Erland Björklund

Development of an analytical method to determine avermectins in water, sediments and soils using liquid chromatography–tandem mass spectrometry

A comprehensive analytical multi-residue method has been developed for the determination of seven avermectins (abamectin, doramectin, ivermectin, emamectin benzoate, eprinomectin, moxidectin and selamectin) in surface water, sediment and soil samples. Solid samples were extracted applying pressurised liquid extraction followed by a solid-phase extraction (SPE) clean-up step. For aqueous samples, extraction was done utilising only SPE. All compounds were measured using liquid chromatography coupled to tandem mass spectrometry using atmospheric pressure chemical ionisation. The recoveries were 38-67% (relative standard deviation: 9-26%), 63-88% (16-23%) and 63-80% (9-15%) for spiked Rhine water, spiked sediment and spiked soil samples, respectively, and limit of quantifications were 2.5-14 ngl(-1) in water and 0.5-2.5 ngg(-1) in soil and sediment.

Determination of pharmaceuticals in environmental and biological matrices using pressurised liquid extraction—Are we developing sound extraction methods?

Pressurised liquid extraction (PLE) is now a well established and extensively applied extraction technique in environmental analysis for pollutants such as persistent organic pollutants (POPs). During the past decade, an emerging group of environmentally interesting analytes are pharmaceuticals that are continuingly released into the environment. This class is comprised with compounds of various properties. As the field of the analysis of these compounds grows, an increasing number of PLE methods for pharmaceuticals of varying quality are developed and published. This review summarises the critical PLE parameters during PLE method development and highlight them with examples from recently published papers utilising pressurised liquid extraction for the determination of pharmaceuticals in environmental and biological matrices. These recent methods are summarised and critically discussed with the aim to provide important reflections to alleviate in future PLE development for pharmaceuticals in environmental matrices.

H295R cells as a model for steroidogenic disruption: A broader perspective using simultaneous chemical analysis of 7 key steroid hormones

The effects of three model endocrine disruptors, prochloraz, ketoconazole and genistein on steroidogenesis were tested in the adrenocortical H295R cell line to demonstrate that a broader mechanistic understanding can be achieved in one assay by applying chemical analysis to the H295R assay. Seven key steroid hormones (pregnenolone, progesterone, dehydroepiandrosterone, androstenedione, testosterone, estrone and 17β-estradiol) were analyzed using a novel and thoroughly validated GC-MS/MS method. In addition to the simultaneous quantification of 7 steroid hormones, the present method also negates the potential problems of cross-reactivity that can be encountered in some immunoassays. Although all 3 test compounds decrease the concentrations of the main sex steroids, the chemicals exerted different effects upstream in the pathway. Exposure to prochloraz resulted in increased hormone levels upstream of steroid 17 alpha-hydroxylase/17,20 lyase (P450c17) and decreases downstream. Ketoconazole inhibited the entire pathway, while exposure to genistein resulted in increased hormone levels upstream of 3-β-hydroxysteroid dehydrogenase (3β-HSD) and decreases downstream. The results demonstrate that chemical analysis combined with the H295R cell assay is an useful tool for studying the mechanisms by which endocrine disruptors interfere with the steroidogenic pathway.

Simultaneous determination of endogenous steroid hormones in human and animal plasma and serum by liquid or gas chromatography coupled to tandem mass spectrometry

Analytical methodologies based on liquid or gas chromatography coupled to tandem mass spectrometry for the simultaneous determination of two or more endogenous steroid hormones in human and animal plasma and serum has received increased attention the last few years. Especially in the clinical setting steroid profiling is of major importance in disease diagnostics. This paper discusses recent findings in such multi-steroid hormone procedures published from 2001 to 2012. The aim was to elucidate possible relationships between chosen analytical technique and the obtained analyte sensitivity for endogenous steroid hormones. By evaluating the success, at which the currently applied techniques have been utilized, more general knowledge on the field is provided. Furthermore the evaluation provides directions in which future studies may be interesting to conduct.

Selective pressurized liquid extraction of three classes of halogenated contaminants in fish

Pressurized liquid extraction (PLE) combined with in-cell clean-up of co-extracts, so-called selective-PLE (S-PLE), is a fast and accepted method for the analysis of halogenated organic contaminants in fish. However, many of the existing methods were optimized for use with single classes of contaminants. The main objective of this research was to develop an S-PLE method that elutes a minimal amount of fats while simultaneously extracting halogenated pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) from fat-rich fish. The optimized method uses n-hexane:dichloromethane (75:25, v/v) as the extraction solvent, a 0.0078 fat to fat-retainer ratio (FFR) with Florisil as the fat retainer, three individual 5-min extractions with flush volumes of 150% and a selection of labeled surrogate standards (isotope dilution). This method resulted in a mean recovery of 77% for all target analytes in spiked samples and an average relative standard deviation of 6.3%. The method was validated with a certified reference material; the mean measured analyte concentrations agreed with the reference values except in the case of individual endosulfan isomers. It is likely that interconversion from the beta- to alpha-endosulfan isomer had occurred in the CRM, resulting in low measured concentrations for beta-endosulfan and high measured concentrations for alpha-endosulfan when compared with the reference values. Finally, the method was tested on three fish species with varying fat content. Different contaminant patterns were observed in the various species.

Analysis and environmental concentrations of the herbicide dichlobenil and its main metabolite 2,6-dichlorobenzamide (BAM): a review.

Dichlobenil is an herbicide which has been applied in many countries for weed control in non-agricultural areas such as railroads, car parks and private gardens. In the aquatic environment it has been used for control of floating aquatic weeds. Dichlobenil is relatively persistent in the environment, and primarily bound to solid matrices. Of great concern is its main degradation product 2,6-dichlorobenzamide which is water soluble and therefore transported downward in aquifers, contaminating groundwater resources. It is often found in concentrations exceeding 0.1 μg/L, which is the maximum allowed concentration of pesticides in groundwater set by the European Commission. In many countries, the usage of dichlobenil and the problems associated with groundwater contamination by 2,6-dichlorobenzamide have resulted in intensive research and monitoring of these compounds. This review gives the first overview of analytical strategies available for determining dichlobenil and 2,6-dichlorobenzamide in environmental matrices. It also summarizes studies presenting measured environmental concentrations of dichlobenil and 2,6-dichlorobenzamide identified in the literature during the past two decades. Thereby a preliminary picture of the distribution of dichlobenil and 2,6-dichlorobenzamide in the environment can be outlined for the first time.

Determination of ten steroid hormones in animal waste manure and agricultural soil using inverse and integrated clean-up pressurized liquid extraction and gas chromatography-tandem mass spectrometry

This paper presents a novel analytical methodology for the simultaneous determination of nine native and one synthetic steroid hormone in animal manure and agricultural soil. The optimized method applies pressurized liquid extraction (PLE) on manure samples packed in a 22 mL PLE cell: firstly by flushing the sample with heptane to remove unwanted matrix components (inverse-PLE, i-PLE) and secondly, performing internal clean-up (ic-PLE) and eluting the steroid hormones by attaching an additional 11 mL PLE cell downstream packed with graphite, silica and alumina. The PLE extracts were further cleaned by a two step solid phase clean-up (aminopropyl and silica gel), and in combination with a one hour derivatization the samples could be analyzed utilizing a GC-MS/MS system with PTV injector. Cholesterol, sitosterol and coprostanols were added and monitored during method development experiments as surrogates for environmental interfering compounds. The optimization demonstrated that the surrogate interfering compounds could be fractionated from the steroid hormones during the i-PLE step. The absolute PLE recoveries for the steroid hormones were between 67 and 107% from 0.5 g manure spiked with 50 ng. The method was applied on several manure and agricultural soil samples, demonstrating high levels of steroid hormones in manure and amended soils.

Determination of 2,6-dichlorobenzamide and its degradation products in water samples using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry.

An analytical method was developed for the determination of 2,6-dichlorobenzamide (BAM) and five degradation products thereof including 2-chlorobenzamide (OBAM), 2,6-dichlorobenzoic acid (DCBA), 2-chlorobenzoic acid (OBA), benzoic acid (BA) and benzamide (BAD) in water samples. Solid-phase extraction was combined with liquid chromatography coupled to tandem mass spectrometry using electrospray ionisation. Groundwater spiked at a concentration of 1.0 microg/L gave recoveries on day 1 between 91 and 102% (relative standard deviation: 2.2-26.5%) for OBAM, BAM, DCBA, BA and OBA, while BAD showed a somewhat lower recovery of 60% (relative standard deviation: 25%). Corresponding figures on day 3 gave recoveries of 97-110% (relative standard deviation: 3-22%) for OBAM, BAM, DCBA, BA and OBA, while BAD had a recovery of 51% (relative standard deviation: 4%). The final SPE-LC-MS/MS method had a LOD(Method) of 0.009, 0.007, 0.010, 0.021, 0.253 and 0.170 microg/L groundwater for BAD, OBAM, BAM, DCBA, BA and OBA and a LOQ(Method) of 0.030, 0.023, 0.035, 0.071, 0.842 and 0.565 microg/L groundwater in the same order of appearance. Analysis of three different Danish groundwaters confirmed the occurrence of BAM at levels exceeding the threshold value of 0.1 microg/L, while no degradation products were found above LOD(Method).

Volatile organic compounds in landfill odorant emissions on the island of Mallorca

This study provides data on the occurrence of volatile organic compounds (VOCs) in the biogas emission from a landfill located on the island of Mallorca (Balearic Islands, Spain), where 200,000 tonnes of urban solid wastes are dumped every year. Three different sampling cells, of differing waste ageing were investigated in August 2008, during the main tourist season and the warmest possible weather conditions. Samples were collected in Nalophan™ bags according to the standard European method EN 13725 followed by VOCs adsorption onto Carboxen 1000™ and Tenax TA™ materials prior to thermal desorption and analysis by GC-MS. In total 42 VOCs were analysed, using external standards, out of which 36 were positively identified. Detected VOCs in µg m−3 were alkanes (19–62), aldehydes (65–98), ketones (78–129), alcohols (67–78), esters (25–33), BTEX (83–106), halogenated compounds (16–39), terpens (1.4–2.4) and reduced sulphur compounds (2.6–4.2), showing different concentrations on each one of the three cells. Emitted VOCs showed some similarities with other previous studies from China and Turkey, while large differences to an Italian study. The benzene-to-toluene ratio (B:T) showed values in the range of 0.13 to 0.20 characteristic of biogas. H2S and NH3 gases emitted by the landfill were measured in-situ utilising Dräger™ Tubes for Short-Term-Measurements, showing concentration levels of ≤800 µg m−3 and <300 µg m−3, respectively, which is higher than the determined VOCs in accordance with previous studies. Samples were examined with dynamic olfactometry following standard European method EN 13725, to determine a potential statistical linear correlation between odour and VOC concentrations. Such correlations were not observed probably owing to the large number of compounds emitted from garbage which are not quantified, yet causing positive results in olfactometry.

Development of an analytical methodology for the determination of the antiparasitic drug toltrazuril and its two metabolites in surface water, soil and animal manure

This paper presents the development, optimization and validation of a LC-MS/MS methodology to determine the antiparasitic veterinary drug toltrazuril and its two main metabolites, toltrazuril sulfoxide and toltrazuril sulfone, in environmental surface water, soil and animal manure. Using solid phase extraction and selective pressurized liquid extraction with integrated clean-up, the analytical method allows for the determination of these compounds down to 0.06-0.13 ng L(-1) in water, 0.01-0.03 ng g(-1)dw in soil and 0.22-0.51 ng g(-1) dw in manure. The deuterated analog of toltrazuril was used as internal standard, and ensured method accuracy in the range 96-123% for water and 77-110% for soil samples. The developed method can also be applied to simultaneously determine steroid hormones in the solid samples. The antiparasitic drug and its metabolites were found in manure and soil up to 114 and 335 pg g(-1) dw, respectively. Little is known regarding the environmental fate and effects of these compounds; consequently more research is urgently needed.