Simple determination of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) using solid-phase microextraction and gas chromatography-mass spectrometry

Solid-phase microextraction (SPME) is a simple, sensitive and less destructive method for the determination of dimethylsulfide (DMS) in seawater. Combined with detection by gas chromatography-mass spectrometry (GC-MS), the method had sufficient sensitivity (minimum detectable concentration of DMS was 0.05 nM), and practical levels of reproducibility (relative standard deviation ≤7%) and linearity (r ² > 0.995) over a wide concentration range (0.5 to 910 nM). The protocol developed was applied to a Sagami Bay water sample to determine concentrations of DMS and DMSP, and in situ DMSP-lyase activity.     

紫菜特征挥发性物质分析

应用顶空固相微萃取和气相色谱-质谱联用技术,对坛紫菜(Porphyra haitanensis)、条斑紫菜(Porphyra yezoensis)与其一个突变品系的生长藻体挥发性物质进行分析,共分离鉴定出66种挥发性组分,3个紫菜试样中分别含有36、44和45种.鉴定组分中有21种为紫菜共有挥发性物质,其中8-十七烯和...     

Occurrence and Distribution of Organic Contaminants in the Aquatic System in Berlin. Part III: Determination of Synthetic Musks in Berlin Surface Water Applying Solid-phase Microextraction (SPME) and Gas Chromatography-Mass Spectrometry (GC-MS)

Polycyclic musks and nitro musks were found as environmental pollutants in screening analyses of 30 representative surface water samples collected from rivers, lakes, and canals in Berlin. These synthetic musks, which are used as fragrances in cosmetics, detergents, and other products, are discharged by the municipal sewage treatment plants into Berlinπs surface waters. In particular, the polycyclic musks 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(g)-2-benzopyrane (HHCB; Galaxolide®, Abbalide®) and 7-acetyl-1,1,3,4,4,6-hexamethyltetraline (AHTN; Tonalide®, Fixolide®) were found in the receiving surface waters at considerable concentrations up to the μg/L-level. In the Wuhle, a small brook almost totally consisting of sewage effluents, maximum concentrations were 12.5 μg/L for HHCB and 6.8 μg/L for AHTN. Additionally, the polycyclic musk 4-acetyl-1,1-dimethyl-6-tert-butylindane (ADBI; Celestolide®, Crysolide®) and 1-tert-butyl-3,5-dimethyl-2,6-dinitro-4-acetylbenzene (musk ketone) were detected at low concentrations in most of the samples. Two other nitro musks, namely 1,1,3,3,5-pentamethyl-4,6-dinitroindene (musk moskene) and 1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene (musk xylene), were only detected in a single surface water sample. Solid-phase microextraction (SPME) with detection by gas chromatography-mass spectrometry (GC-MS) has proven to be a rapid and reliable tool for the screening of synthetic musks in surface and sewage water samples. Internal calibration with a suitable internal standard enables reproducible quantitation of the analytes down to the low ng/L-level.     

Sorption of ortho‐Phenylphenol to Soils

Conflicting sorption coefficients for ortho‐phenylphenol (OPP) have been reported in the literatures, which resulted in the conflicting assessments on OPP mobility in soil. To ascertain the sorption coefficient of OPP, batch experiments were performed based on OECD guideline 106, using three types of soils. Headspace solid‐phase microextraction (HS‐SPME) and GC‐MS were applied to the determination of OPP concentration in the liquid phase. The sorption isotherms obtained for all three soils under equilibrium conditions were described well, assuming linear sorption. The organic carbon normalized distribution coefficients (K_oc) ranged from 894 to 1703 L kg^?1, which suggested that OPP is moderately mobile in soil. The results also showed that the K_oc value of OPP can be predicted precisely from K_ow, whereas it was underestimated by one order of magnitude when water solubility is used.     

Nachweis von Industriechemikalien (HPS,BPS und SPS) im Oberflächenwasser

Occurrence of Industrial Chemicals (HPS, BPS, and SPS) in Surface Water The paper gives the results of water examinations for different phenylsulfonamides. Random samples taken every month between May 1999 and August 2000 from surface water out of the river Rhine (kilometer 838), the river Ruhr (Mülheim Styrum) and the river Emscher (Oberhausen center) were tested for the corrosion inhibiting agent 6‐[methyl(phenylsulfonyl)amino]‐hexanoic acid (HPS) as well as its metabolites 4‐[methyl‐(phenylsulfonyl)amino]‐butanoic acid (BPS) and sarkosin‐N‐(phenylsulfonyl) (SPS). Furthermore, the sewage plant effluents of two municipal wastewater treatment plants from the rural area were also included in the monitoring program. The analytical method includes solid‐phase extraction (SPE), a derivatization step as well as gas chromatography mass spectrometry (GC‐MS). SPS is regularly found in all investigated surface waters, but only occasionally in the effluents of the two rural sewage plants. The median values for SPS amount to 0.09 μg/L in the river Rhine, 0.60 μg/L in the river Ruhr, and 0.70 μg/L in the river Emscher. BPS can only be found in the river Ruhr (median value: 0.08 μg/L) and in the river Emscher (median value: 0.41 μg/L). HPS was regularly found in a surface water for the first time. This substance can be detected in the Emscher through the whole measurement period. The median value for HPS amounts to 1.78 μg/L. Aditionally, the validation characteristics of an alternative analytical method including solid‐phase microextraction (SPME) is worked out. The fully automated process includes an on‐fiber methylation step and the GC‐MS. The repeatability standard deviation of the process amounts to RSD < 12%. Detection limits between 0.07 and 0.70 μg/L are achieved.     

Development of a SPME-GC Method for the Determination of Organic Compounds in Wastewater

A manual SPME method is presented for the analysis of organic compounds in industrial wastewater. 24 compounds commonly found in the wastewater of a chemical plant in northern Germany have been selected as reference compounds. Precision, linearity, and detection limits have been determined. Moreover, the effect of methanol content, pH value, salt content, and an excess of compounds on the extraction process have been studied. Several compounds have been investigated for their applicability as internal standards to quantify the compounds of interest. Since the method will later be transferred to a fully automated SPME-GC system, which will be operated directly on-site at an industrial wastewater purification plant, special attention has been paid to the analysis of real wastewater samples. In this context, the fibre stability has been studied by performing 53 extraction/desorption cycles from one wastewater sample. Neither a decrease in fibre performance nor in precision has been observed indicating that the proposed method is suitable for the analysis of real wastewater.     

Kinetics and Products of the Gas-Phase Reaction of OH Radicals with 5-Hydroxy-2-Pentanone at 296± 2 K

The 1,4-hydroxycarbonyl 5-hydroxy-2-pentanone is an important product of the gas-phase reaction of OH radicals with n-pentane in the presence of NO. We have used a relative rate method with 4-methyl-2-pentanone as the reference compound to measure the rate constant for the reaction of OH radicals with 5-hydroxy-2-pentanone at 296 ± 2 K. The carbonyls were sampled by on-fiber derivatization using a Solid Phase Micro Extraction (SPME) fiber coated with O> -(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride with subsequent thermal desorption of the oxime derivatives and quantification by gas chromatography with flame ionization detection. For comparison, the reference compound was also analyzed following sample collection onto a Tenax adsorbent cartridge. Products of the reaction were investigated using coated-fiber SPME sampling with gas chromatography-mass spectrometry analysis as well as by using in situ atmospheric pressure ionization mass spectrometry. A rate constant for the reaction of OH radicals with 5-hydroxy-2-pentanone of (1.6 ± 0.4) × 10^–11 cm³ molecule^–1 s^–1 was obtained at 296 ± 2 K. Two dicarbonyl products, of molecular weight 86 and 100, were observed and are attributed to CH₃C(O)CH₂CHO and CH₃C(O)CH₂CH₂CHO, respectively. Reaction schemes leading to these products are presented.     

利用鳕鱼皮蛋白制备热反应型肉香调味基料的研究

以复合酶深度水解鳕鱼皮蛋白为主要原料,通过与半胱氨酸和葡萄糖的美拉德反应制得肉香风味,并通过固相微萃取-气相-质谱联用技术检测鉴定出大量的肉香味物质.为鳕鱼皮蛋白水解物制备肉香调味基料提供理论依据.     

固相微萃取技术在油气化探中的应用

使用美国Supelco公司固相微萃取装置和烃类标样建立了固相微萃取—气相色谱—质谱法（SPME-GC/MS）准确定性、定量检测C5～C15烃类的技术。在河南南阳凹陷进行了顶空气和SPME-GC/MS对比分析,结果表明顶空气甲烷与SPME指标的油气指示意义吻合;对四川盆地川中地区地表水及油田水的检测结果表明,根据钻井油田水的SPME-GC/MS谱图特征可以较为准确地判断钻井油气属性;在鄂尔多斯盆地西峰油田的油气化探中,发现SPME技术检测出的C5～C15总烃异常区域与长8主力油气藏范围的对应关系很好。     

Artefaktfreie GC-Bestimmung von Trihalogenmethanen in Schwimmbeckenwasser nach Anreicherung mittels Headspace-Festphasenmikroextraktion

Artefact-free Determination of Trihalomethanes in Chlorinated Swimming-pool Water Using Headspace Solid-phase Microextraction and Gas Chromatography Headspace solid-phase microextraction (headspace SPME) is a rather new technique for the solvent-free extraction and concentration of volatile substances from water into an organic polymer layer covering a fused-silica fiber. In combination with gas chromatography, the method represents a powerful tool for sensitive headspace investigations. As the adsorption of low boiling substances is favoured at low temperatures, the method can be operated at ambient temperature without formation of artefacts. Therefore, the method is ideally suited for the analysis of volatile disinfection by-products in water including several thermolabile THM-precursors. For the artefact-free determination of trihalomethanes it is superior to headspace gas chromatography under the conditions of the German standard method DIN 38407-F5. Compared to gas chromatography after pentane extraction (DIN 38407-F4), headspace SPME is simpler, less- laborious, better reproducible, and, especially for polar, easily water-soluble components, much more sensitive. In addition, it operates solvent-free and can be automated. Using a 100-μ polydimethylsiloxane-coated fiber, the method is linear over at least 2 orders of magnitude and has a relative standard deviation of 2… 7% in the upper ng/L range. With a 65-μ polydimethylsiloxane/divinylbenzene-coating on the fiber, the sensitivity of the method can be extended to limits of quantitation in the low ng/L range. However, this fiber, shows an increased susceptibility to matrix effects as observed in the presence of diisopentyl ether, which can only be compensated by using the method of standard addition.