Method Submissions-5th Set of Nutrients_6-30-14 - page 103

FOODCOMPOSITIONANDADDITIVES
Improvement ofAOACOfficialMethod984.27 for the
DeterminationofNineNutritionalElements inFoodProductsby
InductivelyCoupledPlasma-AtomicEmissionSpectroscopyAfter
MicrowaveDigestion:Single-LaboratoryValidationandRingTrial
ERIC POITEVIN,MARINE NICOLAS , LAETITIA GRAVELEAU , JANIQUE RICHOZ,DANIEL ANDREY , andFLORENCE M ONARD
NestléResearchCenter, Vers-Chez-Les-Blanc, CH-1000Lausanne 26, Switzerland
Collaborators:A. Abrahamson; A. Baillon; J. Barrios; S. Berger; R. Berrocal; R. Bos; L. Brullebaut; C. Caseiro; L.F. Choo;
G. Cole; G. Daix; C. Dekussche;G.-S. Dhillon; A. Fortineau; C. Gaudin;M.J. Gonzales; R. Leal; R.O.Mabiog; T. Noorlos;
R. Reba; C. Senechal
Asingle-laboratoryvalidation (SLV) anda ring trial
(RT)wereundertaken todetermineninenutritional
elements in foodproductsby inductivelycoupled
plasma-atomicemissionspectroscopy inorder to
improveandupdateAOACOfficialMethod984.27.
The improvements involvedoptimizedmicrowave
digestion, selectedanalytical lines, internal
standardization, and ionbuffering. Simultaneous
determinationof nineelements (calcium, copper,
iron, potassium,magnesium,manganese, sodium,
phosphorus, andzinc)wasmade in foodproducts.
Sampledigestionwasperformed throughwet
digestionof foodsamplesbymicrowave
technologywitheither closedor openvessel
systems. Validationwasperformed tocharacterize
themethod for selectivity, sensitivity, linearity,
accuracy, precision, recovery, ruggedness, and
uncertainty. The robustnessandefficiencyof this
methodwasproved throughasuccessful internal
RTusingexperienced food industry laboratories.
Performancecharacteristicsare reported for
13certifiedand in-house referencematerials,
populating theAOACtriangle foodsectors,which
fulfilledAOACcriteriaand recommendations for
accuracy (trueness, recovery, and z-scores) and
precision (repeatabilityand reproducibilityRSD
andHorRat values) regardingSLVandRT. This
multielementalmethod iscost-efficient,
time-saving, accurate, and fit-for-purpose
according to ISO17025NormandAOAC
acceptabilitycriteria, and isproposedasan
improvedversionofAOACOfficialMethod984.27
for fortified foodproducts, including infant
formula.
Robust and efficient methods with well-characterized
reference materials are needed by food-testing and
nutrition laboratories to facilitate compliance with
nutritional labeling laws and claim requirements, to provide
traceability for food exports needed for acceptance inmany
foreign markets, and to improve the accuracy of nutrition
information that is provided to assist consumers in making
sound dietary choices (1, 2). Inductively coupled plasma-
atomic emission spectroscopy (ICP-AES) is one of themost
commonly used techniques within the food industry for
accurate and cost-efficient routine analyses of nutritional
minerals infoodproducts, plants, pet food, rawmaterials, and
feeding stuffs (3–15).
AOACMethod 984.27 was validated 25 years ago via a
collaborative study in which acid digestion with
HNO3/HClO4 and ICP-AES analysis with radial grating
configuration were used to determine nine nutritional
minerals in infant formula (16). Standard procedures for the
decompositionof food samples usually involvedry-ashing in
a muffle furnace or wet digestion with combined
acids (6, 10, 17). Compared to the classical digestion
procedures, microwave digestion has some significant
advantages with respect to speed of analysis, analyte loss,
sample contamination, and safe acid handling during sample
preparation (8). The use of microwave digestion before
ICP-AES analysis provides an accurate method for the
determination of nutritional minerals targeted for labeling of
foodproducts (5).
The objective of this study is to improve AOACMethod
984.27 in terms of sample preparation time and throughput
usingmicrowavedigestion, andanalytical performanceusing
the latest generation of ICP-AES equipment under robust
conditions (18), internal standardization (19, 20), and ion
buffer (21) tocorrect for physical andchemical interferences,
to compensate for matrix effects (22–25) induced by the
complexity of the food samples, and to improve short-term
accuracy(repeatability)andlong-termstability(reproducibility
and calibration curve validity in a long analysis batch.
1484 POITEVINETAL.: JOURNALOF AOACI NTERNATIONAL VOL. 92,NO. 5, 2009
ReceivedApril 30, 2009.AcceptedbySGJune19, 2009.
Correspondingauthor’s e-mail:eric.poitevin@rdls.nestle.com
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