) co-p ecipi a ion (24 h); (3) Mine alisa ion (2 h); (4)
adiochemis y (3 h); (5) elec odeposi ion (2 h); (6) eco e y o Pu om planche s (24 h) and (7) p epa a ion o he
ca hodes o AMS (3 h) and eassessmen o
239
Pu by A idus-ICP-SFMS and AMS. This igu e appea s in colou in he
online e sion o Radia ion P o ec ion Dosime y.
H. HERNA
´NDEZ-MENDOZA ET AL.
298
C ea inine measu emen s
Measu emen s o c ea inine concen a ions in u ine
ha e been commonly used in he labo a o y o es i-
ma e 24 h exc e ion o adionuclides om u ine
samples collec ed in a day, hen 14 samples o 24 h
human u ine (V
sample
¼1725+114 ml) we e collec ed
om se e al heal hy adul male olun ee s. The ana-
ly ical p ocedu e was ini ia ed he same day o he
collec ion by he de e mina ion o c ea inine con en
in he u ine samples, in o de o check whe he
hose me he equi emen s needed p e ious o bio-
assay. The me hod is based on he Ja e
´ eac ion:
addi ion o sodium pic a e in o he u ine and o -
ma ion o a ed-coluo ed complex (sodium
pic ama e)
(23)
. The colou in ensi y is di ec ly p o-
po ional o he concen a ion o c ea inine a a spe-
ci ic wa eleng h (520 nm), which is measu ed wi h a
spec opho ome e
(24)
.
Co-p ecipi a ion
The me hod ca ied ou o co-p ecipi a ion is
desc ibed in Kuwaba a and Noguchi
(8)
and Rob edo
e al.
(9)
The 24 h u ine samples we e ans e ed in o
espec i e g adua ed cylinde s, acidi ied wi h concen-
a ed HNO
3
o pH¼1, and hea ed in a ho pla e
wi h magne ic s i ing a 808C du ing 2 h. Then, he
ho samples we e spiked wi h known amoun s o
242
Pu (8.4 pg) as in e nal s anda d, and
239
Pu ( om
8 o 40 g, see Table 1). Nex , 1 ml o concen a ed
o hophospho ic acid was added, con inuing he
hea ing and he s i ing o a u he 1 h. Then, he
Pu was co-p ecipi a ed by he addi ion o concen-
a ed ammonium hyd oxide un il pH¼9, keeping
he same condi ions o 1 h. The p ecipi a e was
allowed o se le o e nigh and hen sepa a ed by
decan ing and cen i uga ion. The supe na an was
disca ded, and he g adua ed cylinde was washed
se e al imes wi h 0.5 M HNO
3
. The washings we e
also ans e ed in o he cen i uge ube, and he p e-
cipi a e was dissol ed wi h 5 ml
21
o 8 M HNO
3
plus slow addi ion 3 ml o concen a ed H
2
O
2
. The
p ocedu al blanks (unspiked u ine samples) we e
p ocessed in he same way.
Mine alisa ion, adiochemis y, elec odeposi ion
and p epa a ion o he ca hodes o AMS
A summa y o he p ocesses in ol ed in his sec ion
is gi en in Figu e 1. A de ailed desc ip ion has been
p o ided in p e ious s udies
(25)
.
Reco e y o Pu o planche s eassessmen
In o de o de e mine he adiochemical yield du ing
Pu pu i ica ion, he samples we e p e iously mea-
su ed by AS. A e ha , he ex ac ion o he
elec odeposi s was ca ied ou by dipping he plan-
che s in o 20 ml o 5 % HNO
3
o e nigh . Nex , he
planche s we e insed wi h 5 % HNO
3
and he
esul ing solu ions we e hea ed o d yness, dilu ed o
10 ml o he same acid in olume ic lasks, and
di ided in wo win aliquo s o he A idus-ICP-
SFMS and he AMS de e mina ions. In he case o
he ICP-SFMS aliquo s, 4.4 g o
237
Np we e also
added as an ex e nal s anda d.
RESULTS AND DISCUSSION
C ea inine es
The Pu is a long-li ed adionuclide ha is exc e ed
om he human body in e y small amoun s, which
canno always be easily de ec ed by AS. The ecom-
menda ions o good ou ine analysis o Pu in u ine
es ablish ha he sample mus con ain he c ea inine
equi alen o , a leas , o 24 h exc e ion
(26)
. This
con ibu es o minimise he unce ain y o he esul s
no malised o 24 h exc e ion, specially when analys-
ing spo u ine samples
(7,13,27)
. The e o e, he de e -
mina ion o c ea inine in u ine is essen ial o
moni o ing he exc e ion o long-li ed adionuclides
and i is also a decisi e es o accep ing o ejec ing
he sample
(28)
. In his wo k, he a e age c ea inine
concen a ion was 1.1+0.13 g l
21
(n¼15), which is
in ag eemen wi h he ICRP-89 ecommenda ions
o accep ing u ine samples o dosime y s udies
(10)
.
T ea men o sample and pu i ica ion o Pu
The co-p ecipi a ion o Pu wi h calcium phospha e
in ammonia medium was pe o med o p e-concen-
a e i , because i is adequa e o pe o m in human
u ine a a sub-pg/l concen a ion le el o Pu.
No mally, he ou ine bioassay o long-li ed adio-
nuclides equi es mine alisa ion o he sample, which
is usually ca ied ou by we ashing o he p ecipi a e
ollowed by mu le u nace incine a ion
(9)
. This
p ocess is e y ime-consuming and edious.
The e o e, in his wo k, he mine alisa ion was pe -
o med by mic owa e-assis ed acidic diges ion (8 M
HNO
3
and concen a ed H
2
O
2
) o he calcium phos-
pha e p ecipi a e, which accele a es he p epa a ion
o he sample.
When using MS and adiochemis y echniques
o Pu quan i ica ion in low-le el samples, he elim-
ina ion o ma ix elemen s con ained in he sample
is a mus . In his wo k, his was achie ed using
anion-exchange esins (BioRad AG1X2). The pu i i-
ca ion o Pu using AG1X2 esin does no p esen
signi ican d awbacks in con as o o he Pu pu i i-
ca ion p ocesses which, in p inciple, a e as e
(5)
.In
case, he necessa y ime o p ocessing 10 samples
was 2–4 h. Mo eo e , as measu ed by AS, AG1X2
REASSESSMENT OF
239
PU BY ARIDUS-ICP-SFMS AND AMS
299
esin o e s an excellen chemical eco e y o he Pu
ac ion in u ine samples (Table 1).
Op imisa ion o A idus-ICP-SFMS pa ame e s
The ins umen al se ings we e op imised o he
quan i ica ion o
237
Np
239
Pu and
242
Pu.
Op imisa ion was pe o med in h ee s eps:
(1) Tuning he pa ame e s o A idus (a gon and ni-
ogen low) o ob ain he maximum in ensi ies
o
115
In and
238
U iso opes, using a dilu ion
(1:10) o he ce i ied mul ielemen solu ion in
low esolu ion mode. The signal in ensi y o
hese iso opes was abou 7.010
5
cps and
1.010
6
cps, espec i ely, and he
238
U oxides
con en in he plasma was 0.6 %.
(2) Op imisa ion o maximum ion in ensi y o
242
Pu and minimum backg ound a m/z¼239
using a
242
Pu s anda d solu ion o 0.4 pg l
21
.
The backg ound signal ob ained du ing his s ep
was 0.3+0.1 cps o m/z¼239. Addi ionally, a
s abili y es was also pe o med o moni o ing
he signal o
237
Np,
238
U,
239
Pu,
240
Pu and
242
Pu
iso opes (10, 0.1, 32, 2.7 and 42 pg l
21
, espec -
i ely) in s anda d samples o hese iso opes
du ing 15 min.
(3) Op imisa ion o he me hod o he measu e-
men o
237
Np,
238
U,
239
Pu,
240
Pu and
242
Pu iso-
opes. Ins umen al ope a ion condi ions a e
summa ised in Table 2.
Reassessmen o he Pu by MS echniques
The main p oblem when measu ing
239
Pu by ICP-
SFMS appea s when U is p esen in he sample (mo-
lecula isoba ic in e e ence due o he o ma ion o
238
U
1
H
þ
in he plasma), and also om he ailing
e ec o he
238
U peak, which leads o an inc ease in
he backg ound signal a m/z¼239. Some al e na-
i es ha e been conside ed in he li e a u e in o de
o a oid hese p oblems: one op ion consis s in using
a low- low mic onebulize coupled wi h a memb ane
desol a o as sample in oduc ion sys em (A idus)
(6)
,
and he second op ion consis s in using deu e a ed
wa e as sample sol en
(29)
. In his wo k, he in lu-
ence o
238
U on he backg ound signal a m/z¼239
was in es iga ed using he A idus-ICP-SFMS. Thus,
a ce i ied s anda d solu ion o 0.1 ppb o
238
Uin
HNO
3
5%[(
238
U)10
5
(
239
Pu)samples] was mea-
su ed, ob aining a backg ound signal a m/z¼239 o
1.0+0.3 cps (n¼10). The backg ound signal
ob ained wi h HNO
3
5 % blanks a m/z¼239 was
0.3+0.1 cps, indica ing ha he con ibu ion o
238
U o he
239
Pu signal is negligible in hese condi-
ions. These esul s a e in good ag eemen wi h
o he wo ks o he analysis o Pu in u ine
samples
(3)
.
Ex e nal calib a ion was employed du ing he
eassessmen o
239
Pu and
242
Pu in AS planche s o
A idus-ICP-SFMS analysis (Figu e 2). All he solu-
ions (blanks, s anda ds and samples) we e spiked
wi h
237
Np as an ex e nal s anda d, o moni o he
ins umen s abili y du ing he measu emen s
(Figu e 3).
The esul s indica e he excellen chemical eco -
e y achie ed wi h he p oposed ex ac ion p ocess
o he eassessmen o Pu om AS planche s
Table 2. Ins umen al condi ions op imised o he
measu emen o Pu om planche s by A idus-ICP-SFMS.
Solu ion up ake a e 0.1 ml min
21
RF powe 1300 W
Cool gas low a e 16.0 l min
21
Auxilia y gas low a e 0.70 l min
21
Nebulize gas low a e 1.194 l min
21
Ion ex ac ion lens
po en ial
22000 V
Mass esolu ion (m/Dm) 300
Iso ope
237
Np;
238
U;
239
Pu;
240
Pu;
242
Pu
Samples pe peak 100
Se ling ime 10 ms
Sample ime 10 ms
Poin s pe wid h 10
Peak shi 1.0
Mass window 100 %
In eg a ion window 20 %
Scan ype E-Scan
De ec ion mode T iple (ion coun ing,
analogue and Fa aday)
To al analysis ime pe
sample
3 min
Sample /skimme cone Nickel
A idus desol a o Sweep gas (A ): 4.57 ml min
21
Ni ogen low: 6 ml min
21
Nebulize Mic o low nebulize PFA-100
Table 1. Resul s o adiochemical yield o Pu (measu ed by
AS). All he samples we e ini ially spiked wi h 8.4 pg o
242
Pu.
Sample
239
Pu added
( g)
a
242
Pu measu ed
(pg)
Reco e y yield o
242
Pu (%)
1 8 6.49+0.43 78
2 10 6.82+0.58 82
3 10 6.24+0.50 75
4 17 6.74+0.43 81
5 20 6.49+0.70 78
6 26 6.74+0.67 81
7 32 6.24+0.67 75
8 35 8.07+0.80 97
9 40 6.07+0.66 73
a239þ240
Pu measu ed is below he MDA.
H. HERNA
´NDEZ-MENDOZA ET AL.
300

(Table 3). Howe e , i mus be poin ed ou ha , in
he case o AMS measu emen s, he p esence o
millig ams o i on coming om he planche (due o
co osion) can a ec he sensi i i y o he analysis
due o a dilu ion e ec on he sample
(7)
.
The calcula ion o he
239
Pu con en in he ini ial
u ine samples was pe o med by he iso ope dilu ion
me hod, conside ing he
239
Pu/
242
Pu iso opic a io
measu ed by A idus-ICP-SF-MS in he Pu ac ion
leached om he planche s (90 %) and he amoun
o spike ini ially added o he samples; hese esul s
a e shown in Table 3, column wo and he esul s
we e con i med by AMS. The le els o
239
Pu concen-
a ion by bo h me hods no showed signi ican di -
e ence in esul s.
Limi o de ec ion (LOD) and MDA o
239
Pu
using A idus-ICP-SFMS we e calcula ed om he
analysis o a se ies o 10 p ocedu al blanks, and
compa ed wi h hose epo ed in p e ious publica-
ions by AS, AMS and con en ional ICP-SFMS
(Table 4)
(25)
.
The ob ained esul s wi h he new se up a e
abou one o de o magni ude lowe han hose
epo ed by con en ional ICP-SFMS, and compa es
wi h hose ob ained by AMS. LOD o Pu by AS
was calcula ed using he Cu ie c i e ion
(30)
and,
hen, MDA was calcula ed conside ing he LOD, he
a e age chemical yield o Pu (80+7 %) and he
o al olume o u ine (1725+114 ml). In he case o
A idus-ICP-SFMS and AMS, he LOD and AMD
calcula ions we e made as desc ibed in a p e ious
wo k
(7,25)
.
Acco dingly wi h
(8)
, and assuming an acu e in ake
by inhala ion o a ype S subs ance, an exc e ion o
2.3 10
–6
(Bq o Pu/Bq in ake) is p edic ed a he
i s day o he in ake
(13)
. The e o e, conside ing he
MDA le els o Pu epo ed he e (7.410
26
Bq pe
sample o A idus-ICP-SFMS, and 1.010
26
Bq
pe sample o AMS), i can be concluded ha he
me hod de eloped in his pape p o ides enough
sensi i i y o pe o m he eassessmen o planche s
when AS is unable o gi e any in o ma ion du ing
in e nal dosime ic con ols. Minimum de ec able
doses can be hen calcula ed a gi en days a e
Figu e 2. Calib a ion cu es o
239
Pu and
242
Pu measu ed
by A idus-ICP-SFMS.
Figu e 3. Ins umen al s abili y o he A idus-ICP-SFMS,
moni o ed du ing he analyses using
237
Np as ex e nal
s anda d.
Table 3. Reassessmen o
239
Pu on planche s by A idus-
ICP-SFMS and AMS.
Sample A idus-ICP-SFMS AMS
239
Pu ( g)
a 239
Pu ( g)
b 239
Pu ( g)
b
1 5.4+0.9 8.1+1.7 8.2+0.8
2 6.5+0.8 10.1+1.7 9.8+0.6
3 7.2+0.5 10.0+1.2 10.3+0.8
4 13.7+0.7 17.1+1.7 17.4+0.9
5 13.9+0.8 20.0+2.1 19.5+0.9
6 19.3+1.2 27.1+3.0 25.8+1.4
7 22.4+1.2 32.3+3.4 31.6+1.6
8 30.6+1.4 36.1+3.4 34.8+1.3
9 27.6+1.4 40.1+4.0 38.3+1.8
a
Resul ob ained o
239
Pu wi h ex e nal calib a ion by
A idus-ICP-SFMS.
b
Calcula ed mass o
239
Pu used me hod o iso ope dilu ion
me hod, conside ing he
239
Pu/
242
Pu iso opic a io
measu ed.
REASSESSMENT OF
239
PU BY ARIDUS-ICP-SFMS AND AMS
301
in ake om he MDA o he me hod, u ina y exc e-
ion a e (24 h u ine samples) and dose coe icien . I
he u ine is collec ed on he i s day o acu e in ake
o ype S
239
Pu a e an acciden , he minimum de-
ec able dose o he me hod is 0.03 mS o A idus-
ICP-SFMS, and 0.004 mS o AMS. One yea a e
he in ake, he minimum de ec able dose o his
me hod is lowe han 0.5 mS o bo h echniques.
CONCLUSIONS
Di e en analy ical me hods o quan i ying
239
Pu
in u ine wi h MS echniques ha e been op imised
and e alua ed in his pape . The esul s indica e ha
hey a e sui able o dosime ic moni o ing o he
s a occupa ionally exposed o Pu. The analy ical
echniques employed (A idus-ICP-SFMS and AMS)
ha e shown success in hese kinds o con ols, exhi-
bi ing excellen sensi i i y o Pu analysis, and a e-
ma kable inc ease o p oduc i i y when compa ed
wi h AS. This opens he possibili y o gi ing suppo
o he in e nal dosime y se ice o ou ine analysis
in hose cases whe e he Pu con en is below he
MDA achie ed by AS, bo h in u ine samples and in
he eassessmen o planche s.
FUNDING
This wo k was suppo ed by he P ojec Cen o de
In es igaciones Ene ge
´ icas, Medioambien ales y
Tecnolo
´gicas (CIEMAT) 2007/P1423 and wi h cola-
bo a ion he Cen o Nacional de Acele ado es de
Se illa.
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Me hod LOD MDA
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AS 20.2+2.2 51.1+5.2
HR-ICP-MS
a
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REASSESSMENT OF
239
PU BY ARIDUS-ICP-SFMS AND AMS
303