Determination of Phenolic Compounds from Lignin Decomposition Products in Marine Sediments by Ultra-High Performance Liquid Chromatography-High Resolution Mass Spectrometry
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摘要:
木质素分解产物酚类化合物是指示海洋环境中陆源有机碳来源的重要生物标志物，因此，开发检测海洋沉积物中木质素分解产物酚类化合物的简便方法，对研究海洋有机碳的来源及生物地球化学循环过程具有重要意义。本文采用固相萃取（SPE）和超高效液相色谱-飞行时间质谱技术(UHPLC-TOF/MS)，建立了一种同步测定海洋沉积物中木质素分解产物酚类化合物（11种）的方法。首先对海洋沉积物样品进行氧化铜氧化碱分解和SPE净化处理，再采用填料粒径为1.8μm的反相C18柱进行分离，电喷雾TOF/MS全扫描模式检测，内标法定量。结果表明：沉积物中木质素的11种主要分解产物酚类化合物在20min内分离良好；方法具有良好的精密度（相对标准偏差RSD均小于9.0%），在线性范围内相关系数（R2）均不小于0.9989，加标回收率在86.8%～93.2%之间。应用该方法对莱州湾表层沉积物中木质素分解产物酚类化合物进行测定，12个表层沉积物样品中11种目标化合物的检出率均为100%；相关诊断比值：肉桂基酚系列单体总量与香草基酚系列单体总量的比值C/V在0.18～0.81之间，均值为0.38；丁香基酚系列单体总量与香草基酚系列单体总量的比值S/V在0.18～0.45之间，均值为0.26；对羟基酚系列单体中酮的量与对羟基酚系列单体总量的比值PON/P在0.01～0.07之间，均值为0.03；P系列单体总量与V和S系列单体总量之和的比值P/(V+S)在0.55～3.77之间，均值为1.44；V系列中酸类单体与醛类单体的比值(Ad/Al)v在0.12～1.07之间，均值为0.49；S系列单体中酸类单体与醛类单体的比值(Ad/Al)s在0.15～1.26之间，均值为1.02。表明莱州湾表层沉积物中的木质素主要来源于被子植物草本组织，并且具有中等或偏高程度的降解，但仍有少量新鲜植物有机质。本研究也表明UHPLC-TOF/MS是测定海洋沉积物中木质素分解产物酚类化合物的高效方法，能对沉积物中木质素含量和有机质来源进行有效指示。
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关键词:
- 电喷雾飞行时间质谱法 /
- 木质素 /
- 酚类化合物 /
- 有机碳 /
- 莱州湾
Abstract:BACKGROUNDLignin is an important component of marine organic carbon. It is also an important biomarker for extracting information on the evolution of the land and marine environment and tracking the source of organic marine matter. However, the existing analytical techniques are difficult to determine lignin directly. So, the content of phenolic compounds in the decomposition products of lignin in marine sediments were generally determined to indicate the content of lignin and the source of organic matter. The content of phenolic compounds in the decomposition products of lignin in marine sediments is often used to reflect the content of lignin. In addition, by calculating the diagnostic ratio of individual phenolic compounds, it also provides important information about the classification, source, and diagenesis of terrestrial organic matter in marine sediments. However, phenolic compounds in the decomposition products of lignin have the characteristics of strong polarity and low volatility, so they cannot be directly detected by gas chromatography and need to be derivatized first, which makes the sample processing complicated and often results in incomplete derivatization. Therefore, it is of great significance to develop a simple and reliable method for determination of phenolic compounds of the lignin decomposition products in marine sediments to explore the source of organic matter and understand the environmental evolution process.
OBJECTIVESTo establish a simple and reliable method for the determination of phenolic compounds of lignin decomposition products in marine sediments using solid phase extraction (SPE) combined with ultra-high performance liquid chromatography-high resolution mass spectrometry, and to trace the content level and source of lignin in the sediments of Laizhou Bay in China.
METHODSMarine sediment samples were first decomposed with oxidative-alkaline CuO and extracted by solid phase extraction. Briefly, the oxidation was carried out in a polytetrafluoroethylene digestion tank. 1.00g of sediment sample, 500mg of copper oxide, and 100mg of ammonium ferrous sulfate were accurately weighed and placed in the tank. The components were thoroughly mixed with the sample and then the digestion tank was transferred to a glove box filled with nitrogen. 8.0mL of aqueous sodium hydroxide solution with a concentration of 8.0% (bubbled with N2 to remove dissolved oxygen) was added to the tank. The digestion tank was covered tightly and transferred to an oven heating to 150℃ for reaction, which was terminated after 3h. After the digestion tank cooled to room temperature, it was carefully unscrewed, and an internal standard (ethyl vanillin) solution was added. Subsequently, the hydrolysate was transferred to a centrifuge tube, spun at 8000r/min for 10min, and the supernatant and reaction residue was separated. 2.0mL of 1.0% sodium hydroxide solution was added to rinse the residue, and centrifuged at 8000r/min for 10min. Combining the centrifuged supernatant obtained twice, the solution was acidified to pH=1 with hydrochloric acid. After the solution was left to stand for 30 minutes, solid phase extraction was performed. The SPE procedure was as follows: A hydrophilic-lipophilic balance (HLB) SPE cartridge (200mg, 6mL) was conditioned with 5mL of methanol and 5mL of ultrapure water. Sample solution was passed through the cartridge in a flow rate 1.0mL/min, and then the cartridges were rinsed with 10mL water, and dried under vacuum for about 3min. Phenolic compounds were eluted with 10mL ethyl acetate, and were evaporated by a rotary evaporator, reconstituted with sample solvent. Then, ultra-high performance liquid chromatography using ZORBAX Eclipse XDB-C18 column with packing particle size of 1.8μm was used to directly separate all target compounds at 28℃, with gradient elution. The mobile phase was composed of ultrapure water with 0.1% formic acid (V/V) and acetonitrile/methanol (9:1, V/V) , and the flow rate was set to 0.25mL/min. Electrospray ionization (in positive) time of flight mass spectrometry was applied to detect target compounds in full scan mode, and quantification was performed using an internal standard determination.
RESULTSFirstly, chromatographic conditions and solid phase extraction conditions were systematically optimized. Ultra-high performance liquid chromatography was used for the chromatographic separation of phenolic compounds from lignin decomposition products in marine sediments. The separation effects of three mobile phase systems, namely, water-acetonitrile, water- methanol, and water-methanol-acetonitrile, were compared. When using a water-methanol -acetonitrile ternary mobile phase system, the resolution of various phenolic compounds was superior to the commonly used water-acetonitrile or water-methanol binary mobile phase systems in the literature. In addition, the effects of mobile phase acidity (trifluoroacetic acid, formic acid, and acetic acid were added into the mobile phase) on the separation of various phenolic compounds were investigated. The results showed that adding a certain concentration of all three acids to the mobile phase provided better separation results. Considering the compatibility with mass spectrometry, it was finally determined that adding 0.1% formic acid into the mobile phase achieved good peak patterns and resolution. In order to determine the ionization mode suitable for the analysis of phenolic compounds from lignin decomposition products in marine sediment, electrospray ionization (ESI) mass spectrometry was performed on each target phenolic compound in ESI+ and ESI− mode, respectively. Under ESI+ mode, various target phenolic compounds were less affected by interfering substances in the sample matrix, and the MS response value for most of the phenolic compounds was higher than that found in ESI− mode. Hence, ESI-TOF/MS in positive mode was selected to determine phenolic compounds of lignin decomposition products in marine sediment. Subsequently, the fragmentation voltage was optimized to obtain the highest sensitivity for all target phenolic compounds, which was the main mass spectrometric condition that affected the quantification accuracy and sensitivity. The effect of fragmentation voltage on the MS response signal of each target phenolic compound was investigated in the range of 80V to 200V. Overall, considering the detection sensitivity of the [M+H]+ ion peak of each target compound, 130V was selected as the optimal fragmentation voltage to determine phenolic compounds of lignin decomposition products in marine sediment. The effect of pH (1.0-2.5) of the loading solution for solid phase extraction on the extraction efficiency of various target phenolic compounds was systematically investigated, to ensure that the phenolic compounds of lignin decomposition products in marine sediments have a good recovery rate during the SPE process. When the pH of the loading solution was 1.0 and 1.5, the recovery rate of various phenolic compounds by using HLB solid phase extraction column was significantly higher than that of the loading solution adjusted pH to 2.0 and 2.5. When the pH of the sample solution was 1.0 and 1.5, although the recoveries of syringaldehyde and acetovanillone were relatively similar, the recoveries of other phenolic compounds were the highest at a pH of 1.0. Considering the recovery rate of all the target phenolic compounds and applicability of the method, the pH of the sample solution was confirmed to adjust to 1.0. In this study, HLB SPE column with 200mg of packing material was used to enrich phenolic compounds in sample extraction solution. Generally, 5-10mL of eluting solvent can ensure the full elution of all target phenolic compounds adsorbed on the SPE column. Therefore, based on the results of literature research, ethyl acetate was finally selected as the eluting solvent, with a dosage of 10mL. Under the optimum experimental conditions, the 11 main decomposition phenol compounds of lignin in marine sediments were well separated within 20 minutes. The proposed method had good precision (RSD was less than 9.0%), the correlation coefficient (R2) was not less than 0.9989 in the linear range, and the recovery rate of all spiked phenol compounds in blank marine sediment was in the range of 86.8%-93.2%, thereby indicating that the developed method would be suitable to determine the target decomposition phenol compounds of lignin in marine sediment. Subsequently, the method was used to determine the phenolic compounds of lignin decomposition products in the surface sediments of Laizhou Bay. The detection rate of 11 target phenolic compounds in 12 surface sediment samples was 100%, and the concentration of Σ8 in 12 surface sediment samples ranged from 0.001mg/10gds to 0.019mg/10gds. The value of C/V was between 0.18 and 0.81, with an average of 0.38; the value of S/V was between 0.18 and 0.45, with an average of 0.26; PON/P value was between 0.01 and 0.07, with an average of 0.03; P/(V+S) value was between 0.55 and 3.77, with an average of 1.44; (Ad/Al)v value was between 0.12 and 1.07, with an average of 0.48; the value of (Ad/Al)s was between 0.15 and 1.26, with an average of 1.02.
CONCLUSIONSThe above diagnostic ratios indicate that the lignin in the surface sediments of Laizhou Bay originate mainly from the herbaceous tissue of angiosperms, while the proportion of organic matter in vascular plants is relatively low. The degradation degree of terrestrial organic matter in most sampling stations is medium or high, but there is still a small amount of fresh plant debris. The proposed method has the advantages of high efficiency, simple for sample pretreatment, and is a powerful technique for the determination of main decomposition product phenolic compounds of lignin in marine sediments.
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天然气水合物，是在一定条件下(合适的温度、压力、气体饱和度及水的盐度等)由水和天然气组成的冰状笼形结晶化合物。形成天然气水合物的主要气体为甲烷，甲烷分子含量超过99%的天然气水合物通常称为甲烷水合物(Methane Hydrate)[1]。天然气水合物的结构类型有Ⅰ型、Ⅱ型、H型和一种新型的水合物(由生物分子和水分子生成)[2-3]。Kvenvolden等[4]和Milkov[5]曾预测全球有机碳超过1×105亿吨(甲烷在标准温压条件下为21×1015 m3)，主要以甲烷形式存在，并赋存于水合物中。目前，冻土带和海底已经开展了天然气水合物的相关实验及开采[6]。与冻土带所蕴藏的天然气水合物相比，海底沉积层中发育的水合物资源量可能更为巨大[7], 在全球79个国家累计已发现超过230个天然气水合物矿点(NGHD)[8]。因此，合理开采海底天然气水合物将是解决全球能源危机的有效途径[9-10]，同时天然气水合物也可能诱发海底地质灾害[11]以及影响全球气候的变化[12], 所以了解天然气水合物的稳定条件成了一个核心的科学问题。
甲烷水合物稳定性受控于温度、压力、孔隙水盐度和气体组分等因素。天然气水合物主要发育在具备水合物生成的温压、气源等条件的海洋沉积层中和极地地区[13-15]，所以研究水合物发育区的压力、温度、地温梯度、导热率及热流等参数，可以预测水合物赋存范围[16]。似反射层与海底之间所限定的厚度为天然气水合物稳定存在的厚度即天然气水合物稳定带(GHSZ)[17]。天然气水合物稳定带(GHSZ)是指温度和压力处于天然气水合物形成和稳定存在的热力学范围内的特定区域[18]。因而，预测目标区水合物资源量必须明确水合物稳定带厚度，对评估天然气水合物资源具有重要意义[19-21]。已有研究表明甲烷水合物实际存在区的厚度随盐度的增大而变薄，盐的存在降低了气体水合物的稳定性，导致水合物稳定带的厚度比纯水情况下的厚度变薄[22-23]。孔隙水中的盐类对水合物的生成和稳定存在有抑制作用[7, 24-25]，1888年Villard[26]第一次在CH4-H2O二元体系中获得了甲烷水合物。Deaton等[27]最早提出了研究水合物的抑制性，直到1983年de Roo等[28]才将盐度考虑进来，并系统研究了CH4-H2O-NaCl三元体系下甲烷水合物相平衡时的温压条件。事实上，盐度对水合物系统的影响是预测海底甲烷气水合物存在、分布和演变的一个重要因素。海相水合物形成于含海水(Cl-、Na+、Mg2+、SO42-、Ca2+以及过渡金属Fe、Mn、Cu、Co、Ni)的沉积层中，所以必须明确水合物在复杂体系中的平衡，拟为确定水合物的形成、分解以及资源量奠定基础[25, 29-30]。研究盐类对甲烷水合物的稳定性主要是通过实验测试(目测法、等压法、等容法)和热力学计算来确定天然气水合物的相平衡点[28, 31-37]。
1. 天然气水合物相平衡的研究方法
1.1 气体水合物相平衡热力学方法
气体水合物相平衡热力学主要解决气体水合物形成和稳定存在的温度、压力条件，预测已知状态系统是否可形成水合物，其理论依据主要是多相系统相平衡理论[34]。气体水合物相平衡的理论模型已经研究得比较成熟，并在指导水合物理论研究和工程应用方面发挥了积极的作用。Parrish等[38]第一次基于van der Waals-Platteeuw统计热力学模型[34]预测纯水条件下水合物的形成。随后这种方法被不断修改，但大多数预测模型的基本思想都来源于van der Waals-Platteeuw统计热力学模型[34]，预测模型的缺点就是所需的参数较多，计算繁琐，应用起来不方便[23-25, 30-32, 35-37, 39-41]。由于水合物形成于地层中，地层水是一个复杂的盐水体系，水合物形成的温度与纯水体系差异较大。Englezos等[42]、Shabani等[43]、Javanmardi等[44-45]的模型可用于预测盐水体系中水合物的相平衡。在盐水体系中，离子与水分子反应降低了水的活性，因此将盐对水合物的影响转移到水活性的变化，将溶液中水的活性加入到模型中来预测水合物相平衡。这些热力学模型计算水合物生成条件时，大多忽略了气体在富水相的溶解对水合物生成条件的影响，这会给计算结果带来一定的误差。水合物模型在适宜的温度(小于290 K)和压力(小于20 MPa)条件下的预测结果较好，而在高压下，如大于20 MPa，模型的预测结果与实验数据偏差较大，表明当前的水合物模型对于水合物稳定性描述并不完美[46]。
1.2 气体水合物相平衡实验分析方法
以往采用压力-温度-体积测试仪(简称PVT仪)来研究气体水合物的形成热力学，通过目测PVT仪中天然气水合物的形成过程，确定形成时的温度和压力，但是PVT仪器笨重且昂贵，不方便使用，实验过程中遇到固体微粒时，PVT方法就无法测量。此外，PVT无法定量评价天然气水合物的动力学性质[31]。后来将差示扫描量热仪(Differential Scanning Calorimetry，缩写DSC)应用到天然气水合物的研究中，它的原理主要是根据实验过程中热流量的变化判断水合物的形成，与样品的黏度、透明度等无关，是研究水合物一种简单、可靠的工具[47-48]。但是不能满足水合物的微观观测和定量研究。
相比于PVT仪、DSC、热力学计算，用原位拉曼光谱技术研究甲烷水合物生成条件可以有效地避免热力学方程中复杂参数的求算，同时具有可视、准确、结果可靠的优势。显微激光拉曼光谱是将入射激光通过显微镜聚焦到样品上，从而可以在不受周围物质干扰情况下，准确获得所照样品微区的有关化学成分、晶体结构、分子相互作用以及分子取向等各种拉曼光谱信息[49-50]。近些年来，国内外学者[51-56]已成功地应用激光拉曼光谱分析天然气水合物形成条件。Subramanian等[52]的研究表明，不同类型甲烷水合物的拉曼光谱明显不同，Ⅰ型甲烷水合物和Ⅱ型甲烷水合物的特征拉曼峰的峰强具有明显的差别，可以在拉曼谱图上明确区分开来(图 1)。Chazallon等[53]发现，甲烷水合物不仅在C—H键处有其独特的拉曼峰，同时其O—H键也有一个特征峰位于3051 cm-1。所以，通过拉曼光谱可以清楚地识别体系中甲烷所处的相态特征，这为原位甲烷水合物拉曼光谱分析提供了依据。吕万军等[56]通过原位拉曼光谱结合透明高压腔，测定甲烷水合物形成过程中溶液中饱和甲烷浓度的变化来确定水合物的形成条件。Jager等[33]结合显微拉曼光谱，可以将Ⅰ型甲烷水合物的形成和分解在拉曼谱图上清楚地确定，随着水合物的形成和分解，其拉曼峰也发生着相应的变化。因此，原位拉曼光谱技术可以准确测定甲烷水合物在不同盐水体系中形成和分解的温压条件。
2. 盐类对甲烷水合物的影响
根据DSDP(Deep Sea Drilling Project，深海钻探工程)和ODP(Offshore Driling Platform，海上钻井平台)[57]采集的海底沉积物，对孔隙水成分进行分析，结果表明海洋沉积孔隙水中，Cl-、SO42-、Na+、Ca2+、Mg2+、K+、NH4+是主要离子，CO32-和PO43-相对含量低一些。以下将从氯化物、硫酸盐、碳酸盐三大盐类出发，探讨盐类对甲烷水合物稳定性的影响以及相平衡条件。
2.1 氯化物对甲烷水合物稳定性的影响
2.1.1 氯化钠对甲烷水合物稳定性的影响
国内外学者[24, 28, 58-61]通过不同的实验研究了盐类，特别是NaCl对甲烷水合物稳定性的影响。对于NaCl-CH4-H2O体系，各种实验手段殊出同归，最后的实验数据皆表明随着NaCl浓度的增加，甲烷水合物稳定存在的温压范围逐渐缩小，NaCl浓度越高，甲烷水合物稳定存在的温度越低，压力越高。盐度每增加1 mol/L，在压力恒定的情况下，温度降低3~4 K；同样在温度恒定的情况下，压力升高2 MPa左右(图 2a)。除了NaCl，其他氯化物对甲烷水合物稳定性的影响也不容忽视，但整体的影响趋势是一致的，都是随着盐度的增加，甲烷水合物稳定存在的温压范围缩小[61-63]。
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2.1.2 其他氯化物对甲烷水合物稳定性的影响
目前针对CaCl2、MgCl2、KCl等对甲烷水合物的抑制作用研究甚少，Kharrat等[61]对不同浓度的CaCl2-CH4-H2O体系进行分析，随着CaCl2浓度的增加，甲烷水合物稳定存在的温压范围逐渐缩小，CaCl2浓度越高，甲烷水合物稳定存在的温度越低，压力越高。盐度每增加0.5 mol/L，在压力恒定的情况下，温度降低幅度由小变大最后趋于稳定，开始时温度只下降2.5 K，盐度在1.530 mol/L后温度稳定下降4 K左右；同样在温度恒定情况下，压力升高降低幅度由小变大最后趋于稳定，开始时压力只升高约2 MPa，盐度在1.530 mol/L后压力稳定升高约5 MPa(图 2b)。
Atik等[62]和Kang等[32]对不同浓度的MgCl2-CH4-H2O体系进行分析，随着MgCl2浓度的增加，甲烷水合物稳定存在的温压范围逐渐缩小，MgCl2浓度越高，甲烷水合物稳定存在的温度越低，压力越高。盐度每增加0.5 mol/L左右，在压力恒定的情况下，温度降低幅度由小变大；同样在温度恒定的情况下，压力升高幅度由小变大(图 2c，d)，即MgCl2盐度越高，对甲烷水合物的抑制作用强度越大。
Mohammadi等[63]对不同浓度的KCl-CH4-H2O体系进行分析，但是有关的实验数据较少，只对0.676 mol/L和1.315 mol/L的KCl进行了实验测试。随着KCl浓度的增加，甲烷水合物稳定存在的温压范围逐渐缩小，KCl浓度越高，甲烷水合物稳定存在的温度越低，压力越高。盐度每增加0.5 mol/L左右，在压力恒定的情况下，温度降低2 K；同样在温度恒定的情况下，压力升高1 MPa(图 2e)。
2.1.3 氯化物对甲烷水合物抑制作用大小
当氯化物浓度小于0.5 mol/L时，NaCl、CaCl2、MgCl2和KCl对甲烷水合物的抑制作用大小相近。但随着浓度的上升，当氯化物浓度大于1.5 mol/L后CaCl2对甲烷水合物稳定存在时的温压条件影响较大，浓度每升高0.5 mol/L，温度下降4 K，压力升高5 MPa。而其他盐类对甲烷水合物的抑制作用相近。浓度相近(大于1mol/L，小于1.5 mol/L)的NaCl、CaCl2、MgCl2和KCl对甲烷水合物的抑制作用进行对比，发现MgCl2对甲烷水合物的抑制作用最强，KCl最弱。抑制作用大小依次是MgCl2>CaCl2>NaCl>KCl(图 2f)。
2.2 硫酸盐和碳酸盐对甲烷水合物稳定性的影响
大部分的实验都是研究氯化物对甲烷水合物稳定性的影响，但是很少考虑到硫酸盐和碳酸盐对甲烷水合物的抑制作用，相关的研究也比较少。Lu等[65]通过实验确定了1 mol/L和0.5 mol/L的MgSO4对甲烷水合物稳定存在时的温压条件的影响，增加0.5 mol/L的MgSO4，在压力恒定的情况下，温度降低2 K；同样在温度恒定的情况下，压力升高0.7 MPa(图 3a)。相比于氯化物，MgSO4对甲烷水合物稳定存在时的压力影响较小。
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Mohammadi等[64]将K2CO3考虑进来，实验研究0.319 mol/L和1.064 mol/L的K2CO3对甲烷水合物的抑制作用，随着浓度的升高，甲烷水合物稳定存在的温压范围缩小，K2CO3浓度上升0.745 mol/L，在压力恒定的情况下，温度降低1.2 K；同样在温度恒定的情况下，压力升高1 MPa(图 3b)。相比于氯化物和MgSO4，K2CO3对甲烷水合物的影响更小。但是关于硫酸盐和碳酸盐对甲烷水合物抑制性的研究还较少，还不能明确硫酸盐和碳酸盐大类对甲烷水合物稳定性的影响，有待进一步的实验研究。
3. 盐类对甲烷水合物的抑制作用强弱
研究者们对不同盐类和不同离子对甲烷水合物的抑制作用大小进行了对比分析。何勇等[7]实验发现盐类对甲烷水合物的抑制作用大小为：NaCl>KCl>CaCl2>MgCl2>Na2SO4；Sylva等[24]的实验结果(图 4)与何勇等[7]的相近：FeCl3>NaCl>CaCl2≈AgNO3≈MnSO4>CuSO4≈FeSO4，可以看出NaCl是除了FeCl3外对甲烷水合物抑制作用最强的盐类。前人的系统研究结果与本文统计(基于Sylva等[24]、Mohammadi等[63-64]、Kang等[32]、Atik等[62]、Kharrat等[61]、de Roo等[28]、Maekawa等[59]、Lu等[60]的数据)的实验结果(即盐类浓度小于1.5 mol/L大于1 mol/L时，盐类对甲烷水合物的抑制作用大小为MgCl2>CaCl2>NaCl>KCl；盐类浓度大于1.5 mol/L时，CaCl2的抑制作用较强)存在较大的差异。可能由于统计的实验数据来自不同的实验测试方法，导致实验结果存在较大的差异。在阴阳离子对水合物稳定性的抑制作用大小上也出现了争议，有的认为Mg2+>Ca2+>Na+>K+，SO42->CO32->Cl-[66-67]，也有的认为Cl->SO42-，Mg2+≈Na+>Ca2+[60, 68-69]。实验结果差异较大，造成实验结果不一致的原因可能是在实验之前未完全将反应釜和溶液中的空气驱净，导致水合物合成受影响，也有可能是实验对比的盐类浓度上有差异，不同浓度的离子可能对甲烷水合物的抑制作用程度不一样。Lu等[60, 65]和Atik等[62]认为阴离子的存在对水合物稳定性的影响更大。在电解质溶液中，盐离子和水分子反应会降低水的活性，导致水合物不易形成[70-72]。理论上，阴离子半径越小、阳离子的半径越大和价位越高，对水分子的静电效应越强、溶剂效应和盐析效应越强，水的活性越低[73-74]。
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关于氯化物、硫酸盐和碳酸盐等抑制作用大小的比较，需要在同一实验测试条件下完成，但是前人并没有系统地研究其他盐类(如硫酸盐、碳酸盐等)对甲烷水合物稳定性的影响，未在不同盐类体系下针对甲烷水合物的稳定性进行横向和纵向的对比。关于盐类对甲烷水合物抑制作用的研究，已经从分子水平发展到离子水平。阴阳离子对甲烷水合物稳定性影响强度上存在较大的争议，阳离子如Mg2+、Na+、Ca2+、K+对甲烷水合物抑制作用大小的排序不统一，阴离子如SO42-、CO32-、Cl-对甲烷水合物的抑制作用大小争议更大。水的活性影响着甲烷水合物的形成，水的活性则受控于阴阳离子的半径电价等因素，因此探讨阴阳离子的性质对研究甲烷水合物在海水中的稳定性具有重要的意义。
4. 存在问题与展望
盐类对甲烷水合物的抑制作用是毋庸置疑的，但关于KCl、硫酸盐、碳酸盐等盐类对甲烷水合物影响的研究甚少，盐类对甲烷水合物的抑制作用大小存在差异，在不同盐类抑制作用强弱上也存在较大的争议。目前的研究结果还不够系统，与实际地质条件下的甲烷水合物稳定环境还存在一定差别。根据已有的研究成果，盐类对水合物稳定性影响的研究未来应关注以下几点。
(1) 以往的研究中对NaCl关注较多，关于NaCl对甲烷水合物的影响的研究已比较成熟，随着盐度的增加，NaCl对甲烷水合物的抑制作用越强，盐度每增加1 mol/L，在压力恒定的情况下，温度降低3~4 K；同样在温度恒定的情况下，压力升高2 MPa左右。但是地层水中还存在其他离子，如SO42-、CO32-、K+、Ca2+、Mg2+、NH4+，目前的研究成果与实际地质条件还存在一定差距，实际地层中的盐离子种类更多，更复杂，且不同的地质因素[如生物活动、水岩交互作用、深部物质(如甲烷气体)上流]会影响地层水盐度和离子种类的变化。因此，还需进行更加系统的研究，特别是要加强氯化物-甲烷-水、硫酸盐-甲烷-水、碳酸盐-甲烷-水等体系的详细研究。
(2) 本文数据统计结果显示，盐类浓度小于1.5 mol/L大于1 mol/L时，盐类对甲烷水合物的抑制作用大小为MgCl2>CaCl2>NaCl>KCl，盐类浓度大于1.5 mol/L时，CaCl2的抑制作用较强。盐类和离子对甲烷水合物的抑制作用大小和机制还需进一步确认，有待于系统地研究关于氯化物、硫酸盐、碳酸盐对甲烷水合物的抑制作用，并进行横向和纵向上的对比。同时阴阳离子对水合物稳定的影响强度还需进一步验证和分析，对比阴阳离子对甲烷水合物的稳定性影响的强弱，明确阳离子Mg2+、Na+、Ca2+、K+和阴离子SO42-、CO32-、Cl-对甲烷水合物的抑制作用大小，以及离子本身的性质如何影响着水的活性。明确盐类和阴阳离子的抑制作用大小，以及盐类和离子特性如何影响水合物的形成和稳定，对未来甲烷水合物的勘探和开发具有借鉴意义。
(3) 选取合适的实验手段，减小实验误差。将目测法、等容法、等压法三者相结合，目前实验手段中将高压可视反应腔与显微激光拉曼技术相结合可实现。这种实验手段能够在高压可视反应腔中清楚地观察到水合物的形成分解过程实现定性的研究，同时可根据拉曼谱图定量观测甲烷水合物的形成过程中液相中饱和甲烷浓度，准确获取甲烷水合物稳定形成时的温压条件。
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图 1 中国莱州湾表层沉积物采样站位图
Figure 1. Surface sediment sampling station in the Laizhou Bay, China.
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图 2 UHPLC-TOF/MS 全扫描分析提取离子色谱图
(A) 11种目标化合物和内标物的混合标准溶液； (B)海洋沉积物样品提取溶液。按照保留时间从前到后依次排序：对羟基苯甲酸、香草酸、对羟基苯甲醛、丁香酸、对羟基苯乙酮、香草醛、对羟基肉桂酸、丁香醛、香草乙酮、阿魏酸、乙酰丁香酮、乙基香兰素（内标）。
Figure 2. UHPLC-TOF/MS full-scan analysis extraction ion chromatogram (EIC).
(A) Mixed standard solution of 11 target compounds and internal standard; (B) Extraction solution of marine sediment sample. Sort by retention time from front to back: p-hydroxybenzoic acid, vanillic acid, p-hydroxybenzaldehyde, syringic acid, p-hydroxyacetophenone, vanillin, p-hydroxy-cinnamic acid, syringaldehyde, acetovanillone, ferulic acid, acetosyringone and ethyl vanillin (internal standard).
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图 3 固相萃取过程中不同pH（pH=1.0、1.5、2.0、2.5）上样溶液对各种目标化合物回收率的影响
Figure 3. Effect of different pH of the sample solution on the recovery of various target compounds during solid phase extraction: pH=1.0, pH=1.5, pH=2.0, pH=2.5.
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图 4 方法的专属性考察结果（沉积物加标样品UHPLC-TOF/MS分析EIC图）
1—对羟基苯甲酸；2—香草酸；3—对羟基苯甲醛；4—丁香酸；5—对羟基苯乙酮；6—香草醛；7—对羟基肉桂酸；8—丁香醛；9—香草乙酮；10—阿魏酸；11—乙酰丁香酮；12—乙基香兰素（内标）。
Figure 4. Results for the specificity validation of the method (UHPLC-TOF/MS EIC chromatogram of the spiked sediment sample).
1—p-hydroxybenzoic acid; 2—vanillic acid; 3—p-hydroxybenzaldehyde; 4—syringic acid; 5—p-hydroxyacetophenone; 6—vanillin; 7—p-hydroxy-cinnamic acid; 8—syringaldehyde; 9—acetovanillone; 10—ferulic acid; 11—acetylsyrinone; 12—ethyl vanillin (internal standard).
表 1 超高效液相色谱-飞行时间质谱分析木质素主要分解产物酚类化合物和内标物的分子式、保留时间及精确分子质量
Table 1 Molecular formulas, retention times and exact molecular mass of the main decomposition products of lignin (phenolic compounds) and the internal standard analyzed by ultra-high performance liquid chromatography-time-of-flight mass spectrometry (UHPLC-TOF/MS).
序号 酚类化合物 分子式 保留时间(min) 精确分子量[M+H]+ 精确分子量[M-H]- 1 对羟基苯甲酸 C7H6O3 5.14 139.0395 137.0244 2 香草酸 C8H8O4 7.37 169.0495 167.0272 3 对羟基苯甲醛 C7H6O2 8.08 123.0441 121.0295 4 丁香酸 C9H10O5 9.35 199.0601 197.0455 5 对羟基苯乙酮 C8H8O2 11.46 137.0597 135.0452 6 香草醛 C8H8O3 11.61 153.0546 151.0401 7 对羟基肉桂酸 C9H8O3 12.90 165.0546 163.0401 8 丁香醛 C9H10O4 13.91 183.0652 181.0506 9 香草乙酮 C9H10O4 14.65 167.0703 165.0557 10 阿魏酸 C10H10O4 15.89 195.0652 193.0506 11 乙酰丁香酮 C10H12O4 16.68 197.0808 195.0663 12 乙基香兰素 C9H10O3 19.08 167.0703 165.0557 
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表 2 最佳实验条件下 11种目标化合物的线性方程相关系数及方法的检出限和定量限
Table 2 Correlation coefficients for linear analysis, detection limits and quantification limits of the method for UHPLC-TOF/MS determination of 11 target compounds under the optimal experimental conditions.
序号 酚类化合物 R2 方法检出限
（ng/g）方法定量限
（ng/g）1 对羟基苯甲酸 0.9989 5.34 17.80 2 香草酸 0.9989 7.27 24.23 3 对羟基苯甲醛 0.9991 0.67 2.13 4 丁香酸 0.9996 1.79 5.98 5 对羟基苯乙酮 0.9991 0.38 1.25 6 香草醛 0.9997 0.49 1.64 7 对羟基肉桂酸 0.9989 4.16 13.95 8 丁香醛 0.9993 0.47 1.58 9 香草乙酮 0.9994 0.23 0.76 10 阿魏酸 0.9994 5.13 17.1 11 乙酰丁香酮 0.9997 0.13 0.42
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表 3 三种不同添加浓度水平下11种目标化合物的回收率和回收率的RSD（n=6）
Table 3 The recovery rate and its RSD of 11 target compounds under three different spiked levels (50.0ng/g, 100.0ng/g, 400.0ng/g) in the spiked recovery experiment with blank marine sediment （n=6）.
酚类化合物 不同加标浓度水平下目标化合物回收率（%）（n=6） 不同加标浓度水平下目标化合物回收率的RSD（%）(n=6) 加标50.0ng/g 加标100.0ng/g 加标400.0ng/g 加标50.0ng/g 加标100.0ng/g 加标400.0ng/g 对羟基苯甲酸 87.8 90.1 91.9 8.4 7.0 5.8 香草酸 89.3 87.7 87.4 6.4 6.0 6.1 对羟基苯甲醛 86.8 90.0 88.9 7.0 7.2 6.3 丁香酸 88.7 88.1 89.4 8.3 6.3 7.5 对羟基苯乙酮 89.5 91.1 92.3 7.3 6.5 5.5 香草醛 87.4 88.5 87.8 5.2 5.5 4.6 对羟基肉桂酸 88.9 89.3 89.6 6.2 6.5 4.6 丁香醛 89.1 90.7 91.5 8.2 8.5 6.5 香草乙酮 87.5 88.9 89.5 7.4 5.3 5.5 阿魏酸 86.9 89.9 91.0 6.1 8.1 6.2 乙酰丁香酮 90.8 91.2 93.2 8.8 6.2 4.1
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表 4 莱州湾表层沉积物中11种木质素主要分解产物酚类化合物的含量
Table 4 Content of 11 main phenolic compounds from lignin decomposition products of the surface sediment samples collected from the Laizhou Bay, China.
站位 酚类化合物含量(ng/g)(ds) 对羟基苯甲酸 香草酸 对羟基苯甲醛 丁香酸 对羟基苯乙酮 香草醛 对羟基肉桂酸 丁香醛 香草乙酮 阿魏酸 乙酰丁香酮 L1 62.33 26.08 136.41 5.98 3.48 20.65 17.75 5.60 2.33 22.17 0.50 L2 324.43 100.31 425.50 108.50 53.58 671.40 243.67 265.19 110.36 113.53 25.96 L3 350.21 507.56 511.59 119.13 39.5 481.33 297.51 233.46 79.82 122.80 26.18 L4 101.58 204.40 254.26 7.73 16.47 195.19 86.06 64.19 31.78 20.14 7.76 L5 176.82 326.83 425.68 46.14 25.88 317.00 74.67 99.34 46.57 50.57 9.33 L6 223.73 408.17 381.33 86.76 39.31 393.35 249.20 176.55 77.37 112.05 29.02 L7 114.31 73.84 297.40 9.86 5.17 69.67 39.80 22.06 7.27 34.99 2.23 L8 214.02 414.12 419.47 62.57 22.06 303.95 135.91 127.37 48.75 34.99 11.52 L9 180.05 195.33 421.15 29.25 14.86 188.62 110.52 70.42 22.43 32.43 6.37 L10 193.59 255.99 401.93 26.20 15.22 256.06 79.62 67.27 37.39 32.44 5.40 L11 156.60 57.41 325.48 5.83 5.39 47.84 33.30 12.90 4.06 28.22 1.42 L12 147.93 101.40 317.60 13.95 5.56 96.48 26.98 25.10 9.89 31.64 2.66
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表 5 莱州湾表层沉积物样品中11种木质素的分解产物酚类化合物的各项特征参数
Table 5 Characteristic parameters of 11 phenolic compounds from lignin decomposition products in surface sediment samples of the Laizhou Bay, China.
站位 木质素不同分解产物酚类化合物的各项特征参数 C(ng/g) S(ng/g) V(ng/g) P(ng/g) C/V S/V P/(V+S) PON/P (Ad/Al)v (Ad/Al)s Σ8(mg/10g ds) L1 39.92 12.08 49.06 202.23 0.81 0.25 3.31 0.02 1.07 1.26 0.0010 L2 357.19 399.65 882.06 803.50 0.40 0.45 0.63 0.07 0.41 0.15 0.016 L3 420.31 378.76 1068.71 901.30 0.39 0.35 0.62 0.04 0.51 1.05 0.019 L4 106.20 79.68 431.38 372.31 0.25 0.18 0.73 0.04 0.12 1.05 0.0062 L5 125.24 154.82 690.40 628.38 0.18 0.22 0.74 0.04 0.46 1.03 0.0097 L6 361.24 292.34 878.88 644.37 0.41 0.33 0.55 0.06 0.49 1.04 0.015 L7 74.79 34.14 150.78 416.88 0.50 0.23 2.25 0.01 0.45 1.06 0.0026 L8 170.90 201.47 766.82 655.54 0.22 0.26 0.68 0.03 0.49 1.36 0.011 L9 142.95 106.03 406.39 616.06 0.35 0.26 1.20 0.02 0.42 1.04 0.0066 L10 112.06 98.87 549.43 610.75 0.20 0.18 0.94 0.02 0.39 1.00 0.0076 L11 61.51 20.16 109.31 487.46 0.56 0.18 3.77 0.01 0.45 1.20 0.0019 L12 58.61 41.72 207.77 471.09 0.28 0.20 1.89 0.01 0.56 1.05 0.0031 平均值 169.24 151.64 515.92 567.49 0.38 0.26 1.44 0.03 0.49 1.02 0.0083
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[1] Zhang T,Li X G,Sun S W,et al. Determination of lignin in marine sediment using alkaline cupric oxide oxidation-solid phase extraction-on-column derivatization-gas chromatography[J]. Journal of Ocean University of China, 2013, 12(1):63−69. doi: 10.1007/s11802-011-1936-z
[2] Jex C N,Pate G H,Blyth A J,et al. Lignin biogeochemistry:From modern processes to Quaternary archives[J]. Quaternary Science Reviews, 2014, 87:46−59. doi: 10.1016/j.quascirev.2013.12.028
[3] Sun S,Schefuß E,Mulitza S,et al. Origin and processing of terrestrial organic carbon in the Amazon system:Lignin phenols in river,shelf,and fan sediments[J]. Biogeosciences, 2017, 14:2495−2512. doi: 10.5194/bg-14-2495-2017
[4] 王映辉,许云平. 黄河下游—河口—邻近海域表层沉积物中木质素的特征及其示踪意义[J]. 海洋科学,2016,40(2):55−64. Wang Y H,Xu Y P. Characteristics and environmental implications of lignin in surface sediments from the lower Yellow River—estuary—adjacent sea[J]. Marine Sciences, 2016, 40(2):55−64.
[5] 巩菲,刘月,张大海,等. 黄河济南段柱状沉积物中木质素的分布特征[J]. 海洋湖沼通报,2017,156(3):53−59. Gong F,Liu Y,Zhang D H,et al. Distribution characteristics of lignin from the core in Jinan section of the Yellow River[J]. Transactions of Oceanology and Limnology, 2017, 156(3):53−59.
[6] Yang B,Ljung K,Nielsen A B,et al. Impacts of long-term land use on terrestrial organic matter input to lakes based on lignin phenols in sediment records from a Swedish forest lake[J]. Science of the Total Environment, 2021, 774:145517. doi: 10.1016/j.scitotenv.2021.145517
[7] Gordon E G,Goni M A. Sources and distribution of terrigenous organic matter delivered by the Atchafalaya River to sediments in the northern Gulf of Mexico[J]. Geochimica et Cosmochimica Acta, 2003, 67(13):2359−2375. doi: 10.1016/S0016-7037(02)01412-6
[8] 王心怡,李中乔,金海燕,等. 应用木质素示踪楚科奇海表层沉积物中有机碳的来源和降解程度[J]. 海洋学报,2017,39(10):19−31. Wang X Y,Li Z Q,Jin H Y,et al. Sources and degradation of orgnic carbon in the surface sediments across the Chukchi Sea,insighes from lignin phenols[J]. Haiyang Xuebao, 2017, 39(10):19−31.
[9] Tolu J,Gerber L,Boily J F,et al. High-throughput characterization of sediment organic matter by pyrolysis-gas chromatography/mass spectrometry and multivariate curve resolution:A promising analytical tool in (paleo) limnology[J]. Analytica Chimica Acta, 2015, 880:93−102. doi: 10.1016/j.aca.2015.03.043
[10] 刘月,王敏,张婷,等. 杭州湾外泥质区柱状沉积物中木质素的分布特征及其环境指示意义[J]. 海洋环境科学,2017,36(1):8−14. Liu Y,Wang M,Zhang T,et al. Distribution characteristics of lignin in sediment cores from the mud area off Hangzhou Bay and the implication for regional sedimentary environment[J]. Chinese Journal of Marine Environmental Science, 2017, 36(1):8−14.
[11] 凌媛,王永,王淑贤,等. 生物标志物在海洋和湖泊古生态系统和生产力重建中的应用[J]. 地学前缘,2022,29(2):327−342. Ling Y,Wang Y,Wang S X,et al. Application of biomarkers in reconstructing marine and lacustrine paleoecosystems and paleoproductivity:A review[J]. Earth Science Frontiers, 2022, 29(2):327−342.
[12] Hedges J I,Ertel J R. Characterization of lignin by gas capillary chromatography of cupric oxide oxidation products[J]. Analytical Chemistry, 1982, 54(2):174−178. doi: 10.1021/ac00239a007
[13] 叶君,胡利民,石学法,等. 基于木质素示踪北极东西伯利亚陆架沉积有机碳的来源、输运与埋藏[J]. 第四纪研究,2021,41(3):752−765. Ye J,Hu L M,Shi X F,et al. Sources,transport and burial of terrestrial organic carbon in the surface sediments across the East Siberian Arctic Shelf,insights from lignin[J]. Quaternary Sciences, 2021, 41(3):752−765.
[14] 江智婧,朱均均,李鑫,等. 反相高效液相色谱法定量分析木质素的主要降解产物[J]. 色谱,2011,29(1):59−62. doi: 10.3724/SP.J.1123.2011.00059 Jiang Z J,Zhu J J,Li X,et al. Determination of main degradation products of lignin using reversed phase high performance liquid chromatography[J]. Chinese Journal of Chromatography, 2011, 29(1):59−62. doi: 10.3724/SP.J.1123.2011.00059
[15] Sun L,Spencer R G M,Hernes P J,et al. A comparison of a simplified cupric oxide oxidation HPLC method with the traditional GC-MS method for characterization of lignin phenolics in environmental samples[J]. Limnology and Oceanography:Methods, 2015, 13:1−8.
[16] Owen B C,Haupert L,Jarrell T M,et al. High-performance liquid chromatography/high-resolution multiple stage tandem mass spectrometry using negative-ion-mode hydroxide-doped electrospray ionization for the characterization of lignin degradation products[J]. Analytical Chemistry, 2012, 84:6000−6007. doi: 10.1021/ac300762y
[17] 欧阳新平,陈子龙,邱学青. 超高效液相色谱/高分辨质谱法测定木质素氧化降解产物中单酚类化合物[J]. 分析化学,2014,42(5):723−728. Ouyang X P,Chen Z L,Qiu X Q. Determination of monophenolic compounds from lignin oxidative degradation using ultra performance liquid chromatography/high resolution mass spectrometry[J]. Chinese Journal of Analytical Chemistry, 2014, 42(5):723−728.
[18] 营娇龙,秦晓鹏,郎杭,等. 超高效液相色谱-串联质谱法同时测定水体中37种典型抗生素[J]. 岩矿测试,2022,41(3):394−403. Ying J L,Qin X P,Lang H,et al. Determination of 37 typical antibiotics by liquid chromatography-triple quadrupole mass spectrometry[J]. Rock and Mineral Analysis, 2022, 41(3):394−403.
[19] 莫力佳,石勇,高建华,等. 辽东半岛东岸泥区有机碳来源及其对流域和海岸环境变化的响应[J]. 地球化学,2021,50(2):199−210. Mo L J,Shi Y,Gao J H,et al. Source and distribution of lignin in mud deposits along the southeastern coast of Liaodong Peninsula and its response to environmental changes of the catchment[J]. Geochimica, 2021, 50(2):199−210.
[20] 朱帅,沈亚婷,贾静,等. 环境介质中典型新型有机污染物分析技术研究进展[J]. 岩矿测试,2018,37(5):586−606. Zhu S,Shen Y T,Jia J,et al. Review on the analytical methods of typical emerging organic pollutants in the environment[J]. Rock and Mineral Analysis, 2018, 37(5):586−606.
[21] Heidke I,Scholz D,Hoffmann T. Quantification of lignin oxidation products as vegetation biomarkers in speleothems and cave drip water[J]. Biogeosciences, 2018, 15:5831−5845. doi: 10.5194/bg-15-5831-2018
[22] 王全成,胡丹阳,杨柳明,等. 固相萃取-高效液相色谱法测定森林土壤中木质素[J]. 实验室科学,2021,24(5):40−44. doi: 10.3969/j.issn.1672-4305.2021.05.010 Wang Q C,Hu D Y,Yang L M,et al. Determination of lignin in forest soil by solid phase extraction/high performance liquid chromatography[J]. Laboratory Science, 2021, 24(5):40−44. doi: 10.3969/j.issn.1672-4305.2021.05.010
[23] 于雅晨,李坤兰,马英冲,等. 反气相色谱法测定有机溶剂型木质素的溶解度参数[J]. 色谱,2013,31(2):143−146. Yu Y C,Li K L,Ma Y C,et al. Determination of the solubility parameter of organosolv lignin by inverse gas chromatography[J]. Chinese Journal of Chromatography, 2013, 31(2):143−146.
[24] 李鹏辉,蒋政伟,李家全,等. 木质素降解产物酚羟基测定方法研究进展[J]. 光谱学与光谱分析,2022,42(9):2666−2671. Li P H,Jiang Z W,Li J Q,et al. Research progress in quantitative determination of phenolic hydroxyl groups in lignin[J]. Spectroscopy and Spectral Analysis, 2022, 42(9):2666−2671.
[25] Heinonen J,Tamper J,Laatikainen M,et al. Chromatographic recovery of monosaccharides and lignin from lignocellulosic hydrolysates[J]. Chemical Engineering & Technology, 2018, 41(12):2402−2410.
[26] Wang Y L,Chen J H,Gao L Y,et al. Determination of eight typical lipophilic algae toxins in particles suspended in seawater by ultra performance liquid chromatography-tandem mass spectrometry[J]. Chinese Journal of Analytical Chemistry, 2016, 44(3):335−341. doi: 10.1016/S1872-2040(16)60911-8
[27] Tsutsuki K,Esaki I,Kuwatsuka S. CuO-oxidation products of peat as a key to the analysis of the paleo-environmental changes in a wetland[J]. Soil Science and Plant Nutrition, 1994, 40(1):107−116. doi: 10.1080/00380768.1994.10414283
[28] 戴群英,邹立,彭燕. 黄河口潮间带沉积物中木质素的分布以及降解特征[J]. 海洋环境科学,2017,36(2):210−215. Dai Q Y,Zou L,Peng Y. Distribution and degradation of lignin in the sediment of intertidal mudflat of Yellow River Estuary[J]. Marine Environmental Science, 2017, 36(2):210−215.
[29] 冯朝军,潘建明,王红群,等. 微波消解-气相色谱法测定沉积物中的木质素[J]. 岩矿测试,2011,30(1):23−26. Feng C J,Pan J M,Wang H Q,et al. Gas chromatographic determination of lignin in sediment samples assisted with microwave digestion[J]. Rock and Mineral Analysis, 2011, 30(1):23−26.
[30] Kaiser K,Benner R. Characterization of lignin by gas chromatography and mass spectrometry a simplified CuO oxidation method[J]. Analytical Chemistry, 2011, 84:459−464.
[31] Yan G,Kaiser K. A rapid and sensitive method for the analysis of lignin phenols in environmental samples using ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry with multiple reaction monitoring[J]. Analytica Chimica Acta, 2018, 1023:74−80. doi: 10.1016/j.aca.2018.03.054
[32] 谢秀风,郗敏,孔范龙,等. 木质素作为湿地陆源性溶解性有机质(DOM)示踪剂的研究进展[J]. 海洋湖沼通报,2015, 37(3):125−129. Xie X F,Xi M,Kong F L,et al. Proceedings in the application of wetland lignin to tracing terrestrial organic mattes[J]. Transactions of Oceanology and Limnology, 2015, 37(3):125−129.
[33] 李先国,杜培瑞,孙书文,等. 山东半岛东北岸近海表层沉积物中木质素的分布特征及有机物来源[J]. 海洋湖沼通报,2013(2):81−88. Li X G,Du P R,Sun S W,et al. Distribution characteristics of lignin and sources of organic matter in surface sediments offshore of north eastern Shandong Peninsula[J]. Transactions of Oceanology and Limnology, 2013(2):81−88.
[34] 黄佳埼,林昕,汪福顺,等. 乌江流域下游梯级水库沉积物中木质素的特征及有机碳来源辨析[J]. 上海大学学报(自然科学版),2021,27(2):271−279. Huang J Q,Lin X,Wang F S,et al. Characteristics of lignin in sediment cores from cascade reservoirs downstream of the Wujiang River and source analysis of organic carbon[J]. Journal of Shanghai University (Natural Science), 2021, 27(2):271−279.
[35] 李先国,王敏,孙书文,等. 渤海表层沉积物中木质素的分布特征及其对陆源有机物来源的示踪意义[J]. 海洋环境科学,2013,32(3):327−332. Li X G,Wang M,Sun S W,et al. Distribution of lignin in the surface sediments of Bohai Sea and its implication for tracing terrigenous organic matter[J]. Marine Environmental Science, 2013, 32(3):327−332.
[36] 尚文郁, 孙青, 谢曼曼, 等. 中国东北干旱-半干旱地区湖泊沉积物木质素酚类化合物特征及其气候指示意义[J]. 岩矿测试, 2023,42(2): 346-360. Shang W Y, Sun Q, Xie M M, et al. Characteristics and climatic implications of lignin-derived phenolic compounds in Arid Lake, northeastern China[J]. Rock and Mineral Analysis, 2023,42(2): 346-360.
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