Anthony A. Provatas

Solid Phase Extraction and QuEChERS Sample Preparation Methods for Rapid Screening of Polycyclic Aromatic Hydrocarbons in Avian Blood and Egg Tissue by UPLC-UV

This article reports modern and effective sample preparations designed for rapid screening of large number of samples of avian blood utilizing liquid–liquid extraction and egg using QuEChERS techniques. A UPLC-UV methodology for determination of polycyclic aromatic hydrocarbons (PAHs) on the afore mentioned matrices was developed based on samples associated with the Gulf of Mexico after the Deep Water Horizon oil spill. Both sample preparation methods provided comparable recovery results for 15 EPA priority pollutants PAHs. A UPLC system equipped with photo-diode array detector and tandem mass spectrometer was utilized for the quantification and confirmation of the analytes, respectively. The surrogate compound, naphthalene-d8, was used to monitor the extraction efficiency and chrysene-d12 as the quantitative internal standard. The recoveries of the analytes in the quality control (QC) samples were 65–110% with surrogate recoveries greater than 80%, whereas for the avian egg tissue recoveries were 43–100% and greater than 80% for the quality control (QC) samples and surrogate, respectively.

Development of a comprehensive analytical method for furanocoumarins in grapefruit and their metabolites in plasma and urine using UPLC-MS/MS: a preliminary study

Abstract To develop a comprehensive analytical method for photoactive furanocoumarins, grapefruit (whole, flesh, peel and juice) was extracted using QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method. Seven furanocoumarins: bergaptol, psoralen, 8-methoxypsoralen, bergapten, 6′,7′-dihydroxybergamottin (6′,7′-DHB), epoxybergamottin and bergamottin were determined in grapefruit using UPLC-MS/MS. The concentrations of furanocoumarins in the plasma and urine of six healthy young adults before and after ingestion of grapefruit or grapefruit juice were also determined. Recovery rates of furanocoumarins by QuEChERS method from matrix spike sample and laboratory calibrate sample were 125.7 ± 25.4% and 105.7 ± 6.3%, respectively. Bergamottin and 6′,7′-DHB were predominant compounds in grapefruit flesh, juice and plasma, while bergaptol and 6′,7′-DHB were major compounds detected in the urine. The results demonstrated that bergamottin and 6′,7′-DHB were metabolized to bergaptol. Overall, the analytical methods developed in the present study can be applied to the analysis of various furanocoumarins in plant sources and biological samples.

Blubber-depth distribution and bioaccumulation of PCBs and organochlorine pesticides in Arctic-invading killer whales

Sightings of killer whales (Orcinus orca) in Greenland have increased in recent years, coincident with sea ice loss. These killer whales are likely from fish-feeding North Atlantic populations, but may have access to marine mammal prey in Greenlandic waters, which could lead to increased exposures to biomagnifying contaminants. Most studies on polychlorinated biphenyl (PCB) and organochlorine (OC) contaminants in killer whales have used biopsies which may not be representative of contaminant concentrations through the entire blubber depth. Here, we measured PCB and OC concentrations in 10 equal-length blubber sections of 18 killer whales harvested in southeast Greenland (2012-2014), and 3 stranded in the Faroe Islands (2008) and Denmark (2005). Overall, very high concentrations of ΣPCB, Σchlordanes (ΣCHL), and Σdichlorodiphenyltrichloroethane (ΣDDT) were found in the southeast Greenland and Denmark individuals (means of ~40 to 70mgkg-1 lipid weight). These concentrations were higher than in the Faroe Island individuals (means of ~2 to 5mgkg-1 lipid weight) and above those previously reported for other fish-feeding killer whales in the North Atlantic, likely in part due to additional feeding on marine mammals. On a wet weight basis, concentrations of all contaminants were significantly lower in the outermost blubber layer (0.15-0.65cm) compared to all other layers (p<0.01), except for Σhexachlorocyclohexanes. However, after lipid correction, no variation was found for ΣCHL and Σchlorobenzene concentrations, while the outermost layer(s) still showed significantly lower ΣPCB, ΣDDT, Σmirex, Σendosulfan, and dieldrin concentrations than one or more of the inner layers. Yet, the magnitude of these differences was low (up to 2-fold) suggesting that a typical biopsy may be a reasonable representation of the PCB and OC concentrations reported in killer whales, at least on a lipid weight basis.

Rapid quick, easy, cheap, effective, rugged, and safe extraction with novel phospholipid cleanup: A streamlined ultra high performance liquid chromatography with ultraviolet detection approach for screening polycyclic aromatic hydrocarbons in avian blood cells and plasma

A streamlined method has been developed for the isolation and analysis of polycyclic aromatic hydrocarbons in avian blood cells and plasma utilizing quick, easy, cheap, effective, rugged, and safe extraction in combination with novel phospholipid cleanup technology. A variety of traditional extraction and cleanup techniques have been employed in the preparation and analysis of polycyclic aromatic hydrocarbonsin a variety of matrices; liquid-liquid partitioning, solid-phase extractions, gel permeation chromatography, and column chromatography are all effective techniques, however they are laborious and time consuming processes that require large amounts of solvent. Using quick, easy, cheap, effective, rugged, and safe extraction coupled with phospholipid cleanup, samples can be quickly screened while maintaining high throughput and sensitivity. With a liquid chromatography approach, analysis times may be kept short at 16 min while maintaining high analyte recovery. Recoveries in quality control samples ranged from 70 to 109%, with average surrogate recoveries of 80.6 ± 1.10%. The result of using a quick, easy, cheap, effective, rugged, and safe extraction approach in conjunction with phospholipid cleanup is a methodology that significantly reduces sample preparation time and solvent use while maintaining high sensitivity and reproducibility.

The effects of model androgen 5α-dihydrotestosterone on mummichog (Fundulus heteroclitus) reproduction under different salinities.

Endocrine disrupting substances (EDSs) have the potential to disturb sensitive hormone pathways, particularly those involved in development and reproduction. Both fresh and estuarine water bodies receive inputs of EDSs from a variety of sources, including sewage effluent, industrial effluent and agricultural runoff. Based on current literature, freshwater species appear to respond to lower levels of EDSs than estuarine or marine species. Therefore, effects elicited by EDSs in freshwater teleosts may not be an accurate representation of how EDSs affect teleosts in estuarine and marine environments. To address this potential difference, a short-term reproductive bioassay was conducted under conditions of low and high salinity using mummichog (Fundulus heteroclitus), a euryhaline species that is native to the east coast of North America. The goals of this study were to determine the response of mummichog when exposed to an androgenic EDS and whether salinity affected the response. A model androgen, 5α-dihydrotestosterone (DHT), was selected for this experiment. Impacts on reproduction were evaluated at multiple biological levels, including physiological (sex steroid levels), organismal (gonad size and gonad morphology), and functional (egg production) endpoints. Under conditions of high salinity, egg production was significantly reduced at all exposure concentrations. Under conditions of low salinity, there were no significant differences based on DHT treatment; however, egg production in all treatment groups including the control were significantly reduced relative to the high salinity control group. Other reproductive endpoints, such as sex steroid production, showed stronger correlation to fecundity in females than males. This study demonstrates that mummichog fecundity is sensitive to androgenic endocrine disruption while also underscoring the importance of how changes in salinity, an environmental variable, can impact reproduction.

Rapid QuEChERS Approach Using Novel Solid Phase Extraction for Insecticides in Lobster and Shellfish Tissue with Gas Chromatography–Tandem Mass Spectrometry

Novel, rapid, inexpensive, and simple QuEChERS extraction followed by phospholipid solid phase extraction was successfully developed and validated for the determination of methoprene, resmethrin, bifenthrin, cyhalothrin, and permethrin in lobster and shellfish tissues by gas chromatography–tandem mass spectrometry. This method is equivalent in final sample purity to the traditional gel permeation and open column chromatography sample preparation techniques, but has clear advantages due to reductions in time, labor, solvent use, and can be performed with minimal staff training. The proposed methodology was effectively applied to the analysis of North Atlantic lobster (hepatopancreas and muscle) and shellfish tissue. The linearity of the calibration curves for all analytes were R2 > 0.9991. The surrogate recoveries were 98.2 ± 18.0%, while the target compound recoveries, for fortified samples, were in the range of 62.0%–128.8% with RSD values <17.2% for all compounds. The detection limits for the analytes ranged from 0.0056 µg/g to 0.76 µg/g with 84.4–119.5% accuracy and relative standard deviations less than 3.77%.

Approaches to a photocleavable protecting group for alcohols

A new protecting group for the alcohol functionality was devised and shown to be removed photochemically under ultraviolet light in the presence of a radical scavenger in high yields.

QuEChERS sample preparation followed by ultra-performance liquid chromatography – tandem mass spectrometry for rapid screening of dioctyl sulfosuccinate sodium salt in avian egg tissue

A quantification method was developed for the determination of dioctyl sulfosuccinate sodium salt (DOSS) in avian egg samples based on a QuEChERS extraction technique followed by UPLC-MS/MS analysis. DOSS is an anionic surfactant that is part of the Corexit® 9500 dispersive mixture that prevents the formation of oil slicks on water bodies. It was extensively used when the Deepwater Horizon rig exploded and a large amount of crude oil was released into the Gulf of Mexico. QuEChERS provided a simple, effective and time saving sample preparation method prior to analysis without reducing analytical sensitivity and became an excellent substitute to lengthy traditional extraction methods. Weak anionic exchange cleanup significantly reduced matrix effects and improved analyte sensitivity. Ultra-performance liquid chromatography provided an effective separation method, while MS/MS provided the necessary selectivity and increased sensitivity. Our method achieved baseline separation of DOSS, surrogate (sodium octyl sulfate – d17) and the internal standard (sodium dioctyl sulfate – d25), with limits of detection (LOD) and limits of quantitation (LOQ) for DOSS being 260 and 500 pg/mL, respectively. Quality control recoveries were 70.5 ± 7.3% (mean ± standard deviation, n = 3) for the laboratory control sample and 72.4 ± 4.9% (n = 3) for the matrix spike. The extraction efficiency was monitored by adding surrogate compound to every sample with recoveries of 104.6 ± 14.1 for SDS-d1 and 81.8 ± 6.8 for SOS-d17. Currently, limited peer reviewed scientific data are reported on the effects of oil dispersants on the environment. Our analytical method for the determination of DOSS in avian egg matrix can be used to provide reliable data on the fate and effects of DOSS in biological systems.

Regioselective Dye-Induced Photocleavage of Epoxides as an Alternative Mild Synthetic Route to a Targeted Alcohol Functionality

The regioselective cleavage of epoxides using visible light and a catalytic dye is reported in this study as an alternative mild synthetic approach. The epoxide radical anion is generated via visible light in an electron transfer reaction, induced by non-toxic dyes, leading to ring opening and formation of the corresponding alcohol with the hydroxyl group on the less substituted carbon in excellent yields.

Quantification of Polycyclic Aromatic Hydrocarbons in Avian Dried Blood Spots by Ultra-performance Liquid Chromatography with Simple Liquid Extraction and Phospholipid Solid-phase Extraction Preparation

ABSTRACT Here, a simple, reliable method for the quantification of the 16 EPA priority polycyclic aromatic hydrocarbons in dried blood spots is outlined using liquid extraction and phospholipid solid-phase sample cleanup coupled with analysis by ultra-performance liquid chromatography with ultraviolet–visible detection. Whole blood spotted on Whatman FTA cards was efficiently quantified by extraction into acidified methanol and passed through a phospholipid solid-phase extraction well plate before injection into a liquid chromatography under reverse-phase conditions. The analyte recoveries in quality control samples ranged from 63.4 to 104.1%, with relative standard deviations from 0.48 to 2.04%. These figures of merit are comparable with measurements in whole blood or serum using similar techniques. The method detection limits were from 45.0 ng·g−1 for benzo[g,h,i]perylene to 118.7 ng·g−1 for chrysene, with matrix spike recoveries from 64.3 to 99.4%, demonstrating acceptable sensitivity and low matrix interference. With a simple liquid extraction approach and short 16-min liquid chromatography, the dried blood spots were effectively and rapidly analyzed.