On-line Solid-phase Extraction Research Articles

Selective Determination of Acidic Drugs in Water Samples Using Online Solid Phase Extraction Liquid Chromatography with Alginate Incorporated Multi-Walled Carbon Nanotubes as Extraction Sorbent

A rapid and effective method is developed for selective determination of five selected acidic drugs (salicylic acid, naproxen, diclofenac, ibuprofen and mefenamic acid) in water samples by using online solid phase extraction (Online-SPE) prior to liquid chromatography diode array detector (LC-DAD) analysis. In this study, Alginate incorporated multi-walled carbon nanotubes (Alg-MWCNT) beads were prepared and utilized as solid phase extraction sorbent. Optimization of online SPE-LC operating parameters such as valve switching time, composition of acetonitrile and buffer pH was conducted using Box-Behnken Design of Response Surface Methodology (RSM) to evaluate the interactive effects of these three variables. Under the optimized conditions (valve switching time: 1.5 min, composition of acetonitrile: MSA, 60:40 and buffer pH: pH 2), the method showed good linearity (1–500 μg L−1) with coefficient of determination (R2) of 0.9971–0.9996 and low limits of detection ≤ 0.018 µg L–1. The method showed high relative recoveries in the range of 75–110% for river water and tap water samples, respectively with RSDs of ≤ 7.8 (n = 3). This method was successfully applied to the determination of acidic drugs in river and tap water samples. In addition, Alg-MWCNT sorbent offered high degree of selectivity and efficiency for online SPE-LC-DAD analysis.

Mass spectrometric quantification of urinary 6-sulfatoxymelatonin: age-dependent excretion and biological variation.

Regulators of circadian rhythm, including melatonin, influence fundamental biological processes. Measuring the melatonin metabolite 6-sulfatoxymelatonin in urine can estimate melatonin production. 6-sulfatoxymelatonin is mainly analyzed by immunoassays, but these methods are hampered by cross-reactivity and poor reproducibility when used to analyze small molecules. Therefore, we validated a high-throughput liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify 6-sulfatoxymelatonin in urine. We evaluated age-dependent 24-h excretion of 6-sulfatoxymelatonin into urine and the biological variation of urinary excretion in healthy individuals. The online solid phase extraction method combined with LC-MS/MS was validated according to international guidelines, and used to measure the excretion of 6-sulfatoxymelatonin into urine of 240 healthy individuals. Biological variation of 6-sulfatoxymelatonin excretion was examined in 10 healthy individuals. Urinary 6-sulfatoxymelatonin results were well within the validation criteria (interassay coefficient of variation:<5.4%, quantification limit: 0.2nmol/L). There was an age-related decrease in 6-sulfatoxymelatonin excretion into 24-h urine [F(5, 234)=13.9; p<0.001]. Within-subject variation of 6-sulfatoxymelatonin was 39.2% in day urine, 15.1% in night urine, and 12.2% in 24-h urine. Between-subject variation was 39.1% in day urine, 37.9% in night urine, and 36.8% in 24-h urine. This MS-based method enables straightforward, reproducible, and sensitive quantification of 6-sulfatoxymelatonin in urine. Urinary 6-sulfatoxymelatonin levels decreased with age. Biological variation of 6-sulfatoxymelatonin excretion into urine was high between subjects and lower within subjects, indicating that repeated measurements of 6-sulfatoxymelatonin in 24-h urine are needed in future studies.

Monolithic Column Prepared with UiO-66-2COOH MOF as Monomer for Enrichment and Purification of Ursolic Acid in Plants by Online Solid-Phase Extraction

A method for preparing a metal–organic framework (MOF)–polymeric monolith was established by in situ radical polymerization with derivatized UiO-66-2COOH and N-isopropylacrylamide (NIPAAm) as co-monomers. It was worth noting that the obtained monolith possessed characteristics of relatively uniform porous structure and a high surface area (84.16 m2 g−1). The adsorption capacity of the monolith increased from 22.87 to 44.92 mg−1 due to the addition of MOF. The monolith was used as adsorbent and coupled with HPLC for the online purification and extraction of ursolic acid (UA) in medicinal plant. The limit of detection (LOD, S/N = 3) and the limit of quantification (LOQ, S/N = 10) were 0.17 μg mL−1 and 0.57 μg mL−1, respectively; the relative standard deviation (RSD) of intra-day and inter-day assays for five plant samples were 1.00–3.67% and 2.43–5.76%, respectively; a good accuracy was demonstrated by the recovery of 92.2–103.28%. The results indicated that the MOF–polymer monolith was feasible for the online enrichment and purification of UA in plant.

Occupational exposure to antineoplastic drugs in hospital environments: potential risk associated with contact with cyclophosphamide- and ifosfamide-contaminated surfaces.

Cyclophosphamide (CP) and ifosfamide (IP) contaminations have been detected in hospital environments. This study was conducted to determine if there was any contamination in the spaces (floors and door handles) between the hospital exit and the antineoplastic drugs (ADs) preparation and administration units. At the same time, the authors proposed a new automation of the analytical procedure to considerably decrease the time needed for sample preparation and analysis. To evaluate the ADs contamination of surfaces, 829 wipe tests were performed in a campaign involving 3 hospitals located in Italy. Sampling was performed using an innovative kit. The levels of ADs were measured in each wipe sample using liquid chromatography/triple quadrupole. On-line solid-phase extraction guarantees the construction of a robust and reproducible analytical method. The CP and IP recoveries from stainless steel, polycarbonate and polyvinyl chloride ranged >80%, and the wipe holders and the automation tested ensured desorption efficiencies close to 100% for both the ADs. Of the 552 wipes taken on the spaces between the hospital exit and the preparation, administration and pharmacy warehouse units, 22 were greater than or equal to the limit of quantification, all adjacent to the administration units. This study provides an insight into the exposure situation against ADs residues. In order to improve environmental monitoring programs, the authors propose to evaluate the ADs contamination also outside the preparation, administration and pharmacy warehouse units. Med Pr. 2020;71(5):519-29.

3D-Printed Column with Porous Monolithic Packing for Online Solid-Phase Extraction of Multiple Trace Metals in Environmental Water Samples

In this study, we used a multimaterial three-dimensional printing (3DP) technology and porous composite filaments (Lay-Fomm, Gel-Lay, and Lay-Felt) to fabricate solid phase extraction (SPE) columns for the enhanced extraction of multiple metal ions. When employed as sample pretreatment devices in an automatic flow injection analysis/inductively coupled plasma mass spectrometry (ICP-MS) system, these 3D-printed SPE columns performed the near-complete extractions of Mn, Co, Ni, Cu, Zn, Cd, and Pb ions from natural water samples prior to ICP-MS determination. After optimizing the column fabrication, the extraction conditions, and the automatic analysis system, the column packed with the porous composite Lay-Fomm 40 was found to provide the highest extraction performance-the extraction efficiencies of the listed metal ions were all greater than 99.2%, and the detection limits of the method ranged from 0.3 to 6.7 ng L-1. The detection of these metal ions in several reference materials (CASS-4, SLEW-3, 1640a, and 1643f) validated the reliability of this method; spike analyses of collected water samples (groundwater, river water, and seawater) demonstrated the applicability of the method. The nature of the printing materials enhanced the analytical performance of 3D-printed sample pretreatment devices. Such approaches will be useful to diversify the range of sample preparation schemes and analytical methods enabled by 3DP technologies.

Development and validation of a simple online-SPE method coupled to high-resolution mass spectrometry for the analysis of stanozolol-N-glucuronides in urine samples.

Stanozolol is still the most commonly used illicit anabolic-androgenic steroid (AAS) in professional sports. Therefore, accurate and fast analysis and long detection windows are of great interest in the field of antidoping analysis. In this work, a very simple, fast, and highly sensitive online solid-phase extraction method coupled with liquid chromatography-high-resolution tandem mass spectrometry (HPLC-HRMSMS) for the analysis of stanozolol-N-glucuronides was developed. This fully validated procedure is characterized by only a few manual steps (dilution and addition of internal standard) in the sample preparation. A limit of identification (LOI) of 75 pg/mL, high accuracy (87.1%-102.1%), precision (3.1%-7.8%), and sensitivity was achieved. Furthermore, good linearity (> 0.99) and robustness, as well as no carry-over effects, could be observed. In addition to excellent confirmation analysis performance, this method shows sufficient potential for the identification and characterization of unknown metabolites. Using this method, it was possible to unambiguously confirm the presence of 1'N- and 2'N-stanozolol-glucuronide in human urine for the first time due to the access to reference material.

Determination of Deoxynivalenol and Its Derivative in Corn Flour and Wheat Flour Using Automated On-line Solid-Phase Extraction Combined with LC-MS/MS.

An automated on-line solid-phase extraction (SPE) combined with LC-MS/MS method was developed for determination of deoxynivalenol (DON), 3-acetyl-DON and 15-acetyl-DON in corn flour and wheat flour samples. The extraction solvent of the samples was injected into the automated on-line SPE system to remove matrix interference. After washing step, the targets were eluted from the SPE cartridge into liquid chromatography (LC) column. Several SPE parameters including injection volume, elution volume and eluting flow rate were assessed and optimized. Method validation was evaluated and good linearity was obtained (R2 > 99%) with the limit of detection of 0.1-0.2μg/kg. Recoveries were evaluated in spiked corn flour and wheat flour samples at three concentrations and the values ranged from 86.5% to 99.7%. The benefit of the present method with automated on-line SPE system is the ability to inject directly pure extracts into LC-MS/MS, offering faster analyses and improving analysis efficiency.

Identification and characterisation of thiolated polysulfides in must and wine using online SPE UHPLC-HRMS.

3-Mercaptohexanol and 4-methyl-4-mercaptopentanone are volatile thiols with a low perception threshold and are found in relatively low concentrations in several types of wines, e.g. Sauvignon blanc. They contribute positively to the flavour of a wine when in their free form, but they can oxidise, especially in the presence of Cu2+ and sulfur residues originating from pesticide treatments on the grapes. This condensation reaction results in the formation of polysulfides, which during storage can cause the release of H2S: a compound known to give rise to off-flavour in wine. The formation of these polysulfides has been proposed to originate from cysteinyl and glutathionyl S-conjugate precursors, but they have not yet been characterised. In this work, a method using ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry and online solid-phase extraction was designed and optimised for detection of these S-conjugates. The method allowed the detection of 21 suspected symmetrical and asymmetrical S-conjugates in thiol-supplemented aqueous solutions, of which 17 were also recovered in supplemented synthetic musts and wines. Moreover, the proposed method was used to investigate polysulfide formation upon addition of two different types of sulfur. Differences in formation of S-conjugates were evident in the synthetic samples: a higher relative abundance was observed upon addition of wettable sulfur compared to washed sulfur. For the commercial wines, differences in polysulfide formation were minor and merely related to the differences between the wines and not to the type of sulfur added.

Analysis of per- and polyfluorinated alkyl substances in sub-sampled water matrices with online solid phase extraction/isotope dilution tandem mass spectrometry.

Sorption of PFASs onto surfaces of laboratory materials has been frequently reported. Due to the often complex and poorly understood nature of such sorption, workarounds have often included use of whole samples only, accompanied by sample vessel rinsing to desorb active surfaces. The resulting methods tend to require considerable sample preparation times and preclude typical activities such as aliquoting and dilution of water samples prior to extraction. This manuscript reports an approach for PFAS analysis which uses subsampling of water matrices from vessels including centrifuge tubes and autosampler vials, through the optimized use of solvent to reduce PFAS retention on subsampling vessels. Online solid phase extraction (SPE) using a weak anion exchange resin is then used to concentrate sample aliquots to improve sensitivity and allow for removal of matrix interferences. With the technique of ultra performance liquid chromatography (UPLC) coupled to isotope dilution tandem mass spectrometry, statistically based quantitation limits ranged from sub ng/L to single digit ng/L for carboxylate, sulfonate, and sulfonamide PFASs analytes from C4 to C12. Linear calibration ranges were from 0.25 to 4000ng/L. Matrix effects relevant for drinking water treatment studies, such as cations, organic carbon, and competing PFAS compounds, were evaluated and found to not impact method performance within QC criteria consistent with study data quality objectives.

Urinary Concentrations of Phthalate Metabolite Mixtures in Relation to Serum Biomarkers of Thyroid Function and Autoimmunity among Women from a Fertility Center.

Background:Although previous epidemiological studies have explored associations of phthalate metabolites with thyroid function, no studies to date have assessed associations of mixtures with thyroid function and autoimmunity among potentially susceptible subgroups such as subfertile women.Objective:We aimed to explore associations of mixtures of urinary phthalate metabolites with serum markers of thyroid function and autoimmunity.Methods:This cross-sectional study included 558 women attending a fertility center who provided one spot urine and one blood sample at enrollment (2005–2015). We quantified urinary concentrations of eight phthalate metabolites using mass spectrometry, and biomarkers of thyroid function [thyroid-stimulating hormone (TSH), free and total thyroxine (, ) and triiodothyronine (, ), and autoimmunity [thyroid peroxidase and thyroglobulin antibodies (TPOAb and TgAb, respectively)] in serum using electrochemiluminescence assays. We applied principal component analysis (PCA) and Bayesian kernel machine regression (BKMR) to identify the main patterns of urinary phthalate metabolites. We used linear mixed models to assess the association between PCA-derived factor scores in quintiles and serum thyroid function and autoimmunity, adjusting for age, body mass index (BMI), specific gravity (SG), and, for the PCA, other factor scores.Results:We observed two factors using PCA, one representing the di(2-ethylhexyl) (DEHP) and another non-DEHP metabolites. Compared to women in the lowest quintile of the DEHP factor scores, women in the highest quintile had significantly lower serum concentrations of , , , and [absolute difference: ; 95% confidence interval (CI): , ; ; absolute difference: ; 95% CI: , ; ; absolute difference: ; 95% CI: 0.54, ; ; and absolute difference: ; 95% CI: , ; , respectively]. Using BKMR, we observed that mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) was the primary contributor to these negative associations. DEHP and non-DEHP factor scores were not associated with serum TSH, TgAb, or TPOAb.Conclusions:Mixtures of urinary DEHP metabolites were inversely associated with serum biomarkers of thyroid function but not with autoimmunity, which were within normal ranges for healthy adult women. https://doi.org/10.1289/EHP6740

On-line polydopamine coating as a new way to functionalize polypropylene fiber sorbent for solid phase extraction

Effective process, including a cartridge packing polypropylene fiber sorbent modified by following on-line polydopamine coating, for on-line solid phase extraction in 2D UHPLC system has been developed. Hydrophobic surface of mechanically stable polypropylene fibers was hydrophilized using an automated and reproducible in situ coating process to enable good wettability and effective extraction of polar compounds. Polymerization mixture consisting dopamine and TRIS buffer was circulated through the cartridge containing polypropylene fibers using a peristaltic pump to achieve polymerization. This process was optimized in terms of dopamine amount in the polymerization mixture, its flow rate, and polymerization time. Best results were obtained with 25 mL polymerization mixture containing 20 mg dopamine circulated through the cartridge at a flow rate of 2.07 mL min−1 for 60 min. Prepared cartridges were evaluated via measurement of the recovery and reproducibility using chlorogenic acid as a model compound. Overall reproducibility of our multistep process including eight cartridges in 2D UHPLC system, each measured in triplicate, was 3.61% (n = 24).

Analysis of 2-aminopyridine labeled glycans by dual-mode online solid phase extraction for hydrophilic interaction and reversed-phase liquid chromatography

Quantitative analysis of glycans released from glycoproteins using high-performance liquid chromatography (HPLC) requires fluorescent tag labeling to enhance sensitivity and selectivity. However, the methods required to remove large amounts of excess labeling reagents from the reaction mixture are time-consuming. Furthermore, these methods, including solvent extraction and solid phase extraction (SPE), often impair quantitative analysis. Here, we developed an online sample cleanup procedure for HPLC analysis of 2-aminopyridine (AP)-labeled glycans using a six-port/two-way valve and two small columns: one packed with a strong cation exchange resin (SCX) and the other comprising ODS silica gel. AP-labeled glycans delivered from an injection port were separated from excess AP by passing through an SCX column (4.6 mm i.d., 1 cm long) regulated to 40°C. The AP-labeled glycans were trapped on an ODS column (4.6 mm i.d., 1 cm long) to further separate them from inorganic contaminants. By changing the valve position after 2 min to connect the ODS column to an analysis column, AP-labeled glycans trapped in the ODS column were eluted with an acetonitrile-containing eluent followed by hydrophilic interaction liquid chromatography (HILIC) separation on an amide column or reversed-phase mode separation on a C30 column. This method was successfully used to analyze N-linked glycans released from several glycoprotein samples.

Rapid analysis of fifteen sulfonamide residues in pork and fish samples by automated on-line solid phase extraction coupled to liquid chromatography–tandem mass spectrometry

The aim of this work was to develop an automated on-line solid phase extraction (SPE) with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples. Samples were extracted with 0.2% formic acid acetonitrile solution, purified by on-line SPE device with HLB column, then separated by XBridge C18 column, using 0.1% formic acid solution and acetonitrile as the mobile phase. Mass spectrometric data was acquired under multiple reaction monitoring (MRM) mode using positive ionization electrospray. Internal standard method was used in the quantification, good linear relationship was got in range of 0.1–100ng/mL and correlation coefficient was higher than 0.9990. The limits of detection were in the range of 0.125–2.00μg/kg and the limits of quantitation were in the range of 0.250–5.00μg/kg. Recoveries of the method were in range of 78.3%–99.3%, relative standard deviation were lower than 10%. The method was simple, sensitivity, and could be used for routine supervision and analysis of fifteen sulfonamides in pork and fish.

Enrichment of histidine containing peptides by on-line immobilised metal affinity solid-phase extraction capillary electrophoresis-mass spectrometry

The analysis and detection of targeted peptides has received due attention in many fields of proteomics research, such as discovery of biomarkers. In this regard, capillary electrophoresis-mass spectrometry (CE-MS) is widely used, however, direct analysis of low-abundance peptides such as histidine-containing peptides (His-peptides) in complex matrixes by CE-MS remains an analytical challenge. In the present study, an immobilised metal affinity solid-phase extraction containing Ni(II) coupled on-line to capillary electrophoresis-mass spectrometry (IMA-SPE-CE-MS) method has been developed to selectively enrich His-peptides from protein tryptic digests and enhance sensitivity. The method was optimised with α-casein and validated with other standard proteins (β-casein and κ-casein). Later, it was applied to an Escherichia Coli (E. Coli) whole cell lysate. IMA-SPE-CE-MS was very selective and allowed an enrichment factor up to 100-fold. The on-line enrichment and separation method coupled to MS detection is straightforward and advantageous over off-line pretreatment methods in terms of simplicity, cost-effectiveness and throughput.

SUN-212 Interference in Serum Androstenedione Measured by LC-MS/MS in Newborns Samples

Introduction: Liquid chromatography followed by mass spectrometry (LC-MS/MS) is considered the gold standard method to measure steroids. Newborn screening for congenital adrenal hyperplasia (CAH) involves measurement of 17α-hydroxyprogesterone (17-OHP) in blood dried spots by immunoassay. Because this testing has high false-positive rates, serum samples to measure 17-OHP, androstenedione, 21-desoxicortisol and cortisol simultaneously by liquid chromatography-tandem mass spectrometry (LC-MS/MS) are used for confirmatory test in our laboratory. Objective: To report an interference in androstenedione levels measured by LC-MS/MS assay in serum samples from newborns. Patients and methods: The method for androstenedione measurements was based on protein precipitation followed by a semi-automated and multiplexed on-line solid phase extraction coupled reverse phase separation and detection of underivatized analyte by tandem mass spectrometry. Among 312 samples 82 presented unexpected androstenedione results considering that 17OHP levels were <5 ng/mL. These samples presented a high variability among 4 replicates (CV ranged from 20 to 133%). These samples also showed an inadequate ion ratio resulting in pseudo-elevated androstenedione, indicating a coeluition of an isobaric interferent. In routine samples from other patients this problem was not observed. Results: Since this fact suggests a possible interference in LC-MS/MS measurements and modification in chromatographic method was unable to resolve from the interference, alternative method for sample preparation was developed. Liquid-liquid extraction with diethyl ether was performed and eliminated the interference and provided substantial decrease in androstenedione values (9.3+12.94 ng/mL vs 5.2+9.59 ng/mL after extraction) with ion ration normalization and CV less 10% between replicates. The identity of this compound is still unknown. Therefore, it will be necessary additional studies to clarify this artifact. Conclusions: Although the measurement of androstenedione by reverse phase chromatography without derivatization followed by tandem mass spectrometry is the simplest and commonest approach to determine androstenedione, it is susceptible to interferences causing falsely elevated androstenedione levels in newborns.

Occurrence and Behavior of Residual Pharmaceuticals in the Nakdong River Basin

Objectives:This study was conducted to evaluate the detection characteristics of Nakdong River basin (wastewater treatment plant (WWTP) effluents, tributaries and main streams) by selecting 18 kinds of pharmaceuticals which were detected frequently. It was intended to be used as basic data for advanced treatment of WWTP and securing safe water source.Methods:The selected 18 pharmaceuticals investigated in this study were acetaminophen, atenolol, carbamazepine, caffeine, diclofenac, iopromide, lincomycin, metoprolol, primidone, propranolol, sulfachloropyridazine, sulfamethazine, sulfamethoxazole, tetracycline, trimethoprim, chlorotetracycline, oxytetracycline and sulfathiazole. The residual pharmaceuticals was analyzed LC-MS/MS equipped with on-line solid phase extraction (SPE) system and the limit of quantifications (LOQ) of 18 residual pharmaceuticals were 1~5 ng/L. Sampling points were 27 from the upstream to the downstream, including mainstream, tributary, and WWTP effluents. Sampling was conducted four times in Feb., Jun., Aug. and Nov. 2018.Results and Discussion:The most frequently detected residual pharmaceutical in all WWTP effluents, tributaries and mainstream sites was caffeine, followed by carbamazepine, lincomycin, sulfamethoxazole and iopromide. In addition, iopromide was detected as the highest mean concentration of 44.9~985.4 ng/L followed by caffeine (63.2~337.1 ng/L) and carbamazepine (13.8~145.0 ng/L), sulfamethoxazole (12.3~114.8 ng/L) and diclofenac (3.1~144.1 ng/L). In particular, the proportion ratio of caffeine gradually decreased as going to the downstream, whereas iopromide gradually increased. However, the concentrations of caffeine in the sampling sites of the downstream were higher than those of the upstream sites. The total concentrations of detected residual pharmaceuticals gradually increased from the upstream to the middle stream, showed the highest detected concentration at the Goryeong area in the middle stream of the Nakdong River, and then gradually decreased due to the dilution effect. Residual pharmaceuticals in the Nakdong River basin, which could not be completely removed from the WWTPs, entered into the water system and contaminated source water of the downstream. This process is a typical contaminant pattern of the source water by the emerging micropollutants.Conclusions:The most frequently detected residual pharmaceutical in all WWTP effluents, tributaries and mainstream sites was caffeine, followed by carbamazepine, lincomycin, sulfamethoxazole and iopromide. In addition, iopromide was detected as 44.9~985.4 ng/L, showing the highest mean concentration at the sampling points, and caffeine (63.2~337.1 ng/L) and carbamazepine (13.8~145.0 ng/L), sulfamethoxazole (12.3~114.8 ng/L) and diclofenac (3.1~144.1 ng/L) in order. The total concentrations of detected residual pharmaceuticals gradually increased from the upstream to the middle stream, showed the highest concentration at the Goryeong area in the middle stream of the Nakdong River basin, and then gradually decreased due to the dilution effect.

Polymeric monolithic microcartridges with gold nanoparticles for the analysis of protein biomarkers by on-line solid-phase extraction capillary electrophoresis-mass spectrometry

In this study, polymeric monoliths with gold nanoparticles (AuNP@monolith) were investigated as microcartridges for the analysis of protein biomarkers by on-line solid-phase extraction capillary electrophoresis-mass spectrometry (SPE-CE-MS). “Plug-and-play” microcartridges (7 mm) were prepared from a glycidyl methacrylate (GMA)-based monolithic capillary column (5 cm x 250 µm i.d.), which was modified with ammonia and subsequently functionalized with gold nanoparticles (AuNPs). The performance of these novel microcartridges was evaluated with human transthyretin (TTR), which is a protein related to different types of familial amyloidotic polyneuropathies (FAP). Protein retention depended on the isoelectric point of the protein (TTR pI~5.4) and elution was achieved with a basic phosphate solution. Under the optimized conditions, limits of detection (LODs) for TTR by AuNP@monolith-SPE-CE-MS were 50 times lower than by CE-MS (5 vs 250 mg•L−1, with an ion trap (IT) mass spectrometer). The sensitivity enhancement was similar compared to SPE-CE-MS using immunoaffinity (IA) microcartridges with intact antibodies against TTR. Linearity, repeatability in migration times and peak areas, reusability, reproducibility and application to serum samples were also evaluated.

Liquid chromatography tandem mass spectrometry determination of 34 priority and emerging pollutants in water from the influent and effluent of a drinking water treatment plant

This study evaluates the applicability of a method based on the direct injection of a large volume of water samples to identify and quantify 34 priority and emerging substances, most of them discussed in Directive 2013/39/EU on priority substances in the field of water policy, and Decision 2018/840/EU (Watch List). The method directly injects 500 µL of filtered water sample and so does not use a pre-concentration step. The method was satisfactorily validated for influent and effluent water from a drinking water treatment plant, at three concentrations (1, 10 and 100 ng L−1) with precision and accuracies in the range 1–17% and 71–122% respectively. Sensitivity was good with detection limits in the range 0.15–10 ng L−1 and complied with EU limits in all cases except for estrone, 17-β-estradiol and 17-α-ethinylestradiol. For these hormones, an on-line solid phase extraction was developed and evaluated. The methods were applied to the analysis of water collected at the influent and effluent of a drinking water treatment plant and revealed the presence of 18 of the target compounds in the influent water and 8 in the effluent water. This showed that most the compounds had been efficiently removed by the processes of the drinking water treatment plant.

A coupled method of on-line solid phase extraction with the UHPLC‒MS/MS for detection of sulfonamides antibiotics residues in aquaculture

The use of a variety of antibiotics in fish farming raises serious concern about the development of antibiotic resistance. Sulfonamides antibiotics (SAs), which are widely used in aquaculture and generate large eco‒toxicological effects with significant mutagenicity and teratogenic consequences, are still difficult to determine in aquatic organisms. In this study, an automatic technology was developed by coupling on‒line solid phase extraction system (on‒line SPE) with ultra‒high‒performance liquid chromatography spectrometry‒mass spectrometry (UHPLC‒MS/MS). Particularly, using a single on‒line column in the process of sample pretreatment, e.g., HLB or C18, phospholipids that potentially caused the matrix effect cannot be removed form biological sample. We applied a mixed cation exchange column (Oasis® MCX) connected with a hydrophilic lipophilic balance column (Oasis® HLB) in series in on‒line SPE clean‒up to remove interferences and finally obtained a clear and stable eluant. The on‒line SPE working conditions and UHPLC‒MS/MS parameters were optimized for their sensitivity, accuracy, decision limit, and detection capability, which were further calibrated for fish, shrimp and crab. The results showed that the limits of detection and limits of quantification ranged from 1.46 to 15.5 ng/kg, and 4.90–51.6 ng/kg, respectively. Accuracy values covered 71.5%–102% at the three concentration levels (0.1, 0.5, 1.0 μg/kg) for all compounds and average repeatability (relative standard deviation, RSD%) ranged from 3.47% to 14.2%. This on‒line SPE coupled with UHPLC‒MS/MS method is a way forward for an automatic, powerful detection technology for determination of antibiotics from complex matrix.

Tracking the occurrence of psychotropic pharmaceuticals in Brazilian wastewater treatment plants and surface water, with assessment of environmental risks

According to the World Health Organization, >360 million people worldwide suffer from mental diseases such as depression, anxiety, or bipolar disorder, for which psychotropic drugs are frequently prescribed. Despite being highly metabolized in the human organism, non-metabolized portions of these drugs are excreted, subsequently reaching wastewater treatment plants (WWTPs), where they may be incompletely removed during treatment, leading to the contamination of surface waters. In this work, ten psychotropic drugs widely consumed in Brazil (alprazolam, amitriptyline, bupropion, carbamazepine, clonazepam, escitalopram, fluoxetine, nortriptyline, sertraline, and trazadone) were monitored at five WWTPs located in the metropolitan region of Campinas (São Paulo State, Brazil). The drugs were determined in the influents, at different stages of the treatments, and in the effluents. Surface waters from the Atibaia River and the Anhumas Creek were also monitored. Quantitation of the pharmaceuticals was carried out by online solid-phase extraction coupled with ultra-high performance liquid chromatography and tandem mass spectrometry. The method was validated and presented a limit of quantitation of 50 ng L−1 for all the drugs assessed. Six of the substances monitored were quantified in the samples collected from the different treatment processes employed at the WWTPs. These technologies were unable to act as barriers for these psychotropics drugs. The concentrations ranged from 50 to 3000 ng L−1 in the WWTP effluents, while the main contaminants were found in surface waters at concentrations from 25 to 3530 ng L−1. The levels of the psychotropic detected in this work did not appear to present risks to the aquatic biota.