An affordable method for the simultaneous determination of the most studied pharmaceutical compounds as wastewater and surface water pollutants

There is still an increasing need of knowledge about the presence of pharmaceuticals in the environment in many countries. To contribute to the improvement of this knowledge it should be useful to get not only more reliable methods, but also analytical methods that do not require expensive equipment and, consequently, could be used even in the less developed areas. In the present work, a novel analytical method for the simultaneous determination of several priority pharmaceuticals, as aquatic media pollutants, in wastewater and surface water is reported. The method involves sample treatment by SPE, followed by LC with diode array and fluorescence detection. Parameters that affect the efficiency of the SPE step such as elution solvents, sample pH and cartridge sorbents were evaluated and optimized. The best results were obtained using acetone as elution solvent, acidifying samples to pH 2 and employing Oasis HLB as SPE sorbent. Recoveries of the pharmaceuticals from influent and effluent wastewater and surface water samples were in the range from 61.4 to 123%. LODs were in the range of 0.001–0.323 μg/L and LOQs were between 0.020 and 1.078 μg/L.     

Optimized cleanup methods of organic extracts for the determination of organic pollutants in biological samples

The analytical performances of various adsorbents used to clean up an organic extract of biological samples, particularly for the determination of polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), both in mussel tissue and in krill samples, are critically compared. DDT and its degradation products, namely DDE and DDD, are also considered. Silica gel, alumina, aminopropyl-silica, cyanopropyl-silica, florisil, graphitized nonporous carbon and silica gel–alumina mixture (3:1) were used for column chromatography cleanup in combination with modified supercritical CO₂ as a mobile phase. Recovery and reproducibility were evaluated by analyzing standard solutions and standard reference materials containing various classes of pollutants. A silica gel–alumina mixture was found to be the most effective in the cleanup of organic extracts, allowing quantitative recoveries of all analytes to be obtained. Finally, the application of the optimized procedure to the determination of PCBs in Antarctic krill samples is presented.     

Concentration and determination of trace organic pollutants in water

Organic pollutants in water are isolated on a mini-sampler tube containing a macroporous resin. The sorbed pollutants are next thermally transferred to a second sorption tube and then to an analytical column where they are separated and determined by temperature-programmed gas chromatography. Excellent recoveries were obtained for tests in which model organic compounds of various classes were added to water. The water sample is much smaller than that required with previous analytical methods.     

持久性有机化学污染物(POPs)的定性与定量分析

目前在持久性有机污染物研究方面出现了许多新的研究动向、研究计划相关环境条约以及新的名词.例如:POPs(Persistent Organic Pollutants)持久性有机污染物;PBT(Persistent Bioaccumulative& Toxic Chemicals);持久性生物可积累性毒性化合物;BFRs(Brominated Flame Retardants)溴化阻燃剂;EEDs(Environmental Endocrine Disruptors)环境内分泌干扰物,PTS(Persistent Toxic Substances)等.     

Gas chromatographic methods for the determination of trace organic pollutants in environmental samples

Some problems, special features, and tendencies of the determination of trace organic compounds in various environmental samples with the use of chromatographic methods are considered.     

Green analytical chemistry in sample preparation for determination of trace organic pollutants

The principles of green chemistry are applied to not only chemical engineering and synthesis, but also increasingly analytical chemistry. We describe environment-friendly analytical techniques applied to isolate and to enrich trace organic pollutants from solid and aqueous samples. Amounts of organic solvents used in analytical laboratories are reduced by applying solventless extraction, extraction using other types of solvent, assisted solvent extraction and miniaturized analytical systems.     

Analytical multimethod for the determination of low volatile organic pollutants in sediments and sewage sludges

By means of selected target compounds with different physical and chemical properties an analytical method has been developed for the analysis of a wide variety of low volatile xenobiotics in sediments and sewage sludges. After an exhaustive extraction at different pH values first high molecular matrix compounds have been separated by GPC. Fractionation of the samples into five separate groups of substances has been performed by successive column chromatography using deactivated alumina and silica gel. For the determination of phenols a derivatization step with pentafluorobenzolychloride has been incorporated into the sample preparation. Removal of sulphur and aliphatic hydrocarbons has been accomplished by an additional clean up with TBA-sulfite reagent and silica gel. Recoveries of the most target compounds exceeded 80%.     

Application of micro-solid-phase extraction for the determination of persistent organic pollutants in tissue samples

A novel, simple and efficient method for determining persistent organic pollutants (POPs) in tissue samples has been developed. This technique involves the use of simultaneous microwave-assisted digestion (MAD) and micro-solid-phase extraction (micro-SPE), in which the sorbent is held within a propylene membrane envelope, with gas chromatographic-mass spectrometric (GC-MS) analysis. The POPs studied included eleven organochlorine pesticides and five polychlorinated biphenyl congeners. Optimization of the MAD-micro-SPE parameters was performed. The relative standard deviations (RSDs) of the method ranged from 0.14 to 12.7%. Correlation coefficients up to 0.9999 were obtained across a concentration range of 1.25-50 ng g(-1). The method detection limits for POPs ranged from 0.002 to 0.009 ng g(-1). A preliminary study applying the MAD-micro-SPE procedure to human ovarian cancer tissue showed that it was capable of detecting the presence of a wide spectrum of different POPs in benign and malignant tumors.     

Development of a stir bar sorptive extraction and thermal desorption-gas chromatography-mass spectrometry method for the simultaneous determination of several persistent organic pollutants in water samples

Stir bar sorptive extraction (SBSE) and thermal desorption followed by capillary gas chromatography coupled to mass spectrometry (SBSE-TD-GC-MS) was applied to the simultaneous determination of ultra-traces of 16 polycyclic aromatic hydrocarbons (PAHs), 12 polychlorinated biphenyls (PCBs), 6 phthalate esters (PEs) and 3 nonylphenols (NPs) in water samples. The parameters that could affect the sorption-desorption efficiency were studied. A Plackett-Burman design was used for the screening of the main effects of the experimental parameters related to the desorption step (desorption time, desorption temperature, desorption flow, cryo-focusing temperature and vent pressure). Afterwards, two central composite designs were used to find the optimal process settings for the extraction and desorption steps. The best analytical compromise conditions for the simultaneous determination of analytes from spiked water samples were found to be: sample volume (20 mL), sodium chloride addition (30%), methanol addition (20%), desorption time (10 min), desorption temperature (300 degrees C), desorption flow (23 mL min(-1)), cryo-focusing temperature (-50 degrees C) and vent pressure (7 psi). Remarkable recovery, repeatability and reproducibility were attained. Furthermore, excellent linearities (r(2) = 0.959-0.999) and low detection limits (0.1-10 ng L(-1)) were also achieved for the congeners studied. The proposed methodology was applied for the simultaneous determination of PAHs, PCBs, PEs and NPs in sea and estuarine waters. The influence of humic acids on the recovery was also studied.     

An analytical multi-residue approach for the determination of semi-volatile organic pollutants in pine needles

Vegetation (and pine needles in particular) has been widely used as an alternative to other conventional sampling devices to assess the atmospheric presence of semi-volatile organic contaminants (SVOCs). While most analytical procedures developed focus only on one or two chemical classes, this this work intends to establish a multi-component protocol to quantify brominated flame-retardants (BFRs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polynuclear aromatic hydrocarbons (PAHs) and one class of contaminant of emerging concern, the synthetic musks fragrances (SMCs). Pine needles extracts were obtained by ultrasonic solvents extraction (USE), and different cleanup approaches using solid-phase extraction (SPE) employing combinations of sorbents and solvents as well as gel permeation chromatography (GPC) were tested. SPE with alumina followed by GCP yielded the best results, with average recoveries over 80%.     

Chemiluminescence method with potassium permanganate for the determination of organic pollutants in seawater.

A chemiluminescence method with potassium permanganate was developed for use as an indicator of organic pollutants in fresh water. This method could be applied to the determination of organic pollutants in seawater as well. However, the flow chemiluminescence method suffered from the interference of chloride ions at the same concentration of seawater because of the production of manganese dioxide in the oxidation of chloride ions with permanganate. The conditions (concentrations of potassium permanganate and sulfuric acid and sample volume, i.e. flow injection method) were chosen to minimize the interference of chloride ions. The chemiluminescence method shows a good correlation with the chemical oxygen demand method on fresh water added artificial sea salt and seawater samples. Natural seawater was analyzed by the chemiluminescence method. The results obtained were compared with those obtained by chemical oxygen demand under the alkaline condition and total organic carbon methods. The chemiluminescence method has higher sensitivity and reproducibility than the conventional chemical oxygen demand and total organic carbon methods.     

A review of the determination of persistent organic pollutants for environmental forensics investigations

The field of environmental forensics emerged in the 1980s as a consequence of legislative frameworks enacted to enable parties, either states or individuals, to seek compensation with regard to contamination or injury due to damage to the environment. This legal environment requires stringent record keeping and defendable data therefore analysis can sometimes be confined to data to be obtained from certified laboratories using a standard accredited analytical method. Many of these methods were developed to target specific compounds for risk assessment purposes and not for environmental forensics applications such as source identification or age dating which often require larger data sets. The determination of persistent organic pollutants (POPs) for environmental forensic applications requires methods that are selective but also cover a wide range of target analytes which can be identified and quantified without bias. POPs are used in a wide variety of applications such as flame retardants, fire suppressants, heat transfer agents, surfactants and pesticides mainly because of their chemical inertness and stability. They also include compounds such as dioxins that can be unintentionally produced from industrial activities. POPs are persistent in the environment, bioaccumulative and/or toxic and therefore require analytical methods that are sensitive enough to meet the low detection limits needed for the protection of the environment and human health. A variety of techniques, procedures and instruments can be used which are well suited for different scenarios. Optimised methods are important to ensure that analytes are quantitatively extracted, matrix coextractables and interferences are removed and instruments are used most effectively and efficiently. This can require deviation from standard methods which can open the data up to further scrutiny in the courtroom. However, when argued effectively and strict QA/QC procedures are followed the development and optimization of methods based on investigation specific scenarios has the potential to generate better quality and more useful data.     

A rapid method for the determination of organic carbon in soil

TIURIN'S method for the determination of organic carbon in soil is modified to give results practically identical with those of the dry combustion method. The standard deviation of a single determination is only 12%. By using 50 mg of soil and 10 ml of 0.2 N dichromate solution, soils with a carbon, content up to 12% can bo analysed. The method is suitable for all soils except those containing much chloride or reducing substances other than organic carbon Carbonates do not interfere.     

Advances in the gas chromatographic determination of persistent organic pollutants in the aquatic environment

Environmental chemists have been challenged for over 30 years to analyse complex mixtures of halogenated organic pollutants like polychlorinated biphenyls (PCBs), polychlorinated alkanes (PCAs), polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and polychlorinated furans (PCDD/Fs). Gas chromatography (GC) often proved to be the method of choice because of its high resolution. The recent developments in the field of comprehensive two-dimensional GC (GCxGC) show that this technique can provide much more information than conventional (single-column) GC. Large volume injection (e.g. by programmed temperature vaporiser, or on-column injection) can be employed for the injection of tens of microliters of sample extract, in that way substantially improving the detection limits. Electron-capture detection (ECD) is a sensitive detection method but unambiguous identification is not possible and misidentification easily occurs. Mass spectrometric (MS) detection substantially improves the identification and the better the resolution (as with MS/MS, time-of-flight (TOF) MS and high-resolution (HR)MS), the lower the chances of misidentification are. Unfortunately, this comes only with substantially higher investments and maintenance costs. Co-extracted lipids, sulphur and other interferences can disturb the GC separation and detection leading to unreliable results. Extraction, and more so, sample clean-up and fractionation, are crucial steps prior to the GC analysis of these pollutants. Recent developments in sample extraction and clean-up show that selective pressurised liquid extraction (PLE) is an effective and efficient extraction and clean-up technique that enables processing of multiple samples in less than 1h. Quality assurance tools such as interlaboratory studies and reference materials are very well established for PCDD/Fs and PCBs but the improvement of that infrastructure is needed for brominated flame retardants, PCAs and toxaphene.     

A new HPLC method for the simultaneous determination of fluazifop-butyl and fluazifop in soil samples

Summary The analytical method presented here enables the extraction of fluazifop-butyl and fluazifop from soil samples avoiding hydrolysis of the ester and allowing a better release of the acid form. Then the quantitative determination of both the compounds can be performed in one run by means of RP-HPLC. This is achieved by using a phenyl phase and an ion-pair reagent (tetrabutylammonium hydrogensulfate).     

Submicro determination of hydrogen in organic compounds: Application to the determination of water and simultaneous determination of nitrogen

The calcium hydride reaction with water is used as a basis for determining hydrogen. The liberated hydrogen is collected and measured in a gasometer. Representative organic compounds containing only CHO, mixed with a catalyst, are combusted in a porcelain boat in an atmosphere of pure, dry carbon dioxide. Hydrogen is collected over 50% KOH, as in the Pregl-Dumas method for nitrogen, the volume of gas is corrected for T and P and the percentage of hydrogen is calculated. The hydrogen gas occupies 14 times the volume of nitrogen thus permitting use of the micro quantities.     

Pulsed large volume injection gas chromatography coupled with electron-capture negative ionization quadrupole mass spectrometry for simultaneous determination of typical halogenated persistent organic pollutants

A pulsed large-volume injection gas chromatography coupled with electron-capture negative ionization quadrupole mass spectrometry (pLVI-GC/ECNI-qMS) was developed for the simultaneous determination of typical halogenated persistent organic pollutants (H-POPs). By monitoring the characteristic ions of large mass-to-charge ratio (m/z) for each of the H-POPs rather than the chlorine and/or bromine ions, this method avoided the possible interferences arising from the H-POPs themselves and from complex matrices encountered frequently in current GC/qMS methods; and allowed, on the other hand, the use of (13)C-labeled and perdeuterated analogues as internal standards for reliable quantification. pLVI up to 120 microL improved the instrumental detection limits down to pg-fg mL(-1), comparable to or lower than those obtained by the recognized GC/high-resolution MS methods reported so far. The H-POPs including 12 polybrominated diphenyl ethers, 1 polybrominated biphenyl, 10 polychlorinated biphenyls (PCBs), 4 hexachlorocyclohexane isomers, and hexachlorobenzene were involved in this study. The method developed demonstrated good linearity (r(2) = 0.9904-0.9999) within 0.5 to 50,000 pg mL(-1) for PCBs and 0.05 to 5000 pg mL(-1) for other H-POPs, and was satisfactory in terms of both repeatability (0.07%-2.2%) and reproducibility (2.1%-8.4%). It was validated by analyzing a NIST standard reference material SRM-1946 of Lake Superior fish tissue with low 0.01 to 63 pg g(-1) method detection limits, and successfully applied to the determination of the H-POPs in five reference materials of different matrices.