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11.
Lignin serves as one of the most important molecular fossils for tracing Terrestrial Organic Matters (TOMs) in marine environment. Extraction and derivatization of lignin oxidation products (LOPs) are crucial for accurate quantification of lignin in marine sediment. Here we report a modification of the conventional alkaline cupric oxide (CuO) oxidation method, the modification consisting in a solid phase extraction (SPE) and a novel on-column derivatization being employed for better efficiency and reproducibility. In spiking blanks, recoveries with SPE for the LOPs are between 77.84% and 99.57% with relative standard deviations (RSDs) ranging from 0.57% to 8.04% (n=3), while those with traditional liquid-liquid extraction (LLE) are from 44.52% to 86.16% with RSDs being from 0.53% to 13.14% (n=3). Moreover, the reproducibility is greatly improved with SPE, with less solvent consumption and shorter processing time. The average efficiency of on-column derivatization for LOPs is 100.8% ± 0.68%, which is significantly higher than those of in-vial or in-syringe derivatization, thus resulting in still less consumption of derivatizing reagents. Lignin in the surface sediments sampled from the south of Yangtze River estuary, China, was determined with the established method. Recoveries of 72.66% to 85.99% with standard deviation less than 0.01mg/10g dry weight are obtained except for p-hydroxyben-zaldehyde. The lignin content Σ8 (produced from 10 g dry sediment) in the research area is between 0.231 and 0.587 mg. S/V and C/V ratios (1.028 ± 0.433 and 0.192 ± 0.066, respectively) indicate that the TOMs in this region are originated from a mixture of woody and nonwoody angiosperm plants; the high values of (Ad/Al) v suggest that the TOMs has been highly degraded. 相似文献
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介绍了开源的纯Java语言图像处理程序——ImageJ,以及如何利用ImageJ程序包进行二次开发.利用该程序包,实现了从WinView所获取的图片文件格式TIFF、SPE到FITS文件格式的批量转换.并在此基础上,提出了如何利用该程序包实现其它图片格式之间相互单独以及批量转换的方法. 相似文献
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建立了分析土壤和水中的莠去津农药残留的反相高效液相色谱方法。使用去离子水对土壤中的莠去津进行提取，Sep—Pak C18反相固相萃取柱对土壤浸提液和水样进行富集、浓缩、纯化，并用1．5—2mL的甲醇洗脱，利用甲醇—水作为流动相，采用等梯度淋洗技术进行高效液相色谱分析。莠去津在土壤中不同添加水平回收率分别为87．0％—93．3％，水中则为97．3％—103．2％，介于80％—120％。莠去津的最小检出量为0．01ng，土壤和水中莠去津最低检出浓度分别为1．5ng／g和0．03μg／L水平。该方法由于用水提取及固相萃取技术的使用，使整个前处理过程有机试剂的使用量仅为数毫升，适用于监测环境中的莠去津农药污染。 相似文献
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固相萃取-衍生化-气相色谱-质谱联用测定不同水体中类固醇雌激素方法研究 总被引：3，自引：1，他引：2
针对地下水及地表水体样品中痕量类固醇雌激素(SEs)污染问题,本文建立了固相萃取-衍生化-气相色谱-质谱联用(SPE-GC-MS)同时测定不同水体中5种SEs:雌酮(E1)、17α-雌二醇(17α-E2)、17β-雌二醇(17β-E2)、17α-乙炔基雌二醇(EE2)、雌三醇(E3)的分析检测方法。通过优化固相萃取过程和衍生化条件以及复杂样品的二次净化过程,发现用Oasis HLB柱萃取,用乙酸乙酯洗脱,40℃条件衍生化20 min可以达到最佳效果,并且经甲醇活化过的Generik NAX柱对复杂样品的二次净化效果较好。本方法对E1、17α-E2、17β-E2和EE2、E3检测的线性范围分别为5~1000 ng/L和10~1000 ng/L;方法检出限和定量限分别为2~3 ng/L和6.5~10 ng/L;对水样的加标回收率范围为80%~120%;该方法测定SEs峰面积的日内相对标准偏差为6.8%~10%。应用此方法对鱼塘水、河水、地下水、污水处理厂二级出水进行了SEs污染水平检测,结果表明该检测技术可以有效应用于不同水质地表及地下水体类固醇雌激素化学风险识别与评估。 相似文献
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In the present study an analytical method was tested for the determination of selected pesticides and metabolites using solid‐phase extraction (SPE) and gas chromatography ion‐trap mass spectrometry (GC‐MS). The extraction efficiency of C18, Isolut ENV+, and Lichrolut EN for SPE was compared for trifluralin, fenitrothion, endosulfan, propargite, 2,4‐D, 3‐methyl‐4‐nitrophenol, 2‐(4‐tert‐butylphenoxy)cyclohexanol, endosulfan sulfate, and 2,4‐dichlorophenol. Isolut ENV+ and C18 showed good results as sorbents and acetone as an elution solvent for SPE for the selected pesticides. Recoveries varied between 36% and 176% with a relative standard deviation of 2...18%. Because of coextracts from the SPE materials, recovery values higher than 100% were obtained for fenitrothion, endosulfan sulfate, and 2,4‐D with C18 as well as for endosulfan sulfate and 3‐methyl‐4‐nitrophenol with Isolut ENV+. A standard addition method was used to verify the occurrence of coextracts in the sample after SPE. 相似文献
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莱州湾海域水体中有机氯农药和多氯联苯的浓度水平和分布特征 总被引：18，自引：0，他引：18
以固相萃取/气相色谱法测定了莱州湾海域水体中22种有机氯农药和多氯联苯类化合物的浓度水平和分布特征。结果表明,莱州湾海域表层水体中有机氯农药浓度范围为N.D.~32.7ng/L,底层水中的浓度范围为N.D.~11.7ng/L。在该海域水体中共检出有机氯农药3种,β-666是水体中主要的有机氯农药污染物。多氯联苯类在底层水样中检出2种,总浓度范围在4.5~27.7ng/L之间。该海域有机氯农药和多氯联苯的分布特征是近岸高,离岸低,由近岸向湾外延伸方向依次递减。并对莱州湾表层水中总有机氯农药与海水盐度、氯度、溶解氧和pH间的关系作了初步探讨,得出总有机氯农药与盐度、氯度间有一定的相关关系,相关系数均为0.59。方法测定5种有机氯农药化合物的空白加标回收率为97.3%~126.0%,相对标准偏差为2.8%~8.6%;测定5种多氯联苯类化合物的空白加标回收率为88.6%~151.8%,相对标准偏差为6.7%~10.4%。 相似文献
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《Limnologica》2021
The influence of dissolved organic matter (DOM) on mineral extraction from salt lake brines depend on DOM quality. This study contributes to our knowledge of DOM’s metal binding behavior in hypersaline environments by characterization of DOM from lakes in the Qaidam Basin, i.e., Qarhan Lake (LQDOM), Da Qaidam (DQDOM) and West Ginair Salt Lake (WGDOM). The DOM was fractionated based on solid phase extraction (SPE) and ultrafiltration (UF), and the spectral and metal binding behavior of these fractions were studied by absorption spectroscopy, Pb(II) titration techniques and fluorescence parallel factor (PARAFAC) analysis. The results showed that bulk DOM generally contained more dissolved organic carbon (DOC), lower specific UV absorbance (SUVA254), higher fluorescence and biological indices, comparable humification index, and lower condition stability constants compared to the other nature waters. Compared with UF, SPE-derived DOM exhibited higher DOC recovery and aromaticity and lower carbohydrate yield. It appeared that the SPE procedure used affects the spectral composition of bulk DOM to a larger extent than UF. Source and molecular weight (MW)-dependent differences in abundance and quality of brine DOM was indicated by higher SUVA254 in high MW DOM, for LQDOM and DQDOM, and humic-like fluorophores were mainly in high MW-DOM in each lake. Moreover, the high MW humic-like component exhibited higher metal binding potential than the bulk and low MW counterparts for LQDOM and DQDOM, while the inverse was observed for WGDOM. This study revealed the effects of isolation techniques on interpretation of DOM characteristics, and meanwhile highlighted the importance of origin- and MW-dependent DOM in manipulating the behavior, fate, and bioavailability of heavy metals in salt lake brine. 相似文献
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Token Bos经过适当修改和发展可以移植到以太网上，再通过对硬实时协议栈RTCC的改造，可以将两种协议融合为一种基于以太网技术的具有传输硬实时、软实时和非实时数据功能的综合业务网络访问控制技术（ISE），即可在一套系统中同时实现传统网络业务和硬实时数据传输业务。 相似文献
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作为新污染物的磺胺类(Sulfonamides,SAs)是应用最早的一类人工合成抗菌药物,被广泛应用于人类、农业、畜牧业和水产养殖。进入体内的磺胺类合成药物随代谢排入水环境中,对水生生态系统和人类健康构成潜在威胁。环境中磺胺类合成药物的准确分析测定是探析其环境生物地球化学特性的基础,近年来,随着科学技术的进步,已构建了适于水环境中痕量磺胺类合成药物的快速灵敏测定方法,特别是样品的前处理与分离富集技术有了跨越式的发展。总结归纳了近年来水环境中磺胺类合成药物的样品前处理技术以及分析方法的研究进展,分析了不同环境样品前处理技术和分析方法的优缺点,在此基础上,前瞻分析了水环境磺胺类合成药物分析测定的发展思路。具有回收率高、选择性强、重现性好、成本低、环境友好及可自动化等优势的固相萃取(Solid phase extraction,SPE)作为液相萃取(Liquid-liquid extraction,LLE)的替代方法,现已被广泛应用于水环境中痕量磺胺类合成药物的分离和富集,随着新型吸附剂材料的发展,SPE的灵敏度和选择性得到了明显提升。液相色谱(Liquid chromatography,LC)与串联质谱(Tandem mass spectrometry,MS/MS)联用技术是目前磺胺类合成药物的主要定量分析方法,具有检测限低、灵敏度高、多种目标物的同时检测及重现性好等优点。未来应从重点关注磺胺类代谢产物及降解产物在水环境中残留的角度,开发更为操作简单、快速且灵敏的分析测定方法,以便更有效地监管水环境中人工合成药物的生态环境效应。 相似文献