commiss direct juli relat commun method analysi determin eruc acid content oil fat intend human consumpt foodstuff ad oil fat eec commiss european commun regard treati establish european econom commun regard council direct eec juli relat fix maximum level eruc acid oil fat intend human consumpt foodstuff ad oil fat articl thereof articl direct eec juli eruc acid content product refer articl direct calcul total level fatti acid fat compon greater articl direct eec eruc acid content determin commun method analysi regul eec septemb draw reduct sampl determin oil content impur moistur oil seed lai annex vi introduc regul eec method analysi determin eruc acid content colza rape seed method screen method constitu fatti acid oil fat analyz ga liquid chromatographi normal condit distinguish eruc acid isom docoseno acid cetol acid determin level eruc acid oil fat foodstuff oil fat ad cetol acid isom docoseno acid level eruc acid determin oil fat foodstuff oil fat ad screen analysi method found total docoseno acid ci docoseno acid pend introduct improv method analysi determin eruc acid method analysi consid suitabl present measur provid direct accord opinion stand committe foodstuff adopt direct articl member state requir analysi determin eruc acid content product refer articl direct eec carri laid articl articl screen purpos determin total docoseno acid content product refer articl method set annex vi regul eec total ci docoseno acid content product refer articl method set annex vi regul eec ga liquid chromatographi condit ci tran isom docoseno acid separ stationari phase suitabl purpos cyanopropylpolysiloxan liquid crystal total content docoseno acid determin paragraph ci docoseno acid determin paragraph oj oj oj product refer articl calcul total fatti acid content fat compon exce determin requir eruc acid content determin method set annex hereto articl member state bring forc law regul administr provis compli direct februari forthwith inform commiss thereof articl direct address member state brussel juli commiss étienn davignon member commiss annex determin eruc acid content oil fat intend human consumpt fat oil compon foodstuff oil fat ad introduct sampl prepar gener mass sampl present laboratori analysi larger quantiti requir prepar sampl analysi laboratori sampl homogen analyz contain sampl prepar store air tight moistur tight contain reagent water water requir solvent diluent wash distil water deminer water equival puriti quot solut quot quot dilut quot mention reagent aqueou solut dilut meant chemic chemic recogn analyt qualiti apparatu list apparatu list item special specif analyt balanc quot analyt balanc quot mean balanc sensit mg express result result result refer offici analysi report obtain determin repeat satisfactori calcul percentag state result express percentag total fatti acid sampl receiv laboratori number signific figur number signific figur result express govern precis method ii determin eruc acid scope field applic method determin eruc acid content oil fat cetol acid ci isom docoseno acid occur fish oil ii hydrogen oil fat tran ci isom docoseno acid definit eruc acid content content eruc acid determin method principl methyl ester compon fatti acid oil fat separ low temperatur argent thin layer chromatographi quantit determin ga liquid chromatographi reagent diethyl ether peroxid free freshli distil hexan silica gel thin layer chromatographi silica gel column chromatographi silver nitrat solut litr dissolv silver nitrat water make ml water methyl eruc solut mg ml dissolv mg methyl eruc ml hexan dilut ml hexan methyl tetracosano intern standard solut mg ml dissolv mg methyl tetracosano ml hexan dilut ml hexan develop solvent toluen hexan dichlorofluorescein solut litr dissolv warm stir mg dichlorofluorescein ml aqueou methanol apparatu apparatu thin layer chromatographi includ deep freez unit capabl maintain develop tank content temperatur minu minu ºc glass plate mm ultra violet lamp glass column length mm intern diamet mm filter glass wool sinter glass altern small funnel sinter glass filter applic deposit solut form narrow band streak tlc plate ga liquid chromatograph electron integr section iii annex vi commiss regul eec procedur prepar fatti acid methyl ester mg oil fat compon sampl analysi prepar solut mg ml fatti acid methyl ester hexan method section ii annex vi commiss regul eec thin layer chromatographi prepar plate place silica gel ml round bottom flask add ml silver nitrat solut shake minut obtain fulli homogen slurri spread slurri usual manner plate thick layer approxim mm quantiti slurri suffici prepar mm plate plate partial air dry prefer leav dark minut fulli dry activ plate place oven maintain ºc hour minut plate activ carefulli store dark cabinet reactiv note activ ºc hour found satisfactori provid plate darken result score line coat mm side top plate reduc edg effect develop applic methyl ester applic deposit solut methyl ester prepar sampl narrow streak mm long mm side plate mm bottom appli similar solut equal volum prepar solut methyl ester methyl eruc solut care applic solut fragil natur coat note desir methyl eruc solut appli plate assist identifi methyl eruc band develop figur applic methyl ester stand bottom edg plate diethyl ether ether ascend mm area sampl applic concentr methyl ester narrow band develop plate pour develop solvent tank depth mm place tank complet lid deep freez cabinet held minu ºc temperatur case advantag line tank hour place plate carefulli tank solvent ascend half third height plate remov plate gentli evapor solvent nitrogen stream replac plate tank solvent ascend top plate remov plate previous dry nitrogen stream sprai carefulli dichlorofluorescein solut view plate ultra violet light locat band methyl eruc sampl refer intensifi band sampl methyl eruc ad figur separ methyl ester fraction scrape methyl eruc band deriv sampl ml beaker take care avoid loss similarli transfer silica gel locat methyl eruc band ml beaker band fatti acid methyl ester fraction add ml methyl tetracosano standard solut ml diethyl ether beaker stir transfer content beaker separ column funnel silica gel elut methyl ester ml portion diethyl ether collect filtrat small flask evapor filtrat small volum gentl nitrogen stream transfer methyl ester small point bottom glass tube remov solvent evapor nitrogen stream methyl ester concentr bottom tube dissolv methyl ester hexan ga liquid chromatographi carri procedur section iii annex vi commiss regul eec analyz methyl ester solut obtain fraction methyl eruc ii fraction remaind methyl fatti acid obtain electron integr peak area chromatogram fraction methyl eruc methyl eruc intern standard total methyl ester peak area exclud intern standard ef ii chromatogram fraction remaind te fatti acid methyl ester total methyl ester peak area exclud intern standard rf intern standard express result method calcul formula eruc acid content sampl express term methyl ester percentag total fatti acid methyl ester prepar sampl gt pic file quot quot gt ef rf peak area refer correct calibr factor practic purpos methyl eruc formula equival level eruc acid express percentag total level fatti acid sampl peak area obtain percentag valu ef rf calcul ef rf method calcul assum level tetracosano acid sampl neglig signific amount acid shown present tetracosano acid obtain chromatogram fraction remaind fatti acid methyl ester reduc gt pic file quot quot gt peak area methyl tetracosano deriv sampl form part peak area attribut intern standard chromatogram remain fraction fatti acid methyl ester peak area methyl palmit obtain chromatogram remain fraction peak area methyl tetracosano obtain chromatogram methyl ester total fatti acid determin analysi refer articl direct peak area methyl palmit obtain chromatogram methyl ester total fatti acid determin analysi refer articl direct deriv formula proport fatti acid fraction methyl eruc express percentag total fatti acid sampl gt pic file quot quot gt repeat differ valu determin carri simultan rapid success sampl analyst condit exce result sampl take greater figur typic thin layer chromatogram show separ methyl ester eruc acid cetol acid tran isom docoseno acid gt pic file quot quot gt