萃取技术在环境样品预处理中的应用及发展

对萃取技术包括传统技术以及新近发展起来的如固相萃取、固相微萃取、膜萃取、超临界流体萃取、微波萃取等技术在环境样品预处理方面的运用进行综述,分析各自的优缺点以及发展前景.     

Fractionation and elemental association of Zn, Cd and Pb in soils contaminated by Zn minings using a continuous-flow sequential extraction

Fractionation and elemental association of Zn, Cd, and Pb in soils near Zn mining areas were studied using a continuous-flow sequential extraction approach. The recently developed sequential extraction procedure not only gave fractional distribution data for evaluation of the mobility or potential environmental impact of the metals, but also the extraction profiles (extractograms) which were used for study of elemental association. In addition, the elemental atomic ratio plot extractogram can be used to demonstrate the degree of anthropogenic contamination. Seventy-nine soil samples were collected in the vicinity of a Zn mine and were fractionated into 4 phases i.e. exchangeable (F1), acid soluble (F2), reducible (F3) and oxidizable (F4) phases. Most samples were contaminated with Zn, Cd and Pb. The reducible phase is the most abundant fraction for Zn and Pb (>50%) while Cd is concentrated in the first 3 extraction steps. The distribution patterns of Cd were obviously affected by soil pH. 55% of Cd appears predominantly in the F1 fraction for acidic soils while in neutral and alkaline soils, it was mostly (70%) found in the F2 + F3 fractions. The extractograms obtained from the continuous-flow extraction system revealed close association between Zn, Cd, Pb and Fe in the acid soluble phase, Cd-Pb and Zn-Fe in the reducible phase for contaminated soils. A correlation study of the 3 metals using a correlation coefficient was also performed to compare the results with the elemental association revealed by the extractograms. Atomic ratio plot extractograms of Zn/Fe, Cd/Fe and Pb/Fe in the reducible phase, where contaminated metals are predominant, can be used to evaluate the degree of anthropogenic contamination. From the elemental atomic ratio plot, it is obvious that the contaminants Cd and Pb are mostly adsorbed on the surface of Fe oxides. Zn, which is present in an approximately 1 ratio 1 ratio with Fe in contaminated soils, does not show a similar trend to that found for Cd and Pb.     

百里酚对酸雨样品分析的影响

在东亚酸雨监测网湿沉降监测的技术指南中 ,百里酚 (thymol)作为杀菌剂被推荐用于预先加入采样容器以抑制微生物对有机酸的分解 ,解决没有冰箱或难以使用冰箱地区的酸雨样品保存问题。本文实验了它对酸雨样品分析的影响。由于百里酚与苯酚结构相似 ,造成靛酚法的铵离子分析中吸光度有所降低。此外 ,在每 10 0 ml样品中百里酚加入量大于 40 mg时 ,离子色谱的基线明显变差     

Spatial and temporal distribution of butyltin compounds in a Northern Chesapeake Bay Marina and river system

This study was designed to: determine dibutyltin (DBT), tributyltin (TBT) and tetrabutyltin (TTBT) bi-weekly for a four month period (June-September 1986) in the Port Annapolis Marina, Mears Marina, Back Creek and Severn River area of Northern Chesapeake Bay; measure DBT, TBT and TTBT for five successive days (Thursday-Monday) to determine possible daily effects (weekday versus weekend) and determine DBT, TBT and TTBT every two hours for one full tidal cycle in the study area. Maximum concentrations of TBT were reported at both Port Annapolis Marina (1801 ng L^–1) and Mears Marina (1171 ng L^–1) during early June followed by significant reductions in TBT during late summer and early fall. All 4 Back Creek Stations also had highest concentrations of TBT in early June; significant reductions occurred during the next three months. The highest concentration of TBT reported in the Severn River (48 ng L^–1) occurred in September. The lowest TBT value (5 ng L^-1) at this station occurred in June. TTBT was not detected in any of the samples. The day of week sampled (Thursday-Monday) during the daily experiments was not found to significantly affect TBT concentrations. TBT evaluations every two hours during the tidal cycle demonstrated that values peaked at 1400 and 1600 hr time intervals. Peak concentrations of TBT occurred during a rising tide. The possible consequence of the measured TBT concentrations for aquatic biota are discussed.     

固相萃取技术在我国环境化学分析中的应用

固相萃取(SPE)是目前常用的一种样品预处理方法,它具有高效、快速、方便和高选择性等特点,已在我国空气、水质、临床药物中毒,法医毒物检验等环境化学分析中获得了广泛的应用.     

A new mussel certified reference material (CRM 477) for the quality control of butyltin determination in the marine environment

The analytical techniques used for the determination of butyltin compounds in biological tissues are generally based on a succession of steps (e.g., extraction, derivatization, separation, detection) which are all prone to systematic errors. An interlaboratory programme performed at the EU level and based on a stepwise approach has enabled one to identify and remove most of these errors and to improve considerably the state of the art so that certification of a mussel reference material has been made possible. This paper describes the preparation of this mussel reference material containing monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT), the homogeneity and stability studies and the analytical work performed for the certification of the contents of MBT [Sn(C4H9)3+], DBT [Sn(C4H9)2(2+)] and TBT [Sn(C4H9)3+]. The results obtained by a group of expert EU laboratories are discussed along with the methods used to certify the mass fractions (based on dry mass) of monobutyltin (1.50 +/- 0.28 mg kg-1 as MBT cations), dibutyltin (1.54 +/- 0.12 mg kg-1 as DBT cations) and tributyltin (2.20 +/- 0.19 mg kg-1 as TBT cations). The paper also describes an attempt to certify the content of triphenyltin in this material which, although reasonable agreement was found among the participants' results, failed owing to the instability of this compound. This new material will be of great support to ensure the quality control of butyltin determination in shellfish, as carried out in environmental monitoring programmes.     

水和废水中含油水样的成套采集技术研究──一种新型适用的含油水样采样器

在查阅大量文献的基础上,分析总结了现有采样器的优缺点,并依据采集有代表性含油水样的理论要求,设计制作了一种独具特色而又科学适用的新型合油水样采样器。本采样器可用于采集含油水样和其它水样。     

Fractionation of traffic-emitted Ce, La and Zr in road dusts

The introduction of catalytic converters has led to a new environmental problem since catalysts emit platinum group elements (PGEs) which are among the least distributed elements in nature. Along with PGEs the vehicle exhaust catalysts contain also a number of stabilizers, commonly oxides of rare earth elements and alkaline earth elements such as Ce, La and Zr. Since vehicular emission of these elements has received little attention so far this work attempts to offer insight into their distribution and fate in the environment by measuring their speciation in road dust samples collected along several highways in Germany and a city centre (Saarbrücken). Speciation of the elements (fractionation into associated mineralogical phases) was carried out via a conventional sequential extraction protocol and the complexing abilities of humic substances in the organic matter were investigated by selective extraction methods in combination with size segregation. For evaluation purposes soil samples spiked with catalytic converter material were analyzed, showing a much lower fraction of Ce, La and Zr mobilized in comparison to the road dust samples. It was found that the elements were effectively bound to humic substances in road dust with a preference for complexation with low molecular weight compounds (<1600 Da).     

Exposure to anti-cancer drugs during preparation and administration. Investigations of an open and a closed system

Systems for the preparation and administration of drugs are designed to ensure that the drug is not contaminated. They do not necessarily consider the work environment for the medical staff and new techniques are therefore desirable. The aim of this work is to compare a new closed system for the preparation and administration of drugs with the traditional technique with regard to airborne emission and surface spillage of drugs. Platinum, determined using adsorptive voltammetry, was used as the tracer for airborne emission. Air samples were collected during the preparation and administration, and the collected platinum on the filters was determined by adsorptive voltammetry. For determination of spills and leakage onto surfaces the radioisotope 99m-technetium was used as a tracer. The radiation from the isotope was determined on protective gloves and bench covers after preparation and administration. The mean airborne emission was 6 ng m(-3) with the closed system and 15 ng m(-3) with the traditional pump technique. The average surface spillage using the closed technique was 0.005 microL. This is significantly smaller than with the traditional technique, which resulted in an average spillage of 64 microL. Our results also show that the dominant part of the leakage is surface spillage. Inexperienced nurses could also adequately handle the closed system.     

Fractionation and bioavailability of phosphorus in a tropical estuary, Southwest India

Phosphorus fractionation was employed to find the bioavailability of phosphorus and its seasonal variations in the Panangad region of Cochin estuary, the largest estuarine system in the southwest coast of India. Sequential extraction of the surficial sediments using chelating agents was taken as a tool for this. Phosphate in the water column showed seasonal variations, with high values during the monsoon months, suggesting external runoff. Sediment texture was found to be the main factor influencing the spatial distribution of the geochemical parameters in the study region. Similarly, total phosphorus also showed granulometric dependence and it ranged between 319.54 and 2,938.83 ??g/g. Calcium-bound fraction was the main phosphorus pool in the estuary. Significant spatial variations were observed for all bioavailable fractions; iron-bound inorganic phosphorus (5.04?C474.24 ??g/g), calcium-bound inorganic phosphorus (11.16?C826.09 ??g/g), and acid-soluble organic phosphorus (22.22?C365.86 ??g/g). Among the non-bioavailable phosphorus, alkali-soluble organic fraction was the major one (51.92?C1,002.45 ??g/g). Residual organic phosphorus was comparatively smaller fraction (3.25?C14.64% of total). The sandy and muddy stations showed distinct fractional composition and the speciation study could endorse the overall geochemical character. There could be buffering of phosphorus, suggested by the increase in the percentage of bioavailable fractions during the lean pre-monsoon period, counteracting the decreases in the external loads. Principal component analysis was employed to find the possible processes influencing the speciation of phosphorus in the study region.     

Fractionation of Aluminum in Soil and Relation to Its Concentration in Fruits

Aluminum concentrations in the fruit samples taken from different regions were determined by atomic absorption spectrometry after dry ashing digestion. To identify the aluminum phases being most responsible for fruit-available aluminum, the soil samples near the fruit plants were also analyzed for aluminum by using various digestion and selective extraction reagents. The relation between the aluminum concentrations in fruits and in soil extracts was studied. The obtained aluminum concentrations in the fruits were in the range of 1.5 to 42.0 mg kg^-1 on dry weight basis. It was observed that the aluminum concentrations of morello cherry(R² = 0.79) and mulberry (R² = 0.99) were correlated to the aluminum concentrations in citric acid extracts of the soils. While the aluminum concentrations of the EDTA and acetic acid extracts in some soils samples include 35% and 25% of total aluminum, respectively, the other soils contain only 1–2%.     

Multiresidue analysis of neonicotinoids by solid-phase extraction technique using high-performance liquid chromatography

For routine monitoring of pesticides, a multiresidue analysis through solid-phase extraction technique and using high-performance liquid chromatography (HPLC) in cotton seed cake (CSC) has been developed. Extraction of fortified samples was carried out with aqueous acetone under vacuum. The concentrated extract was loaded onto the solid-phase extraction units, preconditioned with acetonitrile. The extraction units were then washed with hexane and finally eluted with acetonitrile. The pesticide residues were determined using a multiresidue method by reversed-phase HPLC. The average percentage recoveries were found to range between 65.47% and 110% at spiking levels of 10 to 40 mg/kg. The method developed shows a healthy rate of recovery and can successfully be utilized for the extraction and screening of neonicotinoid residues in CSC. The detection limits for imidacloprid, acetamiprid, and thiacloprid using this method were found to be 5, 10, and 20 mg/kg, respectively.     

固相微萃取-毛细管气相色谱法快速分析水中酚类化合物

固相微萃取是一种快速、简便、集萃取浓缩进样于一体的样品前处理技术,具有分析时间短、灵敏度高、无需有机溶剂的优点.本工作用固相微萃取富集水中酚类化合物,毛细管气相色谱分离分析,整个分析过程只需45min,检出限可达1.0～10.0μg/L,已用于地面水、海水、工厂废水中酚类化合物含量的测定.     

Statistical analysis of aerosol species, trace gasses, and meteorology in Chicago

Both canonical correlation analysis (CCA) and principal component analysis (PCA) were applied to atmospheric aerosol and trace gas concentrations and meteorological data collected in Chicago during the summer months of 2002, 2003, and 2004. Concentrations of ammonium, calcium, nitrate, sulfate, and oxalate particulate matter, as well as, meteorological parameters temperature, wind speed, wind direction, and humidity were subjected to CCA and PCA. Ozone and nitrogen oxide mixing ratios were also included in the data set. The purpose of statistical analysis was to determine the extent of existing linear relationship(s), or lack thereof, between meteorological parameters and pollutant concentrations in addition to reducing dimensionality of the original data to determine sources of pollutants. In CCA, the first three canonical variate pairs derived were statistically significant at the 0.05 level. Canonical correlation between the first canonical variate pair was 0.821, while correlations of the second and third canonical variate pairs were 0.562 and 0.461, respectively. The first canonical variate pair indicated that increasing temperatures resulted in high ozone mixing ratios, while the second canonical variate pair showed wind speed and humidity’s influence on local ammonium concentrations. No new information was uncovered in the third variate pair. Canonical loadings were also interpreted for information regarding relationships between data sets. Four principal components (PCs), expressing 77.0 % of original data variance, were derived in PCA. Interpretation of PCs suggested significant production and/or transport of secondary aerosols in the region (PC1). Furthermore, photochemical production of ozone and wind speed’s influence on pollutants were expressed (PC2) along with overall measure of local meteorology (PC3). In summary, CCA and PCA results combined were successful in uncovering linear relationships between meteorology and air pollutants in Chicago and aided in determining possible pollutant sources.     

固相微萃取-毛细管气相色谱法快速同步分析水中有机氯及有机磷农药

固相微萃取是一种快速、简便,集萃取浓缩进样于一体的样品前处理技术,具有分析时间短、灵敏度高、无需有机溶剂的优点.用固相微萃取富集水中8种有机氯及7种有机磷农药,毛细管气相色谱ECD检测器分离分析,整个分析过程只需26min,检出限可达0.002～1μg/L,已用于地表水中有机氯及有机磷农药含量的测定.     

固相微萃取一毛细管气相色谱法快速分析水中有机氯农药

固相微萃取是一种快速、简便、集萃取浓缩进样于一体的样品前处理技术,具有分析时间短、灵敏度高、无需有机溶剂的优点.本工作用固相微萃取富集水中有机氯农药,毛细管气相色谱分离分析,整个分析过程只需30min,检出限可迭0.01至0.1μg/L,已用于降雨、地面水、海洋中有机氯农药含量的测定.     

海水中半挥发性有机化合物的萃取/GC-MS/SIM定量分析方法研究

采用萃取/GC-MS/SIM法对海水中250种半挥发性目标化合物同时进行定量分析,方法的最低检出限范围在0.004μg/L～0.060μg/L之间,绝大多数化合物的回收率在60%～150%之问.     

Fractionation of heavy metals and assessment of contamination of the sediments of Lake Titicaca

Chemical weathering is one of the major geochemical processes that control the mobilization of heavy metals. The present study provides the first report on heavy metal fractionation in sediments (8–156 m) of Lake Titicaca (3,820 m a.s.l.), which is shared by the Republic of Peru and the Plurinational State of Bolivia. Both contents of total Cu, Fe, Ni, Co, Mn, Cd, Pb, and Zn and also the fractionation of these heavy metals associated with four different fractions have been determined following the BCR scheme. The principal component analysis suggests that Co, Ni, and Cd can be attributed to natural sources related to the mineralized geological formations. Moreover, the sources of Cu, Fe, and Mn are effluents and wastes generated from mining activities, while Pb and Zn also suggest that their common source is associated to mining activities. According to the Risk Assessment Code, there is a moderate to high risk related to Zn, Pb, Cd, Mn, Co, and Ni mobilization and/or remobilization from the bottom sediment to the water column. Furthermore, the Geoaccumulation Index and the Enrichment Factor reveal that Zn, Pb, and Cd are enriched in the sediments. The results suggest that the effluents from various traditional mining waste sites in both countries are the main source of heavy metal contamination in the sediments of Lake Titicaca.