Supporting Information for:
Gross Actinide Preconcentration using Phosphonate-Based Ligand and Cloud Point
Extraction
Charles Labrecquea, Julien Légaré Lavergne and Dominic Larivièrea†
1.
a
Laboratoire de radioécologie, Département de chimie, Université Laval,
1045 Avenue de la Médecine, Québec, QC, Canada, G1V 0A6
† To
whom correspondence should be addressed. E-mail:
dominic.lariviere@chm.ulaval.ca
Département de chimie, Faculté des sciences et de génie
Université Laval
1045, avenue de la Médecine, Bureau 1250D
Pavillon Alexandre-Vachon
Québec, Qc, Canada
G1V 0A6
Téléphone: 418-656-7250
Télécopieur : 418-656-7916
E-Mail: dominic.lariviere@chm.ulaval.ca
Content
1.
ICP-MS conditions
S2
2.
Soil Digestion
S3
3.
Fusion Protocol
S4
4.
CPE conditions
S5
5.
Equation Used
S6
6.
Wet ashing
S7
S1
ICP-MS conditions
Table S1: ICP-MS conditions for actinide measurements.
Tune Parameter
Parameter
Value
Parameter
Plasma Parameter
Plasma Mode
Hot
Plasma Gas Flow Rate 15.1 L∙min-1
Auxiliary Gas Flow Rate 0.7 L∙min-1
Makeup Gas Flow Rate 0.44 L∙min-1
RF Power
1500 W
Reflected Power
>5 W
Lenses Parameter (volts)
Extract 1
Extract 2
6.7
-230
Omega Lens
27.2
Q1 Entrance
-3
Q1 Exit
Cell focus
Deflect
2
-1.0
13.8
Value
Cell parameters
Use Gas
False
He flow
0.0 mL∙min-1
N2 flow
0.0 mL∙min-1
O2 flow
0%
NH3 flow
0%
OctP RF
150V
Energy
5.0V
Discrimination
Q1 parameters (volts)
Q1 bias
-8.0
Q1 pre-filter
-44.0
bias
Q1 post-filter
-26.0
bias
S2
Soil digestion
Soil solutions were prepared using fluxer digestion (0.5 g of soil was dissolved in
3.4 g of flux) for soil and sediments; solutions with high amounts of iron (such as
red sludges) used a mix of LiMBO2/LiTBO2 (lithium metaborate and lithium
tetraborate) (0.3 g of red sludge, 1.5 g of LiMBO2 and 1.5 g LiTBO2.The fluxes
were purchased from Corporation Scientifique Claisse and are composed of
ultrapure lithium metaborate : lithium bromide (98.5:1.5) and lithium tetraborate :
lithium bromide (99:1).(Bouchard, M.; Rivard, S. Ness, S. ISO 9516-1 Simplified
Borate Fusion & WDXRF Analytical Method for Iron Ores Analysis Including
Exploration Samples; Technical Report from Corporation Scientifique Claisse:
Quebec, QC, 2013) Lithium bromide was added to ensure that the flux would not
stick to the crucibles.
The protocol used for the fusion was a revised method from the one suggested
by the manufacturer for the M4 Fluxer. (Table S3) but the same fusion
parameters were used regardless of the flux mix used. The parameters used
allowed for completely dissolved environmental samples on which cloud point
extraction was attempted. Pouring of the fused sample into 100 mL 3 M HNO3
solution was preferred; this was found to be the optimal concentration to enhance
the solubility of lithium metaborate and tetraborate and enhance the solubility of
most metals in solution. After dissolution, the samples were clear solutions and
were stable for weeks so did not require further filtration.
Solutions were treated with PEG-6000 to eliminate the silica (Dai, X.; KramerTremblay S. Health Phys. 2011, 101, 144-147.) in solution, which could impact
the analysis by clogging the ICP-MS nebuliser and limit the redispersion of the
surfactant-rich phase containing the analyte.
S3
Fusion Protocol
Table S2 : Fusion Protocol Used for the Dissolution of Environmental Samples.
Function
Steps
Time (min)
Proposed Protocol
0
1
2
3
4
5
6
7
8
Total
Pre-heating
Oxidation
First dissolution
Cooling
Heating
Final dissolution
Cooling
Pouring
Stirring
00:05
00:30
00:30
–
01:00
03:00
00:10
10:00
15:15
S4
CPE conditions
Table S3: Optimised CPE system conditions
1
Parameters
Conditions
Units
Sample
6.5
mL
[HNO3]
0.1-2
M
[TTX-114]
1.07
mmol L-1
[H2DEH[MDP]]1
165
µmol L-1
[CTAB]
100
µmol L-1
[KBr]
10
mmol L-1
[KBrO3]
1,5
mmol L-1
Textraction
4
°C
Tphase separation
20
°C
RCFaverage
4 700
G
Concentration used for liquid samples, For soils a concentration of 825 µM
was used.
S5
Equations used
The following figures of merit of the complete methodology were assessed for the
optimal conditions of the method: minimal detectable activity, pre-concentration
factor, detection limits, and quantification limits. The chemical recovery (CR, %)
and pre-concentration factor (PF) by alpha spectrometry were determined using
the following previously reported equations (Labrecque, C et al. Talanta 2013,
107, 284-291.):
𝐶𝑅 =
𝑃𝐹 =
𝐶𝑆𝑅𝑃
× 100
𝐶𝑠𝑝𝑖𝑘𝑒𝑑
𝐸𝑞. 1
𝐶𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑉𝑖𝑛𝑖𝑡𝑖𝑎𝑙 − 𝐶𝑠𝑢𝑝𝑒𝑟𝑛𝑎𝑡𝑎𝑛𝑡 𝑉𝑠𝑢𝑝𝑒𝑟𝑛𝑎𝑡𝑎𝑛𝑡
𝐸𝑞. 2
𝐶𝑠𝑢𝑝𝑒𝑟𝑛𝑎𝑡𝑎𝑛𝑡 𝑉𝑠𝑢𝑝𝑒𝑟𝑛𝑎𝑡𝑎𝑛𝑡
where CSRP is defined as the activity in the surfactant-rich phase, Csupernatant is
defined as the concentration in the supernatant after the phase separation, and
Vsupernatant and VSRP are the volume of the supernatant phase after the phase
separation and the redispersed surfactant-rich phase, respectively.
In the recovery equation, the Cspiked is the concentration of the analyte that has
been added to the solution. Chemical recovery was used to determine if the
plutonium mass balance was near quantitative and to monitor the analyte
recoveries for the analysis. Chemical recoveries (Eq. 1) are used to directly
measure the quantities in the SRP. This differs from most strategies, which rely
on a differential between the Csupernatant and Cinitial, and are of no interest for the
analysis of real samples. (Pepper, S.E. et al. J. Radioanal. Nucl. Chem. 2009,
282, 909-912; Favre-Reguillon, A. et al. Talanta 2004, 63, 803-806.)
S6
Wet ashing
Wet ashing was used to provide a clean fraction of preconcentrated actinides.
Various techniques of wet ashing were tried and HNO3:H2SO4 (5:1) was found to
be the safest while both HNO3:H2SO4(H2O2) (5:1) and HNO3:HClO4 (5:1) were
found efficient at digesting the SRP.
S7