Methods to be Reviewed by OMB in 2016

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1128 Mottier et al. : Journal of AOAC I nternational Vol. 98, No. 4, 2015
Quantification is performed by the isotopic dilution approach
using 13C labeled sodium fluoroacetate as internal standard (IS).
Positive identification of fluoroacetate in samples is
conducted according to the confirmation criteria defined in EU
Commission Decision 2002/657/E
B. Chemicals and Materials
Commercial references are only a guideline. Use equivalent
chemicals or materials when listed items are not locally
available.
(a ) Chemicals.—Before using chemicals, refer to the Sigma-
Aldrich Guide to Chemical Safety
and/or other adequate manuals or safety data sheets approved
by your local authorities and ensure that the safety guidelines
are applied.
(1 ) Water for chromatography.—CAS No. 7732-18-5 (e.g.,
Merck LiChrosolv ® art. 15333; .
(2 ) Acetonitrile, hypergrade for LC-MS.—CAS No. 75-05-8
(e.g., Merck LiChrosolv art. 100029; .
(3 ) n-Hexane.—For gas chromatography; CAS No.
110-54-3 (e.g., Merck SupraSolv® art. 104371; www.chemdat.
info).
(4 ) QuEChERS extraction packets.—10 g, 200 foil packs
per box, each pack containing 4 g magnesium sulfate (MgSO 4)
and 1 g sodium chloride (NaCl). CAS Nos. 7487-88-9 and
7647-14-5 (e.g., Agilent art. 5982-7550; ).
(5 ) Ammonium formate.—LC-MS ultra, eluent additive for
UHPLC-MS. CAS No. 540-69-2 (e.g., Fluka art. 14266; www.
).
(6 ) Sulfuric acid.—Concentrated, w = 95–97%. CAS No.
7664-93-9 (e.g., Merck art. 100731; ).
(7 ) Formic acid.—Concentrated (e.g., Merck art. 100264;
. CAS No. 64-18-6.
(8 ) Sodium fluoroacetate.—CAS No. 62-74-8, w =
99%, 10 µg/mL in water (e.g., Dr. Ehrenstorfer art. DRE-
L13772000AL; ).
(9 ) 13C2 -Sodium fluoroacetate.—w = 99%, isotopic purity
>99.5% (e.g., BDG Synthesis art. 130042-10; ).
(b ) Materials.—
(1 ) Falcon tubes, conical, polypropylene.—50 mL (e.g.,
Becton Dickinson Labware art. 352070; www.bdbiosciences.
com).
(2 ) Falcon tubes, conical, polypropylene.—15 mL
(e.g., Becton Dickinson Labware art. 352097; http://www.
).
(3 ) Centrifuge with rotors adapted for 50 and 15 mL
tubes.—4000 × g, temperature controlled (e.g., Multifuge
Heraeus; .
(4 ) Vortex.—e.g., Millian Genie 2 .
(5 ) Centrifuge with rotor adapted for 2 mL tubes.—17000 × g
(e.g., Heraeus Frisco 17; .
(6) Microcentrifuge tubes, polypropylene.—2 mL (e.g.,
Trefflab art. 9607246901; .
(7) Analytical balance.—With precision range 0.01 mg.
(8) Shaker.—GenoGrinder Model 2010 (www.
).
(9) Evaporator.—e.g., Reacti-Vap Evaporator (art.
TS-18825; .
(c) Special equipment and instrumentation.—Where a
specific model is cited, an alternative may be used if it has the
same characteristics.
(1) HPLC system.—Agilent 1200 SL (www.agilent.
com) coupled to a Sciex 5500 triple stage quadrupole mass
spectrometer equipped with a TurboIonSpray® ionization
source .
(2) HPLC column.—Acquity UPLC BEH Amide, 2.1 ×
100 mm, 1.7 µm (Waters art. 186004801; .
econtamination .—No specific requirement.
C. Preparation of Reagents
Volumes of glassware are purely indicative and may be
modified as long as the proportion of reagents is maintained.
(a) Sodium fluoroacetate stock standard solution, 10 µg/mL
in water .—The stock standard solution is available as ready-
to-use 10 mL solution. Store at room temperature for the time
given in the certificate of analysis.
(b) Sodium fluoroacetate working standard solution,
1.0 µg/mL in acetonitrile–water (9 + 1).—Into a 10 mL
volumetric flask, pipet 1.0 mL of the stock standard solution
10 µg/mL, C(a). Complete to volume with acetonitrile. Store
at –20°C for no longer than 6 months. Allow warming at room
temperature before use.
(c) Sodium fluoroacetate working standard solution,
0.2 µg/mL in acetonitrile.—Into a 10 mL volumetric flask, pipet
2.0 mL of the stock standard solution 1 µg/mL, C(b). Complete
to volume with acetonitrile. Store at –20°C for no longer than
6 months. Allow warming at room temperature before use.
(d) Sodium fluoroacetate working standard solution,
0.05 µg/mL in acetonitrile.—Into a 10 mL volumetric flask,
pipet 2.5 mL of the stock standard solution 0.2 µg/mL, C(c).
Complete to volume with acetonitrile. Store at –20°C for no
longer than 6 months. Allow warming at room temperature
before use.
(e) 13C2-Sodium fluoroacetate (IS) stock standard solution,
1000 µg/mL in water.—Into a 10 mL volumetric flask, weigh
10 ± 0.1 mg of standard. Dissolve and complete to the mark
with water.
Alternatively (to minimize analyst exposure during weighing)
weigh the container containing the analyte first (w1, in mg),
then transfer its whole content into a 10 mL volumetric flask.
Dissolve and complete to mark with water for chromatography.
Weigh again the empty original container once dried (w2, in mg).
Concentration of this solution in µg/mL is 1000 × (w1– w 2)/10.
Store at –20°C for no longer than 6 months. Allow warming at
room temperature before use.
(f) 13C2-Sodium fluoroacetate (IS) working standard solution,
10 µg/mL in acetonitrile.—Into a 10 mL volumetric flask, pipet
100 µL of the stock solution 1000 µg/mL, C(e). Complete to
volume with acetonitrile. Store at –20°C for no longer than
6 months. Allow warming at room temperature before use.
(g) 13C2-Sodium fluoroacetate (IS) working standard
solution, 0.2 µg/mL in acetonitrile.—Into a 50 mL volumetric
Figure 2015.03A. Chemical structure of sodium fluoroacetate
(NaFC2H2O2; CAS No. 62-74-8; MW 100 g/mol).
___________________________________________________________
1
ive, Scientific Business Development,
enior Director, Approv l Processes & AOAC Research Institute,
r Director, Publications,
RNATIONAL
tate is also a naturally occurring poison found in at least 40 plants native in
nd West Africa and Brazil.
gure 1. Chemical structure of sodium fluoroacetate
(NaFC 2H 2 O2 ; CAS 62-74-8; MW 100 g/mol)
ONa
O F
Candidates for 2016 Method of the Year
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