Analytical methods, samples from Lake

In move 2, Describe Experimental Methods (hgure 3.1), authors describe how they obtained their data. The move involves two submoves. The hrst submove, describe procedures, includes analytical procedures (e.g., the steps used to prepare, extract, concentrate, and/or derivatize a sample), held-collection procedures (e.g., the steps used to collect water samples from a polluted lake), and synthetic procedures (e.g., the steps used to synthesize target compounds), to name only a few. In some journals (particularly those describing analytical procedures), this submove also includes procedures used to ensure the accuracy and precision of the work. Such procedures are described as quality assurance/quality control (QA/QC). 

Recent studies directed at assessing the fate and transport of Hg in natural waters used improved analytical methods and clean techniques for sampling and analysis (9, 10). Some lake studies (II, 12) were directed at assessing the effects of point-source Hg inputs, such as chloroalkali manufacturing plants and mining operations other studies (13-16) were developed in response to concerns over recent observations of elevated Hg levels in fish from lakes remote from point sources. 

Dongjin Pyo also reported some other procedures The extraction by SFE was performed with a Beckman 116 pump (System Gold programmable solvent module 126), a 15 cm X 10 mm I.D. ODS column and Agilent HPLC 1100 series diode-array detector. Methanol/0.05 M phosphate buffer (52 48), pH 3, was used as a mobile phase at a flow rate of 2 mL/min. The analytical results obtained from real lake samples indicate the viability of the method for the determination of microcystins in real samples. 

According to the procedure proposed. Member States were extensively consulted during 2006 for revision of CEN biologic standard methods (Table 1.3.6) for their relevance in the context of the WFD and to identify priority areas for future standardisation activities. It became apparent from this process that sampling and quality assurance methods are mostly needed at community level, and also that published standard methods often do not take into account water category type-specific features, as is required in the Directive. This consultation process enabled the identification of a number of candidate sampling and analytical methods fulfilling short-tenn standardisation needs for lakes, rivers and coastal waters. 

The choice of an analytical method depends on its performance characteristics (detection limits, accuracy and precision, speed etc). Other conditions to be reached are the concerned element, the concentration in the sample of interest, the variability of their concentration. The concentration of metal ions in studied Seaside Lakes were determined by flame atomic absorption spectrometry (FAAS) (Chirila et al., 2003a), inductively coupled plasma atomic emission spectrometry (ICP-AES) (Chirila et al., 2002), molecular absorption spectrometry in visible (Chirila and Carazeanu, 2001). These investigations were carried out in the biotope (sediment and water) and biocenosis (different plants and fish) from one ecosystem (Tabacarie Lake) and in water samples from the other Seaside lakes. 

Other LC-MS/MS methods for the detection of toxins in water include the analysis of lipophihc phyco-toxins in coastal waters [69]. This method has the identification capability of the MS/MS method, which uses collision-induced dissociation (CID)-produced mass spectra to correlate LC retention times from the analytes of interest. Another MS/MS method finds toxins from cyanobacteria in lake water and reinforces the need for quantification of toxins. The total amount of toxins not only exists in the water but also in the cell walls of the algae, and contributes to the overall toxin load in the sample [70]. This method uses the confirmative properties of the LC-MS/MS system and provides the desired nanogram per miUihter detection limits. 

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