This work focuses on a revision of analytical methodologies for the determination of industrial chemicals that have an endocrine-disrupting effect on food commodities. These food commodities have ...been divided into two major categories: crops and food of animal origin. The reviewed methods have been commented on in terms of sample preparation, analytical methods, and the occurrence of the studied compounds.
► The analytical methodology employed is based mainly in LC–MS and GC–MS. ► The reviewed methods have been commented attending to sample preparation. ► The reviewed methods have been commented attending to analytical methods sample. ► In addition the occurrence of the studied compounds has been commented. ► These contaminants in general do not exceed the SLM.
We present the first Chandra and Swift X-ray study of the spiral galaxy NGC 4088 and its ultraluminous X-ray source (ULX N4088-X1). We also report very long baseline interferometry (VLBI) ...observations at 1.6 and 5 GHz performed quasi-simultaneously with the Swift and Chandra observations, respectively. Fifteen X-ray sources are detected by Chandra within the D25 ellipse of NGC 4088, from which we derive the X-ray luminosity function (XLF) of this galaxy. We find the XLF is very similar to those of star-forming galaxies and estimate a star-formation rate of 4.5 M sub(middot in circle) yr super(-1). The Chandra detection of the ULX yields its most accurate X-ray position, which is spatially coincident with compact radio emission at 1.6 GHz. The ULX Chandra X-ray luminosity, L sub(0.2-10.0 keV) = 3.4 x 10 super(39) erg s super(-1), indicates that N4088-X1 could be located at the high-luminosity end of the high-mass X-ray binary (HMXB) population of NGC 4088. The estimates of the black hole (BH) mass and ratio of radio to X-ray luminosity of N4088-X1 rule out a supermassive BH nature. The Swift X-ray spectrum of N4088-X1 is best described by a thermal Comptonization model and presents a statistically significant high-energy cutoff. We conclude that N4088-X1 is most likely a stellar remnant BH in an HMXB, probably fed by Roche lobe overflow, residing in a super-Eddington ultraluminous state. The 1.6 GHz VLBI source is consistent with radio emission from possible ballistic jet ejections in this state.
► Selective and sensitive method for determination of multi-class pesticides. ► GC–MS with a triple stage quadrupole analyzer (GC–TSQ–MS). ► Working in negative chemical ionization mode using methane ...as reactive gas. ► Analysis of real samples intended for baby food. ► Extraction method: liquid extraction using ethyl acetate as extraction solvent.
Multiresidue methods (MRMs) for pesticides residues determination in fruit and vegetables, based on GC–MS, are mainly performed in electron impact ionization mode. However an important group of them provide much better response working in negative chemical ionization mode due to the elimination of a high percentage of background signal.
Considering that a selective and sensitive method has been developed for the determination of multiclass pesticide residues in different commodities by GC–MS with a triple stage quadrupole analyzer (GC–TSQ–MS); the pesticide signal has been optimized in MS–MS whilst working in negative chemical ionization mode using methane as the reagent gas.
The proposed method was fully validated for 53 compounds in tomato, apple and orange matrices. The obtained limits of determination were lower than 0.1μg/kg for more than 50% of the pesticides studied, and lower than 1μg/kg for all pesticides studied, except for cypermethrin, boscalid, bifenthrin and deltamethrin. Linearity was studied in the 0.5–50μg/kg range and a linear response was obtained for all pesticides in all matrices. Recoveries were evaluated at two different levels (1 and 50μg/kg) and recoveries were ranged between 70 and 120% in tomato, apple and orange, except in the cases of chlorfenapyr, ofurace, chlozolinate, chlorothalonil, tolylfluanid and dichlofluanid with recovery values close to 60% at 1μg/kg fortification levels. Repetitivity was evaluated and the relative standard deviation (RSD%) was lower than 10% in all cases.
The developed method was employed in the analysis of real samples intended for baby food and the obtained results showed that 50% of the samples were positive for different pesticide residues. The concentration range detected was between 5 and 100μg/kg. The positive detection of OCs was particularly noticeable; these included chlorothalonil, fenhexamide, clorpyrifos and lambda cyhalothrin, which are very persistent and toxic with low acute reference dose. Endosulfan sulfate, which is not approved, was detected at a low concentration.
The processing factors (the pesticide concentration found in the wine/pesticide concentration found in grapes) of acetamiprid, azoxistrobin, carbaril, carbendazime, cyprodinil, dimethoate, ...dimethormorf, imazalil, imidacloprid, kresoxim methyl, penconazole, procymidone and thiabendazole were determined in a wine-making process. Pesticide analysis was performed using a multi-residue method for the determination of different pesticides both in wine and in grapes by extraction with acetonitrile followed by LC/MS. The pesticide distribution was studied for each step of the process, and the pesticide processing factors were calculated and found to vary among the different pesticides studied. pKₒw was found to affect a pesticide’s processing factor; a linear correlation was obtained for all pesticide processing factors, except for dimethoate, which was the most water soluble. However, no correlation was found between the processing factor and the water solubility of pesticides.
This work presents a new multi-residue analytical method based on solid phase extraction (SPE) with Oasis HLB sorbent, followed by gas chromatography tandem mass spectrometry (GC–MS/MS) for the ...simultaneous determination of a group of 10 acidic and neutral pharmaceuticals and related compounds in wastewaters. The typical derivation step was avoided, allowing the determination of acidic and neutral pollutants in a single analysis as well as providing a fast and easy method suitable for routine monitoring. Target pollutants include: anti-inflammatory drugs (ibuprofen, acetaminophen and diclofenac); an antiepileptic agent (carbamazepine); stimulants (caffeine and nicotine); an antiseptic (triclosan); a plasticizer (bisphenol A) and two of their more relevant metabolites (2,8-dichlorodibenzo-
p-dioxin and 1,7-dimethylxanthine). Recoveries between 66 and 112% were achieved for all the target compounds (except for 2,8-dichlorodibenzo-
p-dioxin). Good linearity was observed within the studied ranges (
R
2
>
0.993). Acceptable intra and inter-day precision was obtained, with relative standard deviation between 2 and 18%. The application of the optimized MS/MS mode allowed method detection limits in the range of 0.2–16
ng/L, with the exception of ibuprofen (120
ng/L). Finally, the methodology was successfully applied to the analysis of hospital effluent samples. All target analytes were detected at concentrations between 1
ng/L and 83215
μg/L. Even in the absence of derivatization, all the analytes showed good peak shape, except acetaminophen, which exhibited peak tailing. However, the method proved to be repetitive and reproducible, and the peak shape did not represent a problem for the reliable quantification of this compound. For most of the analytes studied, the detection limits achieved compare well against values reported in previously published methods.
Two GC–MS methods, based on the application of
N,
O-bis(trimethylsilyl)trifluoroacetamide-derivatization–GC–MS (selected-ion monitoring) and GC–MS–MS without derivatization, respectively, were ...optimised and applied to the determination of a group of five selected endocrine disrupting compounds (EDCs) in wastewaters. Both methods included solid-phase extraction with Oasis HLB cartridges allowing an enrichment factor for wastewater samples of 100-fold. The investigated EDCs were estrone, 17β-estradiol, 17α-ethynylestradiol, 4-
tert-octylphenol and bisphenol A. Results obtained from the validation studies yielded comparable results in both cases. Recoveries in spiked wastewaters at 50
ng/l were higher than 90% for all the compounds, except for 4-
tert-octylphenol (75%). Repeatability and reproducibility were adequate, varying from 1.6 to 14%, except for estrone which reproducibility was 28% when the derivatization–GC–MS method was applied. Limits of detection calculated ranged from 2.5 to 27.5
ng/l with differences between both methods from 1.1 (estrone) to 10.4 (bisphenol A) times. Both methods were successfully applied to the analysis of the target compounds in sewage treatment plant influents and effluents. Traces of bisphenol A, 4-
tert-octylphenol, estrone and 17β-estradiol were detected at concentration levels ranging from 13.3 to 1105.2
ng/l.
This work reports a method for extraction and analysis of thiosultap sodium, thiocyclam, and nereistoxin in pepper. Different extraction methods were tested to attain the best recoveries. The final ...extraction method combines acetonitrile extraction in an acidic medium with ultrasonic extraction followed by a cleanup step with anhydrous MgSO₄. The analyses were performed on a Linear Ion Trap Quadrupole LC-MS/MS in negative mode for thiosultap sodium and in positive mode for thiocyclam and nereistoxin. Recovery studies carried out on peppers spiked at different fortification levels (20 and 200 μg∙kg⁻¹) yielded average recoveries in the range 58-87% with RSD (%) values below 20%. Calibration curves covering two orders of magnitude were performed and they were linear over the concentration range studied (0.001-0.5 mg∙l⁻¹). Instrumental detection limits were in the low μg∙kg⁻¹ range. Stability studies of thiosultap sodium in water were performed by evaluating a 100-μg∙l⁻¹ solution of this compound in water. It was analyzed over 7 days, after which more than 80% degradation of thiosultap sodium could be observed.
Liquid chromatography with time-of-flight mass spectrometry (LC–TOF-MS) method has been developed for simultaneous confirmation by accurate mass measurement and quantitative determination of ...antibiotics (enrofloxacin, oxolinic acid, flumequine, erythromycin), fungicides (malachite green MG, leucomalachite green LMG) and parasiticide (emamectin benzoate) residues in edible portion of salmon. Confirmation of chemotherapeutant residues has been based on the system of identification points (IPs) established in the Commission Decision 2002/657/EC concerning the use of mass spectrometry (MS) techniques. A validation study on matrix is presented evaluating accuracy in terms of precision (
λ
ppm 0.83–1.15) and trueness (0.22–0.70
Da). Limits of detection (LODs) and limits of quantification (LOQs) were in ranges of 1–3 and 3–9
μg/kg, below the maximum residue limits (MRLs) established in current EU legislation (100–200
μg/kg) for these chemotherapeutants. Considering the EU guidelines, decision limits (CCα) and detection capabilities (CCβ) were determined (ranges of 103–218 and 107–234
μg/kg, respectively) for authorised substances. For no authorised compounds (MG and LMG), LODs were 2 and 1
μg/kg, respectively, but exceed the MRPL (minimum required performance limit) established in the legislation which corresponds to the sum of MG and LMG (2
μg/kg). Acceptable intra-day and inter-day variability, in terms of relative standard deviation (R.S.D.) of the analytical method, were obtained (2–15%). Linearity was demonstrated from the LOQs of the analytes to 600
μg/kg (
r
>
0.9991). The method has involved an extraction procedure based on solid–liquid extraction (SLE) with recoveries higher than 80% for most target chemotherapeutants, with exception of enrofloxacin (40%).
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