何迎春,王正虹,李 林,*,周倩如
(1.西南大學(xué)食品科學(xué)學(xué)院,重慶 400716;2.重慶市疾病預(yù)防控制中心,重慶 400042)
固相萃取/固相微萃取-氣相色譜法測定飲用水中多溴聯(lián)苯醚
何迎春1,王正虹2,李 林1,*,周倩如2
(1.西南大學(xué)食品科學(xué)學(xué)院,重慶 400716;2.重慶市疾病預(yù)防控制中心,重慶 400042)
目的:建立固相萃取/固相微萃取-氣相色譜法測定飲用水中多溴聯(lián)苯醚(BDE-47和BDE-99)含量的新方法。方法:固相萃取-氣相色譜直接取水樣100mL,過LC-C18柱,經(jīng)正己烷洗脫,洗脫液于80℃水浴揮干,異辛烷定容至1mL,直接進(jìn)樣1μL測定,該法對BDE-47和BDE-99的檢出限分別為0.0008μg/L和0.0009μg/L,回歸方程相關(guān)系數(shù)分別為0.9996和0.9997,RSD(n=6)分別為1.0%~4.9%和0.96%~4.4%;固相微萃取-氣相色譜直接取水樣10mL置于15mL固相微萃取瓶中,于40℃條件下固相微萃取吸附25min后,纖維頭經(jīng)風(fēng)干,立即進(jìn)樣測定。該法對BDE-47和BDE-99的檢出限分別為0.0000μg/L和0.0044μg/L,回歸方程相關(guān)系數(shù)分別為0.9996和0.9992,RSD (n=6)分別為6.7%~11.4%和6.0%~10.1%。結(jié)果:隨機(jī)抽樣某市52個(gè)水樣進(jìn)行檢測,均未檢出BDE-47和BDE-99。結(jié)論:建立飲用水中多溴聯(lián)苯醚固相萃取/固相微萃取-氣相色譜檢測的新方法,兩種方法操作簡便、快速,精密度、準(zhǔn)確度及回收率均令人滿意。
固相萃?。还滔辔⑤腿。粴庀嗌V;多溴聯(lián)苯醚;飲用水
多溴聯(lián)苯醚(polybrominated diphenyl ethers,PBDEs)是一種性能優(yōu)良的溴代阻燃劑,目前廣泛應(yīng)用于電子電氣產(chǎn)品、塑料制品和室內(nèi)裝飾材料中,因其高檢出率、高毒性、持久性和蓄積性成為學(xué)者們的研究熱點(diǎn)。環(huán)境中PBDEs 主要來源于生產(chǎn)和制造PBDEs的工廠、電子產(chǎn)品、工業(yè)廢水、生活垃圾及醫(yī)院或其他機(jī)構(gòu)塑料類制品等。PBDEs研究主要集中在土壤或沉積物[1-2]、環(huán)境水源[3-4]、生物體[5-6]、人體[7-8]、血液[9]、母乳[10]、牛奶[5,9]、空氣[11]等。環(huán)境水樣前處理方法有固相萃取(solid phase extraction,SPE)[12]、固相微萃取(solid phase microextraction,SPME)[13-14]、分散液相微萃取法(dispersive liquid-liquid microextraction,DLLME)[12,15]、攪拌子吸附萃取法(stir bar sorptive extraction,SBSE)[16]等。PBDEs主要的檢測方法有氣質(zhì)聯(lián)用(gas chromatography-mass spectrometry,GC-MS)法[17-20],該法一般需配備NCI離子源,價(jià)格昂貴;高效液相色譜法(high performance liquid chromatography,HPLC)法[15,21]對PBDEs靈敏度不理想。目前我國還沒有飲用水中多溴聯(lián)苯醚的衛(wèi)生標(biāo)準(zhǔn)和檢測標(biāo)準(zhǔn)。本實(shí)驗(yàn)擬建立一種操作快速、簡便,回收率和精密度較為理想的飲用水中PBDEs檢測方法,既為制定國家衛(wèi)生標(biāo)準(zhǔn)的建立提供參考,也便于各級監(jiān)測機(jī)構(gòu)對飲用水中PBDEs污染進(jìn)行調(diào)查工作,預(yù)防飲用水受到污染而引發(fā)的中毒事件。
1.1 材料與試劑
多溴聯(lián)苯醚標(biāo)準(zhǔn)品(BDE-47、BDE-99,50μg/mL)美國Accustandard公司;異辛烷(色譜純) 美國Tedia公司;二氯甲烷(色譜純) 美國Sigma公司;甲醇、乙腈、正己烷(色譜純) 天津市四友精細(xì)化學(xué)品有限公司;環(huán)己烷(色譜純) 天津市光復(fù)精細(xì)化工研究所;丙酮(色譜純) 天津市科密歐化學(xué)試劑有限公司;氯化鈉(優(yōu)級純) 天津光復(fù)科技發(fā)展有限公司。
1.2 儀器與設(shè)備
7890A氣相色譜儀[配有微池電子捕獲檢測器(μECD)]美國Agilent公司;固相萃取儀、SupelcleanTMLC-C18柱(6mL,500g) 固相萃取柱、PDMS(厚度100μm) 美國Supelco公司;數(shù)字型磁力加熱攪拌裝置(PC-420D) 美國Corning公司;HWS28型電熱恒溫水浴鍋 上海一恒科學(xué)儀器有限公司。
1.3 方法
1.3.1 樣品處理
隨機(jī)抽取某市自來水樣品17個(gè)、二次供水樣品17個(gè)、市售礦泉水樣品14個(gè)、桶裝水樣品2個(gè)、管材浸泡水樣品2個(gè)共52個(gè)樣品,其中自來水和二次供水采樣于某市區(qū)部分賓館、酒店、飯店、血站;礦泉水購自某市區(qū)超市;桶裝水為實(shí)驗(yàn)室自制三級水;管材浸泡水為水樣于實(shí)驗(yàn)室利用PPR管浸泡24h后測定。
1.3.2 色譜條件
SPE-GC色譜條件:色譜柱:J&W HP-5毛細(xì)管柱(30m×0.32mm,0.25μm);升溫程序:150℃保持1min,以40℃/min升至280℃,保持3min;進(jìn)樣口溫度:280℃;載氣(N2)流速:2.5mL/min;進(jìn)樣量:1μL;不分流進(jìn)樣;檢測器溫度:290℃;尾吹氣流量(N2):30mL/min。
SPME-GC色譜條件:解吸溫度:270℃;手動進(jìn)樣;其他同SPE-GC色譜條件。
1.3.3 樣品前處理
SPE-GC前處理:水樣直接取100mL,過LC-C18柱,正己烷洗脫,洗脫液于80℃水浴揮干,異辛烷定容至1mL,直接進(jìn)樣1μL測定;SPME-GC前處理:水樣直接取10mL置于15mL固相微萃取瓶中,于40℃條件下SPME吸附25min后,纖維頭經(jīng)風(fēng)干,立即進(jìn)樣測定。
1.3.4 標(biāo)準(zhǔn)曲線(工作曲線)的繪制
SPE-GC:分別準(zhǔn)確取BDE-47和BDE-99 50μg/mL標(biāo)準(zhǔn)溶液適量配制成0.0、1.0、10.0、50.0、100.0、500.0、1000.0μg/L,每個(gè)質(zhì)量濃度平行測定3次,以質(zhì)量濃度為X軸,峰面積均值為Y軸,繪制標(biāo)準(zhǔn)曲線;SPME-GC:分別準(zhǔn)確取BDE-47和BDE-99 50μg/mL標(biāo)準(zhǔn)溶液適量配制成0.0、10.0、20.0、50.0、100.0、500.0、1000.0ng/L,每個(gè)質(zhì)量濃度平行測定3次,以質(zhì)量濃度為X軸,峰面積平均值為Y軸,繪制工作曲線。
2.1 SPE樣品前處理?xiàng)l件優(yōu)化
2.1.1 洗脫劑種類與體積選擇
PBDEs極性介于非極性到中等極性之間,根據(jù)相似相容原理,選擇從非極性到極性7種不同洗脫劑,即環(huán)己烷、正己烷、二氯甲烷-正己烷、二氯甲烷、丙酮、乙腈、甲醇,該條件下采用二氯甲烷2mL+甲醇-水(1:1,V/V)5mL活化;流速約20滴/min進(jìn)行加標(biāo)回收率實(shí)驗(yàn),結(jié)果表明正己烷作為洗脫劑洗脫效率高于其他6種洗脫劑。
從1~5mL檢驗(yàn)洗脫劑的洗脫效果,結(jié)果顯示2mL洗脫劑就能將吸附于SPE柱填料上的目標(biāo)物洗脫。
2.1.2 活化劑種類與體積選擇
以正己烷為洗脫劑,流速約20滴/min,對二氯甲烷2mL+甲醇-水(1:1)5mL、甲醇7mL、二氯甲烷2mL+甲醇-水(2:1) 5mL、二氯甲烷2mL+甲醇-水(3:2) 5mL、甲醇-水(2:1)7mL、甲醇-水(3:2)7mL、二氯甲烷7mL、二氯甲烷2mL+甲醇5mL 8種活化劑配比進(jìn)行選擇,結(jié)果表明:二氯甲烷+甲醇回收率效果優(yōu)于其他7種活化劑,因此選擇二氯甲烷(2mL)+甲醇(5mL)作為活化劑。
活化劑一般用量在10mL以下,過多將降低回收率。本實(shí)驗(yàn)分別以二氯甲烷1mL+甲醇3mL、二氯甲烷2mL+甲醇5mL和二氯甲烷3mL+甲醇7mL 3種混合比例對SPE柱活化。結(jié)果顯示,二氯甲烷2mL+甲醇5mL活化效果最好。
2.1.3 SPE柱流速優(yōu)化
流速直接影響待測物洗脫效率,流速過快目標(biāo)物與SPE填充材料沒有充分作用,洗脫效果較差;流速過慢,導(dǎo)致作用時(shí)間過長,無法洗脫待測物,所以必須選擇合適的流速來保證最佳洗脫效果。采用Supelco固相萃取儀來進(jìn)行SPE實(shí)驗(yàn),由于流速不能全自動控制,只能手動控制流速。實(shí)驗(yàn)表明,約30滴/min流速對BDE-47和BDE-99洗脫效果最佳。
2.2 SPME前處理?xiàng)l件優(yōu)化
2.2.1 SPME解吸溫度及時(shí)間優(yōu)化
固相微萃取解吸溫度直接影響纖維頭吸附的目標(biāo)物解吸是否徹底,溫度過低解吸不完全,過高可能超過纖維頭的最高溫度,導(dǎo)致纖維萃取頭使用壽命大大縮短。選擇250~280℃,根據(jù)峰面積與解吸溫度的相關(guān)性來選擇解吸溫度,SPME其他條件:萃取溫度常溫(21℃)、萃取時(shí)間20min、轉(zhuǎn)速1150r/min、解吸時(shí)間3min。從250~270℃BDE-47和BDE-99靈敏度顯著升高,270~275℃ BDE-47和BDE-99靈敏度沒有顯著變化,至280℃達(dá)最高值。另外PDMS萃取頭最高承受溫度為280℃,如果纖維頭溫度過高,將顯著縮短萃取頭使用壽命,所以應(yīng)該選擇低于280℃的解吸溫度。因此選擇270℃作為解吸溫度。
PBDEs解吸一般在前3min完成。本研究選擇1~5min范圍,根據(jù)BDE-47和BDE-99在此范圍的峰面積來選擇最短最適合的解吸時(shí)間,其他條件:解吸溫度270℃、萃取溫度常溫(21℃)、萃取時(shí)間20min、轉(zhuǎn)速1150r/min。在3min左右目標(biāo)物解吸已經(jīng)比較完全,在此后4~5min峰面積沒有顯著增加,因此本實(shí)驗(yàn)選擇3min解吸。
2.2.2 SPME萃取溫度及時(shí)間優(yōu)化
固相微萃取與溫度之間存在明顯正相關(guān),一般隨萃取溫度升高,待測物峰面積都有升高。本實(shí)驗(yàn)選擇常溫(21℃)、30、40、50℃檢驗(yàn)BDE-47和BDE-99峰面積隨萃取溫度變化情況。SPME其他條件:解吸溫度270℃、解吸時(shí)間3min、萃取時(shí)間20min、轉(zhuǎn)速1150r/min;隨溫度的升高,BDE-47和BDE-99靈敏度顯著升高,在40~50℃達(dá)到較高的響應(yīng)值,介于在50℃時(shí)沒有明顯高于40℃時(shí)BDE-47和BDE-99的峰面積,因此選擇萃取溫度為40℃。
SPME是一個(gè)動態(tài)萃取過程,隨纖維萃取頭毛細(xì)管浸入試樣中,試樣中目標(biāo)待測物不斷萃取到纖維頭中。選擇0~35min來考察纖維頭的萃取效果,其他條件:解吸溫度270℃、解吸時(shí)間3min、萃取溫度40℃、轉(zhuǎn)速1150r/min、在0~25min范圍內(nèi)BDE-47和BDE-99峰面積顯著升高,隨時(shí)間進(jìn)一步增加至30、35min它們各自峰面積沒有明顯變化。綜合考慮,選擇萃取時(shí)間為25min。
2.2.3 SPME轉(zhuǎn)速優(yōu)化
通常攪拌子轉(zhuǎn)速對待測物峰面積有極為顯著的影響,選擇轉(zhuǎn)速0~1150r/min來優(yōu)化最佳轉(zhuǎn)速,其他條件:解吸溫度270℃、解吸時(shí)間3min、萃取溫度40℃、萃取時(shí)間25min。在轉(zhuǎn)速500r/min時(shí)BDE-47和BDE-99靈敏度十分低,隨轉(zhuǎn)速的增加它們各自的峰面積靈敏度明顯提升,至1150r/min達(dá)到最大值。由于選擇的磁力攪拌器最大轉(zhuǎn)速為1150r/min,并有研究證明,轉(zhuǎn)速高于1500r/min重復(fù)性不理想,故本實(shí)驗(yàn)轉(zhuǎn)速選擇1150r/min。
2.2.4 SPME離子強(qiáng)度(鹽)影響實(shí)驗(yàn)
固相微萃取通常在加入鹽的情況下有利于待測物的萃取。有研究顯示,NaCl添加量在4%以下對萃取效率沒有影響[13]。本研究選擇0~30% NaCl加入量來考察PBDEs萃取效率(峰面積變化)是否受離子強(qiáng)度的影響。隨離子強(qiáng)度劑(NaCl)加入量的增加,BDE-47和BDE-99峰面積明顯降低,即NaCl的加入會大大降低BDE-47和BDE-99的響應(yīng),具體機(jī)理還待進(jìn)一步研究。本實(shí)驗(yàn)過程中選擇不加鹽(NaCl)。
2.2.5 助溶劑甲醇加入量對萃取效率的影響
表1 多溴聯(lián)苯醚的線性范圍、回歸方程、相關(guān)系數(shù)、檢出限和RSD值Table 1 Linear range, regression equation, correlation coefficient, limit of detection (LOD) and relative standard deviation (RSD) for BDE-47 and BDE-99
有研究顯示甲醇的加入會使萃取效率明顯提高,本實(shí)驗(yàn)選擇從0~30%分別加入不同量甲醇,根據(jù)BDE-47和BDE-99峰面積與甲醇加入量的關(guān)系來確定甲醇加入量。隨甲醇量加入的增加,BDE-47和BDE-99峰面積明顯降低,與已有研究結(jié)果不符,所以本實(shí)驗(yàn)選擇不加助溶劑。
2.3 標(biāo)準(zhǔn)品的色譜測定
采用SPE-GC法、SPME-GC法分離測定BDE-47和BDE-99,標(biāo)準(zhǔn)樣品色譜見圖1。
圖1 BDE-47和BDE-99標(biāo)準(zhǔn)SPE-GC(A)和SPME-GC色譜圖(B)Fig.1 SPE-GC and SPME-GC chromatograms of mixed BDE-47 and BDE-99 standards
2.4 標(biāo)準(zhǔn)曲線(工作曲線)、回歸方程、相關(guān)系數(shù)、檢出限、RSD
在最佳條件下,對加標(biāo)樣品進(jìn)行測定,繪制標(biāo)準(zhǔn)曲線結(jié)果見表1。
SPE-GC法測定結(jié)果表明:BDE-47和BDE-99在0~1000.0μg/L質(zhì)量濃度范圍內(nèi)呈良好的線性關(guān)系,線性相關(guān)系數(shù)分別為0.9996、0.9997;檢出限(水樣取100mL)分別為0.0008、0.0009μg/L(RSN=6);RSD(n=6)分別為1.0%~4.9%、0.96%~4.4%。
SPME-GC法測定結(jié)果表明: BDE-47和BDE-99在0~1.0μg/L質(zhì)量濃度范圍內(nèi)呈良好的線性關(guān)系,線性相關(guān)系數(shù)分別為0.9996、0.9992;檢出限(水樣取10mL)分別為0.0008、0.0044μg/L (RSN=3);RSD(n=6)分別為6.7%~11.4%、6.0%~10.1%。
2.5 加標(biāo)回收實(shí)驗(yàn)
由表2可見,對礦泉水樣進(jìn)行加標(biāo)0.02、0.1、0.5μg/L的SPE-GC法加標(biāo)實(shí)驗(yàn),各測定6次,該法BDE-47和BDE-99回收率分別為91.5%~103.0%、90.7%~102.0%。對礦泉水樣進(jìn)行加標(biāo)1、10、50μg/L的SPMEGC法加標(biāo)實(shí)驗(yàn),各測定6次,該法BDE-47和BDE-99回收率分別為81.1%~91.8%、82.0%~94.8%。
表2 回收率實(shí)驗(yàn)Table 2 Results of recovery tests
2.6 實(shí)樣測定
隨機(jī)抽取52個(gè)水樣按照SPE前處理和SPME前處理方法進(jìn)行處理后,分別采用SPE-GC和SPME-GC檢測BDE-47和BDE-99含量,兩種方法均沒有檢出BDE-47和BDE-99。
3.1 本實(shí)驗(yàn)采用SPE/SPME-GC-μECD測定飲用水中BDE-47和BDE-99含量,兩種方法均具有良好線性、回收率和精密度,干擾實(shí)驗(yàn)結(jié)果顯示不存在干擾。
3.2 采樣嘉陵江上、中、下游源水,利用兩種方法測定其中PBDEs含量,干擾實(shí)驗(yàn)結(jié)果顯示不存在其他雜質(zhì)干擾,且均未檢出BDE-47和BDE-99,表明嘉陵江水源目前沒有受到PBDEs污染。加標(biāo)回收率結(jié)果顯示良好回收率,因此兩種方法均可用于源水中BDE-47和BDE-99的測定。
3.3 實(shí)驗(yàn)發(fā)現(xiàn)玻璃容器對PBDEs存在顯著吸附作用。
[1] WANG Jing, MA Yunjuan, CHEN Shejun, et al. Brominated flame retardants in house dust from e-waste recycling and urban areas in South China: implications on human exposure[J]. Environment International, 2010, 36(6): 535-541.
[2] YUSA V, PARDO O, PASTOR A, et al. Optimization of a microwaveassisted extraction large-volume injection and gas chromatography-ion trap mass spectrometry procedure for the determination of polybrominated diphenyl ethers, polybrominated biphenyls and polychlorinated naphthalenes in sediments[J]. Analytica Chimica Acta, 2006, 557(1/2): 304-313.
[3] FONTANA A R, MARIA F, SILVA M F, et al. Determination of polybrominated diphenyl ethers in water and soil samples by cloud point extraction-ultrasound-assisted back-extraction-gas chromatography-mass spectrometry[J]. Journal of Chromatography A, 2009, 1216(20): 4339-4346.
[4] FONTANALS N, BARRI T, BERGSTROM S, et al. Determination of polybrominated diphenyl ethers at trace levels in environmental waters using hollow-fiber microporous membrane liquid-liquid extraction and gas chromatography-mass spectrometry[J]. Journal of Chromatography A, 2006, 1133(1/2): 41-48.
[5] GOMARA B, GARCIARUIZ C, GONZALEZ M J, et al. Fractionation of chlorinated and brominated persistent organic pollutants in several food samples by pyrenyl-silica liquid chromatography prior to GC-MS determination[J]. Analytica Chimica Acta, 2006, 565(2): 208-213.
[6] FUJITA H, HONDA K, HAMADA N, et al. Validation of high-throughput measurement system with microwave-assisted extraction, fully automated sample preparation device, and gas chromatography-electron capture detector for determination of polychlorinated biphenyls in whale blubber[J]. Chemosphere, 2009, 74(8): 1069-1078.
[7] GOMARA B, HERRERO L, GONZALEZ M J. Feasibility of electron impact and electron capture negative ionization mass spectrometry for the trace determination of tri- todeca-brominated diphenyl ethers in human samples[J]. Analytica Chimica Acta, 2007, 597(1): 121-128.
[8] COVACI A, VOORSPOELS S. Optimization of the determination of polybrominated diphenyl ethers in human serum using solid-phase extraction and gaschromatography-electron capture negative ionization mass spectrometry[J]. Journal of Chromatography B, 2005, 827(2): 216-223.
[9] TAKASUGA T, SENTHILKUMAR K, TAKEMORI H, et al. Impact of fermented brown rice with Aspergillus oryzae (FEBRA) intake and concentrations of polybrominated diphenylethers (PBDEs) in blood of humans from Japan[J]. Chemosphere, 2004, 57(8): 795-811.
[10] BORDAJANDI L, ABAD E, JOSEGONZALEZ M. Occurrence of PCBs, PCDD/Fs, PBDEs and DDTs in Spanish breast milk: enantiomeric fraction of chiral PCBs[J]. Chemosphere, 2008, 70(4): 567-575.
[11] SJTKLIN A, CARLSSON H, THURESSON K, et a1. Flame retardants in indoor air at an elec tronics recycling plant and at other work environments [J]. Environmental Science and Technology, 2001, 35(3): 448-454.
[12] LIU Xiujuan, LI Jianwang , ZHAO Zhixu, et al. Solid-phase extraction combined with dispersive liquid-liquid microextraction for the determination for polybrominated diphenyl ethers in different environmental matrices[J]. Journal of Chromatography A, 2009, 1216(12): 2220-2226.
[13] WANG Junxia, JIANG Dongqing, GU Zhiyuan, et al. Multiwalled carbon nanotubes coated fibers for solid-phase microextraction of polybrominated diphenyl ethers in waterand milk samples before gas chromatography withelectron-capture detection[J]. Journal of Chromatography A, 2006, 1137(1): 8-14.
[14] MONTES R, RODNIGUES I, RUBI E, et al. Suitability of polydimethylsiloxane rods for the headspace sorptive extraction of polybrominated diphenyl ethers from water samples[J] Journal of Chromatography A, 2007, 1143(1/2): 41-47.
[15] LI Yanyan, WEI Guohui, HU Jia, et al. Dispersive liquid-liquid microextraction followed by reversed phase-high performance liquid chromatography for the determination of polybrominated diphenyl ethers at trace levels in landfill leachate and environmental water samples[J]. Analytica Chimica Acta, 2008, 615(1): 96-103.
[16] LLORCAPORCEL J, MARTINEZSANCHEZ G, LVAREZ B, et al. Analysis of nine polybrominated diphenyl ethers in water samples by means of stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry[J]. Chim Acta, 2006, 569(1/2): 113-118.
[17] LCPEZ P, BRANDSMA S A, LEONARDS P E G, et al. Methods for the determination of phenolic brominated flame retardants, and byproducts, formulation intermediates and decomposition products of brominated flame retardants in water[J]. Journal of Chromatography A, 2009, 1216(3): 334-345.
[18] TOLLBACK P, BJORKLUND J, OSTMAN C. Large-volume programmed-temperature vaporiser injection for fast gas chromatography with electron capture and mass spectrometric detection of polybrominated diphenyl ethers[J]. Journal of Chromatography A, 2003, 991(2): 241-253.
[19] KORYTAR P, COVACI A, LEONARDS P E, et al. Comprehensive two-dimensional gas chromatography of polybrominated diphenyl ethers [J]. Journal of Chromatography A, 2005, 1100(2): 200-207.
[20] SANCHEZ A J, BONET J, VELASCO G, et al. Determination and occurrence of phthalates, alkylphenols, bisphenol A, PBDEs, PCBs and PAHs in an industrial sewage grid discharging to a municipal wastewater treatment plant[J]. Science of the Total Environment, 2009, 407(13): 4157-4167.
[21] FRANSCICO V, AMPARO R G, SIGBRITT K. Microwave-assisted extraction for qualitative and quantitative determination of brominated flame retardants in styrenic plastic fractions from waste electricaland electronic equipment (WEEE)[J]. Talanta, 2009, 78(1): 33-39.
Determination of Polybrominated Diphenyl Ethers in Drinking Water by Solid Phase Extraction or Solid-phase Micro-extraction Combined with Gas Chromatography
HE Ying-chun1,WANG Zheng-hong2,LI Lin1,*,ZHOU Qian-ru2
(1. College of Food Science, Southwest University, Chongqing 400716, China;
2. Chongqing Center for Disease Prevention and Control, Chongqing 400042, China)
Objective: To establish a novel method for determining the contents of polybrominated diphenyl ethers (BDE-47 and BDE-99) in drinking water by solid phase extraction (SPE) or solid phase micro extraction (SPME) combined with gas chromatography (GC). Methods: In the SPE-GC method, 100 mL of water sample was purified by LC-C18 SPE column chromatography through elution with hexane. The eluent was evaporated to dryness in water bath at 80℃, and the remaining residue was re-dissolved with isooctane and made up to 1 mL. Finally, 1μL of the solution was injected into GC for the determination. The limits of detection (LOD) for BDE-47 and BDE-99 were 0.0008μg/L and 0.0009μg/L (RSN= 6), respectively, the regression equations showed good linearity with a correlation coefficient of 0.9996 and 0.9997, respectively, and the RSDs for 6 replicate determinations were in the range of 1.0%-4.9% and 0.96%-4.4%, respectively. In the SPME-GC method, 10 mL of water sample was placed into a 15-mL SPME bottle and adsorbed by solid-phase micro-extraction for 25 min at 40 ℃ with a rotation speed of 1150 r/min. Then, the fiber was air-dried, immediately followed by GC analysis. The LODs of the SPME-GC method for BDE-47 and BDE-99 were 0.0000μg/L and 0.0044μg/L (RSN = 6), respectively, the linear correlation coefficients were 0.9996 and 09992, respectively, and the RSDs for 6 replicate determinations varied in the range of 6.7%-11.4% and 6.0%-10.1%, respectively. Results: BDE-47 and BDE-99 were undetected in 52 samples randomly collected from a certain city. Conclusion: Both analytical methods are characterized by simplicity, rapidity, high precision, good accuracy and satisfactory recovery rate.
solid phase extraction;solid phase micro-extraction;gas chromatography;polybrominated diphenyl ethers;drinking water
R282.2
A
1002-6630(2012)08-0236-05
2011-04-24
何迎春(1985—),男,碩士,研究方向?yàn)槭称钒踩c質(zhì)量控制。E-mail:jl2641@126.com
*通信作者:李林(1957—),男,研究員,本科,研究方向?yàn)槭称钒踩c質(zhì)量。E-mail:lilinlqc@163.com