Cubic Fe-bearing majorite synthesized at 18-25 GPa and 1000 °C: implications for element transport, subducted slab rheology and diamond formation.

The chemistry and mineralogy of slabs subducted into lower mantle control slab rheology and impact the deep volatile cycle. It is known that the metamorphism of little-altered oceanic crust results in eclogite rocks with subequal proportions of garnet and clinopyroxene. With increasing pressure, these minerals react to stabilize pyrope-rich tetragonal majoritic garnet. However, some eclogites contain higher proportions of omphacitic clinopyroxene, caused by Na- and Si-rich metasomatism on the ocean floor or during subduction. The mineralogy of such eclogites is expected to evolve differently. Here, we discuss the results of the crystallization products of omphacitic glass at ~ 18 and ~ 25 GPa and 1000 °C to simulate P-T regimes of cold subduction. The full characterization of the recovered samples indicates evidence of crystallization of Na-, Si-rich cubic instead of tetragonal majorite. This cubic majorite can incorporate large amounts of ferric iron, promoting redox reactions with surrounding volatile-bearing fluids and, ultimately, diamond formation. In addition, the occurrence of cubic majorite in the slab would affect the local density, favoring the continued buoyancy of the slab as previously proposed by seismic observations. Attention must be paid to omphacitic inclusions in sublithospheric diamonds as these might have experienced back-transformation from the HP isochemical cubic phase.

Provenance and deposition of a lithified volcanic-rich layer (VRL-5.5) at 5.5 Ma from Central Apennines (Italy).

Two slightly lithified volcanic rich layers (VRL) (former tephra) SVT-2 (San Vittorino) and CAC (Castiglione a Casauria) were sampled from two distinct post-evaporitic Messinian stratigraphic sections (Abruzzo, Central Italy). They crop only few tens of km apart and are predominantly massive, although some specimens show sedimentary structures. Both VRLs were investigated for the first time by field, mesoscopic, X-ray powder diffraction (XRPD), transmission optical microscopy (TOM), scanning electron microscopy (SEM), bulk composition, electron-microprobe analysis (EMPA) and quantitative textural attributes by image analysis. The XRPD analysis detects the presence of a glass phase, plus few (< 2 area %) magmatic-like feldspars, clinopyroxene and biotite and stratigraphically variable sedimentary minerals such as calcite, dolomite, illite and montmorillonite (from 0 to 40 area %). The 2D image analysis performed on SEM microphotographs reveals that both sections are composed of very fine glass shards, magmatic minerals are never isolated, whilst the carbonate crystals mainly fill voids among volcanic particles. Both these VRLs have identical rhyolitic glass compositions that closely overlap with those of previously-studied coeval and stratigraphically related sections occurring in the northern Apennine region and dated as 5.5 Ma. The 2D textural features of glassy particles (length, width, aspect ratio, grain-size distribution, MZ , σi, SKi, KG and roundness) in both SVT-2 and CAC sections are very similar and also close to the northern section of Camporotondo (Marche region). The outcomes provided here indicate that SVT-2 and CAC sections represent the southernmost distal deposits of the same large eruption that occurred about 5.5 Ma (VRL-5.5). They result from distal fallout of tephra through seawater, occasionally remobilised under low energy and localised conditions, especially in the uppermost part of the CAC section. All the VRL-5.5 rocks are probably related to a very large eruption that occurred in the Carpathian-Pannonian magmatic district. The analytical protocols used in this study can be useful to investigate other ancient volcanic-rich layers, corresponding to lithified tephra.

Combined magnetic, chemical and morphoscopic analyses on lichens from a complex anthropic context in Rome, Italy.

Native and transplanted lichens were analyzed as bioaccumulators of airborne particulate matter (PM) in an eastern district of Rome, Italy, where frequent fraudulent fires are set to recover metals, mostly copper, from waste electrical and electronic equipment (WEEE). The presence of native lichens was scarce, due to the drought of spring-summer 2017, thus, sampling was extended to a neighboring area for toughening the dataset to a similar context. The magnetic analyses revealed intense properties connected to the anthropic complexity of the zone, where industrial, traffic and arson-related dusts are emitted and bio-accumulated. Magnetic and chemical analyses were compared, leading to significant linear correlations between the concentration dependent magnetic parameters (susceptibility, saturation magnetization and saturation remanence) and the concentration of heavy metals, among which copper, chrome, lead and zinc. Moreover, selected magnetic particles were chemically and morphologically characterized by Scanning Electron Microscope and Energy Dispersion System microanalyses. Magnetic particles resulted incorporated into the lichens' tissues and their composition, morphology and grain size strongly supported their anthropogenic, mostly combustion-related, origin. Even if, given the complexity of the area, it was not feasible to fully discriminate the multiple anthropogenic sources, magnetic biomonitoring of lichens, especially when combined with microtextural and compositional analyses, confirmed to be an excellent methodology for a rapid characterization of environmental pollution.

Frictional Instabilities and Carbonation of Basalts Triggered by Injection of Pressurized H2O- and CO2- Rich Fluids.

The safe application of geological carbon storage depends also on the seismic hazard associated with fluid injection. In this regard, we performed friction experiments using a rotary shear apparatus on precut basalts with variable degree of hydrothermal alteration by injecting distilled H2O, pure CO2, and H2O + CO2 fluid mixtures under temperature, fluid pressure, and stress conditions relevant for large-scale subsurface CO2 storage reservoirs. In all experiments, seismic slip was preceded by short-lived slip bursts. Seismic slip occurred at equivalent fluid pressures and normal stresses regardless of the fluid injected and degree of alteration of basalts. Injection of fluids caused also carbonation reactions and crystallization of new dolomite grains in the basalt-hosted faults sheared in H2O + CO2 fluid mixtures. Fast mineral carbonation in the experiments might be explained by shear heating during seismic slip, evidencing the high chemical reactivity of basalts to H2O + CO2 mixtures.

Mineralogy and textures of riebeckitic asbestos (crocidolite): The role of single versus agglomerated fibres in toxicological experiments.

Asbestos may cause adverse effects, but relationship between mineralogy and texture of fibres versus toxicity is still lacking. Toxicological studies can be interpreted and compared only if quantitative features of fibres are determined. Here, riebeckitic ("crocidolite") amphibole fibres were analysed by XRPD, FTIR, SEM-EDS and EMP-WDS; only crystals with stochiometry A□BNa2C(Fe2+2.5Mg0.5)CFe3+2TSi8O22W(OH)2 are present in the starting material used for the experiments. Fibres deposited from solutions of 0.1, 1, 10, 25, 50, 75 and 100mg/L were counted by image analysis using SEM images. At 0.1 and 1mg/L the fibres are well separated, whereas between 1 and 10mg/L they start to agglomerate. In-vitro tests performed on fibres deposited at the same mg/L concentrations show that the toxic potential follows a curvilinear increasing trend with a decreasing rate. Since the range of sizes of single fibres and their mineralogy are constant, this decreasing rate can be only attributed to the increasing amount of agglomerated fibres. Hence, single versus agglomerated fibre population is a factor that cannot be neglected in defining the final adverse effects of asbestos. The analytical protocol proposed here is valuable for any aero-dispersed dust, in polluted environments, as well as in the interpretation of experimental studies.

Occurrence of organophosphorus flame retardant and plasticizers in three volcanic lakes of central Italy.

The concentration levels, distribution, and seasonal fluctuations of 12 organophosphorus flame retardants and plasticizers (OPs), of which some are reported to be toxic to aquatic organisms, were investigated in lakes from June 2006 to June 2007. Three volcanic lakes located in the Lazio area (Central Italy) and characterized by a different anthropical impact were selected. Analysis of lake water samples showed that in closed ecosystems (hydrogeological systems), such as small volcanic lakes, OP contamination may occur even in the absence of industries and treated or untreated waste discharges. The selected substances were found at ng/L concentrations in all lakes. In the two more anthropized lakes tributyl phosphate and tripropyl phosphate were the most abundant OPs, with peaks of respectively 784 and 951 ng/L. Maximum pollution levels were reached in October-November, and concentrations decreased to a minimum value in March-April. Chlorinated OPs showed the same trend, but their concentrations were 1 order of magnitude lower and the level decreasing was shifted with respectto alkyl OPs. On the contrary, tris(2-butoxyethyl) phosphate concentrations were quite similar among all water samples analyzed, indicating that their sources were different in nature. One of the three lakes is an important source of drinkable water, so nine wells situated in its neighborhood were also examined. No correlation between lake water and groundwater contamination could be found.

Determination of aflatoxins in olive oil by liquid chromatography-tandem mass spectrometry.

A liquid chromatography-tandem mass spectrometric with electrospray ionization (LC/ESI-MS/MS) method for determining the four naturally occurring aflatoxins (AFs) B1, B2, G1, and G2 in olive oil is proposed. AFs were extracted from oil sample by means of matrix solid phase dispersion (MSPDE), utilizing C18 as dispersing material. No further purification step, such as lipid removal, was performed. Aflatoxin M1, the hepatic metabolite of AFB1, was employed as internal standard. Olive oil extract was analyzed by LC/ESI-MS/MS in positive ionization mode, with multireaction monitoring acquisition. Due to a signal suppression ranging between 4 and 23%, quantitation was performed by matrix-matched calibration curves. The regression line coefficients of determination were above 0.9991. Sample recoveries ranged from 92 to 107%, with relative standard deviations below 13% for spiking levels between 0.5 and 5 ng g(-1); method quantification limits ranged between 0.04 and 0.12 ng g(-1). The developed LC/ESI-MS/MS method, although not as sensitive as LC coupled to fluorescence detection, is rapid, selective, accurate and precise, thus it can be used as confirmatory assay. The MSPDE appears suitable for application to other oleaginous matrices and for multiresidue investigation.

Liquid chromatography/tandem mass spectrometry determination of organophosphorus flame retardants and plasticizers in drinking and surface waters.

A liquid chromatography/electrospray ionization tandem mass spectrometric method for analyzing organophophorus flame retardants and plasticizers in drinking and environmental waters was developed. Five alkyl phosphates, three chlorinated alkyl phosphates, two aryl phosphate and triphenylphosphine oxide were selected for this study. These compounds were extracted from water samples by a hydrophilic polymeric solid-phase extraction cartridge. Accuracy and precision were evaluated analyzing 0.5 L of water samples spiked at concentrations of 10 and 100 ng/L for drinking water and at 300 and 1000 ng/L for river water. Except for trimethyl phosphate, analyte recoveries were better than 80%, and were not dependent on the type of aqueous matrix in which they were dissolved. At the spike levels considered, within-day precision was between 3 and 12% for tap water and between 4 and 14% for river water, and estimated method quantification limits ranged from 0.2 to 3.9 ng/L. A short survey conducted by analyzing some river water samples (River Tiber) ascertained the presence of ten organophosphorus compounds at concentration levels ranging from a few nanograms per liter to 323 ng/L for tris(2-butoxyethyl) phosphate.

A sensitive confirmatory method for aflatoxins in maize based on liquid chromatography/electrospray ionization tandem mass spectrometry.

A liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method for measurement of aflatoxins B1, B2, G1, and G2 in maize is described. Aflatoxins (AFs) were extracted from 1 g samples by using tri-portions of acetonitrile/water (80:20, v/v) (10 + 7 + 7 mL), and 2/5 of the extract diluted to 500 mL by water was cleaned up with a 100 mg Carbograph-4 cartridge. After the addition of the internal standard AFM1, the final extract was analyzed by LC/ESI-MS/MS in positive ion mode using multiple reaction monitoring with a triple-quadrupole instrument. A C(18) column thermostatted at 45 degrees C with a mobile phase gradient of acetonitrile/water with 2 mmol/L ammonium formate was used. Although the matrix suppression effect was negligible, quantitation was achieved by an external calibration procedure using matrix-matched standard solutions to improve accuracy. Sample recoveries at four spiking levels ranged from 81 to 101% (relative standard deviation (RSD)

Aflatoxin M1 determination in cheese by liquid chromatography-tandem mass spectrometry.

A new method for determining aflatoxin M1 (AFM1) in cheese by liquid chromatography-tandem mass spectrometry has been developed. Two methodologies were compared for sample extraction. The first one involves sample extraction with dichloromethane for hard, aged cheese or acetone for fresh cheese and includes a preliminary matrix solid-phase dispersion-extraction step before solid-phase extraction (SPE) clean-up by a Carbograph-4 cartridge. The second method uses a water/methanol solution (90:10, v/v) extraction at 150 degrees C before clean-up. The average recoveries of AFM1 from samples spiked at levels of 0.25-0.45 microg/kg, were 81-92% and the precision (RSD) ranged from 3 to 7% with the first method, whilst the average recoveries were 79-84%, and RSD ranged from 7 to 15% for the second method. Due to different matrix effect, the quantification limits were 0.019-0.025 microg/kg in the first case and 0.048-0.143 microg/kg in the second one, depending on cheese typology.

Simple confirmatory assay for analyzing residues of aminoglycoside antibiotics in bovine milk: hot water extraction followed by liquid chromatography-tandem mass spectrometry.

A simple, selective and sensitive procedure for determining nine widely used aminoglycoside antibiotics (AGs) in bovine whole milk is presented. It is based on matrix solid-phase dispersion with heated water, at 70 degrees C, as extractant followed by liquid chromatography (LC)-tandem mass spectrometry (MS) using an electrospray ion source. After acidification and filtration, 0.2 ml of the aqueous extract was injected into the LC column. MS data acquisition was performed in the multi reaction monitoring mode, selecting two (three, when possible) precursor ion > product ion transitions for each target compound. Analyte recoveries ranged between 70 and 92%. Using aminosidine (an AG not used in veterinary medicine) as surrogate internal standard, the accuracy of the method at three spike levels varied between 80 and 107% with R.S.D. not larger than 11%. The limits of quantification were between 2 ng/ml (apramycin) and 13 ng/ml (streptomycin). They are well below the tolerance levels set by both the European Union and the U.S. Food and Drug Administration.

Simple and rapid assay for analyzing residues of carbamate insecticides in bovine milk: hot water extraction followed by liquid chromatography-mass spectrometry.

A simple, specific and rapid procedure for determining six largely used carbamate insecticides in bovine whole milk is here presented. This method is based on the matrix solid-phase dispersion technique with heated water as extractant followed by liquid chromatography (LC)-mass spectrometry (MS) equipped with a single quadrupole and an electrospray ion source. Target compounds were extracted from milk by water heated at 90 degrees C. After acidification and filtration, 0.2 mL of the aqueous extract was injected in the LC column. MS data acquisition was performed in the selected ion-monitoring mode, selecting three ions for each target compound. Heated water appeared to be an excellent extractant, since absolute recovery data ranged between 76 and 104% with R.S.D. not larger than 8%. Using butocarboxim (an obsolete carbamate insecticide) as surrogate internal standard, the accuracy of the analysis at three spike levels varied between 85 and 105% with R.S.D. not larger than 9%. On the basis of a signal-to-noise ratio of 10, limits of quantification were estimated to range between 3 ppb (propoxur) and 8 ppb (pirimicarb). The effects of temperature, volume and flow rate of the extractant on the analyte recovery were studied.

Simple and rapid liquid chromatography-tandem mass spectrometry confirmatory assay for determining amoxicillin and ampicillin in bovine tissues and milk.

A simple specific and rapid confirmatory method for determining the two amphoteric penicillins, that is, amoxicillin and ampicillin, in bovine muscle, liver, kidney, and milk is presented. This method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by liquid chromatography (LC)-tandem mass spectrometry. With this instrumentation, the selected reaction monitoring acquisition mode with two fragmentation reactions for each analyte was adopted. After acidification and filtration of the aqueous extracts, 25 microL of the tissue final extracts and 50 microL of the milk final extract were injected into the LC apparatus. Absolute recovery of the two analytes in any biological matrix at the 50 ppb level in tissues and the 4 ppb level in milk was 74-95% with relative standard deviations (RSDs) of no larger than 9%. When penicillin V was used as surrogate internal standard, relative recovery of the targeted compounds present in bovine tissues and milk at, respectively, 25 and 2 ppb levels ranged between 100 and 106% with RSDs of no larger than 11%. When fractionation of analytes by using a short chromatographic run was attempted, remarkable signal weakening for the two analytes was experienced. This effect was traced to polar endogenous coextractives eluted in the first part of the chromatographic run that interfered with the gas-phase ion formation of the two penicillins. Slowing the chromatographic run eliminated this unwelcome effect. Limits of quantification of the two analytes in bovine milk were estimated to be <1 ppb, whereas amoxicillin and ampicillin could be quantified in bovine tissues down to 3.1 and 0.8 ppb levels, respectively.

A simple and rapid assay for analyzing residues of carbamate insecticides in vegetables and fruits: hot water extraction followed by liquid chromatography-mass spectrometry.

A simple, specific, and rapid analytical method for determining seven largely used carbamate insecticides in tomato, spinach, lettuce, zucchini, pear, and apple is here presented. This method is based on the matrix solid-phase dispersion technique, with heated water as extractant followed by liquid chromatography (LC)-mass spectrometry (MS) equipped with a single quadrupole and an electrospray ion source. Target compounds were extracted from the vegetal matrixes by water heated at 50 degrees C. After acidification and filtration, 0.25 mL of any aqueous extract was injected in the LC column. MS data acquisition was performed in the selected ion monitoring mode, selecting three ions for each target compound. Heated water appeared to be an excellent extractant because recovery data ranged between 76 (carbaryl in spinach) and 99% (pirimicarb in spinach), with RSDs not larger than 10%. Using trimethacarb (an obsolete carbamate insecticide) as a surrogate internal standard, the accuracy of the analysis varied between 84 and 110%, with RSDs not larger than 9%. On the basis of a signal-to-noise ratio of 10, limits of quantification were estimated to range between 2 (pirimicarb) and 10 ppb (oxamyl) and were not influenced by the type of matrix. When trying to fractionate analytes by using a short chromatographic run time, marked weakening of the ion signals for oxamyl, methomyl, and aldicarb were observed. This effect was traced to polar endogenous co-extractives eluted in the first part of the chromatographic run that interfered with gas-phase ion formation for carbamates. Adopting more selective chromatographic conditions eliminated this effect.

Rapid confirmatory assay for determining 12 sulfonamide antimicrobials in milk and eggs by matrix solid-phase dispersion and liquid chromatography-mass spectrometry.

A rapid confirmatory method for determining 12 sulfonamide (SAs) antibacterials in whole milk and eggs is presented. This method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by liquid chromatography (LC)-mass spectrometry (MS). The LC-MS instrument was equipped with an electrospray ion source and a single quadrupole. After 4 mL of a milk sample containing the analytes had been deposited on sand (crystobalite), this material was packed into an extraction cell. SAs were extracted by flowing 4 mL of water through the cell heated at 75 degrees C. With some modifications, this procedure was applied also to eggs. After pH adjustment and filtration, 0.5 mL of the final extracts was then injected into the LC column. MS data acquisition was performed in the positive-ion mode and by monitoring at least three ions for each target compound. The in-source collision-induced dissociation process produced confirmatory ions. At the 50 ng/g level, recovery of the analytes in milk and eggs was 77-92% with relative standard deviations ranging between 1 and 11%. Estimated limits of quantification (S/N = 10) were 1-3 ng/g of SAs in milk and 2-6 ng/g in eggs. With both matrices, attempts to reduce the analysis time by using a short chromatographic run time caused severe ion signal suppression for the early-eluted SAs. This effect was traced to competition effects by polar endogenous coextractives, maybe proteinaceous species, which are eluted in the first part of the chromatographic run. This unwelcome effect was almost completely removed by simply adopting more selective chromatographic conditions.

Confirmatory analysis of sulfonamide antibacterials in bovine liver and kidney: extraction with hot water and liquid chromatography coupled to a single- or triple-quadrupole mass spectrometer.

A simple, specific, and rapid confirmatory method for determining 12 sulfonamide (SAs) antibacterials in bovine liver and kidney is presented. This method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by liquid chromatography/mass spectrometry (LC/MS) with an electrospray ion source. The method was tailored for use with both single-quadrupole MS (I) and triple-quadrupole MS (II) instruments. After acidification and filtration of the aqueous extract, a 250-microL aliquot was injected into instrument I while only 25 microL was analyzed by instrument II. With instrument I MS data acquisition was performed in the selected ion monitoring (SIM) mode, selecting at least three ions for each target compound. With instrument II the selected reaction monitoring (SRM) mode with three fragmentation reactions for each compound was chosen. With the exception of sulfaquinoxaline (SQX), recovery of the analytes at the 50 ppb level in both liver and kidney was 72-96% with relative standard deviations (RSDs) ranging between 3 and 11%. The very poor recovery of SQX was due to its rapid enzymatic oxidation when in contact with the two tissues. With instrument I, limits of quantification (LOQs, S/N = 10) were 5-14 ppb of SAs. Even lower LOQs (1-8 ppb) were estimated by using instrument II, even though the extract volume analyzed was ten times lower than that with instrument I. With both matrices and using instrument I, severe ion signal suppression was experienced for the early-eluted SAs when trying to fractionate analytes by using a short chromatographic run time. This effect was traced to polar endogenous co-extractives eluted in the first part of the chromatographic run that interfered with gas-phase ion formation for SAs. Adopting more selective chromatographic conditions minimized this effect.

A liquid chromatography-mass spectrometry assay for analyzing sulfonamide antibacterials in cattle and fish muscle tissues.

A simple and rapid method able to determine residues of 12 sulfonamide (SAs) antibacterials in cattle and trout muscle tissues is presented. This method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by liquid chromatography-mass spectrometry (LC-MS). The LC-MS instrumentation was equipped with an electrospray source and a single quadrupole. After 0.8 g of a flesh sample containing the analytes is deposited on sand (crystobalite), this material is packed into an extraction cell. SAs are extracted by flowing 4 mL of water through the cell heated at 80 degrees C. A 0.5-mL aliquot of the bovine tissue extract is then directly injected into the LC column, while the fish tissue extract is filtered prior to LC-MS analysis. MS data acquisition was performed in the positive-ion mode and monitoring at least three ions for each target compound. Confirmatory ions were produced by the in-source collision-induced dissociation process. At the tolerance levels issued by the EU and U.S. Food and Drug Administration, i.e., 100 ppb, recovery of the analytes in bovine and trout muscle tissues was 75-98% with RSDs ranging between 1 and 8%. Estimated limits of quantification (S/N = 10) were 6-15 ppb for SAs in bovine muscle tissue and 3-13 ppb in trout fillet. When trying to reduce the analysis time by using a short chromatographic run time, severe ion signal suppression was experienced for the early-eluted SAs. This effect was traced to competition effects by polar endogenous coextractives, maybe proteinaceous species, which are eluted in the first part of the chromatographic run. This unwelcome effect was removed by simply adopting more selective chromatographic conditions.

A simple and sensitive liquid chromatography-mass spectrometry confirmatory method for analyzing sulfonamide antibacterials in milk and egg.

A simple and specific method able to identify and quantify traces of 14 sulfonamide antibacterials (SAs) in milk and eggs is presented. This method uses a single solid-phase extraction (SPE) cartridge for simultaneous extraction and purification of SAs in the above matrices. Milk and egg samples are passed through a Carbograph 4 sorption cartridge. After analyte desorption, an aliquot of the final extract is injected into a liquid chromatography-mass spectrometry (LC-MS) instrument equipped with an electrospray ion source (ESI) and a single quadrupole. MS data acquisition is performed in the positive-ion mode and by a time-scheduled multiple-ion selected ion monitoring program. Compared to two published methods, the present protocol extracted larger amounts of SAs from both milk and egg and decreased the analysis time by a factor of 3 with milk samples and by a factor of 2 with egg samples. Recovery of SAs in milk at the 5 ppb level ranged between 76 and 112% with relative standard deviations (RSDs) of

Liquid chromatographic-mass spectrometric methods for analyzing antibiotic and antibacterial agents in animal food products.

Public health agencies in many countries rely on detection by mass spectrometry for unambiguous identification of residues of antibiotic and antibacterial agents in animal food products for human consumption. The introduction of relatively inexpensive and robust LC-MS systems has given a strong impulse to develop determinative and confirmatory methods for the above medicines in foodstuffs. This impulse has been also dictated by thermal instability and lack of volatility of many antibiotics and antibacterials that makes the GC-MS technique of difficult application. Analytical methods developed for analyzing components of the major classes of the medicines mentioned above are here reviewed. The discussion is focused on both sample treatment and final LC-MS analysis.

Determination of surfactants and some of their metabolites in untreated and anaerobically digested sewage sludge by subcritical water extraction followed by liquid chromatography-mass spectrometry.

Enormous amounts of sewage sludge are worldwide generated and released into the environment. Analysis of the most common and/or toxic chemicals in sludge should be mandatory before deciding its destination. Surfactants and some of their breakdown products are invariably the most common organic contaminants in domestic sewage sludge. For determining these compounds, we have developed a method based on extraction with subcritical water followed by liquid chromatography-mass spectrometry. On extracting surfactants and their metabolites from 50 mg of sludge, the efficiency of the water extraction device was evaluated in terms of pH of the extractant, temperature, and time of the static extraction. The best extraction conditions were obtained by using carbonate buffer (pH 9.4) at 200 degrees C as extractant, 10 min of static extraction at the pressure of 100 bar followed by 17 min of dynamic extraction. Analyte collection was performed by inserting a solid-phase extraction cartridge downstream the extraction cell. Compared to 16-h Soxhlet extraction with methanol, this procedure was remarkably more efficient in extracting anionic surfactants and acidic metabolites of nonylphenol ethoxylates (NPECs). A short survey was conducted to estimate concentration changes of target compounds after 14-d sludge anaerobic digestion. Results showed that 54-74% of both neutral and weakly acidic ethoxylate species were removed after residence of the sludge in the digester. On the contrary, little, if any, removal of anionic surfactants was observed after the digestion treatment. As expected, the level of nonylphenol increased under anaerobic conditions.