Determination of short-chain carbonyl compounds in drinking water matrices by bar adsorptive micro-extraction (BAμE) with in situ derivatization

Selective determination of formaldehyde by high-performance liquid chromatography with porous graphitic carbon column using N,N'-bis(9-anthrylmethyl)propane-1,3-diamine as derivatizing reagent

Aromatic compounds containing two secondary amino groups were designed and prepared as new derivatizing reagents for aldehydes. One of them, N,N'-bis(9-anthrylmethyl)propane-1,3-diamine (APD), could achieve selective determination of formaldehyde (FA) on a porous graphitic carbon (PGC) column using xylenes, chlorobenzene, and 1-chloronaphthalene as mobile phases by high-performance liquid chromatography (HPLC). The APD-FA derivative was eluted from the PGC column, while the other APD-aldehyde derivatives remained on the column during the HPLC measurements. This specific elution was not observed using mobile phases such as acetonitrile, 1,4-dioxane, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, chloroform, benzene, toluene, benzyl alcohol, 2-ethyl-1-hexanol, and pyridine. The APD-FA derivative had a six-membered ring of two tertiary amines identified using ¹H NMR spectroscopy. When the π-π interaction of the solvent molecule of the mobile phase with PGC overcame that between the APD-FA derivative and PGC, the APD-FA derivative could be eluted from the column. The best resolution between the peak of the APD-FA derivative and that of free APD was observed when using o-xylene. The optimum derivatization and the HPLC conditions for selective HPLC determination of FA were to conduct the derivatization of FA by heating in an aqueous phase with APD in o-xylene at 100 °C. In this method, FA could be derivatized with APD at a mildly neutral pH of 6.7, unlike the low pH required for the derivatization of aldehydes with 2,4-dinitrophenylhydrazine (DNPH), which is commonly used for the derivatization of aldehydes. The detection and quantification limits of FA were 0.8 and 3.5 ng mL^-1 in this HPLC method with fluorescent detection, respectively. This selective HPLC method could be applied to the determination of FA in various water samples. It was found that only APD among the derivatizing reagents containing two secondary diamines was useful for the selective determination of FA.

Occurrence and fate of ozonation disinfection by-products in two Canadian drinking water systems

The occurrence and the fate of 18 ozonation by-products (OBPs) (17 different aldehydes and bromate) were studied over one year in two Canadian drinking water systems. This is the first and only study reporting the occurrence of all these non-halogenated aldehydes (NON-HALs) and haloacetaldehydes (HALs) simultaneously, based on the multi-point monitoring of water in full-scale conditions from source to distribution network. In general, the application of both post-ozonation and liquid chlorine contributed to the formation of OBPs (aldehydes and bromate). NON-HALs were present in higher concentrations than HALs. Formaldehyde, acetaldehyde, glyoxal and methylglyoxal were the most common forms of NON-HALs in the two water systems that were studied. Chloral hydrate (CH), the hydrated form of trichloroacetaldehyde, was the most dominant HAL observed. The nature of the organic matter and the water temperature proved to be important parameters for explaining the variability of aldehydes. Summer and autumn (warm seasons) were more favorable for the formation of chloral hydrate and bromate. The highest concentrations of NON-HALs were observed in spring.

Multi-Spheres Adsorptive Microextraction (MSAμE)-Application of a Novel Analytical Approach for Monitoring Chemical Anthropogenic Markers in Environmental Water Matrices

Multi-spheres adsorptive microextraction using powdered activated carbons (ACs) was studied as a novel enrichment approach, followed by liquid desorption and high-performance liquid chromatography with diode array detection (MSAµE(AC)-LD/HPLC-DAD) to monitor caffeine (CAF) and acetaminophen (ACF) traces in environmental matrices. In this study, commercial activated carbons (N, N_OX, and R) were tested, with the latter showing a much better performance for the analysis of both anthropogenic drugs. The main parameters affecting the efficiency of the proposed methodology are fully discussed using commercial AC(R). Textural and surface chemistry properties of the ACs sample were correlated with the analytical results. Assays performed on 30 mL of water samples spiked at 10 µg L⁻¹ under optimized experimental conditions, yielding recoveries of 75.3% for ACF and 82.6% for CAF. The methodology also showed excellent linear dynamic ranges for both drugs with determination coefficients higher than 0.9976, limits of detection and quantification of 0.8–1.2 µg L⁻¹ and 2.8–4.0 µg L⁻¹, respectively, and suitable precision (RSD < 13.8%). By using the standard addition method, the application of the present method to environmental matrices, including superficial, sea, and wastewater samples, allowed very good performance at the trace level. The proposed methodology proved to be a feasible alternative for polar compound analysis, showing to be easy to implement, reliable, and sensitive, with the possibility to reuse and store the analytical devices loaded with the target compounds for later analysis.

Bar adsorptive microextraction technique - application for the determination of pharmaceuticals in real matrices

In the present work, bar adsorptive microextraction using miniaturized devices (7.5 × 3.0 mm) coated with suitable sorbent phases, combined with microliquid desorption (100 μL) followed by high-performance liquid chromatography with diode array detection (BAμE-μLD/HPLC-DAD), is proposed for the determination of trace level of six pharmaceuticals (furosemide, mebeverine, ketoprofen, naproxen, diclofenac and mefenamic acid) in environmental water and urine matrices. By comparing ten distinct sorbent materials (five polymeric and five activated carbons), the polymer P5 proved to be the most suitable to achieve the best selectivity and efficiency. The solvent volume minimization in the liquid desorption stage demonstrated remarkable effectiveness, being more environmentally friendly, and simultaneously increased the microextraction enrichment factor two-fold. Assays performed through BAμE(P5, 0.9 mg)-μLD(100 μL)/HPLC-DAD on 25 mL of ultrapure water samples spiked at the 4.0 μg/L level yielded average recoveries ranging from 91.4% (furosemide) to 101.0% (ketoprofen) with good precision (RSD < 10.6%), under optimized experimental conditions. The analytical performance showed convenient detection limits (25.0 - 120.0 ng/L), good linear dynamic ranges (0.1 to 24.0 μg/L), appropriate determination coefficients (r ² > 0.9983), and excellent repeatability through intraday (RSD < 10.4%)) and interday (RSD < 10.0%) assays. By using the standard addition methodology, the application of the present analytical approach on environmental waters and urine samples revealed the occurrence of trace levels of some pharmaceuticals. The solvent minimization during the back-extraction step associated with the miniaturization of BAμE devices proved to be a very promising analytical technology for static microextraction analysis. Graphical abstract BAμE operating under the floating sampling technology for the determination of pharmaceuticals in aqueous media.

Determination of Trace Levels of Irgarol in Estuarine Water Matrices by Bar Adsorptive Microextraction

Bar adsorptive microextraction (BAµE), using selective sorbent phases, followed by liquid desorption in combination with large volume injection-gas chromatography coupled to mass spectrometry (BAµE-LD/LVI-GC-MS), is proposed for the determination of trace levels of irgarol in estuarine water matrices. While we compared several polymers and activated carbons, one of the latter coatings showed much higher selectivity through BAµE. Assays performed on 25 mL of ultra-pure water sample fortified at 0.6 µg/L levels of irgarol yielded recoveries of 74.5 ± 8.6%, under optimized experimental conditions. The proposed analytical procedure showed convenient detection limits (16.0 ng/L) and good linear dynamic range (0.2-16.0 µg/L), with determination coefficients of 0.9982. Good precision was also achieved with RSD lower than 12.0%. The application of the present analytical approach on estuarine water samples by using the standard addition methodology revealed good sensitivity and linearity. The proposed methodology, using nanostructured sorbents and operating under the floating sampling technology, proved to be a suitable analytical alternative to monitor irgarol in estuarine water matrices. Moreover, it is easy to implement, reliable, sensitive, require low sample volume and have the possibility to choose the most selective sorbent coating according to the target compound involved.

Application of bar adsorptive microextraction (BAμE) for anti-doping control screening of anabolic steroids in urine matrices

This study proposes a new analytical methodology for the determination of trace levels of testosterone (T) and epitestosterone (E) in urine matrices using bar adsorptive microextraction combined with liquid desorption followed by high-performance liquid chromatography with diode array detection (BAμE-LD/HPLC-DAD). The comparison of different sorbent coatings (five activated carbons, one styrene-divinylbenzene, two modified pyrrolidone, one ciano and one n-vinylpyrrolidone polymers) through BAμE showed that the latter phase presented much higher selectivity and capacity offering multiple mechanisms of interaction. Assays using this phase were performed on 25mL of water samples spiked at the 8.0μg/L level, yielded average recoveries of 92.1 and 93.4% for T and E, respectively, under optimized experimental conditions; BAμE (n-vinylpyrrolidone): 16h (1000rpm), pH 5.5; LD: acetonitrile, 30min under sonication treatment. From the developed analytical methodology, suitable detection limits were achieved (0.4μg/L) and good linear dynamic ranges (1.4-16.0μg/L) with remarkable determination coefficients (r(2)>0.9978). By using the standard addition methodology, the application of the present analytical approach on urine samples revealed good sensitivity. The proposed method, which operated under the floating sampling technology, proved to be a suitable sorption-based static microextraction alternative for screening T, E and the T/E ratio in urine samples for doping control purposes. The methodology showed to be easy to implement, demonstrating good reproducibility, sensitivity and robustness, allowing the possibility to choose the most selective sorbent coating according to the compounds of interest.

Improvements on bar adsorptive microextraction (BAμE) technique--application for the determination of insecticide repellents in environmental water matrices

Bar adsorptive microextraction combined with micro-liquid desorption followed by large volume injection-gas chromatography-mass spectrometry operating in the selected-ion monitoring acquisition mode (BAµE-µLD/LVI-GC-MS(SIM)), is proposed for the determination of trace levels of three insecticide repellents (N,N-diethyl-meta-toluamide (DEET), cis and trans permethrin (PERM)) in environmental water matrices. By comparing different sorbent coatings (five activated carbons and six polymers) through BAµE, an activated carbon (AC2) proved to be the best compromise between selectivity and efficiency, even against polydimethylsiloxane through stir bar sorptive extraction. The novel improvement proposed on the back-extraction stage performed in a single step, by reducing the desorption solvent volume at the microliter level, demonstrated remarkable performance turning possible to save time, making easier the practical manipulation and more environmentally friendly. Assays performed by BAµE(AC2)-µLD/LVI-GC-MS(SIM) on 25 mL of ultrapure water samples spiked at the 1.0 μg/L level, yielded recoveries ranging from 73.8±8.8% (trans-PERM) to 96.4±9.9% (DEET), under optimised experimental conditions. The analytical performance showed convenient detection limits (8-20 ng/L) and good linear dynamic ranges (0.04-4.0 µg/L) with suitable determination coefficients (r(2)>0.9963, DEET). Excellent repeatability were also achieved through intraday (RSD<14.9%) and interday (RSD<11.9%) experiments. The novel improvement on downsizing the BAµE device to half-size proved to be either a promising option in forthcoming to reduce still more the desorption solvent volume without losing microextraction efficiency. By using the standard addition methodology, the application of the present analytical approach on tap, ground, river, swimming-pool and estuary water samples revealed good sensitivity at trace level and absence of matrix effects.

Determination of trace levels of benzophenone-type ultra-violet filters in real matrices by bar adsorptive micro-extraction using selective sorbent phases

Bar adsorptive micro-extraction (BAμE), using selective sorbent phases, followed by liquid desorption in combination with high performance liquid chromatography-diode array detection (BAμE-LD/HPLC-DAD), is proposed for the determination of trace levels of four benzophenone-type UV filters (benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2,4-hydroxybenzophenone and 4-hydroxybenzophenone) in real matrices. By comparing three polymers (P1, P2 and P3) and five activated carbons (AC1, AC2, AC3, AC4 and AC5) phases, P2 (a modified pyrrolidone polymer) and AC4 coatings showed much higher selectivity and capacity through BAμE, where the former offers multiple mechanisms of interaction and faster equilibrium kinetics. Assays performed on 25mL of ultra-pure water samples spiked at the 8.0μg/L level, yielded recoveries ranging from 76.6±8.3% to 103.5±6.4% depending on the sorbent phase used (P2 or AC4), under optimized experimental conditions. The analytical performance showed convenient detection limits (0.3-0.5μg/L) and good linear dynamic ranges (1.0-24.0μg/L) with remarkable determination coefficients (r(2)>0.9969). Excellent repeatability was also achieved through intraday (RSD<13.0%) and interday (RSD<8.9%) experiments. By using the standard addition methodology, the application of the present analytical approach on sea water, wastewater, commercial cosmetic products and urine samples revealed good sensitivity, absence of matrix effects and the occurrence of levels of some benzophenones. The proposed methodology that uses nanostructured particles and operates under the floating sampling technology proved to be a sorption-based static micro-extraction alternative to monitor benzophenone-type UV filters in real matrices. Moreover, is easy to implement, reliable, sensitive, requiring low sample volume and the possibility to choose the most selective sorbent coating according to the target compounds involved.

Novel sorption-based methodologies for static microextraction analysis: A review on SBSE and related techniques

Stir bar sorptive extraction (SBSE) became a well-established analytical technique in the last years, for which hundreds of applications in almost all types of scientific fields can be found in the literature. In spite of the great enrichment capacity and outstanding performance to operate at the ultra-trace level, this remarkable static sorption-based method is already not quite effective for some complex systems, in particular to monitor the large group of polar organic compounds. This review aims to cover the state-of-the-art in SBSE, as well as supplying a discussion of the analytical potential of the novel adsorptive microextraction techniques, as complementary enrichment approaches, by explaining the main principles and providing technical know-how for the beginners.

Comparison of the selectivity of different sorbent phases for bar adsorptive microextraction--application to trace level analysis of fungicides in real matrices

Bar adsorptive micro-extraction combined with liquid desorption followed by large volume injection-gas chromatography-mass spectrometry operating in the selected-ion monitoring acquisition mode (BAμE-LD/LVI-GC-MS(SIM)) was developed for the determination of trace levels of ten fungicides (azoxystrobin, difenoconazole, metalaxyl-M, myclobutanil, penconazole, tebuconazole, flusilazole, cyprodinil, procymidone and benalaxyl) in aqueous matrices. By comparing different sorbent coatings (two activated carbons, two styrene-divinylbenzene and one modified pyrrolidone polymers) through BAμE, the latter phase showed much higher selectivity and capacity offering multiple mechanisms of interaction, even against polydimethylsiloxane by stir bar sorptive extraction. Assays performed on 25 mL of water samples spiked at the 0.8 μg/L level, yielded recoveries ranging from 100.0 to 107.8%, under optimized experimental conditions; BAμE(modified pyrrolidone) - equilibrium time: 4h (1000 rpm), pH 5.5; LD - solvent:methanol/acetonitrile (1/1), 15 min with sonification. The analytical performance showed convenient detection limits (4.0-30.0 ng/L) and excellent linear dynamic ranges (0.04-1.60 μg/L) with remarkable correlation coefficients (r(2)>0.9980). Excellent repeatability was also achieved through intraday (RSD<13.7%) and interday (RSD<9.9%) assays. By using the standard addition methodology, the application of the present analytical approach on tap and ground water, as well as, wine samples revealed good sensitivity and absence of matrix effects. The proposed method operating under floating sampling technology proved to be a suitable sorption-based static microextraction alternative to monitor fungicides in real matrices, showing to be easy to implement, reliable, sensitive, requiring low sample volume and the possibility to choose the most selective sorbent coating according to the targets of interest.

Development of a powdered activated carbon in bar adsorptive micro-extraction for the analysis of morphine and codeine in human urine

In the present work, bar adsorptive microextraction using an activated carbon (AC) adsorbent phase followed by liquid desorption and high-performance liquid chromatography with diode array detection was developed to monitor morphine (MOR) and codeine (COD) in human urine. Under optimized experimental conditions, assays performed in aqueous media spiked at the 30.0 µg/L level yielded recoveries of 41.3 ± 1.3% for MOR and 38.4 ± 1.7% for COD, respectively. The textural and surface chemistry properties of the AC phase were also correlated with the analytical data for a better understanding of the overall enrichment process. The analytical performance showed good precision (relative standard deviation < 8.0%), suitable detection limits (0.90 and 0.06 µg/L for MOR and COD, respectively) and convenient linear dynamic ranges (r(2) > 0.991) from 10.0 to 330.0 µg/L. By using the standard addition methodology, the applications of this analytical approach to water and urine matrices allowed remarkable performance to monitor MOR and COD at the trace level. This new confirmatory method proved to be a suitable alternative to other sorptive micro-extraction methodologies in monitoring trace levels of opiate-related compounds, because it was easy to implement, reliable, sensitive and required a low sample volume.

Cork-based activated carbons as supported adsorbent materials for trace level analysis of ibuprofen and clofibric acid in environmental and biological matrices

In this contribution, powdered activated carbons (ACs) from cork waste were supported for bar adsorptive micro-extraction (BAμE), as novel adsorbent phases for the analysis of polar compounds. By combining this approach with liquid desorption followed by high performance liquid chromatography with diode array detection (BAμE(AC)-LD/HPLC-DAD), good analytical performance was achieved using clofibric acid (CLOF) and ibuprofen (IBU) model compounds in environmental and biological matrices. Assays performed on 30 mL water samples spiked at the 25.0 μg L(-1) level yielded recoveries around 80% for CLOF and 95% for IBU, under optimized experimental conditions. The ACs textural and surface chemistry properties were correlated with the results obtained. The analytical performance showed good precision (<15%), suitable detection limits (0.24 and 0.78 μg L(-1) for CLOF and IBU, respectively) and good linear dynamic ranges (r(2)>0.9922) from 1.0 to 600.0 μg L(-1). By using the standard addition methodology, the application of the present approach to environmental water and urine matrices allowed remarkable performance at the trace level. The proposed methodology proved to be a viable alternative for acidic pharmaceuticals analysis, showing to be easy to implement, reliable, sensitive and requiring low sample volume to monitor these priority compounds in environmental and biological matrices.