AOAC-RI ERP Book - FAOM METHOD.pdf

M ASTOVSKA ET AL .: J OURNAL OF AOAC I NTERNATIONAL V OL . 98, N O . 2, 2015 487

Table 2014.08D. ( continued )

1R RI laboratories 1R RI UHSOLFDWHV

Mean concn, μg/kg

Mean recovery,

PAH

, μg/kg s R

, μg/kg RSD r

, % RSD R

, % HorRat

% s r

9 9 9 8 9 9 8 9 8 9

18 18 18 16 18 18 16 18 16 18

Naph

Phe

Pyr

( 2 ) Ethyl acetate should not be present in the extract applied WR WKH VLOLFD FDUWULGJH EHFDXVH LW FDQ DIIHFW WKH H[WUDFW SRODULW\ WKXV SRWHQWLDOO\ UHWHQWLRQ RI IDW DQG DQDO\WHV RQ WKH VLOLFD JHO 7KH FRH[WUDFWHG IDW DQG —/ LVRRFWDQH DFW DV NHHSHUV GXULQJ WKH ¿UVW HYDSRUDWLRQ VWHS VWHS 8 ), thus the evaporation should EH FRQGXFWHG JHQWO\ XQWLO WKHUH LV QR VLJQL¿FDQW FKDQJH LQ WKH volume, i.e., until only the isooctane and coextracted fat are left LQ WKH HYDSRUDWLRQ WXEH RU ÀDVN ( 3 $GGLWLRQ RI P/ HWK\O DFHWDWH WR WKH HOXHQW LQ VWHS 13 is recommended for a better control of the evaporation process DQG KLJKHU DEVROXWH UHFRYHULHV RI YRODWLOH 3$+V ( 4 7KH GHDFWLYDWLRQ DQG VWRUDJH RI VLOLFD JHO 63( FDUWULGJHV FDQ YDU\ SRWHQWLDOO\ UHVXOWLQJ LQ GLIIHUHQW DPRXQWV RI ZDWHU LQ the silica, thus its potentially different retention characteristics. 7KHUHIRUH LW LV LPSRUWDQW WR WHVW WKH HOXWLRQ SUR¿OHV RI 3$+V DQG fat and determine the optimum volume of the elution solvent to ensure adequate analyte recoveries and fat cleanup. The IROORZLQJ SURFHGXUH LV UHFRPPHQGHG ( a 3UHSDUH D 3$+ VROXWLRQ LQ KH[DQH E\ FRPELQLQJ —/ RI WKH :RUNLQJ 3$+ 6ROXWLRQ $ DQG P/ KH[DQH LQ D YLDO 0L[ ZHOO DQG DSSO\ RQWR D VLOLFD 63( FROXPQ J VLOLFD JHO ZLWK DSSUR[LPDWHO\ J RI PXIÀHG DQK\GURXV VRGLXP VXOIDWH RQ WKH WRS ZKLFK ZDV FRQGLWLRQHG ZLWK P/ KH[DQH±GLFKORURPHWKDQH Y Y DQG P/ KH[DQH ( b (OXWH ZLWK P/ KH[DQH±GLFKORURPHWKDQH Y Y

DGG —/ RI WKH —J P/ & 3$+V VROXWLRQ DQG —/ LVRRFWDQH &DS WKH YLDO DQG YRUWH[ PL[ EULHÀ\ F. Extraction and Cleanup Procedure ( 1 $GG —/ RI WKH —J P/ & 3$+V VROXWLRQ WR “ J RI WKRURXJKO\ KRPRJHQL]HG VHDIRRG VDPSOH LQ D P/ SRO\SURS\OHQH FHQWULIXJH WXEH ( 2 9RUWH[ VDPSOH IRU V DQG OHW HTXLOLEUDWH IRU PLQ ( 3 $GG P/ P/ LQ WKH FDVH RI VKULPS RI SXUL¿HG ZDWHU DQG P/ HWK\O DFHWDWH ( 4 6KDNH WXEH YLJRURXVO\ E\ KDQG IRU PLQ ( 5 $GG J RI PXIÀHG DQK\GURXV PDJQHVLXP VXOIDWH DQG J VRGLXP FKORULGH DQG VHDO WKH WXEH ZHOO HQVXUH WKDW SRZGHU GRHV QRW JHW LQWR WKH VFUHZ WKUHDGV RU ULP RI WKH WXEH ( 6 6KDNH WXEH YLJRURXVO\ E\ KDQG IRU PLQ HQVXULQJ WKDW FU\VWDOOLQH DJJORPHUDWHV DUH EURNHQ XS VXI¿FLHQWO\ GXULQJ VKDNLQJ ( 7 &HQWULIXJH WXEH DW ! UFI IRU PLQ ( 8 7DNH D P/ DOLTXRW RI WKH XSSHU HWK\O DFHWDWH OD\HU DGG —/ LVRRFWDQH DV D NHHSHU DQG JHQWO\ HYDSRUDWH DOO HWK\O DFHWDWH XQWLO RQO\ LVRRFWDQH DQG FR H[WUDFWHG VDPSOH IDW DUH OHIW ( 9 5HFRQVWLWXWH LQ P/ KH[DQH ( 10 &RQGLWLRQ D VLOLFD 63( FROXPQ J VLOLFD JHO ZLWK DSSUR[LPDWHO\ J RI PXIÀHG DQK\GURXV VRGLXP VXOIDWH RQ WKH WRS ZLWK P/ KH[DQH±GLFKORURPHWKDQH Y Y DQG P/ KH[DQH ( 11 $SSO\ WKH H[WUDFW LQ KH[DQH RQWR WKH VLOLFD 63( FDUWULGJH ( 12 (OXWH ZLWK KH[DQH±GLFKORURPHWKDQH Y Y XVLQJ YROXPH GHWHUPLQHG IRU WKH JLYHQ VLOLFD JHO 63( FDUWULGJHV IURP WKH HOXWLRQ SUR¿OHV RI WDUJHW DQDO\WHV DQG IDW ZKLFK DUH dependent on the silica deactivation, see Note ( 4 EHORZ &ROOHFW the eluent. ( 13 $GG P/ LVRRFWDQH DQG P/ HWK\O DFHWDWH WR WKH HOXHQW DV D NHHSHU DQG JHQWO\ HYDSRUDWH GRZQ WR P/ WR UHPRYH KH[DQH DQG GLFKORURPHWKDQH IURP WKH ¿QDO H[WUDFW ( 14 7UDQVIHU WKH ¿QDO H[WUDFW LQWR DQ DXWRVDPSOHU YLDO IRU WKH *& 06 DQDO\VLV Notes 1 7KH IDW FDSDFLW\ RI WKH J VLOLFD JHO 63( FROXPQ LV DSSUR[LPDWHO\ J ,I WKH P/ HWK\O DFHWDWH H[WUDFW DOLTXRW FRQWDLQV PRUH WKDQ J IDW LW LV QHFHVVDU\ WR XVH D VPDOOHU DOLTXRW YROXPH WR DYRLG VDPSOH EUHDNWKURXJK GXULQJ WKH cleanup step.

10 g of homogenized sample - Add 13 C-PAH mixture, vortex, equilibrate (15 min)

Extraction: - Add 5 mL (or 10 mL) water and 10 mL EtOAc, shake (1 min) - Add 4 g anh. MgSO4 and 2 g NaCl, shake (1 min), centrifuge - Evaporate 5 mL aliquot of extract, reconstitute in 1 mL hexane

Silica-SPE clean-up: - Condition 1g silica with 6 mL hexane:DCM (3:1, v/v ) and 4 mL hexane - Apply sample - Elute with 10 mL of hexane:DCM (3:1, v/v )

GC-MS(/MS) analysis

)LJXUH

$ )ORZ FKDUW RI WKH PHWKRG IRU GHWHUPLQDWLRQ RI

PAHs in seafood using GC/MS.