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.
ZHANG TingLI XianguoSUN ShuwenLAN HaiqingDU PeiruiWANG Min
将超声辅助碱液分解杂质与溶剂萃取相结合,采用气相色谱-电子捕获检测（GC-ECD）建立了一种快速高效净化、萃取海洋沉积物中8种常见多溴联苯醚（PBDEs）的分析方法。样品在2.00 mol/L Na OH甲醇溶液中超声30 m in,经正己烷萃取、单层硅胶净化、正己烷洗脱、旋蒸浓缩后定容至100μL,采用GC-ECD分析。结果表明,PBDEs各单体的加标回收率为63.6%～110.3%,相对标准偏差（RSD）为1.7%～15.5%（n=5）;十溴联苯醚（BDE-209）的检出限为0.097 ng/g,其他7种单体的检出限为0.002～0.011 ng/g（信噪比为3）。该方法的准确度和精密度较高,稳定性和回收率良好,可满足沉积物中PBDEs的分析要求。利用建立的方法测定了渤海表层沉积物中PBDEs的含量,8种PBDEs总含量在1.566～6.760 ng/g之间,其中BDE-209的含量为1.461～6.438 ng/g,总体呈现出由近岸向远岸递减的趋势,表明人为活动、表层冲刷和陆地河流的输入对渤海地区PBDEs的含量有重要影响。
通过对东海内陆架T06岩心样品中木质素的测定,依据木质素参数对古环境、古气候的指示作用,探究了陆源有机碳在该区域的沉积记录,以及8.8 ka B.P.以来浙闽沿岸在不同历史环境下有机物的输送机制。研究结果显示,东海内陆架海域东亚冬季风驱动的水动力输送对沉积物中木质素酚类单体的含量变化及其相关参数起着至关重要的调控作用;反之,木质素含量及其相关参数可以在一定程度上指示东亚冬季风的变化,可能是重建东亚冬季风的可靠指标。本研究还发现,木质素相关参数剧烈波动的“50年”时期,可能是由于气候变化和长江流域洪水不断,导致大量非木本被子植物残渣和表层土壤的输入,并最终在水动力和洋流作用下沉积埋藏。
