Development of Analytical Method of Polycyclic Aromatic Hydrocarbons Deposited on Tree Leaves by GC/MS

GC-MS 에 의한 나뭇잎에 침착된 다환방향족 탄화수소의 분석

A new effective and economic method was developed, removing interferences such as chlorophyll and lipid from leaves with small amounts of reagents and solvents in order to analyse PAHs(Polycyclic Aromatic Hydrocarbons). The extract from a soxhlet containing $4{\sim}5g$ of leaves and 100ml of dichlormethane and refluxed for 20 hrs was concentrated and eluted with 60ml of a hexane:dichloromethane (1:1) mixture through a column of 9mm wide inner diameter and 130mm long, packed from the bottom with 2.5g of $Al_2O_3$, 1.5g of $SiO_2$and 2g of anhydrous $Na_2SO_4$. The eluent was concentrated and loaded on a GPC column of 20mm wide inner diameter and 280mm long, packed with 12g of Bio-beads. The column was washed with 37ml of the hexane:dichloromethane(1:1) mixture. Another 43ml of the mixture was eluted as a PAH fraction and collected. This eluent was concentrated under gentle nitrogen to $50{\mu}l$ and analysed using GC-MS. The recoveries, obtained by comparing with the amounts of the internal standards of deuterated PAHs were $43.3{\sim}107.5%$(RSD $2.2{\sim}9.5%$).

나뭇잎에 침착된 PAHs를 분석할 때 기존의 방법들 보다 더 적은 양의 시약과 용매를 사용하여 효율적이고 경제적으로 방해물질을 제거하는 방법을 개발하였으며, 방법은 아래와 같다. 1) 시료 $4{\sim}5g$ DCM 100ml로 속슬렛에서 20시간 추출하고 약 3ml까지 농축한다. 2) 내경 9mm, 길이 130mm column에 아래로부터 $Al_2O_3$2.5g, $SiO_2$1.5g, 무수 Na$_2SO_4$ 2g을 충전시키고 hexane : DCM(1:1) 60ml로 용출한 후 1ml까지 농축한다. 3) 내경 20mm, 길이 200mm column에 Bio-beads 12g을 충전시킨 gPC(gel Permeation Chromatography) column을 사용하여 hexane:DCM(1:1) 80ml로 다시 clean-up 한다. 용출액중 처음 37ml는 방해물질이 포함되어 있으므로 버리고 나머지 43ml는 PAHs fraction이므로 포집하여 약 2ml까지 농축한다. 4) Hot plate위에서 질소로 천천히 final volume $50{\mu}l$까지 농축하여 GC-MS로 분석한다. 5) Deuterated PAHs로 계산한 회수율은 $43.3{\sim}107.5%$(RSD $2.2{\sim}9.5%$)였다.