commiss direct juli lai commun method analysi offici control vinyl chlorid monom level materi articl intend contact foodstuff eec commiss european commun regard treati establish european commun regard council direct eec januari approxim law member state relat materi articl vinyl chlorid monom intend contact foodstuff articl thereof articl direct eec lai materi articl vinyl chlorid monom quantiti exceed milligram kilogram final product articl limit control commun analysi method basi seri inter laboratori collabor trial method annex prove suffici accur reproduc adopt commun method measur provid direct accord opinion stand committe foodstuff adopt direct articl member state requir analysi offici control vinyl chlorid monom level materi articl intend contact foodstuff refer annex quot materi articl quot perform method annex articl member state bring forc law regul administr provis compli direct month notif forthwith inform commiss thereof articl direct address member state brussel juli commiss etienn davignon member commiss oj annex determin vinyl chlorid monom level materi articl scope field applic method determin vinyl chlorid monom level materi articl principl level vinyl chlorid monom level vc materi articl determin mean ga chromatographi quot headspac quot method dissolut suspens sampl dimethylacetamid reagent vinyl chlorid vc puriti greater dimethylacetamid dma free impur retent time vc intern standard condit test diethyl ether ci buten dma intern standard solut intern standard impur retent time vc condit test apparatu instrument piec apparatu mention special made specif usual laboratori apparatu assum ga chromatograph fit automat head space sampler facil manual sampl inject flame ioniz detector detector mention point ga chromatograph column column permit separ peak air vc intern standard combin system signal obtain solut mg vc litr dma mg vc kg dma equal time background nois sampl phial flask fit silicon butyl rubber septa manual sampl techniqu take sampl headspac syring partial vacuum form insid phial flask manual techniqu phial pressur sampl larg phial recommend micro syring ga tight syring manual headspac sampl analyt balanc accur mg procedur caution vc hazard substanc ga ambient temperatur prepar solut carri ventil fume cupboard precaut ensur vc dma lost emploi manual sampl techniqu intern standard intern standard solut util procedur prepar concentr standard vc solut approxim mg kg accur weigh nearest mg suitabl glass vessel place quantiti ml dma weigh add dma quantiti vc liquid ga form inject slowli dma vc ad bubbl dma provid devic prevent loss dma weigh nearest mg wait hour equilibrium attain standard solut refriger prepar dilut standard vc solut weigh amount concentr standard solut vc dilut volum weight dma intern standard solut concentr result dilut standard solut express mg mg kg prepar calibr curv curv compris pair point repeat respons lower mg vc kg dma curv calcul point squar techniqu regress line calcul equat gt pic file quot quot gt recommend iso di prepar seri phial add phial volum dilut standard vc solut dma intern standard solut dma final vc concentr duplic solut approxim equal mg mg kg dma phial quantiti dma point seal phial proce point construct graph ordin valu show area height vc peak duplic solut ratio area height relev intern standard peak abscissa valu show vc concentr duplic solut valid prepar standard solut obtain point repeat procedur point obtain dilut standard solut concentr equal mg vc mg kg dma intern standard solut averag ga chromatograph determin solut differ point calibr curv differ greater reject solut obtain point repeat procedur begin prepar sampl materi articl prepar phial weigh phial mg nearest mg sampl obtain singl materi articl investig reduc small piec ensur equal quantiti weigh phial close phial immedi add phial gram sampl ml dma ml intern standard solut seal phial proce point ga chromatograph determin agit phial avoid contact contain liquid septum obtain solut suspens sampl materi articl homogen put seal phial waterbath hour ºc equilibrium attain agit sampl headspac phial util manual sampl techniqu care exercis obtain reproduc sampl point syring pre warm temperatur sampl measur area height peak relat vc intern standard remov column excess dma method peak dma chromatogram calcul result find interpol curv unknown concentr solut sampl take account intern standard solut calcul amount vc sampl materi articl investig appli formula gt pic file quot quot gt concentr vc sampl materi articl express mg kg concentr vc phial sampl materi articl point express mg mg kg volum mass dma phial sampl materi articl point express litr kg amount sampl materi articl express gram concentr vc materi articl investig express mg kg averag concentr vc mg kg determin point provid repeat criterion point satisfi confirm vc level case content vc materi articl calcul point exce maximum permiss amount result obtain analysi sampl confirm wai column stationari phase polar procedur continu chromatogram obtain evid overlap vc intern standard peak constitu sampl materi articl detector micro electrolyt conduct detector mass spectrometri case molecular ion parent mass found ratio regard high probabl confirm presenc vc case doubt total mass spectrum check repeat differ result determin carri simultan rapid success sampl analyst condit exce mg vc kg materi articl journal chromatograph scienc vol march