高效液相色谱法测定水产品中喹乙醇的残留量

建立了水产品中喹乙醇残留量的测定方法。主要研究了样品的预处理方法,提出了以水为提取剂,以硼砂一硫酸锌为高效蛋白去除剂的样品处理方法。该方法灵敏、准确,适合于水产品中微量喹乙醇残留量的测定。方法的检出限为40μg／kg。     

In situ AFM study of sorbed humic acid colloids at different pH

Humic acid colloids adsorbed on the basal plane of cleaved muscovite are investigated under in situ conditions by non-contact mode atomic force microscopy (AFM) in liquid (also called fluid tapping-mode AFM). Structures are found to be of nanometer scale, consisting of flat particles (8–13 nm in diameter), aggregates of particles (20–100 nm), chain-like assemblies, networks and torus-like structures. In contrast to former investigations colloids are investigated in aquatic solution and structures are not influenced by sample preparation. Nanostructure, surface coverage and particle sizes are found to depend on solution pH. Humic colloids can be distinguished from surface roughness and background noise by image processing. Furthermore, an approach to quantify the surface coverage is discussed. Therefore, non-contact mode AFM in liquid is shown to be a powerful method to study the interaction of colloids at solid–liquid interfaces.     

Protonation of polyamines in NaCl aqueous solution and binding of Cl by polyammonium cations

Equilibrium constants relative to the binding of Cl⁻ by nine open chain polyammonium cations (di, tri and tetra) were determined by potentiometric measurements (H⁺-glass electrode), at T=25°C. To this end the protonation constants of these amines were measured in NaCl aqueous solutions, in the ionic strength range 0.1<I≤1 mol dm⁻³. The different amines (some of which are N-alkyl substituted) were chosen in order to consider several factors affecting the values of protonation constants, the chloride complex formation constants and the dependence on ionic strength of apparent protonation constants. As concerns these last two points, it was found that fully N-alkyl substituted amines behave in a very similar way, with respect to partially or non-substituted ones. Simple linear relationships are reported involving chloride formation constants, parameters for the dependence on ionic strength of protonation constants and charges in polyammonium cations. The complexes formed by two linear polyamines with NO₃⁻ have also been studied for comparison. Literature data are examined.     

Photocatalysis of β-blockers – An overview

Photocatalysis is one of the most effective advanced oxidation processes to remove residual pharmaceuticals from the aquatic environment. β-Blockers are the group of pharmaceuticals commonly found in the environment and are showing potential risk to the aquatic and terrestrial organisms. This paper provides an overview of different photocatalytic procedures found in the literature for the abatement of β-blockers.     

超高效液相色谱法测定水产品中3种喹诺酮类药物残留量

提出了应用超高效液相色谱法测定水产品中诺氟沙星、环丙沙星和恩诺沙星等3种喹诺酮类药物残留量的方法。样品采用酸化乙腈提取,减压蒸干后用流动相溶解,经正己烷脱脂。以ACQUITY UPLCTMBEH C18色谱柱为分离柱,以乙腈与甲酸(0.1+99.9)溶液按体积比10比90混合作为流动相,在激发波长280nm、发射波长450nm的条件下进行荧光光度检测。3种药物的线性范围均为1.25～500μg.L-1,检出限(3S/N)均为0.1μg.kg-1,测定下限(10S/N)均为0.3μg.kg-1。以鲳鱼、对虾、河蟹等空白样品为基体做加标回收试验,测得回收率均大于80%。     

Fulvic acid enrichment in the microlayer of the Gerlache Inlet Sea (Antarctica): preliminary results

The aim of this work was to study the presence of fulvic acids in Antarctic waters, as they appear to be principal film-forming components in the surface microlayer. We obtained a series of samples during two Antarctic Italian Expeditions in 1998/99 and 2000/01 and studied the distribution and the structural differences between fulvic acids extracted from both microlayer and subsurface waters.

Fulvic acids are concentrated in the microlayer and the enrichment factor between microlayer and subsurface water differs between samples. The enrichment factor values for fulvic acids lie between those found for dissolved organic carbon (DOC) and particulate organic carbon (POC) in the literature. Fulvic acids extracted from the microlayer were found to be different in structure from those present in the subsurface layer and enriched in sulphur content. We hypothesised that sulphur-containing compounds are slightly bound and/or occluded in fulvic acid structures. The sulphur-containing compounds analysed in the microlayer could be dimethylsulfide (DMS) and/or its products stemming from photochemical and biological oxidation reactions.     

液相色谱-串联质谱法同时检测水产品中苦参碱和鱼藤酮残留

建立了液相色谱-串联质谱同时检测水产品中苦参碱与鱼藤酮残留的方法.试样以乙酸铵缓冲液乙腈提取,提取液中加入 NaCl盐析后,以正己烷除脂净化.采用 Agilent Zobax SB-C<,18>色谱柱,以乙酸铵缓冲液-乙腈为流动相,梯度洗脱分离后,采用电喷雾电离源串联质谱的正离子模式测定.分析物在0.001～0.05m...     

The determination of the linear alkylbenzene sulfonate isomers in water samples by gas-chromatography/mass spectrometry

A number of 20 compounds of linear alkylbenzene sulfonates (LASs) family were identified by electron impact mass spectrometry (EI-MS) in water samples collected from wastewater treatment plants (WWTP). This paper presents the mass spectra of 20 compounds, the proposed mechanism of formation of the diagnostic ions obtained by EI-MS and the distribution of individual isomers in water samples collected from compartments of WWTP. The individual isomers from four homolog series C(10)-, C(11)-, C(12)- and C(13)-LAS were analyzed as methyl derivatives.     

Analytical chemistry of freshwater humic substances

Dissolved organic carbon (DOC) in aquatic environments represents one of the largest active organic carbon reservoirs in the biosphere. Current ideologies concerning the sources of DOC, how it is formed and utilized, and what determines the quality of DOC are examined. Humic substances can comprise a significant fraction of the DOC and developments in methods of analysis including the isolation and characterization of this fraction are reviewed.