254 / 258
Reddy:
J
ournal of
AOAC I
nternational
V
ol.
98, N
o
. 4, 2015
1135
OFFICIAL METHODS
[Applicable
for
quantitative
determination
of
monofluoroacetate (MFA) in powdered nutritional product.]
Caution
: Monofluoroacetate is highly toxic and volatile below
pH 4. Acetonitrile, ethyl acetate, and pyridine are
toxic and flammable. Hydrochloric acid is toxic and
corrosive.
A. Principle
The method incorporates certain elements from refs (1)
and (2). Samples are prepared by dilution in water followed
by protein precipitation with acetonitrile. An aliquot of the
sample extract is derivatized with 2-nitrophenylhydrazine (2-
NPH) in the presence of 1-ethyl-3-(-3-dimethylaminopropyl)
carbodiimide hydrochloride (EDC). This reaction achieves the
coupling of the carboxyl group of monofluoroacetate to the
amino group of 2-NPH with the formation of an amide bond.
Samples are processed through a solid-phase extraction (SPE)
step in order to exchange sample solvent and achieve a 5-fold
concentration of the extract. A stable-isotope labeled internal
standard is incorporated into the sample preparation to correct for
instrument response and losses in sample preparation. Analysis
is performed by ultra-high pressure liquid chromatography
(UPLC) coupled to tandem quadrupole mass spectrometry (MS/
MS). The MS/MS system is configured to monitor one parent-
daughter (precursor-fragment) ion pair for the analyte and
internal standard, respectively (
see
Figure
2015.04A
).
B. Apparatus
(
a
)
Balance
.—Analytical.
(
b
)
Balance.—
Micro-analytical.
(
c
)
Beakers
.—Various sizes.
(
d
)
Glass bottles
.—100 and 500 mL.
(
e
)
Graduated cylinders
.—10 and 100 mL.
(
f
)
Flasks, volumetric, glass
.—Class A; 10, 25, and 100 mL.
(
g
)
Vortex mixer
.—Vortex-Genie (Cole-Parmer,
http://www. coleparmer.ca), or equivalent.
Determination of Monofluoroacetate in Powdered
Nutritional Products by Derivatization with
2-Nitrophenylhydrazine and LC-MS/MS: First Action
2015.04
Murali Reddy
Abbott Laboratories, 3300 Stelzer Rd, Columbus, OH 43219
Submitted for publication March 2015.
Adopted as a First Action Official Method by the Expert Review
Panel on Sodium Fluoroacetate and approved by the Stakeholder Panel
on Infant Formula and Adult Nutritionals (SPIFAN).
Approved on: March 16, 2015.
DOI: 10.5740/jaoac.int.2015.04
Stakeholder Panel on Infant Formula and
Adult Nutritionals
Expert Review Panel for Working Group for
Sodium Fluoroacetate
Darryl Sullivan (Chair)
, Covance
Martin Alewijn
, RIKILT
John Austad
, Covance
Joe Boison
, CFIA/Univ of Saskatoon
Scott Christiansen
, Perrigo
Jo Marie Cook
, Florida State Dept of Agriculture
Jon DeVries
, Medallion Labs/General Mills
Harvey Indyk
, Fonterra
George Joseph
, AsureQuality
Erik Konings
, Nestle
Alex Krynitsky
, U.S. Food and Drug Administration
Tom Phillips
,Maryland State Dept of Agriculture
Bert Popping
, Merieux NutriSciences
Murali Reddy
, Abbott
John Wong
, U.S. Food and Drug Administration
Figure 2015.04A. Monofluoroacetate C
2
H
2
FO
2
, MW =
77.03, CAS No. 62-74-8.
254