2. AOACRIChemContMethods-2018Awards

M astovska et al .: J ournal of AOAC I nternational V ol . 98, N o . 2, 2015  481

calculations reviewed by a peer, laboratory supervisor, or manager.

a fume hood. Dispose of solvents and solutions according to federal, state, and local regulations. Always handle open containers of solvents inside the fume hood, including the pouring, mixing, evaporating, and preparing standard solution. Keep containers covered or closed when not in use. Hexane and isooctane .—Highly flammable, liquid irritants. Harmful if inhaled, swallowed, or absorbed through the skin. May also cause skin and eye irritation. Ethyl acetate .—Highly flammable, liquid irritants. Harmful if swallowed in quantity. Vapors may cause drowsiness. Toluene .—Highly flammable, liquid irritant. Harmful if inhaled, swallowed, or absorbed through the skin. May also cause skin and eye irritation. May cause drowsiness. Possible teratogen. Dichloromethane .—Noncombustible, liquid irritant. Harmful if inhaled, swallowed, or absorbed through the skin. May also cause skin and eye irritation. Asphyxiant. Causes central nervous system (CNS) depression. Possible carcinogen and mutagen. PAHs .—Carcinogens, respiratory sensitizers, teratogens, reproductive hazard, mutagens. Harmful if inhaled, swallowed, or absorbed through the skin. May also cause skin and eye irritation. See Tables 2014.08B – D for results of the interlaboratory study supporting acceptance of the method. A. Principle Homogenized seafood samples (10 g sample with a 5 µg/kg addition of 13 C-PAH surrogate mixture) are mixed with 5 mL water (or 10 mL water in the case of shrimp and other more viscous samples) and shaken vigorously by hand with 10 mL ethyl acetate in a 50 mL polypropylene centrifuge tube for 1 min. Subsequently, 4 g anhydrous magnesium sulfate and 2 g sodium chloride are added to the mixture to induce phase separation and force the analytes into the ethyl acetate layer. The tube is again shaken by hand for 1 min and then centrifuged for 10 min at >1500 rcf. A 5 mL aliquot of the ethyl acetate layer is evaporated, reconstituted in 1 mL hexane, and cleaned on an SPE column with 1 g silica gel and approximately 0.2 g anhydrous sodium sulfate on the top. The column is conditioned with 6 mL hexane–dichloromethane (3 + 1, v/v)

Data Analysis

The Study Directors reviewed and compiled all the data submitted by the participants. Statistical analysis was conducted using the AOAC spreadsheet for blind duplicates (4) to determine mean analyte concentrations, SD (S r ) and RSD (RSD r ) for repeatability (for blind duplicate data), SD (S R ) and RSD (RSD R ) for reproducibility, number of valid data points, HorRat value (RSD R /predicted RSD R ), and percentage recovery for all data after removal of outliers (3). The following tests were used in the AOAC spreadsheet (4) to determine outliers: ( a ) the Cochran test for removal of laboratories showing significantly greater variability among replicate (within-laboratory) analyses than the other laboratories for a given material, and ( b ) the Grubbs’ tests for removal of laboratories with extreme averages.

AOAC Official Method 2014.08 Polycyclic Aromatic Hydrocarbons (PAHs) in Seafood Gas Chromatography-Mass Spectrometry First Action 2014

[Applicable for the determination of the following PAHs in mussel, oyster, and shrimp: 1,7-dimethylphenanthrene, 1-methylnaphthalene, 1-methylphenanthrene, 2,6-dimethyl- naphthalene, 3-methylchrysene, anthracene, benz[ a ]anthracene, benzo[ a ]pyrene, benzo[ b ]fluoranthene, benzo[ g,h,i ]perylene, benzo[ k ]fluoranthene, chrysene, dibenz[ a,h ]anthracene, fluoranthene, fluorene, indeno[1,2,3- cd ]pyrene, naphthalene, phenanthrene, and pyrene. These were representative PAH analytes selected for the collaborative study. The method has been single-laboratory validated for 32 PAHs in fish and shrimp (1), and, therefore, is expected to be applicable to other GC-amenable PAHs and seafood matrices. The concentration ranges evaluated within the collaborative study are given in Table 2014.08A .] Caution : See Appendix B: Laboratory Safety . Use appropriate personal protective equipment such as laboratory coat, safety glasses or goggles, appropriate chemical-resistant gloves, and

Table 2014.08A. PAH and 13 C-PAH concentrations in the calibration standard solutions Concentration, µg/L

Equivalent concentration, µg/kg

13 C-PAHs BaP and others Chr and others Naph

13 C-PAHs

BaP and others a

Chr and others b

Naph c

Calibration level

1 2 3 4 5 6 7 8

5

12.5

25 50

50 50 50 50 50 50 50 50

0.5

1.25

2.5

5 5 5 5 5 5 5 5

10 20 50

25 50

1 2 5

2.5

5

100 250 500

5

10 25 50

125 250 500

12.5

100 200 500

10 20 50

25 50

1000 2500 5000

100 250 500

1250 2500

125 250

1000

100

a  Analytes at 10 µg/mL in the mixed stock standard solution. b  Analytes at 25 µg/mL in the mixed stock standard solution. c  Analytes at 50 µg/mL in the mixed stock standard solution.

Made with FlippingBook Annual report