Hydrocarbons In Urine Samples Research Articles

Magnetic solid phase extraction coupled to HPLC-UV for highly sensitive analysis of mono-hydroxy polycyclic aromatic hydrocarbons in urine

BackgroundAs a common pollutant, the carcinogenic properties of polycyclic aromatic hydrocarbons have garnered considerable attention. Trace metabolites of polycyclic aromatic hydrocarbons can be detected in urine as a non-invasively approach to monitor the exposure level. Nonetheless, the urine samples have the disadvantages of being large in volume and containing numerous impurities. Given the growing demand to study metabolites with low abundance and potential biomarkers, there is a pressing need for a preconcentration and high-throughput technique for effectively handling complex liquid samples. ResultsPolystyrene-coated magnetic nanoparticles were used to establish a novel magnetic extraction method for monohydroxy polycyclic aromatic hydrocarbons in urine samples. Polystyrene magnetic nanoparticles are an ideal absorbent for solid-phase extraction. After the material was mixed with the sample and adsorbed the target analyte, the analytes on the material were eluted and quantified using high-performance liquid chromatography. Influencing factors were optimized, and the proposed method achieved desirable sensitivity in analyzing low-abundance metabolites in large volumes of complex urine samples. The recoveries of intra-day and inter-day were 78.0–118.0 % and 81.0 %–115.0 %, respectively. The intra-day and inter-day reproducibility were less than 4.5 % and 8.6 %, respectively. The limits of detection were in the range of 0.009–0.041 ng mL−1, and the limits of quantification were in the range of 0.030–0.135 ng mL−1. Significance and noveltyThe application of reusable polystyrene-coated magnetic solid-phase nanoparticles as adsorbents makes the extraction of monohydroxy polycyclic aromatic hydrocarbons from urine samples economical and environmentally benign. The proposed method is simple, sensitive, and efficient compared to existing techniques. The nanoparticles are easy to prepare, showing potential for rapid screening of complex bulk bio-samples in batches with high efficiency and low budget.

Determination of halogenated hydrocarbons in urine samples using a needle trap device packed with Ni/Zn-BTC bi-MMOF via the dynamic headspace method.

In this study, a nickel/zinc–BTC bi-metallic metal–organic framework (bi-MMOF) was employed as a new and efficient adsorbent in a needle trap device (NTD) for headspace (HS) sampling, extraction and analysis of halogenated hydrocarbons (trichloroethylene, tetrachloroethylene, chloroform, and tetrachloroethylene) from spiked and real urine samples. Characterization of the prepared adsorbent was accomplished by FT-IR, PXRD, EDX, elemental mapping, and FE-SEM techniques. According to experimental results, the optimal temperature and extraction time, salt content, temperature and desorption time of the response surface methodology (RSM) and Box–Behnken design (BBD) were determined to be 56 °C and 30 min, 5.5%, 350 °C and 8 min for the studied halogenated hydrocarbons, respectively. The calculated values of detection limit and quantitation limit parameters were in the range of 1.02–1.10 and 2.01–2.4.0 ng L−1, respectively. Moreover, intermediate precision and repeatability of the method were in the range of 4.90–8.20% and 1.50–4.80%, respectively. The recovery percentages of analytes were obtained to be in the range of 95.0–97.0% 10 days after the sampling and storage at 4 °C. This study showed that the proposed HS-NTD:Ni/Zn–BTC method coupled with a GC-FID can be employed as a simple, fast, and sensitive procedure for non-metabolized halogenated hydrocarbons from urine samples in biological monitoring.

Determination of Urinary Hydroxyl PAHs Using Graphene Oxide@Diatomite Based Solid-Phase Extraction and High-Performance Liquid Chromatography.

A diatomite supported graphene oxide composite (GO@Dt–NH2) was fabricated and explored as a solid-phase extraction adsorbent coupled with high performance liquid chromatography to determine the trace hydroxyl polycyclic aromatic hydrocarbons (2-hydroxy-naphthalene, 2-hydroxy-fluorene, 1-hydroxy-phenanthrene, and 1-hydroxy-pyrene) in urine samples. The fabricated composites were characterized by X-ray powder diffractometry and scanning electron microscopy. GO@Dt–NH2 offered enhanced adsorption affinity towards the analytes compared with the bare diatomite. The amount of graphene oxide and the factors affecting solid-phase extraction were investigated in detail. Under the optimized conditions, the method gave good linearity (0.30–200 ng/mL) and a low detection limit (0.10–0.15 ng/mL) for the hydroxyl polycyclic aromatic hydrocarbons. The average recovery for spiked urine samples with three levels ranged from 90.6% to 100%. The intra-day and inter-day relative standard deviations were in the range of 1.8–6.4% and 2.7–11.8%, respectively. Besides, the GO@Dt–NH2 provided enrichment factors of 18–20 and superior purification ability. The developed method was successfully applied to the determination of hydroxyl polycyclic aromatic hydrocarbons in urine samples from smoking volunteers.

Determination of trace hydroxyl polycyclic aromatic hydrocarbons in urine using graphene oxide incorporated monolith solid-phase extraction coupled with LC-MS/MS.

The biomonitoring of hydroxy polycyclic aromatic hydrocarbons in urine, as a direct way to access multiple exposures to polycyclic aromatic hydrocarbons, has raised great concerns due to their increasing hazardous health effects on humans. Solid-phase extraction is an effective and useful technique to preconcentrate trace analytes from biological samples. Here, we report a novel solid-phase extraction method using a graphene oxide incorporated monolithic syringe for the determination of six hydroxy polycyclic aromatic hydrocarbons in urine coupled with liquid chromatography-tandem mass spectrometry. The effect of graphene oxide amount, washing solvent, eluting solvent, and its volume on the extraction performance were investigated. The fabricated monoliths gave higher adsorption efficiency and capacity than the neat polymer monolith and commercial C18 sorbent. Under the optimum conditions, the developed method provided the detection limits (S/N = 3) of 0.02-0.1ng/mL and the linear ranges of 0.1-1500ng/mL for six analytes in urine sample. The recoveries at three spiked levels ranged from 77.5 to 97.1%. Besides, the intra column-to-column (n = 3) and inter batch-to-batch (n = 3) precisions were ≤ 9.8%. The developed method was successfully applied for the determination of hydroxy polycyclic aromatic hydrocarbons in urine samples of coke oven workers.

Quantitative and qualitative analysis of polycyclic aromatic hydrocarbons in urine samples using a non-separative method based on mass spectrometry

In this work, a method for the quantitative and qualitative analysis of 11 polycyclic aromatic hydrocarbons (PAHs) in urine samples is reported. The method is based on the coupling of a programmed temperature vaporizer (PTV) with a quadrupole mass spectrometer (qMS), via a deactivated fused silica tubing. Before the PTV-qMS analysis, the samples were subjected to a liquid-liquid extraction (LLE).The method was rapid since no chromatographic separation was performed. The samples were introduced directly into the PTV, and the analytes were trapped in the Tenax-TA® packed liner while the solvent was purged. After that, all the compounds reached the mass spectrometer, obtaining the fingerprint of the analysed samples.Urine samples free of PAHs and the same samples spiked with the compounds were analysed. The resulting profile signals were used to quantify the analytes using multivariate calibration, and to classify the samples according to the presence or absence of the PAHs. In the latter task, non-supervised and supervised pattern recognition techniques were employed. The calibration models worked satisfactorily and errors lower or equal to 15% were obtained, in most cases, when an external validation set was analysed. Regarding the classification of the samples, most of the supervised pattern recognition techniques provided excellent results (100% success), where all of the samples were classified correctly.

Achieving second order advantage with multi-way partial least squares and residual bi-linearization with total synchronous fluorescence data of monohydroxy–polycyclic aromatic hydrocarbons in urine samples

An attractive approach to handle matrix interference in samples of unknown composition is to generate second- or higher-order data formats and process them with appropriate chemometric algorithms. Several strategies exist to generate high-order data in fluorescence spectroscopy, including wavelength time matrices, excitation–emission matrices and time-resolved excitation–emission matrices. This article tackles a different aspect of generating high-order fluorescence data as it focuses on total synchronous fluorescence spectroscopy. This approach refers to recording synchronous fluorescence spectra at various wavelength offsets. Analogous to the concept of an excitation–emission data format, total synchronous data arrays fit into the category of second-order data. The main difference between them is the non-bilinear behavior of synchronous fluorescence data. Synchronous spectral profiles change with the wavelength offset used for sample excitation. The work presented here reports the first application of total synchronous fluorescence spectroscopy to the analysis of monohydroxy-polycyclic aromatic hydrocarbons in urine samples of unknown composition. Matrix interference is appropriately handled by processing the data either with unfolded-partial least squares and multi-way partial least squares, both followed by residual bi-linearization.

Preparation of an ionic liquid-mediated carbon nanotube-poly(dimethylsiloxane) fiber by sol–gel technique for determination of polycyclic aromatic hydrocarbons in urine samples using head-space solid-phase microextraction coupled with gas chromatography

A novel ‘ionic liquid-mediated multi-walled carbon nanotube (MWCNT)-poly(dimethylsiloxane) (PDMS)’ hybrid coating was prepared by the covalent functionalization of MWCNTs with hydroxyl-terminated PDMS using the sol–gel technique. The prepared fiber was successfully used for the separation and determination of trace amounts of polycyclic aromatic hydrocarbon compounds (PAHs) in four urine samples using head-space solid-phase microextraction coupled to gas chromatography-flame ionization detection. The proposed fiber has high thermal stability and long durability and it can be used more than 210 times without any significant change in its sorption properties. The effects of important parameters such as the exposure time, sampling temperature, sample ionic strength and stirring rate on the extraction efficiency have been studied and optimized. Under the optimal conditions, the method detection limits (S/N = 3) were in the range of 0.0005–0.004 ng mL−1 and the limits of quantification (S/N = 10) between 0.002 and 0.01 ng mL−1. The relative standard deviations for one fiber (repeatability, n = 5) were 4.9–7.5 % and for the fibers obtained from different batches (reproducibility, n = 3), 6.1–8.9 %. The developed method was successfully applied to determine trace levels of PAHs in real urine samples. The obtained relative recoveries for the spiked samples with 0.05 ng mL−1 of each of the PAH compounds were 89.3–107.2 %.

Magnetic solid-phase extraction based on diphenyl functionalization of Fe3O4 magnetic nanoparticles for the determination of polycyclic aromatic hydrocarbons in urine samples

Superparamagnetic Fe3O4 diphenyl nanoparticles were prepared according to a solvothernal procedure and characterized by X-ray diffraction, infrared spectroscopy, surface area measurements, scanning electron microscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. The magnetic phases present in the nanoparticle samples were analyzed by thermomagnetic analysis and the samples’ magnetic properties were studied by vibrating sample magnetometry. The resulting nanoparticles having an average diameter of 200nm were then used as solid-phase extraction sorbent for the determination of polycyclic aromatic hydrocarbons in urine samples. Method validation proved the feasibility of the developed beads for the quantitation of the investigated analytes at trace levels obtaining lower limit of quantitation values in the ng/l range. A good precision with coefficients of variations always lower than 15% was obtained. Finally, the superior extraction performance of the synthesized nanoparticles with respect to commercially available beads was proved.

Multi-way partial least-squares and residual bi-linearization for the direct determination of monohydroxy-polycyclic aromatic hydrocarbons on octadecyl membranes via room-temperature fluorescence excitation emission matrices

Multi-way partial least-squares (N-PLS) is combined to the residual bi-linearization procedure (RBL) for the direct analysis of metabolites of polycyclic aromatic hydrocarbons in urine samples. Metabolite analysis is carried out via a two-step experimental procedure based on solid-phase extraction and room temperature fluorescence spectroscopy. Excitation-emission matrices are recorded from octadecyl (C18) membranes that serve as solid substrates for sample extraction and spectroscopic measurements. Excellent metabolite recoveries were obtained in all cases, which varied from 96.2±1.35% (9-hydroxyphenanthrene) to 99.7±0.49% (3-hydroxybenzo[a]pyrene). Background correction of extraction membranes is carried out with a new alternating least-squares (ALS) procedure adapted to second order data. The performance of N-PLS/RBL is compared to the well-established multivariate curve resolution-alternating least-squares (MCR-ALS) algorithm. Both algorithms provided similar analytical figures of merit, including their ability to handle unknown interference in urine samples. With only 10mL of sample, the limits of detection varied between 0.06–0.08ngmL−1 (1-hydroxypyrene) and 0.016–0.018ngmL−1 (2-hydroxyfluorene). When compared to previously reported univariate calibration data, the limits of detection via N-PLS/RBL and MCR-ALS are approximately one order of magnitude higher. This was somehow expected due to the effect of unexpected components in multivariate figures of merit, i.e. a more realistic approach to the analysis of metabolites in human urine samples.

Solid-phase extraction, sample stacking and capillary zone electrophoresis for the analysis of urinary polycyclic aromatic hydrocarbon metabolites

A capillary zone electrophoresis method is presented for the analysis of six biomarkers of polycyclic aromatic hydrocarbons in urine samples. Baseline resolution of 2-hydroxyfluorene, 2-hydroxynaphthalene, 1-hydroxypyrene, 9-hydroxyphenanthrene, 3-hydroxybenzo[a]pyrene, 4-hydroxybenzo[a]pyrene and 5-hydroxybenzo[a]pyrene was achieved in approximately 17 min with a 20 mM borate buffer prepared in 50% methanol-water (volume/volume). Competitive limits of detection were obtained for all the studied metabolites using commercial instrumentation equipped with an ultraviolet-visible absorption detector. Detection at the sub-parts-per-billion concentration levels was made possible via sample pre-concentration based on solid-phase extraction and sample stacking. Solid-phase extraction was performed with the aid of a twelve port vacuum manifold. Sample stacking was carried out in methanol, i.e. the eluting solvent from the solid-phase extraction procedure. To the extent of our literature search, this is the first application of sample stacking to the analysis of monohydroxy-polycyclic aromatic hydrocarbons in urine samples. Metabolite recoveries varied from 93.2 ± 7.7% (5-hydroxybenzo[a]pyrene) to 108.7 ± 7.8% (2-hydroxynaphthalene). Limits of detection were at the trace level ranging from 0.99 ng mL(-1) (3-hydroxybenzo[a]pyrene) to 8.54 ng mL(-1) (2-hydroxynaphthalene). The new method was found to be free of interference from four pharmacological drugs - naproxen, ibuprofen, diclofenac and amoxicillin - that might be found in urine samples of unhealthy individuals.

Using gold nanoparticles to improve the recovery and the limits of detection for the analysis of monohydroxy-polycyclic aromatic hydrocarbons in urine samples

We present a novel approach to improve the analytical figures of merit of solid-phase extraction high-performance liquid chromatography (SPE-HPLC) for the analysis of monohydroxy-polycyclic aromatic hydrocarbons in urine samples. The novel alternative substitutes the evaporation step that is currently used in SPE-HPLC methodology with a pre-concentration procedure that extracts metabolites with gold nanoparticles. The analytical potential of the new approach is evaluated with the following six metabolites: 9-hydroxyphenanthrene, 2-hydroxyfluorene, 1-hydroxypyrene, 6-hydroxychrysene, 3-hydroxybenzo[ a]pyrene and 4-hydroxybenzo[ a]pyrene. We demonstrate that the substitution of the evaporation step with the gold nanoparticles procedure improves the overall recoveries, the relative standard deviations of the average recoveries and the limits of detection of SPE-HPLC analysis. The overall recoveries of the studied metabolites varied from 59.7 ± 3.6% (2-hydroxyfluorene) to 92.3 ± 2.5% (6-hydroxychrysene). The relative standard deviations of the average recoveries were lower than 6%. The limits of detection were at the parts-per-trillion levels and varied from ∼2 pg mL −1 (6-hydroxychrysene) to ∼18 pg mL −1 (2-hydroxyfluorene).

Immunochemical detection of metabolites of parent and nitro polycyclic aromatic hydrocarbons in urine samples from persons occupationally exposed to diesel exhaust

An immunochemical assay was developed for the detection of metabolites excreted in urine as a result of occupational exposure to PAHs and nitro-PAHs. These metabolites were analyzed in a competitive ELISA, using an existing antibody (4D5) that has been developed against 6-aminobenzo[a]pyrene coupled to bovine serum albumine (B[a]P-BSA). A solid phase extraction (SPE) work-up procedure was optimized by dilution of pooled urine samples from rats exposed to 1-NP, in human urine. The application was validated by comparison of test results with urinary excreted 1-hydroxypyrene (1-OH-P) levels in a study among 28 railroad workers. Excretion of urinary metabolites was determined over two consecutive workdays. The 24 h average excretion of metabolites as determined in the immunoassay was not related to levels of particulate matter in the breathing zones of workers, not to 1-OH-P excretion levels of the day of urine collection. However, it was significantly associated with the personal dust exposure of the day before (P<0.0001), suggesting slow excretion of urinary metabolites. Smoking habits caused minor interference (P<0.1).