Adequate sampling, an important step towards reiable decisions based on analytical results

The efforts spent on judgments of how to perform sampling are often small compared to other steps in the analytical procedure. As a result decisions may be based on irrelevant results. If the sampling is intended to provide information how to reduce and control environmental pollution, it is important to design the sampling strategy according to scientific principles. Sampling will be discussed in relation to determinations of organic as well as inorganic species in different types of polluted matrices, .e.g. water, sediments and air. Examples will be taken from our own research projects about treatment processes for contaminated matrices.. Accurate sampling involves a basic planning including objectives, cost effectiveness versus the budget, variability of contamination leading to statistical considerations, site accessibility and robustness of the used devices. A strategy for the sampling, often in a form of a scheme, is needed. The Laqua Protocol developed within our research projects will be presented. This protocol is flexible and dynamic and can be altered and optimized based on the demands at the individual sampling site. Sampling of complicated matrices often creates problems with interfering agents and breakdown of unstable analytes. In this type of samples the concentrations of analytes are generally several orders of magnitudes lower than the concentrations of major constituents in the sample. Accordingly the advantages of an early work-up, preferably in connection with a sampling procedure, is paid especially attentio

Adequate sampling, an important step towards reiable decisions based on analytical results [Elektronisk resurs]

The efforts spent on judgments of how to perform sampling are often small compared to other steps in the analytical procedure. As a result decisions may be based on irrelevant results. If the sampling is intended to provide information how to reduce and control environmental pollution, it is important to design the sampling strategy according to scientific principles. Sampling will be discussed in relation to determinations of organic as well as inorganic species in different types of polluted matrices, .e.g. water, sediments and air. Examples will be taken from our own research projects about treatment processes for contaminated matrices.. Accurate sampling involves a basic planning including objectives, cost effectiveness versus the budget, variability of contamination leading to statistical considerations, site accessibility and robustness of the used devices. A strategy for the sampling, often in a form of a scheme, is needed. The Laqua Protocol developed within our research projects will be presented. This protocol is flexible and dynamic and can be altered and optimized based on the demands at the individual sampling site. Sampling of complicated matrices often creates problems with interfering agents and breakdown of unstable analytes. In this type of samples the concentrations of analytes are generally several orders of magnitudes lower than the concentrations of major constituents in the sample. Accordingly the advantages of an early work-up, preferably in connection with a sampling procedure, is paid especially attentio

Improved spectrophotometric vitellogenin determination via alkali-labile phosphate in fish plasma - a cost effective approach for assessment of endocrine disruption

Vitellogenin (VTG) is a well known protein biomarker for exposure to environmental estrogens and possible endocrine disruption in fish. VTG is very dominant in plasma after the onset of vitellogenesis and the protein is heavily phosphorylated. This enables indirect quantification through measurement of alkali-labile protein bound phosphate (ALP) as an alternative to the more expensive enzyme linked immunosorbent assay. Good correlation has previously been shown between ALP and actual VTG levels but little effort has been made to investigate the method in an analytical way e.g., to assure the origin of the measured phosphate. During this method development care has been taken to rule out non-VTG sources of phosphate such as phospholipids and free phosphate in the blood plasma. Sample preparation has been simplified and unnecessary steps have been omitted. The common spectrophotometric measurement for ALP involves measurement at two wavelengths and calculation of corrected absorbance values. With a quick phase separation step the spectrophotometric phosphate determination using molybdic acid and ascorbic acid has been improved and all matrix interference has been eliminated. The final ALP method presented here has a detection limit of 3.2 mu g PO43-/ml plasma which is six times lower than similar methods and it also has less variability. A high sample throughput in comparison to previous ALP methods is possible after scaling down sample and reagent volumes to fit in a 96 well microtiter plate. The cost for buying all chemicals and plastic consumer goods for setting up the indirect protocol for the analysis of 1000 samples is only circa 350 euro. This is only 1% of the material cost for buying commercially available test kit for direct quantification of VTG in the same number of samples. The ALP method should thus be of interest also for applied scientists outside advanced research laboratories

A new spectrophotometric method for improved indirect measurement of low levels of vitellogenin using malachite green

Vitellogenin (VTG) is a well-known biomarker for endocrine disruption and the measurement of alkali-labile protein bound phosphate (ALP) has been used as an indirect quantification method for VTG in fish, clam and mussel. One limitation of the ALP method has been the insufficient detection limit but with the method presented here this obstacle has been overcome, enabling measurement in fish species with very low background levels and hence a wider usage of ALP measurements in the future. In a previous publication, relying on spectrophotometric measurement with molybdate, we presented an improved protocol for ALP measurement in fish plasma. The sample preparation in that paper has here been combined with an improved spectrophotometric determination using malachite green as colour reagent. The spectrophotometric measurement was optimised with respect to acidity and reagent concentration. The validated method has a detection limit of 0.3 mu g PO43- ml(-1) plasma, which is 10 times lower than previous spectrophotometric methods using molybdate reagent, and an intra-assay variation of 7%. The new method was used for screening of endocrine effects by placing juvenile rainbow trout at three locations along the Vallkarra brook, Lund Sweden, which receives leachate water from a nearby covered landfill. In comparison with reference fish, ALP was significantly higher (66%) at the 99% confidence level in fish placed close to the landfill. ALP was also significantly higher (33%) at the 95% confidence level in fish from the group placed further downstream. Fish placed in a brook branch not receiving leachate were unaffected. The low levels of ALP in reference fish (5.5 +/- 0.7 SD PO43- mu g/ml plasma) could not have been quantified with such precision with another method for ALP measurement. The indirect quantification of VTG as ALP is a more economic alternative compared to quantification with immunological methods

Occurrence and removal of pharmaceuticals in a municipal sewage treatment system in the south of Sweden.

The occurrence and removal rate of seven pharmaceuticals (ibuprofen, naproxen, diclofenac, fluoxetine, ofloxacin, norfloxacin, ciprofloxacin), two metabolites (norfluoxetine, clofibric acid), one degradation product (4-isobutylacetophenone) and 3 estrogens (17alpha-ethinylestradiol, 17beta-estradiol, estrone) were studied in the inlet and outlet of a tertiary sewage treatment plant (STP) in Sweden as well as between different treatment steps in the STP which includes a conventional activated sludge step. Pharmaceuticals in raw household and raw hospital sewage streams leading to the STP were as well investigated. Hydraulic retention times (HRT) of each treatment step was considered for sampling and for the calculation of the removal rates. These rates were above 90%, except for diclofenac, clofibric acid, estrone and ofloxacin. However, only diclofenac and naproxen showed significant effluent loads (>145 mg/d/1000 inh). Diclofenac was not eliminated during the treatment and in fact even higher concentrations were found at the effluent than in the inlet of the STP. 17alpha-Ethinylestradiol was not detected in any of the samples. Results indicate that a STP such as the one in Kristianstad, Sweden, with a tertiary treatment is sufficient to remove significantly most of the investigated pharmaceuticals. The chemical treatment improved the removal of several pharmaceuticals especially the antibiotics, which showed step removal rates between 55 and 70%. The expected concentration levels of the pharmaceuticals in the surface water (dilution 1 to 10) close to the outlet of the STP are below the no-observed effect-concentration (NOEC). However, despite that this would imply no important effects in the aquatic environment one cannot rule out negative consequences nearby the STP because most of the NOEC values are derived from acute toxicity data. This may underestimate the real impact of pharmaceuticals in the aquatic ecosystem

Determination of dissolved and particle-bound PCB congeners at ultra-trace concentrations in water

Adsorption of 10 PCB congeners in aqueous solutions on glass-fibre filters taken from different boxes but of the same type were not significantly different. The standard deviations using filters from the same box were below 10% at concentration levels of 4.1 ng L-1. At this level, the adsorption of dissolved PCB at the filters was in the range of 5-20%. depending oil the congener. This led to a procedure for determination of dissolved and particle-bound congener in authentic landfill leachate, which included correction for adsorption losses. The procedure was based oil filtration through glass-fibre filters, followed by trapping of the PCB in the eluate on solid-phase extraction (SPE) disks. After separate supercritical fluid (SFE) extractions, with carbon dioxide, of the filters as well as of the SPE disks, the extracts were analysed on a two-column capillary GC-ECD system. Corrections for congener adsorption on glass-fibre filters were made, from which corrected distribution constants between particle-bound and dissolved PCB congener in the water phase could be obtained for authentic landfill leachate. These values (10(4)-10(5)) agreed well with those obtained by others