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► A novel method by US-IL-DLLME-LC-FD for fluoroquinolones determination. ► Simple, rapid and efficient method for water samples. ► Advantages over conventional methods. ► Low ...detection limits.
An ultrasound-assisted ionic liquid dispersive liquid–liquid microextraction (US-IL-DLLME) procedure was developed for the extraction of eight fluoroquinolones (marbofloxacin, norfloxacin, ciprofloxacin, lomefloxacin, danofloxacin, enrofloxacin, oxolinic acid and nalidixic acid) in groundwater, using high-performance liquid chromatography with fluorescence detection (HPLC-FD). The ultrasound-assisted process was applied to accelerate the formation of the fine cloudy solution using a small volume of disperser solvent (0.4mL of methanol), which increased the extraction efficiency and reduced the equilibrium time.
For the DLLME procedure, the IL 1-octyl-3-methylimidazolium hexafluorophosphate (C8MIM PF6) and methanol (MeOH) were used as extraction and disperser solvent, respectively. By comparing C8MIM PF6 with 1-hexyl-3-methylimidazolium hexafluorophosphate (C6MIM PF6) and 1-butyl-3-methylimidazolium hexafluorophosphate (C4MIM PF6) as extraction solvents, it was observed that when using C8MIM PF6 the cloudy solution was formed more readily than when using C6MIM PF6 or C4MIM PF6. The factors affecting the extraction efficiency, such as the type and volume of ionic liquid, type and volume of disperser solvent, cooling in ice-water, sonication time, centrifuging time, sample pH and ionic strength, were optimised.
A slight increase in the recoveries of fluoroquinolones was observed when an ice-water bath extraction step was included in the analytical procedure (85–107%) compared to those obtained without this step (83–96%).
Under the optimum conditions, linearity of the method was observed over the range 10–300ngL−1 with correlation coefficient >0.9981. The proposed method has been found to have excellent sensitivity with limit of detection between 0.8 and 13ngL−1 and precision with relative standard deviation values between 4.8 and 9.4% (RSD, n=5). Good enrichment factors (122–205) and recoveries (85–107%) were obtained for the extraction of the target analytes in groundwater samples.
This simple and economic method has been successfully applied to analyse real groundwater samples with satisfactory results.
Gas and liquid chromatography coupled to triple quadrupole tandem mass spectrometry are currently the most powerful tools employed for the routine analysis of pesticide residues in food control ...laboratories. However, whatever the multiresidue extraction method, there will be a residual matrix effect making it difficult to identify/quantify some specific compounds in certain cases. Two main effects stand out: (i) co-elution with isobaric matrix interferents, which can be a major drawback for unequivocal identification, and therefore false negative detections, and (ii) signal suppression/enhancement, commonly called the “matrix effect”, which may cause serious problems including inaccurate quantitation, low analyte detectability and increased method uncertainty. The aim of this analytical study is to provide a framework for evaluating the maximum expected errors associated with the matrix effects. The worst-case study contrived to give an estimation of the extreme errors caused by matrix effects when extraction/determination protocols are applied in routine multiresidue analysis. Twenty-five different blank matrices extracted with the four most common extraction methods used in routine analysis (citrate QuEChERS with/without PSA clean-up, ethyl acetate and the Dutch mini-Luke “NL” methods) were evaluated by both GC-QqQ-MS/MS and LC-QqQ-MS/MS. The results showed that the presence of matrix compounds with isobaric transitions to target pesticides was higher in GC than under LC in the experimental conditions tested.
In a second study, the number of “potential” false negatives was evaluated. For that, ten matrices with higher percentages of natural interfering components were checked. Additionally, the results showed that for more than 90% of the cases, pesticide quantification was not affected by matrix-matched standard calibration when an interferent was kept constant along the calibration curve. The error in quantification depended on the concentration level. In a third study, the “matrix effect” was evaluated for each commodity/extraction method. Results showed 44% of cases with suppression/enhancement for LC and 93% of cases with enhancement for GC.
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•Estimation of the extreme error due to matrix effects.•Twenty five different matrices were tested by both GC-QqQ-MS/MS and LC-QqQ-MS/MS.•Evaluation of the four most commonly extraction methods used in routine.•“Potential” false negatives were higher in GC than in LC.•Higher percentages of interferences were found for NL-method.
•Nine pharmaceuticals were determined in effluent wastewaters at ngL−1 levels.•US-IL-DLLME was used as sample treatment.•Lowering environmental toxicity.•Analytes were determined by LC with QqLIT-MS ...detection.•Matrix effect was not found for any pharmaceuticals.
A simple, rapid, low environmental toxicity and sensitive ultrasound-assisted ionic liquid dispersive liquid–liquid microextraction (US-IL-DLLME) procedure was developed for the extraction of nine pharmaceuticals (paracetamol, metoprolol, bisoprolol, betaxolol, ketoprofen, naproxen, ibuprofen, flufenamic acid and tolfenamic acid) in wastewater, and their determination using high-performance liquid chromatography with a hybrid triple quadrupole-linear ion trap-mass spectrometer (LC-QqLIT-MS). The IL 1-octyl-3-methylimidazolium hexafluorophosphate (C8MIMPF6) and acetonitrile (ACN) were used as extraction and disperser solvent, respectively, for the DLLME procedure, instead of using toxic chlorinated solvent. The factors affecting the extraction efficiency, such as the type and volume of ionic liquid, type and volume of disperser solvent, cooling in ice-water, sonication time, centrifuging time, sample pH and ionic strength, were optimized. The ultrasound-assisted process was applied to accelerate the formation of the fine cloudy solution using a small volume of disperser solvent (0.5mL of acetonitrile), which increased the extraction efficiency and reduced the equilibrium time. A slight increase in the recoveries of pharmaceuticals was observed when an ice-water bath extraction step was included in the analytical procedure. In this way, enrichment factors between 255 and 340 were obtained. Data acquisition in selected reaction monitoring mode (SRM), allowed the simultaneous identification and quantification of the analytes using two transitions (SRM1 and SRM2). Additionally, the information dependent acquisition (IDA) scan was performed to carry out the identification of those analytes whose second transition was absent or was present at low intensity, also providing extra confirmation for the other analytes. The optimized US-IL-DLLME–LC-QqLIT-MS method showed a good precision level, with relative standard deviation values between 1.1% and 11.3%. Limits of detection and quantification were in the range 0.2–60ngL−1 and 1.0–142ngL−1, respectively. Good enrichment factors (255–340) and recoveries (88–111%) were obtained for the extraction of the target analytes in wastewater samples. This method has been successfully applied to analyze effluent wastewater samples from a municipal wastewater treatment plant located in Almería (Spain) and the results indicated the presence of flufenamic acid and metoprolol in concentration levels of 0.1 and 1.3μgL−1, respectively.
•Two IL-DLLME methods were compared.•Benzoylurea insecticides were determined in effluent wastewaters at ngL−1 levels.•Lowering environmental toxicity.•Analytes were determined by LC with QqLIT–MS ...detection.•Green parameters have been compared.
Two dispersive liquid–liquid microextraction (DLLME) approaches including temperature-controlled ionic liquid dispersive liquid–liquid microextraction (TCIL-DLLME) and ultrasound-assisted ionic liquid dispersive liquid–liquid microextraction (US-IL-DLLME) were compared for the extraction of six benzoylurea insecticides (diflubenzuron, triflumuron, hexaflumuron, teflubenzuron, lufenuron and flufenoxuron) from wastewater samples prior to their determination by high-performance liquid chromatography with a hybrid triple quadrupole-linear ion trap–mass spectrometer (LC–QqLIT–MS/MS). Influential parameters affecting extraction efficiency were systematically studied and optimized and the most significant green parameters were quantified and compared. The best results were obtained using the US-IL-DLLME procedure, which employed the IL 1-octyl-3-methylimidazolium hexafluorophosphate (C8MIMPF6) and methanol (MeOH) as extraction and disperser solvent, respectively. US-IL-DLLME procedure was fast, easy, low environmental toxicity and, it was also able to successfully extract all selected benzoylureas. This method was extensively validated with satisfactory results: limits of detection and quantification were in the range 0.5–1.0ngL−1 and 1.5–3.5ngL−1, respectively, whereas recovery rates ranged from 89 to 103% and the relative standard deviations were lower than 13.4%. The applicability of the method was assessed with the analysis of effluent wastewater samples from a wastewater treatment plant located in an agricultural zone of Almería (Spain) and the results indicated the presence of teflubenzuron at mean concentration levels of 11.3ngL−1. US-IL-DLLME sample treatment in combination with LC–QqLIT–MS/MS has demonstrated to be a sensitive, selective and efficient method to determine benzoylurea insecticides in wastewaters at ultra-trace levels.
Background
In staged liver resections, associating liver partition and portal ligation for staged hepatectomy (ALPPS) achieves sufficient hypertrophy of the future liver remnant (FLR) in 7 days. This ...is based on portal vein ligation and transection, and on occlusion of intrahepatic collaterals. This article presents a new surgical technique for achieving rapid hypertrophy of the FLR, which also involves adding intrahepatic collateral occlusion to portal vein transection.
Methods
Patients scheduled for two‐stage liver resection for primary or secondary liver tumours, in whom the FLR was considered too small, were enrolled prospectively. In the first stage, a tourniquet was placed around the parenchymal transection line, and the right portal vein was ligated and cut (associating liver tourniquet and portal ligation for staged hepatectomy, ALTPS). The tourniquet was placed on the umbilical ligament if a staged right trisectionectomy was planned, and on Cantlie's line for staged right hepatectomy.
Results
From September 2011, 22 ALTPS procedures were carried out (right trisectionectomy in 15, right hepatectomy in 7). Median FLR at 7 days increased from 410 to 700 ml (median increase 61 (range 33–189) per cent). The median duration of the first stage was 125 min and no patient received a blood transfusion. The median duration of the second stage was 150 min and five patients required a blood transfusion. Fourteen patients had complications, most frequently infected collections, and five patients developed postoperative liver failure. Two patients died.
Conclusion
The ALTPS technique achieved adequate hypertrophy of the FLR after 7 days. It may provide a less aggressive modification of the ALPPS procedure.
Simplification of the ALPPS procedure
•An efficient and simple multiresidue method for pollen analyses is validated.•253 pesticides are determined with a single extraction method.•Freeze-out and SPE clean-up with ZrO2 allow an optimum ...analytical performance.•LC–MS/MS and GC–MS/MS are successfully applied.•A large number of pesticides potentially toxic to bees were determined.
Several clean-up methods were evaluated for 253 pesticides in pollen samples concentrating on efficient clean-up and the highest number of pesticides satisfying the recovery and precision criteria. These were: (a) modified QuEChERS using dSPE with PSA+C18; (b) freeze-out prior to QuEChERS using dSPE with PSA+C18; (c) freeze-out prior to QuEChERS using dSPE with PSA+C18+Z-Sep; and (d) freeze-out followed by QuEChERS using dSPE with PSA+C18 and SPE with Z-Sep. Determinations were made using LC–MS/MS and GC–MS/MS. The modified QuEChERS protocol applying a freeze-out followed by dSPE with PSA+C18 and SPE clean-up with Z-Sep was selected because it provided the highest number of pesticides with mean recoveries in the 70–120% range, as well as relative standard deviations (RSDs) typically below 20% (12.2% on average) and ensured much better removal of co-extracted matrix compounds of paramount importance in routine analysis. Limits of quantification at levels as low as 5μgkg−1 were obtained for the majority of the pesticides. The proposed methodology was applied to the analysis of 41 pollen bee samples from different areas in Spain. Pesticides considered potentially toxic to bees (DL50<2μg/bee) were detected in some samples with concentrations up to 72.7μgkg−1, which could negatively affect honeybee health.
Background
We analyze the efficacy of hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) for microscopic residual disease in patients with stage IIIC/IV ovarian cancer after a complete ...cytoreduction of their disease.
Patients and Methods
We analyzed the data of 87 consecutive patients diagnosed with stage IIIC/IV ovarian cancer operated between December 1998 and July 2011. In every patient it was possible to achieve a complete cytoreduction of their disease. (Since January 2008, our center has incorporated the use of HIPEC in patients with peritoneal surface malignancies, including patients with peritoneal dissemination of primary ovarian cancer.)
Results
Of 87 patients, 52 were treated with HIPEC (paclitaxel 60 mg/m
2
, 60 min, 42 °C). After a univariate analysis, factors associated with lower disease-free interval were: performing a gastrointestinal anastomosis, operative time greater than 270 min, poorly differentiated histology, and not being treated with HIPEC. After multivariate analysis, independent prognostic factors included not being treated with HIPEC hazard ratio (HR) 8.77, 95 % CI 2.76–14.42,
p
< 0.01 and the presence of poorly differentiated tumors (HR 1.98, 95 % CI 1.45–8.56,
p
< 0.05). Disease-free survival at 1 and 3 years was 66 and 18 %, respectively, in patients without HIPEC and 81 and 63 %, respectively, in patients treated with HIPEC (
p
< 0.01). HIPEC administration did not alter the results obtained for disease-free survival in patients with undifferentiated tumors.
Conclusions
The treatment of the microscopic disease following complete cytoreduction with HIPEC in patients with advanced ovarian cancer is effective and can prolong disease-free survival. This survival benefit was not seen in undifferentiated tumors.
•Multiresidue method for edible vegetable oils using GC–MS/MS.•Evaluation of different sorbents for the clean-up step using QuEChERS methodology.•Comparison of the novel EMR-Lipid sorbent with Z-Sep ...and PSA.•Procedural Standard Calibration to correct recovery losses.•Several pesticides are detected in most of the olive oil samples.
The aim of this research was to adapt the QuEChERS method for routine pesticide multiresidue analysis in edible vegetable oil samples using gas chromatography coupled to tandem mass spectrometry (GC–MS/MS). Several clean-up approaches were tested: (a) D-SPE with Enhanced Matrix Removal-Lipid (EMR-Lipid™); (b) D-SPE with PSA; (c) D-SPE with Z-Sep; (d) SPE with Z-Sep. Clean-up methods were evaluated in terms of fat removal from the extracts, recoveries and extraction precision for 213 pesticides in different matrices (soybean, sunflower and extra-virgin olive oil). The QuEChERS protocol with EMR-Lipid d-SPE provided the best reduction of co-extracted matrix compounds with the highest number of pesticides exhibiting mean recoveries in the 70–120% range, and the lowest relative standard deviations values (4% on average). A simple and rapid (only 5min) freeze-out step with dry ice (CO2 at −76°C) prior to d-SPE clean-up ensured much better removal of co-extracted matrix compounds in compliance of the necessity in routine analysis. Procedural Standard Calibration was established in order to compensate for recovery losses of certain pesticides and possible matrix effects. Limits of quantification were 10μgkg−1 for the majority of the pesticides. The modified methodology was applied for the analysis of different 17 oil samples. Fourteen pesticides were detected with values lower than MRLs and their concentration ranged between 10.2 and 156.0μgkg−1.
A sensitive and efficient solid-phase microextraction (SPME) method for the determination of seven pyrethroid insecticides including fenpropathrin, λ-cyhalothrin, deltamethrin, fenvalerate, ...permethrin, τ-fluvalinate and bifenthrin in cucumber and watermelon samples using high performance liquid chromatography combined with post-column photochemically induced fluorimetry derivatization and fluorescence detection (SPME–HPLC–PIF–FD) was developed and validated. The optimum SPME conditions were used for the extraction of samples of both matrices (extraction time 30
min, stirring rate 1100
rpm, extraction temperature 65
°C, sample pH 3, soaking time 7
min, desorption time 5
min, ACN content 25%, desorption and soaking solvent was the mobile phase and in static mode). The method was validated in terms of limits of detection (LODs) and the limits of quantification (LOQs) in both IUPAC and EURACHEM criteria. LODs and LOQs were achieved in values lower than the maximum residue levels (MRLs) established in the Spanish regulations for all pesticides in this study (MRLs range between 0.01 and 0.1
mg
kg
−1 for all pyrethroid insecticides in both matrices). LOQs according to the second criterion were between 1.5 and 5
μg
kg
−1 for cucumber; and between 1.3 and 5
μg
kg
−1 for watermelon samples. Precision and recovery studies were evaluated at two concentration levels for each matrix. Good precision was obtained and relative standard deviation values were less than 10% in all cases. Recovery values were calculated at 0.05 and 0.5
mg
kg
−1 levels (
n
=
6) and they ranged between 93% and 108% for cucumber and between 91% and 110% for watermelon samples. Applicability of the method to pyrethroids in cucumber and watermelon of commercial samples was demonstrated.
