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M

astovska

et al

.:

J

ournal of

AOAC I

nternational

V

ol

.

98, N

o

. 2, 2015 

477

Received December 16, 2014.

The method was approved by the Expert Review Panel for

Polycyclic Aromatic Hydrocarbons (PAHs) as First Action.

The Expert Review Panel for Polycyclic Aromatic Hydrocarbons

(PAHs) invites method users to provide feedback on the First

Action methods. Feedback from method users will help verify that

the methods are fit for purpose and are critical to gaining global

recognition and acceptance of the methods. Comments can be sent

directly to the corresponding author or

methodfeedback@aoac.org.

Corresponding author’s e-mail:

katerina.mastovska@covance.com

DOI: 10.5740/jaoacint.15-032

RESIDUES AND TRACE ELEMENTS

A collaborative study was conducted to determine

selected polycyclic aromatic hydrocarbons (PAHs)

and their relevant alkyl homologs in seafood

matrixes using a fast sample preparation method

followed by analysis with GC/MS. The sample

preparation method involves addition of

13

C-PAH

surrogate mixture to homogenized samples and

extraction by shaking with a water–ethyl acetate

mixture. After phase separation induced by addition

of anhydrous magnesium sulfate–sodium chloride

(2 + 1, w/w) and centrifugation, an aliquot of the

ethyl acetate layer is evaporated, reconstituted in

hexane, and cleaned up using silica gel SPE. The

analytes are eluted with hexane–dichloromethane

(3 + 1, v/v

),

the clean extract is carefully evaporated,

reconstituted in isooctane, and analyzed by GC/MS.

To allow for the use of various GC/MS instruments,

GC columns, silica SPE cartridges, and evaporation

techniques and equipment, performance-based

criteria were developed and implemented in the

qualification phase of the collaborative study.

These criteria helped laboratories optimize their

GC/MS, SPE cleanup, and evaporation conditions;

check and eliminate potential PAH contamination

in their reagent blanks; and become familiar with

the method procedure. Ten laboratories from five

countries qualified and completed the collaborative

study, which was conducted on three seafood

matrixes (mussel, oyster, and shrimp) fortified with

19 selected PAH analytes at five different levels of

benzo[

a

]pyrene (BaP) ranging from 2 to 50 µg/kg.

Each matrix had a varying mixture of three different

BaP levels. The other studied PAHs were at varying

levels from 2 to 250 µg/kg to mimic typical PAH

patterns. The fortified analytes in three matrixes were

analyzed as blind duplicates at each level of BaP and

corresponding other PAH levels. In addition, a blank

with no added PAHs for each matrix was analyzed

singly. Eight to 10 valid results were obtained for

the majority of determinations. Mean recoveries of

all tested analytes at the five different concentration

levels were all in the range of 70–120%: 83.8–115%

in shrimp, 77.3–107% in mussel, and 71.6–94.6% in

oyster, except for a slightly lower mean recovery

of 68.6% for benzo[

a

]anthracene fortified at

25 µg/kg in oyster (RSD

r

: 5.84%, RSD

R

: 21.1%) and

lower mean recoveries for anthracene (Ant) and BaP

in oyster at all three fortification levels (50.3–56.5%

and 48.2–49.7%, respectively). The lower mean

recoveries of Ant and BaP were linked to degradation

of these analytes in oyster samples stored at –20°C,

which also resulted in lower reproducibility (RSD

R

values in the range of 44.5–64.7% for Ant and

40.6–43.5% for BaP). However, the repeatability was

good (RSD

r

of 8.78–9.96% for Ant and 6.43–11.9%

for BaP), and the HorRat values were acceptable

(1.56–1.94 for Ant and 1.10–1.45 for BaP). In all other

cases, repeatability, reproducibility, and HorRat

values were as follows: shrimp: RSD

r

1.40–26.9%,

RSD

R

5.41–29.4%, HorRat: 0.22–1.34; mussel: RSD

r

2.52–17.1%, RSD

R

4.19–32.5%, HorRat: 0.17–1.13;

and oyster: RSD

r

3.12–22.7%, RSD

R

8.41–31.8%,

HorRat: 0.34–1.39. The results demonstrate that

the method is fit-for-purpose to determine PAHs

and their alkyl homologs in seafood samples. The

method was approved by the Expert Review Panel

on PAHs as the AOAC Official First Action Method

2014.08.

A

s a response to the 2010 oil spill in the Gulf of Mexico,

AOAC INTERNATIONAL formed the Stakeholder

Panel on Seafood Contaminants (SPSC) and later

issued a call for methods for determination of polycyclic

Determination of Polycyclic Aromatic Hydrocarbons (PAHs)

in Seafood Using Gas Chromatography-Mass Spectrometry:

Collaborative Study

K

aterina

M

astovska

and

W

endy

R. S

orenson

Covance Laboratories Inc., Nutritional Chemistry and Food Safety, 3301 Kinsman Blvd, Madison, WI 53704

J

ana

H

ajslova

Institute of Chemical Technology, Faculty of Food and Biochemical Technology, Department of Food Chemistry and Analysis,

Technická 3, 166 28 Prague 6, Czech Republic

Collaborators: J. Betzand; J. Binkley; K. Bousova; J.M. Cook; L. Drabova; W. Hammack; J. Jabusch; K. Keide; R. Lizak;

P. Lopez-Sanchez; M. Misunis; K. Mittendorf; R. Perez; S. Perez; S. Pugh; J. Pulkrabova; J. Rosmus; J. Schmitz; D. Staples;

J. Stepp; B. Taffe; J. Wang; T, Wenzl