沈抚污水灌区石油烃对土壤及水稻的影响

本文通过对沈抚灌区土壤及水稻的采样分析,同时结合水稻盆栽试验,分析测定了污灌区土壤中石油烃的残留及其对水稻生长的影响。结果表明土壤中石油烃含量同污灌年限、物理性粘粒含量及土壤质地等有着一定的相关关系,土壤中石油烃含量越高对水稻生长发育的影响越大。     

测定土壤硝态氮的紫外分光光度法与其他方法的比较

使用酚二磺酸法、还原蒸馏法、镀铜镉还原．重氮化偶合比色法和改进紫外分光光度法（校正因数法）测定了中国9种不同类型土壤的硝态氮含量，分析了改进紫外分光光度法与其余三种测定方法的差异及其适用性。统计分析表明对于有机质含量低于50g kg^-1的矿质土壤，可以使用2．2作为校正因数，四种分析方法的测定值具有极显著的相关性，尤其是紫外分光光度法与酚二磺酸法的测定结果最为接近，没有极显著差异；对于有机质含量接近和高于50g kg^-1的土壤，校正因数还需要修改。紫外分光光度法具有操作简单、测定速度快等优点，适用于批量快速测定。     

西北石灰性土壤阳离子交换量测定方法比较

阳离子交换量是评价土壤保肥性能和缓冲性能的重要指标,也是改良土壤和合理施肥的重要依据之一。为了给西北石灰性土壤阳离子交换量的测定提供科学依据,通过平行性实验、标准物质检测、实际样品检测,分析比较了目前普遍采用的测定方法乙酸钙交换法和三氯化六氨合钴浸提-分光光度法的优劣。结果表明,2种分析方法均具有较好的精密度和准确度,均适合西北地区石灰性土壤阳离子交换量的测定。从测定结果来看,三氯化六氨合钴浸提-分光光度法的土壤阳离子交换量测定值略高于乙酸钙交换法,在实际样品检测中相对标准偏差介于3.47%～9.46%。但相比之下乙酸钙交换法具有试剂成本较低的优势,而三氯化六氨合钴浸提-分光光度法具有节省时间的优势,检测人员可根据实际情况灵活选择使用。     

硫脲分光光度法测定土壤和沉积物中铋(Bi)量

建立了对土壤和沉积物中铋含量进行测定的新方法———硫脲分光光度法,实验结果表明此分析方法操作简便、选择性好、灵敏度高,测试结果令人满意。     

叶面肥中磷含量测定方法的比较研究

采用分光光度法、电感耦合等离子发射光谱法(ICP-AES)和离子色谱法测定叶面肥样品中的全磷和速效磷的含量。通过样品测试数据的比较,分光光度法和ICP-AES测定全磷的结果一致,能很好的吻合,两种方法可以在叶面肥全磷的测定中相互确认,并应用于常规分析;而分光光度法和离子色谱法测定速效磷的结果在部分叶面肥中存在一定的差异,离子色谱法只能作为分光光度法测定叶面肥中速效磷的一种补充方法。本文为磷元素含量影响叶面肥品质的分析提供了选择测定方法的依据。     

表面活性剂强化过硫酸钠氧化修复石油烃污染土壤

为了提升石油烃污染土壤的修复效率，考察了不同表面活性剂(吐温-80 (Tw-80)、曲拉通X 100 (TX 100)、十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS))对过硫酸钠氧化土壤中石油烃的强化效果，并分析了表面活性剂SDS强化修复效果较优的原因。土壤中石油烃的去除率遵循如下趋势：SDS>SDBS>TX 100>Tw-80。SDS强化修复效果较优可能与其在土壤中吸附量较小对石油烃的增溶效果好、上清液中过渡态金属含量较高及对过硫酸钠分解消耗少有关。通过优化反应参数，可以进一步提高SDS强化过硫酸钠氧化修复石油烃污染土壤的效率，对采自武汉和盘锦的两种石油烃污染土壤都具有较好的修复效果。     

石油污染土壤的生物修复研究

通过田间试验研究了玉米和向日葵两种植物对石油污染土壤的修复作用,考察了外源菌（OX-9）对植物修复的强化和协同效应,对“外源菌一植物”修复效果进行了初步评价。结果表明,在10000mg·k-1污染浓度下,150d玉米、向13葵试验区土壤中石油降解率分别为42．5％和46．4％,较对照区提高了100．5％和118．9％。外源节细菌的施加可使生物修复速度显著加快,150d“DX-9-玉米”和“DX-9-向日葵”试验区石油烃降解率分别达到72．8％和76．4％,较同期单独植物修复的降解率提高了71.3％和64．7％。500d各试验区土壤中石油烃降解率分别为95．5％、96．1％、97．6％和98．9％,土壤中石油烃含量均低于国家标准规定限量（〈500mg·kg-1）;土壤主要理化性质、生物群落分布、呼吸强度及植物不同部位中石油烃的残留量与对照无显著差异。结果表明：玉米、向日葵与节细菌对石油污染土壤的联合生物修复效果显著;经过两年修复,污染土壤恢复健康状态。     

土壤溶解性有机碳四种测定方法的对比和转换

针对土壤溶解性有机碳(DOC)不同测定方法之间可比性较差的问题,应用TOC仪法、容量法、紫外分光光度法和比色法分别测定了中亚热带丘陵山地6个土属共46个新鲜土壤样品的DOC含量。结果表明:参照TOC仪法测得的DOC数据,容量法一致性地低估20%~67%;比色法测定DOC含量较低的底土时(200 mg/kg)仅低估7%~27%,但在分析DOC含量较高的表土(600 mg/kg)时最不敏感,低估达53%~93%;紫外分光光度法在DOC含量较高时也存在一定的低估,但在DOC含量较低时高估65%~189%。4种方法测得的DOC数据均呈极显著正相关关系(P0.01)。统计分析获得的线性或指数方程可应用于将容量法、紫外分光光度法和比色法的测定结果向TOC仪法的数据转换,而且有必要针对表土和底土使用不同的转换方程或参数,这些经验转换方程的建立有助于增强不同研究结果之间DOC数据的可比性,也有利于推动土壤DOC测定标准的完善。     

紫外分光光度法测定农田土壤微生物生物量氮可行性初探

采用氯仿熏蒸浸提-紫外分光光度法和消化法比较测定了田间定位试验不同施肥处理土壤、添加植物残体土壤、添加葡萄糖土壤的微生物生物量碳、氮(SMBC,SMBN)。结果表明,当土壤微生物生物量氮含量较高时(>20 mg kg-1),采用分光光度法与消化法测定的SMBN具有显著正相关关系(P<0.05),但当SMBN量较低时(<20 mg kg-1)时,分光光度法测定与消化法测定的SMBN没有显著相关性。当土壤中添加麦秸和玉米秸时,土壤浸提液颜色较深(黄色),不适合采用分光光度法测定SMBN。因此,熏蒸提取–分光光度法测定SMBN,仅适于土壤浸提液无色透明、且SMBN含量较高的土壤。     

原子荧光光度法测定土壤中汞的不确定度分析

氢化物发生-原子荧光分光光度法测定土壤中汞含量的不确定度主要来源于测量样品消解液中汞的浓度、测量过程中使用的玻璃量具及样品称量产生的不确定度,对这些分量进行量化计算,求得其扩展不确定度为0.00648mg·kg-1。分析结果表明,影响汞含量测定不确定度的主要因素是测量样品消解液中汞的浓度引起的不确定度。     

土壤样品中多环芳烃分析方法研究进展

概述了国内外土壤样品中多环芳烃(PAHs)测定方法的研究状况,其中提取方法包括加速溶剂萃取方法、固相微萃取方法、超临界流体萃取方法、亚临界水萃取方法和流化床提取方法等,测定方法有HPLC法、GC法和免疫分析法等。重点介绍了PAHs的提取过程,同时总结了各种方法的优缺点。     

Rapid and simple analysis of pesticides persisting on green pepper surfaces swabbing with solvent-moistened cotton

A rapid and simple nondestructive extraction (NDE) method that includes wiping off of systemic neonicotinoid insecticides has been developed to streamline sample pretreatment procedures conducted before chromatographic determination. Pesticide residues were extracted from green pepper surfaces by swabbing them with absorbent cotton moistened with acetone or acetonitrile. After spraying of pesticides, the extraction rate decreased gradually, except for thiacloprid. Presumably, extraction rates depend on the physicochemical properties of pesticides, especially water solubility. It was thought that the applicability of the proposed method greatly depended on the systemic speed of each pesticide, and water solubility was placed as the index that was important to making certain. Direct analysis of some insecticides persisting on sample surfaces has been possible only by extraction before chromatographic determination. These findings indicate strongly that the proposed NDE method has collateral conditions, but it appears promising for on-site pretreatment for pesticide residue analysis.     

Rapid analysis of inositol phosphates

Fast and simple analytical methods for the determination of inositol bis- to hexakisphosphates or only inositol hexakisphosphate in foods and feces are presented. The methods are both faster and simpler with regard to analytical detection and sample pretreatment as compared to previously reported methods. The samples are pretreated using extraction and centrifugal ultrafiltration and analyzed using high-performance ion chromatography (HPIC) with gradient or isocratic elution. The analytes are detected using ultraviolet detection after postcolumn reaction. The methods are efficient, highly selective, and appropriate for analyzing inositol phosphates in food and feces samples. The between- and within-day variances were generally below 8 and 5% (relative standard deviation), respectively, for the presented HPIC method with gradient elution.     

甲亚胺测定土壤有效硼的前处理方法研究

土壤有效硼测定通常采用甲亚胺-H比色法,该方法前处理(煮沸)过程分析效率低、操作步骤不易掌控,极易给测定结果带来较大误差。为此,以山西省标准土样TCB-2为检测样品,对甲亚胺-H比色法的煮沸提取步骤进行了改进,分别试验了水浴提取、微波提取时间对土壤有效硼测定的影响,确定水浴法最佳提取时间为50 min,微波提取时间为90 s。对国家土壤标准物质GBW07412a检测结果表明,水浴提取和微波提取测定结果与标准参照值符合,相对标准偏差分别为3.43%和8.91%。     

土壤中水溶性有机碳测定中的样品保存与前处理方法

对棕壤、褐土和红壤样品研究结果表明 ,土壤水溶性有机碳 (WSOC)在中雨停止 72小时后几乎恢复到正常水平 .采集的土样应尽快测定 .如须保存 ,则以冷藏为好 ,同时要避免水分丧失 .样品测试直接用鲜样进行 ,其中水分和大于 1mm颗粒物对结果的干扰可通过校正排除 .提取时间则以 5h为宜     

激光衍射法测定土壤粒径分布的研究进展

常见的土壤粒径分布测试手段有筛分法、沉降法(包括吸管法和密度计法)、激光衍射法等。近年来,由于激光衍射法分析土壤粒径分布具有操作简单、效率高、测试样品用量小、适合批量样品测定的特点,其在土壤粒径分布的测定中得到越来越广泛的应用。本文介绍了激光衍射法测定土壤粒径分布的基本原理和分析方法,综述了该技术在测定土壤粒径分析方面的国内外研究进展,重点分析了激光衍射法测定土壤粒径分布的影响因素,并对激光衍射法测定土壤粒径分布的应用前景进行了展望。研究表明,激光衍射法通过转换方程可以获得精确的结果。在保证足够大的样本量、土壤样本包含多种质地类型,且完善的前处理条件下,可以建立稳定的、适用于大范围预测的模型。激光衍射法测定土壤粒径分布虽然受到一些因素的影响,例如前处理方法、仪器设置以及样品用量等,但是激光粒度仪为粒度测定提供了高效快速的技术手段,为精准农业和数字农业的发展提供了先进的技术支撑。     

环境样品氨基甲酸酯类农药的分离和检测技术研究进展

氨基甲酸酯类农药是一类高效广谱型杀虫剂，近年来在农业生产中被广泛使用，然而由此带来的环境污染和食品健康问题也日益引起关注。无论是样品的前处理方法还是仪器检测方法都有待不断地完善和发展，因此，开发理想的样品前处理方法和更加有效的仪器分析方法成为该领域的研究热点。本文在查阅了近年国内外相关文献61篇的基础上，就环境样品氨基甲酸酯类农药的分离提取方法以及不同方法的优缺点做分析，同时对氨基甲酸酯类农药的仪器分析方法及其发展趋势做总结，以期为研究环境样品氨基甲酸酯类农药的分析技术提供有益的参考。     

Rapid magnetic solid-phase extraction based on magnetic multiwalled carbon nanotubes for the determination of polycyclic aromatic hydrocarbons in edible oils

In this study, magnetic multiwalled carbon nanotubes were fabricated by a simple method and applied to magnetic solid-phase extraction (MSPE) of eight heavy molecular weight polycyclic aromatic hydrocarbons (PAHs) including chrysene, benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene and benzo[g,h,i]perylene from edible oil samples. Several parameters affecting the extraction efficiency were investigated, including the type and volume of desorption solvent, extraction and desorption time, washing solution and the amount of sorbent. Under the optimized conditions, a simple and effective method for the determination of PAHs in edible oils was developed by coupling with gas chromatography-mass spectrometry (GC-MS). The whole pretreatment process was rapid, and it can be accomplished within 10 min. The limits of quantitation for the target PAHs were found to be 0.34-2.9 ng/g. The recoveries in oil sample were in the range 87.8-122.3% with the RSDs less than 6.8% (intraday) and 9.6% (interday). This method was successfully applied to the analysis of PAHs in seven kinds of edible oils from local markets.     

Application of near-infrared reflectance spectroscopy (NIRS) to the evaluation of carotenoids content in maize

The importance of including antioxidant compounds in the diet is well recognized. These compounds remediate the detrimental activity on animal cells of the so-called reactive oxygen substances (ROS). Many papers have reported on the determination of both hydrophilic and hydrophobic antioxidant compounds present in a large number of vegetables, and all methods involve the extraction from the matrix of the compounds to be determined. Because some problems may arise, such as the completeness of the extraction and the stability of the extracted compound during the extraction steps, the possibility of analyzing these compounds in the native matrix would be useful. Here is reported the application of near-infrared spectroscopy (NIRS) to the determination of the content of carotenoids in maize, comparing the obtained data with those derived from high-performance liquid chromatography (HPLC) determination of the extract obtained from the same samples. Equations for predicting carotenoid content in maize were derived using scores from modified partial least-squares (MPLS) as independent variables. Cross-validation procedures indicated good correlations between HPLC values and NIRS estimates. The results show that NIRS, a well-established and widely applied technique, can be applied to determine the maize carotenoids and that samples are readily analyzed in minutes, the only required step being their grinding.     

Isolation and identification of alpha-CEHC sulfate in rat urine and an improved method for the determination of conjugated alpha-CEHC

2,5,7,8-Tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman (alpha-CEHC), the water-soluble metabolite of alpha-tocopherol (alpha-TOH) with a shortened side chain but an intact hydroxychroman structure, has been identified in human urine and are thought to be produced in significant amount at excess intake of alpha-TOH. In previous studies, CEHCs in biological specimens were measured by HPLC, GC-MS or LC-MS, preceded by a hydrolysis procedure using either enzyme or methanolic HCl. In an attempt to analyze alpha-CEHC in rat urine accordingly, we observed that enzyme hydrolysis was relatively inefficient in releasing alpha-CEHC compared to high concentrations of HCl. The HCl releasable alpha-CEHC conjugate was isolated and chemically identified as 6-O-sulfated alpha-CEHC (alpha-CEHC sulfate). Using the synthetic alpha-CEHC sulfate standard, it was found that sulfatase could not hydrolyze to a significant extent. On the other hand, pretreatment with HCl at 60 degrees C in the presence of ascorbate, followed by a one-step ether extraction, not only hydrolyzed the sulfate conjugate completely but also extracted alpha-CEHC with high recovery. The inclusion of ascorbate minimized the conversion of alpha-CEHC to alpha-tocopheronolactone in the HCl pretreatment. A complete procedure for the quantitative analysis of alpha-CEHC including HCl hydrolysis, ether extraction and reverse phase isocratic HPLC-ECD was thus established. In conclusion, alpha-CEHC sulfate was isolated and identified as the HCl-releasable conjugate of alpha-CEHC in rat urine. A rapid and sensitive method with high reproducibility for the determination of free, conjugated and total alpha-CEHC is then established.