一种简便的原位测定红树叶片表面菲的荧光分析方法

采用自行设计的多用途荧光比色皿,建立了一种秋茄(Kandelia obovata,Ko),桐花树(Aegiceras comiculatum,Ac)和白骨壤(Avicennia marina,Am)叶片表面菲(Phenanthrene,Phen)简便的原位测定方法,本方法测定Ko,Ac和Am表面Phen的线性范围分别为6.5 ～ 1200 ng/spot,18.5～600 ng/spot和3.2～700 ng/spot,检出限分别为0.6,0.7和1.3 ng/spot,加标回收率分别为92.4％～101.0％、94.8％～108.2％和93.8％～103.6％,相对标准偏差小于6.5％.本方法的检出限和相对标准偏差均优于固体表面光纤荧光法(Solid surface optical fiber fluorimetry,SSF),线性范围与SSF法处于同一数量级.本方法与SSF法测得的红树叶片表面Phen的浓度并无显著差异(p＞0.05),但本方法极大地简化了操作,提高了重现性.     

光纤荧光法对吸附于红树叶片表面上荧蒽的测定

利用光纤荧光法实现了吸附于白骨壤(Am)、海漆(Ea)、秋茄(Kc)、桐花树(Ac)和老鼠簕(Ai)叶片表面上荧蒽(Fla)的定量测定.所建方法测定吸附于Am、Ea、Kc、Ac和Ai叶片表面上Fla的线性范围分别为2.5 ～500、2.0 ～600、4.5 ～1 100、15 ～600、3.5 ～450 ng/spot,相应的检出限分别为0.91、0.63、1.12、3.52、1.40 ng/spot,方法的相对标准偏差小于7.8%(n=15),加标回收率分别为97% ～108%、78% ～95%、77% ～90%、84% ～108%和78% ～102%.利用所建方法考察了5种红树叶片正反面吸附不同量Fla的信号强度随时间的变化情况.结果表明:在200 min内,叶片正反面上Fla的信号均发生不同程度的衰减,且反面的信号衰减率大于正面;5种红树叶片正反面对Fla的吸附特性均不同;吸附于叶片正面的Fla多残留在叶片表面,而吸附于叶片反面的Fla易向叶片内部迁移.     

显微荧光光谱原位测定红树植物根表面微区中的蒽

自行搭建显微荧光光谱分析( Microscopic fluorescence spectrometric analysis, MFSA)系统,并将其用于吸附于红树植物秋茄( Kandelia obovata, K. obovata)和白骨壤( Avicennia marina, A. marina)根表面微区中蒽( Anthrancene, Ant)的原位测定。在同步扫描模式下,以波长差为60 nm,吸附于K. obovata和A. marina根表面微区中Ant(5.3 pg/μm2)的荧光信号有最大信噪比(5.5和6.8)。所建方法的线性范围分别为5.3 ~63.2 pg/μm2和10.5~52.6 pg/μm2,检出限分别为1.1和5.5 pg/μm2,相对标准偏差均小于12.5%(n=9),加标回收率分别为98.1%~117.0%和81.2%~110.9%。结果表明,搭建的MFSA系统具备原位获取植物根表面微区Ant荧光光谱定量信息和荧光图像信息的能力。     

固体表面荧光法测定吸附于白骨壤和木榄叶片上的蒽

以新鲜白骨壤和木榄叶片为基质,建立了直接测定吸附于叶片表面蒽(An)的固体表面荧光分析法(SSF).考察了白骨壤和木榄叶片上An的吸附量随An暴露浓度、暴露时间等因素的变化情况.方法测定吸附于白骨壤叶片上An的线性范围为0.92～8.71μg/g检出限为5.77 ng/g,加标回收率为79.2%～85.9%;测定吸附于木榄叶片上An的线性范围为89.5～698.2 ng/g,检出限为1.79 ng/g,加标回收率为75.1%～102.3%;对于两种叶片,方法的相对标准偏差都小于10%.     

溶解态菲及其中间代谢产物1-羟基-2-萘甲酸的同时测定

运用导数-同步荧光光谱建立了快速同时测定溶解态菲(Phenanthrene,Phe)及其中间代谢产物1-羟基-2-萘甲酸(1-Hydroxy-2-naphthoic acid,1H2NA)的分析方法。所建方法同时测定Phe与1H2NA的线性范围分别为4.0~1.0×103μg/L和4.0~1.2×103μg/L,检出限分别为0.08μg/L和0.07μg/L,加标回收率分别为96.5%~105.3%和99.2%~106.5%,相对标准偏差均小于1.0%。该方法可应用于实验室条件下溶解态Phe微生物降解过程中Phe和1H2NA的测定,具备原位研究Phe降解过程中间代谢产物1H2NA的应用潜力。     

镍钛合金纤维基体表面纳米多孔复合氧化物的可控生长及其对多环芳烃的选择性固相微萃取

采用水热氧化法制备镍钛合金(NiTi)固相微萃取纤维.实验结果表明,在80℃ 的H2 O2溶液中,直接氧化NiTi纤维基体可在其表面原位生长纳米多孔氧化镍/氧化钛复合涂层,其中氧化镍含量显著高于氧化钛含量.与高效液相色谱-紫外检测器(HPLC-UV)检测技术联用,考察了所制备NiTi纤维对典型芳香族化合物的萃取性能.结果表明,富Ni复合氧化物涂层对多环芳烃(PAHs)表现出良好的萃取选择性.在优化实验条件下,方法的线性范围为0.1~400.0 ng/mL,相关系数大于0.999,PAHs的检出限为0.026~0.056 ng/mL.对于50 ng/mL加标水样,单支NiTi纤维日内和日间测量的相对标准偏差(RSDs)分别为4.8%~6.2%和5.4%~6.5%(n=5),使用5支不同批纤维测量的RSDs为6.4%~8.4%.本方法适用于环境水样中PAHs的富集和测定,相对回收率为89.9%~108.5%,RSDs<8.1%.而且,NiTi纤维机械强度高,化学稳定性好,制备过程精密可控.     

大体积搅拌棒吸附萃取技术与热脱附-气相色谱-质谱法测定地表水中多环芳烃

基于搅拌棒吸附萃取(SBSE)技术建立了气相色谱-质谱测定地表水中16种多环芳烃(PAHs)的分析方法。该法采用多搅拌吸附棒同时富集,依次热脱附冷聚焦后进样的方式有效解决了搅拌棒吸附时间长、富集水样体积小等问题。优化后的结果表明,在0.2~10 ng/L范围内(萘为0.5~10 ng/L范围),16种PAHs的线性关系良好,相关系数(r)均0.99,方法检出限(MDL)为0.03~0.20 ng/L(萘为0.50 ng/L)。用该方法对钱塘江流域地表水进行测定,共检测出11种PAHs,含量为0.13~1.57 ng/L,不同添加水平下的加标回收率为75.6%~108.9%。该法可应用于地表水样品中该类物质的超痕量检测。     

超声提取-气相色谱-质谱法测定本草香中16种颗粒态多环芳烃含量及其排放特征分析

本草香颗粒态多环芳烃(PAHs)的分析对探究人体健康和环境安全的影响具有重要意义,但目前相关研究主要针对竹签香,对于配方更为复杂、日常使用更为频繁的本草香颗粒态PAHs定量分析研究十分有限且缺少针对性。为了研究本草香颗粒态PAHs的排放因子和排放特征,在自制的试验舱内采集5种本草香燃烧后的颗粒物,通过优化萃取溶剂、超声时间和仪器分析条件,建立了超声提取-气相色谱-质谱(GC-MS)测定本草香燃烧后颗粒物上所吸附的16种PAHs的方法。通过采集0.8 g样品,切取整片滤膜样品,使用正己烷-二氯甲烷(1∶1, v/v)进行超声萃取,经浓缩定容过滤后使用气相色谱-质谱分析,内标法定量。结果表明,16种PAHs在0.1~5.0 μg/mL范围内线性良好(相关系数r²>0.998),方法检出限(MDL)为0.4~3.8 ng/g;低、高2个水平的加标回收率分别为77.4%~99.5%和82.0%~101.3%;相对标准偏差(RSD)为0.7%~7.2%。5种本草香颗粒态PAHs的排放因子为4.60~11.89 μg/g。本草香的16种颗粒态PAHs中菲(Phe)的含量均为最高,所占比例为24.85%~42.59%,其次为荧蒽(Flu)、芘(Pyr)、 \stackrel{艹}{屈} (Chr)、蒽(Ant)。本草香颗粒态PAHs中Phe的含量稳定且占比明显高于其他室内燃烧源,可将Phe作为本草香的颗粒态特征PAHs。颗粒态PAHs主要分布在3环和4环上,3环和4环PAHs占比之和为83.84%~96.31%。颗粒态的Phe/Flu比值可作为辨别不同室内燃烧源中燃香释放源的特征比值。该方法所需样品量少,灵敏度高,前处理操作简便,适用于燃香类产品中PAHs的快速检测,同时为了解本草香颗粒态PAHs分布规律和健康危害提供科学数据。     

加速溶剂萃取和凝胶渗透色谱净化GC–MS法测定烟熏腊肉中16种多环芳烃

采用ASE萃取、GPC净化和浓缩,建立GC–MS法快速检测烟熏腊肉中16种多环芳烃(PAHs)的分析方法。将烟熏腊肉与硅藻土充分混合后,放到萃取池中加速溶剂萃取,在优化仪器条件下测定,16种PAHs的线性范围为0.1~4 ng/m L,线性相关系数r为0.985 3~0.999 9。方法检出限在0.172~0.233μg/kg之间,加标回收率为60.3%~93.2%,测定结果的相对标准偏差为4.06%~11.60%(n=6)。该方法检测快速,准确度高,重现性好,适合于烟熏腊肉中16种PAHs的同时测定。     

固体表面荧光法测定吸附于白骨壤和木榄叶片上的葸

以新鲜白骨壤和木榄叶片为基质,建立了直接测定吸附于叶片表面蒽（An）的固体表面荧光分析法（SSF）。考察了白骨壤和木榄叶片上An的吸附量随An暴露浓度、暴露时间等因素的变化情况。方法测定吸附于白骨壤叶片上An的线性范围为0．92～8．71μg/g,检出限为5．77ng/g,加标回收率为79．2％～85．9％;测定吸附于木榄叶片上An的线性范围为89．5～698．2ng／g,检出限为1．79ng/g,加标回收率为75．1％～102．3％;对于两种叶片,方法的相对标准偏差都小于10％。     

In situ simultaneous determination the photolysis of multi-component PAHs adsorbed on the leaf surfaces of living Kandelia candel seedlings

A fiber-optic fluorimetry for in situ simultaneous determination of fluorine (Flu), phenanthrene (Phe) and fluoranthene (Fla) adsorbed on the leaf surfaces of Kandelia candel (Kc) seedlings was developed. Experimental results showed that the linear ranges for determination of Flu, Phe and Fla adsorbed on Kc leaves were 35-700, 5-900 and 2-450 ng/spot, respectively. The detection limits for Flu, Phe and Fla were 9.11, 1.65 and 0.90 ng/spot and with the relative standard deviations less than 10.32%, 7.56% and 4.29% (n = 9), respectively. The recovery results for Flu, Phe and Fla adsorbed on Kc leaves were 83.0-91.2, 78.5-88.5 and 91.5-107.3%, respectively. Under the laboratory experimental conditions, the photolysis processes of Flu, Phe and Fla individual and in mixtures adsorbed on the leaf surfaces of living Kc seedlings were studied. Results showed that the photolysis of Flu, Phe and Fla individual and in mixtures adsorbed on the leaf surfaces of Kc seedlings followed first-order kinetics with photolysis rates in the order of Flu > Fla > Phe on the Kc leaves. An antagonistic effect was found when the three polycyclic aromatic hydrocarbons (PAHs) were co-adsorbed on living Kc seedlings. The experimental results also indicated that photolysis was the main transformation pathway for Flu, Phe and Fla both individual and in mixtures adsorbed on Kc leaves, whereas disappearance of the adsorbed Flu, Phe and Fla as a result of volatilization and leaf absorption could be negligible during the experimental period.     

Use of cotton as a sorbent for on-line precolumn enrichment of polycyclic aromatic hydrocarbons in waters prior to liquid chromatography determination

Using cotton as a solid-phase extraction sorbent of the precolumn, an on-line coupled precolumn preconcentration-liquid chromatography system with fluorescence detection was developed for the determination of PAHs in aqueous samples. Four PAHs including fluorene, phenanthrene, fluoranthene and benzo[k]fluoranthene were preconcentrated by a precolumn packed with 30 mg of absorbent cotton and then separated by C₁₈ analytical column. When 100 ml of sample was enriched, the proposed procedure provided detection limits in the range of 0.5-57 ng l⁻¹. Several water samples spiked with PAHs were analyzed with recoveries in the range of 92-119% at spiking level of 100 ng l⁻¹ for fluorene, phenanthrene and fluoranthene, and 10 ng l⁻¹ for benzo[k]fluoranthene, respectively.     

Detection of polycyclic aromatic hydrocarbon (PAH) compounds in artificial sea-water using surface-enhanced Raman scattering (SERS)

This paper reports an accurate synthesis of surface-enhanced Raman scattering (SERS) active substrates, based on gold colloidal monolayer, suitable for in situ environmental analysis. Quartz substrates were functionalized by silanization with (3-mercaptopropyl)trimethoxysilane (MPMS) or (3-aminopropyl)trimethoxysilane (APTMS) and they subsequently reacted with colloidal suspension of gold metal nanoparticles: respectively, the functional groups SH and NH₂ bound gold nanoparticles. Gold nanoparticles were prepared by the chemical reduction of HAuCl₄ using sodium tricitrate and immobilized onto silanized quartz substrates. Active substrate surface morphology was characterized with scanning electron microscopy (SEM) measurements and gold nanoparticles presented a diameter in the range 40-100 nm. Colloidal hydrophobic films, allowing nonpolar molecule pre-concentration, were obtained. The surfaces exhibit strong enhancement of Raman scattering from molecules adsorbed on the films. Spectra were recorded for two PAHs, naphthalene and pyrene, in artificial sea-water (ASW) with limits of detection (LODs) of 10 ppb for both on MPMS silanized substrates.     

Metallofluorescent indicators as spray reagents for the in situ determination of organophosphorus pesticides on thin-layer chromatograms

Fluorescence-quenched solutions of palladium(II)-calcein and palladium(II)-calcein blue are shown to be sensitive spray reagents for the detection and in situ determination of organothiophosphorus insecticides on thin-layer chromatograms. The palladium is displaced from its non-fluorescent indicator complex by the pesticide producing fluorescent spots on the plate. Visual detection limits for 16 insecticides are given. As little as 10–50 ng of phosphorodithioate pesticides can be detected within l h after spraying and drying the plate, while the detection limits for phosphorothioates are somewhat higher (ca. 50–100 ng). Quantitative measurements may be conveniently made 18–24 h after spraying and drying the plate. Plots of fluorescence (as peak area) versus quantity of pesticide are linear over a 10–15 fold range. The relative standard deviation of replicate spots of Guthion (50–400 ng) and Cygon (50–100 ng) is 4–9 % and less than 15 % for 10 ng of Cygon or 20 ng of Guthion. The method was applied to the analysis of lake water spiked with Cygon. The recovery of 2–20 μg l^-1 of the pesticide was 87–113% with no clean-up other than t.l.c. required.     

A novel analytical approach for investigation of anthracene adsorption onto mangrove leaves

A solid surface fluorimetry approach was established for direct determination of anthracene (An) adsorbed onto fresh mangrove leaves. The experimental results showed that the linear dynamic ranges for determination of An adsorbed onto Avicennia marina (Am), Bruguiera gymnorrhiza (Bg), Kandelia candel (Kc) and Rhizophors stylosa (Rs) leaves varied from 0.92 to 8.71, 0.089 to 0.70, 0.063 to 5.61 and 0.11 to 1.82 microgg(-1), with detection limits of 5.77, 1.79, 4.29 and 1.42 ngg(-1), respectively, and with a relative standard deviation less than 10% (n=5). The experimental recovery results for adsorbed An on Am, Bg, Kc and Rs leaves were among 79.2-85.9, 75.1-102.3, 70.2-93.8 and 73.1-110.8%, respectively. Using the established method, we investigated the effects of exposure time of An and the different quantity of leaf-wax among the four species of mangrove on the amount of An adsorbed. Under the same experimental conditions, the adsorption of An on the upper and lower sides of the same mangrove leaf, and at different regions on the upper side of the same mangrove leaf were also studied. The results demonstrated that the leaves of different mangrove species contained different quantities of leaf-wax, and with the same exposure conditions to An, the quantity of leaf-wax among the four species showed a significant positive correlation with the amount of An adsorbed onto the leaves.     

Ultrasound-Assisted Dispersive Liquid�CLiquid Microextraction Combined with Low Solvent Consumption for Determination of Polycyclic Aromatic Hydrocarbons in Seawater by GC�CMS

Ultrasound-assisted dispersive liquid?Cliquid microextraction (USA-DLLME) with low solvent consumption was demonstrated for gas chromatography-mass spectrometry (GC?CMS) determination of 16 typical polycyclic aromatic hydrocarbons (PAHs) in seawater samples. Factors affecting the extraction process, such as extraction and dispersive solvent, phase ratio, temperature, extraction and centrifugation time, were investigated thoroughly and optimized. The linear range was 20?C2,000 ng L^?1 except for acenaphthylene (Acy) at 10?C2,000 ng L^?1 and phenanthrene (Phe), fluoranthene (Flu) and pyrene (Py) all at 5?C2,000 ng L^?1. Enrichment factors (EFs) ranging from 722 to 8,133 were obtained, achieving limits of detection at 1.0?C10.0 ng L^?1. The method attained good precision (relative standard deviation, RSD) from 3.4 to 14.2% for spiked 50 ng L^?1 individual PAHs standards. Method recoveries were in the range 87?C124% and 70?C127% for spiked samples from simulated seawater and beach seawater, respectively. The proposed USA-DLLME helped to obtain about 1.1?C10 times higher EFs in a minimum amount of solvent and in less time than traditional DLLME.     

Highly sensitive and selective sensing platform based on π–π interaction between tricyclic aromatic hydrocarbons with thionine–graphene composite

We are just beginning to exploit the fascinating potential of thionine, called electrochemical probe that can selectively recognize specific polycyclic aromatic hydrocarbons (PAHs), as tools for the detection of tricyclic aromatic hydrocarbons phenanthrene (PHE) and anthracene (ANT). A novel electrochemical sensing platform by modification of electroactive thionine functionalized graphene onto glass carbon electrode (Th/GRs/GCE) surface was constructed. The immobilized thionine showed a remarkable stability, which may benefit from the π–π stacking force with graphene. Under optimum conditions, the proposed electrochemical sensor exhibited high sensitivity and low detection limit for detecting PHE and ANT. The total amount of PHE and ANT could be quantified in a wide range of 10 pM–0.1 μM with a good linearity (R² = 0.9979) and a low detection limit of 0.1 pM (S/N = 3). Compounds which possess one or two benzene rings or PAHs with more than three rings, such as benzene, naphthalene (NAP), benzo[a]pyrene (BaP) and pyrene (PYR) show little interference on the detection. Consequently, a simple and sensitive electrochemical method was proposed for the determination of PHE and ANT, which was used to determine PHE and ANT in waste water samples. The electrochemical method provides a general tool that complements the commonly used spectroscopic methods and immune method for the detection of PAHs.     

Determination of polycyclic aromatic hydrocarbons in food samples by automated on-line in-tube solid-phase microextraction coupled with high-performance liquid chromatography-fluorescence detection

A simple and sensitive automated method, consisting of in-tube solid-phase microextraction (SPME) coupled with high-performance liquid chromatography-fluorescence detection (HPLC-FLD), was developed for the determination of 15 polycyclic aromatic hydrocarbons (PAHs) in food samples. PAHs were separated within 15 min by HPLC using a Zorbax Eclipse PAH column with a water/acetonitrile gradient elution program as the mobile phase. The optimum in-tube SPME conditions were 20 draw/eject cycles of 40 μL of sample using a CP-Sil 19CB capillary column as an extraction device. Low- and high-molecular weight PAHs were extracted effectively onto the capillary coating from 5% and 30% methanol solutions, respectively. The extracted PAHs were readily desorbed from the capillary by passage of the mobile phase, and no carryover was observed. Using the in-tube SPME HPLC-FLD method, good linearity of the calibration curve (r > 0.9972) was obtained in the concentration range of 0.05–2.0 ng/mL, and the detection limits (S/N = 3) of PAHs were 0.32–4.63 pg/mL. The in-tube SPME method showed 18–47 fold higher sensitivity than the direct injection method. The intra-day and inter-day precision (relative standard deviations) for a 1 ng/mL PAH mixture were below 5.1% and 7.6% (n = 5), respectively. This method was applied successfully to the analysis of tea products and dried food samples without interference peaks, and the recoveries of PAHs spiked into the tea samples were >70%. Low-molecular weight PAHs such as naphthalene and pyrene were detected in many foods, and carcinogenic benzo[a]pyrene, at relatively high concentrations, was also detected in some black tea samples. This method was also utilized to assess the release of PAHs from tea leaves into the liquor.     

Microcalorimetry as a possible tool for phenanthrene toxicity evaluation to eukaryotic cells

Microcalorimetry and measurement of culture turbidity using a Bioscreen C Analyzer System were applied to study the toxic effect of phenanthrene on Cunninghamella elegans IM 1785/21Gp spore germination. The results of C. elegans spore incubation in Bioscreen C microbiology reader showed the inhibition of spore germination by 70% (with 25 mg l⁻¹ of phenanthrene) and total inhibition of the fungus growth with a higher content of the xenobiotic (50-100 mg l⁻¹). The microcalorimetric technique showed to be useful for the estimation of metabolic activity of C. elegans spores in growth medium up to xenobiotic concentrations of 90 mg l⁻¹. These data corresponded with the microscopic observations. The obtained results showed that the microcalorimetry method could be a valuable supplement in the study on the mechanism of PAHs detoxification by fungi.