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한국산업보건학회지, 제26권제1호 (2016) ISSN 2384-132X(Print) ISSN 2289-0564(Online) http://dx.doi.org/10.15269/jksoeh.2016.26.1.20 Original Article GC 를이용한극성용매의분석방법개발연구 오도석 1* ㆍ김성화 1 ㆍ이슬 1 ㆍ황경철 2 1 대한산업보건평가원, 2 동남보건대학교 Study on Development of Analytical Method for Polar Solvents by GC Oh Doe Seok 1* Kim Sung Hwa 1 Lee Seul 1 Hwang Kyung Chul 2 1 Korea Industrial Health Evaluation Co. Ltd. 2 Dongnam Health University ABSTRACT Objectives: The purpose of this study is to simplify and standardize analytical method of polar solvents(methanol, isopropanol, n-butanol, acetone, methylene chloride and MIBK) in the working environmental by GC. Because NIOSH methods are various and complicated. Methods: The method is using the same stationary phase(5% phenyl 95% dimethylpolysiloxane), absorbent(silica gel) and desorption solvent(dmso) for above 6 solvents. For the 6 solvents desorption efficiency, calibration curve, and limit of detection were studied Results: As the results, 6 solvents{2 groups ; first group(methanol/isopropanol/butanol) and second group(acetone/methylene chloride/mibk)} could be separated and quantified within 10 minutes. Desorption efficiency from silica gell of 6 solvents using dimethylsulfoxide(dmso) was methanol 86.2%, isopropanol 103.2%, n-butanol 101.8%, acetone 98.2%, methylene chloride 103.9% and MIBK 106.2% in the range of 0.2, 0.5, 2.0 times of TWA, consequently, satisfied NIOSH estimation level(beyond 75%). Correlation coefficient(r)in the range of 0.2~2.0 times of TWA, was above 0.999 for 6 solvent. LOD(mg/DMSO ml) using calibration curve in the range of 0.2~2 times of TWA was methanol 0.11, isopropyl alcohol 0.20, n-butanol 0.03, acetone 0.50, methylene chloride 0.05, MIBK 0.04 respectably. Conclusions: This method can be used at the sampling and analytical method for polar solvents by GC. Also, will be able to be applied with NIOSH methods. Key words: dimethysulfoxide(dmso), polar solvent, silica gel I. 서론유기용매는다양한물리적성질에의해구분되지만특히극성 (polarity) 에따라무극성 (nonpolar), 약한 (slight) 극성, 적당한 (moderate) 극성, 강한 (strong) 극성으로분류된다. 다양한용매들이작업공정에따라사용되므로작업장의공기중 (airborne) 에는극성에서무극성에이르는다양한용매들이존재한다. 약한극 성및무극성의대부분유기용매들은무극성흡착제인활성탄 (charcoal) 으로채취하여무극성용매인 CS 2 로탈착한후 GC/FID를이용하여분리및정량을한다. 활성탄에흡착된약한극성및무극성용매들의탈착용매로 CS 2 를사용하는것은 GC/FID에서의낮은감도, 짧은머무름시간, 양호한탈착효율때문이다 (Taylor, 1977). 그러나극성인용매에는 CS 2 만을사용하면탈착효율이무극성및약한극성용 *Corresponding author: Oh Doe Seok, Tel. 031-236-3588, E-mail: doesuk@naver.com Korea Industrial Health and Evaluation, 301, 972 Hyohang-ro, Hwasung-si, Gyeonggi-do Received: January 13, 2016, Revised: March 21, 2016, Accepted: March 22, 2016 This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 20

GC 를이용한극성용매의분석방법개발연구 21 매들에비해낮기때문에극성유기용매들을탈착하는용매로는 CS 2 에수 % 정도의극성용매 ( 보조용매 ) 를첨가하여탈착효율을증가시키는방법이나다른극성용매를사용하여탈착효율을높이기위한시도를하였다 (Beck et al., 1990). 또한국내에서도 isobutyl alcohol, n-butyl alcohol, cellosolve acetate, butyl cellosolve, toluene, m-xylene과같은물질을활성탄으로부터탈착하기위하여 CS 2 에 DMF, methanol, pentanol 각각을 1~10% 정도보조용매로가하거나 methylene chloride에 1~10% methanol을넣어탈착효율을개선하기위한연구도보고된바있다 (Son & kim, 1997). 그러나이연구에사용된탈착대상유기용매들도강한극성용매라할수없다. 한편, 미국국립안전보건연구원 (National Institute for Occupational Safety and Health, NIOSH) 분석방법에서는무극성및약한극성의유기용매들 (Group A ; benzene, toluene, o-, m-, p-xylene, ethylbenzene) 을활성탄으로흡착하여, CS 2 로탈착한후 100% PEG(polyethyleneglycol) 정지상을이용하여분리정량을한다. 이물질들에대한머무름시간은대략 3.5~12분정도이다 (NIOSH, 2003). 그러나만약강한극성용매들 (Methanol, isopropanol, n-butanol, acetone, methylene chloride, MIBK) 을 NIOSH 1501 방법에의해분리한다면이론적으로 Group A의물질보다늦게용출되어분석시간이더소요된다. 따라서대부분의작업환경측정기관의실험실에서는무극성및약한극성의방향족탄화수소및그와유사한유기용 매들을분리정량하기위하여 100% PEG 정지상보다덜극성인수 %~ 수십 % 의 phenyl기를함유한 polysiloxane정지상을사용하여 Group A 및그와극성이유사한유기용매들에대해대략 10분내의적당한시간 ( 용량인자, k ; 2<k<10) 에분석을할수있다. 또한, 휘발성유기화합물 (VOC ; C6~C16) 을분리, 정량및확인하기위한컬럼의정지상으로도 100% polysiloxane을사용한 GC/MSD가이용된다. 따라서이러한무극성에서약한극성에이르는용매들을분석하는정지상인 phenyl기를함유한 polysiloxane으로강한극성용매들을분리정량한다면정지상을교체하지않고다양한작업환경중에사용된대표적인강한극성용매들 (Methanol, isopropanol, n-butanol, acetone, methylene chloride, MIBK) 에대해무극성및약한극성에이르는유기용매보다빠른분석시간내에분리및정량을할수있는이점이있다. 위의 6가지극성유기용매별로여러가지흡착제가사용되고, 분석물질과흡착제에따라탈착에도여러가지용매와방법들이혼용되기때문에전처리가번거롭고까다로운면이있다 (NIOSH, 1994)(Table 1). 또한, 지금까지위의여러가지극성용매들에대해단일흡착제를사용하여시료를채취하고, 단일탈착용매를사용하여용매를탈착한연구는보고된바없다. 따라서본연구에서는위의 6 가지의극성용매들을한흡착제를사용하여채취한후한가지용매로탈착용매를단순화하고, 일반적으로사용된정지상 (5% phenyl polysiloxane) 을그대로사용한분석방법 Table 1. Comparison of analytical method for polar solvents Solvent Absorbent Desorption solvent Stationary phase NIOSH method 35% diphenyl-65% dimethyl Methanol Silica gel water/isopropanol(95:5) polysiloxane ; Rtx 2000-35 0.2% Carbowax 1500 on 60/80 Isopropyl alcohol Charcoal 1% 2-butanol in CS 2 1400 Carbopack C n-butyl alcohol Charcoal 5% 2-propanol in CS 2 polyethylene glycol 1405 Acetone, MIBK Charcoal Anasorb CMS * CS 2 stand 30 min CS 2 stand 30 min 10% SP2100 0.1% Carbowax 1500 on Chromosorb WHP 35% diphenyl - 65% dimethylpolysiloxane Ethylene glycol glass fiber filter, 13-mm; XAD-7 methanol; ultrasonicate 30 min Rtx-35 5523 Methylene chloride Charcoal CS 2 Polyethylene glycol 1005 * CMS ; Carbon molecular sieve. 1300 2555 http://www.kiha.kr/

22 오도석ㆍ김성화ㆍ이슬ㆍ황경철 을개발하여위의 6가지극성용매들의분석방법을단순화하고표준화하는데초점을맞추었다. 흡착제로는극성용매들을흡착할수있는극성흡착제인 silica gel을사용하였고, 탈착용매로는유기용매이면서도극성이큰 DMSO(Dimethylsulfoxide) 를선택하였다 (AIHA, 1987). 이를이용하여상기극성용매들에대한흡착제의적합성, 탈착용매의적합성과이에따른탈착효율의검토, GC/FID를이용시상기극성물질들의동시분리정량가능성여부, 노출기준농도의 0.2~2배범위에서의검정곡선의직선성 (linearity) 과검출한계 (limit of detection) 를검토하였다. Ⅱ. 연구대상및방법 1. 대상물질및재료대상물질은극성이강한유기용매이면서작업장에서많이사용되는알코올류 (methanol, isopropyl alchol, n-butanol), 케톤류 (Acetone, MIBK), ethylene glycol 및 methylene chloride를대상으로하였다. 탈착용매로사용된 DMSO(Dimethylsulfoxide) 와상기대상용매들은일반실험실에서사용되는특급시약으로 Junsei 및 JK Baker사의제품을사용하였다. 흡착제인 Silica gel은 SKC(USA) 사제품으로길이 7 cm 유리관, 흡착제량은전단 100 mg, 후단 50 mg이충전된것을사용하였다. 2. 표준용액및탈착시료조제상기 6가지극성용매의표준용액은노출기준 (TLV 및 STEL) 을고려하여공기 10 L를채취하였을때의 0.2~2배범위로조제하였다. 탈착효율에는노출기준의 0.2, 0.5, 2.0배의표준용액을각각실리카겔전단부분을자르고 10 μl마이크로주사기로하나에 2 μl씩주입하여각농도별로 3개씩총 9개를만들어파라필름으로밀봉한후캡을씌워 5 냉장고에하루밤 (12시간) 이상보관한후 2 ml바이알에흡착제전후단 (150 mg) 을빼내넣은후 DMSO 1 ml를가해밀봉한후 60분간실온에서방치하였다. 강력한탈착용매이므로따로방치시간에따른흡착효율은검토하지않았다. 검정곡선의작성은노출기준의 0.2, 0.5, 1.0. 2.0배의표준용액 (ST1~ST4) 을사용하였다. 탈착효율과검정곡선을위한시료조제와분석은일 주일간격으로 2회반복하였다. 3. 기기및분석조건본연구에사용된 GC 및분석조건은다음과같다. Gas chromatograph ; Thermo Finnigan Trace GC, FID detector Column ; HP-5(5% diphenyl-95% dimethylpolysiloxane) OTC(Open tubular column), length 30 m, i.d 0.32 mm, film thickness 0.25 μm Temperature ; Injector 200 Column 45 4min, 15 /min to 180 (gradient) Detector 250 Flow rate ; N2 5 ml /min(make-up 25 ml /min), H2 30 ml /min, Air 300 ml /min Injection volume ; Auto injection 2 μl (Split ratio 100:5) 4. 연구방법 1) 실리카겔의선택활성탄은내부가미세다공성 (microporous) 으로매우큰표면적을가지고있기때문에반응성이크고높은흡착능력을보여지금까지비극성에서약한극성의유기용매를흡착하는대표적인고체흡착제로주로사용되고있다. 그러나이표면의반응성은약한탈착효율을보여머캡탄, 알데히드등과같은반응성화합물의채취에는유용하지않음을의미한다. 그러나실리카겔은대표적인극성고체흡착제지만활성탄보다는덜반응적이다. 실리카겔은구조적으로미세다공성으로큰표면적과더불어 -OH, diol, H 2O를함유하고있는극성성질때문에흡습성이며, 높은습도에서비수용성물질에대해돌파점용량 (breakthrough capacity) 에서의감소를보이는특징이있다. 이런측면에서극성유기용매들의채취에실리카겔이활성탄보다유용할것으로사료된다. 2) 탈착용매 (DMSO) 의선택 Dimethylsulfoxide{DMSO ; (CH 3) 2SO} 는극성과무극성유기화합물을용해하며물뿐만아니라넓은범위의유기용매들과섞이는중요한극성비양성자성 http://www.kiha.kr

GC 를이용한극성용매의분석방법개발연구 23 용매 (Polar aprotic solvent) 로, 이족의다른용매들 {Dimethylformamide ; (CH3) 2NC(O)H, dimethylacetamide ; CH 3C(O)N(CH 3) 2, N-methyl-2-pyrrolidone(NMP), and hexamethylphosphorous triamide ; P(NMe 2) 3} 보다독성이낮으며화학적으로안정하여사용하기가쉽다. DMSO가유기용매임에도불구하고물, 알콜, 아세톤과도잘섞이고유기용매인에테르, 벤젠, 클로르포름등과도완전히혼합하는이유는쌍극자능률 (Dipole moment ; 3.96) 이극성및무극성용매중가장크며, 유전상수 (Dielectric constant ; 47.2) 도다른대표적극성비양자성용매들 (acetone, acetonitrile, tetrahydrofuran, DMF, ethyl acetate, methyl ethyl ketone) 보다크기때문이다 (Table 2). 따라서극성유기용매들을녹기이거나잘섞이는특성을갖고있어강한극성흡착제인실리카겔에흡착된극성유기용매들을어느다른용매보다도잘탈착시킬것으로예측된다. DMSO는물과혼합하면용해능력이약간감소하는경향을나타낸다. DMSO는용해력과세포침투력이높아생화학이나세포생물학에추출물로서폭넓게사용되며, 많은유기화합물들을녹이는용제뿐만아니라진통이나항 염증제같은의약품으로도사용된다. 이외에고분자, 농약, 기계전자, 토목건축등의다양한분야에사용되며, 아직도사용의여지가많아개발의폭이넓은물질중의하나이다. 특히의약용으로스포츠팀과올림픽선수들이고통을없애거나붓는것을줄이고, 헤르페스 ( 포진 ) 의돌발적출현을방지하기위해서도사용되며, 상처나피부치료에도사용한다. 그러나 DMSO와 DMSO에용해된물질은쉽게피부에흡수되기때문에잠재적건강상의위험성도가지고있다, 따라서실험시에는보호장갑을사용하는것이요구된다 (Sadek PC, 1996). 또한, 많은의약품들은물이나아세톤같은다른용매에용해되지않는다. 그러나 DMSO는 -OH를가지지않기때문에약품과반응을잘하지않으면서도강력하게유기물질을용해하는성질이있다. 이러한용매로서의특출한성질을이용하여의약품중의잔류용매를분리및정량할수있다. 합성및발효에의해생산된의약품은유기용매를사용한정제과정과이유기용매를제거하기위한건조과정을거친다. 정제과정에사용된극성용매가최종건조등의과정에서도완전하게제거되지않고완제품에어느정 Table 2. Physical properties for typical organic solvents Poarity Solvent b.p( ) Dipole moment Dielectric constant Density(g/ml) Water 100 1.85 80 0.998 Methanol 68 1.70 33 0.791 Polar protic Ethanol 78 1.69 24.3 0.789 n-propanol 97 1.68 20.1 0.803 n-butanol 118 1.66 17.8 0.810 Formamide 210 3.73 109 1.134 Acetone 56 2.88 20.7 0.786 Tetrahydrofuran 66 1.63 7.52 0.886 Polar aprotic Ethyl acetate 78 1.78 6.02 0.894 Acetonitrile 81 3.92 36.6 0.786 N,N-Dimethylformamide 153 3.82 38.3 0.944 Dimethyl sulfoxide 189 3.96 47.2 1.092 Hexane 69-2.02 0.655 Benzene 80 0 2.28 0.879 Nonpolar Diethyl ether 35 1.15 4.34 0.713 Methylene chloride 40 1.60 9.08 1.326 Carbon tetrachloride 76 0 2.24 1.594 Carbon disulfide 46.3 0 2.64 1.261 http://www.kiha.kr/

24 오도석ㆍ김성화ㆍ이슬ㆍ황경철 도잔류용매로서포함되어있다. 이러한완제의약품에잔류된극성용매는의약품의 3대특성 ( 유효성, 안정성, 안전성 ) 에영향을주어의약품을복용하는환자에게해를끼칠수있으므로, 대략허용한도가정해져있다. 이러한극성잔류용매를분리정량하기위하여합성및발효에의해생산된의약품을완전히용해하여의약품내에잔류용매들 (acetone, butanol, methylene chloride etc.) 을분리정량하는의약품품질관리에도응용된바가있다 (Oh, 1979). 3) 탈착효율비교극성용매들을흡착하기위한흡착제로 NIOSH에서는 silica gel, charcoal, CMS, XAD-7같은다양한흡착제를사용하였다. NIOSH 분석방법에명기된각극성용매의탈착효율은 Table 3에나타내었다. 6가지극성용매에대해사용된실리카겔흡착제와 DMSO 탈착용매에서의탈착효율을 NIOSH 분석방법에의해얻어진탈착효율과비교하였다. 탈착효율평가를위한시료조제는 NIOSH에서정한방법으로각농도별로 3개를조제하여총 9개를조제하였으 며일주일간격으로 2회조제하여총 18개를분석한후평균값을택하였다. 본연구에서탈착효율실험을위한시료는시료주입후파라필름으로감고캡을한기밀상태로시료의손실을우려하여일상적보관방법인냉장고에하루밤 (12시간이상 ) 보관후에사용하였으며, 탈착시간은실온에서한시간방치후정량하였다. 4) 표준용액의조제각용매의검정곡선을작성하기위한검정농도범위는 6가지극성용매들의노출기준 (Table 4) 에따라노출기준의 0.2~2배의범위의양을 micro syringe로취하여미리 DMSO 1 ml를넣은 vial에가한후고무마개를하고알루미늄캡을하여사용하였다. Ⅲ. 결과및고찰 1. DMSO를사용시극성물질들의분리작업환경에서채취된극성용매들의분석방법에전형적으로사용되는방법은 NIOSH의분석방법이다. 극 Table 3. Desorption efficiency for polar solvents Methanol(MeOH) Solvent Desorption efficiency ; Range(av.) Remarks - S59(1975) ; 1.3~6.5 mg, 92~84% methanol - SM,(1996) ; 20~79 μg, 94.2~94.5% NIOSH method 2000 Isopropyl alcohol(ipa) - S56, S65 and S63(1975) ; 103.6%(900~3300 mg/m 3 ), 96.7%(505~1890 mg/m 3 ), 100.3%(165~600 mg/m 3 ) 1400 n-butyl alcohol(buoh) - NIOSH(2002) ; 8~3,040μg/sample), 91% 1405 Acetone(AC) - S1, 127(1994) ; 86% MIBK - S18(1994) ; 91% 1300 Ethylene glycol(eg) - 1996 ; 100 μg, 93.4%, 200 μg, 101% 5523 Methylene chloride(mc) - S329(1998) ; 1.3~5.3 mg, 97% 1005 Table 4. Exposure limit for each polar solvent classification TWA STEL Remarks ppm mg/m 3 ppm mg/m 3 Methanol 200 260 250 310 Isopropyl alcohol 200 480 400 980 1-Butanol C50 C150 - - Acetone 500 1,188 750 1,782 Methylene chloride 50 175 - - MIBK 50 205 75 300 2011, Ministry of employment and labor http://www.kiha.kr

GC 를이용한극성용매의분석방법개발연구 25 성용매로는알코올, 케톤, 글리콜등이대표적이다. NIOSH 방법에서는본연구대상극성용매인 methanol (MeOH), isopropanol(ipa), n-butanol(buoh), acetone (AC), methylisobutylketone(mibk), ethylene glycol (EG), methylene chloride(mc) 에대해흡착제로는 silica gel, charcoal 및 glass fiber filter가사용되고, 탈착용매로는 CS 2, CS 2 와보조용매 (2-Butanol, 2-propanol, water/propanol, methanol) 가사용되었으며, 열린관컬럼 (OTC) 에사용된액상정지상은주로 35% diphenyl- 65% dimethylpolysiloxane과 polyethyleneglycol을사용하여분리정량을한다 (NIOSH, 1994). 유기용매를탈착하는데일반적으로가장많이사용되는 CS 2 는비점이 46.3 로빨리용출되고 GC/FID에서의감도가낮은장점이있으나극성용매들과중첩될가능성이있으며, 극성용매들의탈착효율을증가시키기위해 CS 2 에보조용매로사용되는수 % 의극성용매들 (Isopropanol, 2-butanol etc.) 도작업환경중의목적극성용매들의농도보다높은수준으로중첩될가능성이매우크다. 그러나 DMSO는비점이 189 로극성용매들보다늦게용출되어중첩의우려가없으며, 극성용매들의탈착효율을높이기위한보조용매를전혀사용할필요가없어보조극성용매와목적성분과중첩의우려가전혀없다. 단지높은비점으로늦게용출되는단점이있으나비점이 189 인점을고려할때일반적으로사용되는 polysiloxane 정지상의사용온도가대략 250~350 (Oh, 2012) 이므로온도기울기용리 (Gradient elution) 방법을사용하여최대컬럼온도를 약 200 로설정하면적당한머무름시간에상기 6가지극성용매들을두그룹 {(2 Groups ; first group(methanol /isopropanol /butanol) and second group(acetone/ methylene chloride/mibk)} 으로나누어분리정량할수있으며, 정지상의출혈 (bleeding) 에의한재현성의저하도전혀우려할필요가없다. DMSO를사용한크로마토그램은 Figure 1에보여진다. 6가지극성용매를동일한분석조건으로분석시이웃한두크로마토그램간의분리능 (Rs) 은아래식과같다. 이식에서용량인자 (k) 의적당한값은 2~10 정도이며, 분리인자, α의범위는 1.05 α 2 가적당하다 Rs=( N /4){(α-1)/α}{(k2/(1+k2)} N ; 이론단수 (Number of theoretical plate), α ; 분리인자 (Separation factor) k ; 용량인자 (Capacity factor) (Poole, 2003). CS 2 와 DMSO를용매로사용시각분석조건에서얻어진머무름시간을이용하여계산된분리인자의값은 Table 5, 6과같다. Table 5에서 CS 2 를용매로한머무름시간과 α값을고려하면 CS 2-methanol, acetone-isopropyl alcohol, n-butanol-methylene chloride 만서로머무름시간이유사하고, 분리인자가낮으므로 (α 1.05) 분리에문제가되고, 다른물질들은어느것과혼합하여도분리가양호하다. 따라서 CS 2 를사용하여약한극성에서무극성에이르는시료를분석시에는 acetone-isopropyl alcohol-benzene-mibk-toluene- Figure 1. Chromatogram of CS 2, DMSO, MeOH-IPA-BuOH and AC-MC-MIBK in 5% phenyl 95% dimethylpolysiloxane liquid phase, column length 30 m http://www.kiha.kr/

26 오도석ㆍ김성화ㆍ이슬ㆍ황경철 Table 5. Retention time(tr) and separation factor(α) in CS2 solvent Solvent t R, min α(=t R2/t R1) Methanol(MeOH) 0.873 AC-MeOH, 1.07 IPA-MeOH 1.09 Acetone(AC) 0.932 IPA-AC 1.02 EG-AC 1.12 Isopropyl alcohol(ipa) 0.955 EG-IPA 1.10 MC-IPA 1.46 Ethylene glycol(eg) 1.052 MC-EG 1.38 BuOH-EG 1.35 Methyl chloride(mc) 1.40 BuOH-MC 1.02 - - n-butanol(buoh) 1.425 MIBK-BuOH 1.44 - - MIBK 2.055 DMSO-MIBK 2.95 - - Dimethylsulfoxide(DMSO 6.055 - - - - Table 6. Retention time(tr) and separation factor(α) in DMSO solvent Solvent t R, min α(=t R2/t R1) CS 2(2 peaks) 0.868, 1.082 CS 2-CS 2 1.25 - - Methanol(MeOH) 0.897 MeOH-CS 2 1.03 MeOH-CS 2 1.20 Acetone(AC) 0.988 CS 2-AC 1.10 AC-MeOH 1.10 IPA-AC 1.05 - - Isopropyl alcohol(ipa) 1.034 BuOH-AC 1.40 BuOH-IPA 1.34 n-butanol(buoh) 1.386 MC-BuOH 1.00 Ben-BuOH 1.05 Methylene chloride(mc) 1.386 Ben-MC 1.05 - - Benzene(Ben) 1.45 MIBK-Ben 1.38 - - MIBK 2.003 Tol-MIBK 1.14 - - Toluene(Tol) 2.293 Xyl-Tol 1.86 - - Xylene(Xyl) 4.278 EB-Xyl 1.24 - - Ethylbenzene(EB) 5.288 - - - - Xylene-ethylbebzene을한조로표준용액을조제하면 CS 2 의영향을전혀받지않고서로이웃한물질간의양호한분리능으로약 8분내에분리정량을할수있다. 그러나극성용매들의분리시대상물질의종류에따라 CS 2 와용매들간의상호작용이나컬럼상태등의미세한차이의영향으로 CS 2 의크로마토그램이약간씩달라지므로극성용매의분리에영향을줄수있다. 그렇지만 DMSO로표준용액을제조하여분석시 DMSO의크로마토그램이극성용매의분리에전혀영향을미치지않는다. 다만, acetone, isopropyl alcohol, butanolmethylene chloride의 α값 (Table 5) 이문제가되므로알코올류인 MeOH- IPA-BuOH를한조로하고 AC-MC- MIBK를한조로조제하여동일한분석조건에서분석시양호한분리능과정량이가능할것으로사료된다 (Figure 1). 그러나극성유기용매인 ethylene glycol(eg) 는 GC/FID에서동일분석조건으로분석한결과다른 6가지극성용매보다감도가낮고크로마토그램의폭이넓고 isopropyl alcohol과중첩되는경향을보여일반적극성용매들과동시분석하기에는부적합하였다. 따라서 EG는 NIOSH의 5523분석방법을그대로사용하는것이좋을것으로사료된다. 따라서 EG를제외한 6가지용매에대해 MeOH-IPA-BuOH와 AC-MC- MIBK를각각혼합한표준용액을사용하여동일한분석조건으로분리시양호한분리능과감도로분리정량할수있다. 또한컬럼길이를 50 m 사용시에는분석시간 (t R) 은약 5~8분정도더소요되며이웃한용매간의분리인자 (α=t R2/t R1) 는거의유사하다 (Table 7). 2. 검정곡선및검출한계각용매의검정곡선은노출기준의 0.2~2배의범위로하였고이범위에서검정곡선과상관계수 (r) 는 6가지극성용매에대해 r값이 0.999이상으로직선성이양호 http://www.kiha.kr

GC 를이용한극성용매의분석방법개발연구 27 Table 7. Comparison of retention time and separation factor according to column length Group 1 Group 2 Solvent Retention time and separation factor Column length 30 m Column length 50 m t R, min α(=t R2/t R1) t R, min α(=t R2/t R1) Methanol 0.813-5.517 - IPA 0.955 1.17 6.325 1.14 BuOH 1.425 1.49 7.85 2.41 DMSO 6.055 4.25 11.798 1.50 Acetone 0.932-6.200 - MC 1.40 1.50 6.722 1.08 MIBK 2.055 1.46 10.128 1.50 DMSO 6.055 2.94 11.822 1.16 Table 8. Calibration curve and limit of detection for each solvent Solvent Times of TWA, mg/dmso ml Calibration curve LOD, mg/dmso ml 0.2 0.5 1.0 2.0 y=ax+b r Each Average Methanol 0.5263 1.3157 2.6314 5.2628 1st 2634x+196 0.9992 0.19 2nd 2499x+199 0.9999 0.03 0.11 IPA 0.9105 2.2763 4.5525 9.1051 1st 4006x+443 0.9991 0.34 2nd 3+462802x 0.9999 0.06 0.20 BuOH 0.1337 0.3341 0.6683 1.3365 1st 5320x+92 0.9990 0.04 2nd 4968x+96 0.9999 0.02 0.03 Acetone 2.3582 4.7163 9.4326 18.8652 1st 3350x+2360 0.9978 0.64 2nd 3185x+2418 0.9992 0.35 0.50 MC 0.4408 0.8816 1.7631 3.5263 1st 936x+58 0.9996 0.05 2nd 1082x+16 0.9996 0.05 0.05 MIBK 0.5313 1.0627 2.1253 4.2506 1st 5708x+22 0.9999 0.04 2nd 5168x+11 0.9998 0.04 0.04 하였다. 이에따른검출한계는계산은일차검정곡선 (y=ax+b) 에적용되는 LOD=3σ E/S(σ E ; 표준오차 =σ/n 1/2, S; 검정곡선의기울기 )(Burkart, 1986) 을사용하였고, 검정곡선의표준편차 (σ) 는검정곡선을이용하여잔차를구하고이들잔차의표준편차를이용하였다. 검정곡선은일주일간격으로 2회작성하였다. 6가지용매에대한검출한계평균및범위 (mg/dmso ml) 는 methanol 0.11(0.03~0.19), IPA 0.20(0.06~0.34), BuOH 0.03(0.02~0.04), acetone 0.50(0.35~0.64), MC 0.05 (0.05), MIBK 0.04(0.04) 이었다 (Table 8). 검출한계에대한정의는여러가지표현으로정의되고있지만, 종종만족스럽지못하고오차를일으킬위험이있으므로 분석화학자에게는중요한도전적문제이다 (Oh, 2010). 검출한계의계산법은현재까지도논쟁중에있는사항으로여러가지계산방법이있으므로사용방법에따라조금씩달라질수있다. 3. 탈착효율 NIOSH의분석방법에서정한노출기준의 0.2~2배사이에서의회수율은 75% 이상 (NIOSH, 1994) 으로하고있다. 극성용매들을흡착하기위한흡착제로 NIOSH에서는 silica gel, charcoal, CMS, XAD-7같은다양한흡착제를사용하였다. 본연구에서도매우극성인용매들을흡착하기위하여극성이강한흡 http://www.kiha.kr/

28 오도석ㆍ김성화ㆍ이슬ㆍ황경철 Table 9. Desorption efficiency(d.e) for polar solvents from silica gel using DMSO Solvent Methanol IPA BuOH Acetone MC MIBK Times of TWA & D.E at each conc.(n=3, average) Total D.E(%) 0.2 0.5 2.0 Average(n=9) Average(n=18) Range 1st 86.2 93.8 92.7 90.9 2nd 76.4 76.2 91.5 81.4 86.2 76.2~93.8 1st 112.5 109.6 101.8 108.0 2nd 104.6 88.1 102.5 98.4 103.2 98.4~112.5 1st 108.7 105.6 100.6 105.0 2nd 105.0 89.4 101.7 98.7 101.8 89.4~108.7 1st 79.0 112.9 102.7 98.2 2nd 87.6 107.5 99.6 98.2 98.2 79.0~112.9 1st 88.2 113.2 103.9 101.8 2nd 107.2 110.0 100.9 106.0 103.9 88.2~113.2 1st 98.7 116.9 105.5 107.0 2nd 103.1 108.8 103.9 105.3 106.2 98.7~116.9 착제인 silica gel을사용하여흡착제를단순화하였으며, 탈착용매로는강력한유기용매인 DMSO를사용하여역시단순화하였다. Silica gel과 DMSO를사용한탈착효율이 NIOSH의분석방법개발과평가수준인 75% 를만족하는지를검토한결과 6가지용매에대한탈착효율의평균및범위는 methanol 86.2(76.2~93.8)%, IPA 103.2(98.4~112.5)%, BuOH 101.8(89.4~108.7)%, acetone 98.2(79.0~112.9)%, MC 103.9(88.2~113.2)%, MIBK 106.2(98.7~116.9)% 이였다 (Table 9). 일반적으로정도관리용탈착효율실험을위한시료는유기용매에대해활성탄관을밀봉하여보관하므로실온에보관하여도시료의손실이없지만본연구에서탈착효율실험을위한시료는밀봉상태가아닌기밀상태 ( 시료주입후파라필름으로감고캡을함 ) 로시료의손실을우려하여일상적보관방법인냉장고에하루밤보관후에사용하였으며, 탈착시간은실온에서한시간방치후정량하였다. Ⅳ. 결론작업환경중의극성용매 (methanol, isopropyl alcohol, n-butanol, acetone, methylene chloride and methylisobutylketone) 의분리정량을위해흡착제, 탈착용매, GC 컬럼을단순화및표준화한결과는다음과같다. 1. 열린관컬럼 (OTC) HP-5(5% phenyl 95% dimethylpolysiloxane), 30 m를사용하여강한극성용매 6가지를한컬럼에서 10분내로분리정량할수있도록컬럼을일원화하였다. 컬럼길이 50 m를사용시분석시간은약5~8분정도더소요되나분리능은전체적으로더좋아진다. 2. 극성용매 6가지를흡착하기위하여흡착제를 silica gel로단순화하였다. 3. 탈착용매를 DMSO로일원화하였으며, 6가지용매는 1그룹용매 (methanol/ipa/n-butanol) 와 2그룹용매 (acetone/methylene chloride/mibk) 로구분하여분석하였다. 4. 탈착효율은노출기준의 0.2, 0.5, 2배범위에서 NIOSH기준 (75%) 을만족하며, 각용매의탈착효율은 methanol 86.2%, IPA 103.2%, BuOH 101.8%, acetone 98.2%, methylene chloride 103.9%, MIBK 106.2% 이였다. 5. 검정곡선은 6가지용매의노출기준 0.2~2배사이에서상관계수 r은 methanol, IPA, BuOH, acetone, methylene chloride, MIBK 모두 0.999이상의상관관계를보였으며, 검출한계는 (mg/dmso ml) methanol 0.11, IPA 0.20 BuOH 0.03, acetone 0.50, methylene chloride 0.05, MIBK 0.04이였다. 따라서상기개발된분석방법으로작업환경중의극성용매들을분리및정량할수있으며, NIOSH방법과더불어활용될수있을것으로사료된다. http://www.kiha.kr

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