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1128 

Mottier et al.

: J

ournal of

AOAC I

nternational

Vol. 98, No. 4, 2015

Quantification is performed by the isotopic dilution approach

using

13

C 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

C (1).

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

(www.sigmaaldrich.com)

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;

www.emdmillipore.com)

.

(

2

) 

Acetonitrile, hypergrade for LC-MS

.—CAS No. 75-05-8

(e.g., Merck LiChrosolv art. 100029;

www.chemdat.info)

.

(

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;

www.agilent.com

).

(

5

) 

Ammonium formate

.—LC-MS ultra, eluent additive for

UHPLC-MS. CAS No. 540-69-2 (e.g., Fluka art. 14266; www.

sigmaaldrich.com

).

(

6

) 

Sulfuric acid

.—Concentrated,

w

= 95–97%. CAS No.

7664-93-9 (e.g., Merck art. 100731;

www.merckmillipore.com

).

(

7

) 

Formic acid

.—Concentrated (e.g., Merck art. 100264;

www.chemdat.info)

. 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;

www.lgcstandards.com

).

(

9

) 

13

C

2

-Sodium fluoroacetate

.—

w

= 99%, isotopic purity

>99.5% (e.g., BDG Synthesis art. 130042-10;

http://bdg.co.nz

).

(

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.

bdbiosciences.com

).

(

3

) 

Centrifuge with rotors adapted for 50 and 15 mL

tubes.

—4000 ×

g

, temperature controlled (e.g., Multifuge

Heraeus;

www.thermo.com)

.

(

4

) 

Vortex

.—e.g., Millian Genie 2

(http://www.milian.com)

.

(

5

) 

Centrifuge with rotor adapted for 2 mL tubes

.—17000 ×

g

(e.g., Heraeus Frisco 17;

www.thermoscientific.com)

.

(

6

) 

Microcentrifuge tubes, polypropylene

.—2 mL (e.g.,

Trefflab art. 9607246901;

www.treff-ag.ch)

.

(

7

) 

Analytical balance.—

With precision range 0.01 mg

.

(

8

) 

Shaker

.—GenoGrinder

Model

2010

(www.

spexsampleprep.com

).

(

9

) 

Evaporator

.—e.g.,

Reacti-Vap

Evaporator

(art.

TS-18825;

www.thermo.com)

.

(

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

(www.sciex.com)

.

(

2

) 

HPLC column

.—Acquity UPLC BEH Amide, 2.1 ×

100 mm, 1.7 µm (Waters art. 186004801;

www.waters.com)

.

( d )  Glassware d

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

) 

13

C

2

-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 (w

1

, 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 (w

2

, in mg).

Concentration of this solution in µg/mL is 1000 × (w

1

– w

2

)/10.

Store at –20°C for no longer than 6 months. Allow warming at

room temperature before use.

(

f

) 

13

C

2

-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

) 

13

C

2

-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

(NaFC

2

H

2

O

2

;

CAS No. 62-74-8; MW 100 g/mol).

___________________________________________________________

1

ive, Scientific Business Development,

amishra@aoac.org

enior Director, Approv l Processes & AOAC Research Institute,

dmckenzie@aoac.org

r Director, Publications,

rrathbone@aoac.org

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

2

H

2

O

2

;

CAS 62-74-8; MW 100 g/mol)

ONa

O F

247