Application of the QuEChERS method for the determination of organochlorine pesticide residues in Brazilian fruit pulps by GC-ECD

The Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was applied to the extraction of 14 organochlorine pesticides (OCPs) residues from commercial fruit pulps available in supermarkets in Fortaleza, Northeastern Brazil. The analyses were carried out by gas chromatography (GC), coupled to an electron-capture detector (ECD), and were confirmed by GC-tandem mass spectrometry (MS). The parameters of the analytical method, such as accuracy, precision, linear range, limits of detection and quantification, were determined for each pesticide. The results showed good linearity (R² ≥ 0.9916) and the overall average recoveries were considered satisfactory obtaining values between 69 and 110%, RSD of 2–15 %, except for hexachlorobenzene (HCB) in açai, acerola and guava pulp samples. The OCPs were detected in guava (α–HCH; lindane) and soursop (α, β–HCH isomers) samples. The QuEChERS method and GC–ECD were successfully used to analyze OCPs in commercially available Brazilian fruit pulps and can be applied in routine analytical laboratories.     

降水中甲酸、乙酸和草酸的离子色谱法测定及样品保存研究

甲酸、乙酸和草酸是降水中有机酸的主要成分。研究选用离子色谱法同时测定降水中的甲酸、乙酸和草酸,并对降水样品中3种有机酸的保存条件进行了研究。优化后的色谱条件为4. 0 mmol/L Na_2CO_3和1. 2 mmol/L NaHCO_3混合淋洗液,淋洗液流速为1. 0 m L/min,进样体积为200μL,电导池温度为30℃,柱温为室温。甲酸、乙酸和草酸的检出限分别为0. 002、0. 005、0. 005 mg/L,实际降水样品测定时平行样的相对标准偏差为1. 4%～12%,加标回收率为95%～118%。样品采集后需尽快用0. 45μm聚醚砜微孔滤膜过滤,4℃以下冷藏密封保存,2 d内测定。若用氢氧化钠溶液调节p H至8～10,样品可保存7 d。     

顶空-气相色谱法(氮磷检测器)测定固定污染源废气中三甲胺

建立了顶空-气相色谱法测定固定污染源废气中三甲胺的分析方法。弱酸性吸收液采集固定污染源废气中的三甲胺,碱液中和后顶空进样气相色谱仪氮磷检测器分析。并对平衡温度、平衡时间、盐析效应、氨水和氢氧化钠条件实验进行优化,在最佳实验条件下,三甲胺的方法检出限为0. 46μg/m~3(以采集20 L空气样品计),加标回收率为97%～107%,相对标准偏差在9. 26%以下。利用该方法对垃圾焚烧发电厂厂界空气及鱼粉厂有组织废气中三甲胺进行检测分析,该方法能够满足国家标准及上海地方标准中三甲胺排放限值的要求。     

The Many Modalities of Social Networking: The Role of Twitter in Greens Politics

The popular microblogging service, Twitter, contains a variety of potential orientations—interpersonal, broadcast, news, advertising, public service, political, and so on—in its operation and applications. As an evolving social media platform, specificity and context are essential in understanding its significance and use-value. This paper investigates the multiple modalities of Twitter in the context of formal politics and, in particular, the Greens party in Australia. Presenting original evidence drawn from the Greens Members of Parliament and their advisers, it is shown how Twitter is mobilized in response to particular news agendas and stories, unfolding political events and processes, and an ongoing need for the Greens to speak simultaneously to committed environmentalists and the broader electorate. These uses reveal that Twitter is an important addition to the “media ecology mix” in the conduct of environmental politics, playing a direct role in political communication, strategies, and actions.     

高效液相色谱-三重四级杆/复合线性离子阱质谱法测定饮用水中22种邻苯二甲酸酯

建立了一种同时测定饮用水中22种邻苯二甲酸酯(PAEs)的高效液相色谱-三重四级杆/复合线性离子阱质谱方法:饮用水样品经针头过滤器过滤,选用Biphenyl液相色谱柱进行分离,以含0.1%甲酸的水溶液和含0.1%甲酸的甲醇溶液为流动相,电离模式为电喷雾正离子,选用多反应监测触发增强子离子扫描模式进行检测。结果表明,22种PAEs的灵敏度良好,定量限为0.001～0.1 μg/L。配制浓度为0.1～100.0 μg/L的混标溶液进行进样分析,分析结果显示,22种PAEs在该范围内的线性关系良好,相关系数均大于0.995,方法的平均回收率为82.9%～108.9%,相对标准偏差为0.9%～11.2%。同时,使用增强子离子扫描谱图进行搜库匹配,定性准确性高。该方法适用于饮用水中PAEs的检测。     

Green Screen or Smokescreen? Hollywood's Messages about Nature and the Environment

This paper examines ideologies about nature and the environment in popular, animated Hollywood films—including The Lorax, Wall-E, and Ice Age 2—through a symptomatic reading. The primary goal of the analysis is to elucidate key omissions in these texts through an assessment of the problematic—defined in this research as an a-priori answer to perceived audience concerns regarding the role of consumerism and corporate culture in environmental problems. Silences in the films revolve around: how environmental problems are defined; what the consequences are; who the responsible parties are; and what potential solutions exist to mitigate them. The significance of the research is underscored by the formation of an increasingly intimate relationship between children, consumer culture, and commercial media in the USA, as well as the increasingly dire information emerging about global environmental issues. This analysis reveals the dual, often conflicting, messages that commercial film provides for its young audiences about pivotal environmental problems and their potential resolution.     

Analysis of metabolic changes in Trichoderma asperellum TJ01 at different fermentation time-points by LC-QQQ-MS

Trichoderma spp. are among the most widely recognized biocontrol fungi used to inhibit pathogens and promote plant growth. These functions are related to primary and secondary metabolites. This study investigated the different metabolites in Trichoderma asperellum TJ01 cultured for 24 and 72?h using liquid chromatography with triple-quadrupole mass spectrometry. Compared to the 24?h culture of T. asperellum TJ01, the 72?h culture with amino acid metabolism tended to decrease while sugar and lipid metabolisms tended to increase. Furthermore, the 72?h culture had a higher proportion of upregulated flavonoids, in combination with a higher proportion of downregulated alkaloids, and equal proportions of upregulated and downregulated polyphenols and hormones. This study also identified a few valuable medicinal substances such as trigonelline and 5-hydroxytryptophan in T. asperellum TJ01 fermentation cultures.     

An LC-MS/MS method for creatine and creatinine analysis in paraquat-intoxicated patients

Abstract

A sudden increase in serum creatinine after paraquat intoxication has been reported in several clinical studies. However, this dramatic change of creatinine may be possibly due to an interconversion of creatine-creatinine in relation to paraquat toxicity. In order to investigate the creatine-creatinine relationship, a liquid chromatography tandem mass spectrometry in combination with electrospray ionization was developed and validated for simultaneous determination of creatine and creatinine in the serum. The chromatographic separation was achieved on a Gemini® C₆-Phenyl column with a gradient elution consisting of 0.1% formic acid in ultrapure water and methanol as the mobile phase. The method yielded suitable levels of specificity and selectivity, and calibration curves of creatine and creatinine in serum were linear over the concentration range of 0.5–200?µg mL^?1. The limit of quantification of both compounds was 0.5?µg mL^?1, and the method was accurate within the recovery range of 96.23–102.75%, indicating the robustness of the method. The method was successfully applied to toxicological samples from paraquat-intoxicated patients, and the concentrations of creatine and creatinine were quantified. High creatine concentrations in serum samples were observed which may lead to high serum creatinine despite normal kidney function as creatine is converted to creatinine in proportion to its concentration.     

苦味酸测定中关键问题的研究

目前测定苦味酸的国标方法为《生活饮用水标准检验方法有机物指标》(GB/T 5750.8—2006)中的衍生物-液液萃取-气相色谱法,在实际测试过程中,发现水样pH值和基质效应会影响苦味酸测定。当pH值为8~12时,生成的氯化苦响应强度变化不大;在pH约为13时,响应强度最大。水质中除腐殖酸、硝基甲烷及2,4,6-三硝基甲苯会影响苦味酸测定外,硝基酚类和甲基酚类同样起到正干扰作用,因此,国标方法不能全面和准确地测定水中的苦味酸含量。     

云南曲靖某煤化工基地及周边土壤中多环芳烃的检测研究

采用快速溶剂提取处理土壤样品,利用气相色谱质谱内标法测定土壤中多环芳烃,其检出限范围为2.01~3.68μg/kg,相对标准偏差为2.6%~14.7%,加标回收率为67.1%~119%。结果表明,此方法具有良好的灵敏度、准确度和精密度。本研究对11个不同采样点土壤进行了检测分析,并考察了土壤中多环芳烃的污染水平。