A novel miniaturized homogenous liquid–liquid solvent extraction-high performance liquid chromatographic-fluorescence method for determination of ultra traces of polycyclic aromatic hydrocarbons in sediment samples

Predicting the total PAHs concentrations in sediments from selected congeners using a multiple linear relationship

In this study, we observed that four congeners, including naphthalene (Nap), acenaphthylene (Acy), phenanthrene (Phe), and benz(a)anthracene (BaA), are the characteristic congeners for predicting the emission and the sediment concentrations of polycyclic aromatic hydrocarbons (PAHs). A novel multiple relationship of the total PAHs concentrations (C_∑PAHs) in sediments with the concentrations of four congeners was established (p < 0.01, R² = 0.95) using published data over the past 30 years. Moreover, the multiple linear relationship of the total PAHs emission factors with the emission factors of four congeners was also established (p < 0.01, R² = 0.99). Interestingly, the ratio of multicomponents coefficient from the multiple linear relationship in sediments to that from the multiple linear relationship in emission sources correlated positively with octanol–water partition coefficient (logK_ow) (p < 0.01, R² = 0.88) of the four PAHs congeners. Therefore, a novel model was established to predict C_ΣPAHs in sediments using the emissions and logK_ow of the four characteristic PAHs congeners. The percent sample deviation between calculated C_∑PAHs and their observed values was 54%, suggesting the established model can accurately predict C_ΣPAHs in sediments.

Advances in pretreatment and analysis methods of aromatic hydrocarbons in soil

Benzene compounds that are prevalent in the soil as organic pollutants mainly include BTEX (benzene, toluene, ethylbenzene, and three xylene isomers) and PAHs (polycyclic aromatic hydrocarbons). These pose a severe threat to many aspects of human health. Therefore, the accurate measurement of BTEX and PAHs concentrations in the soil is of great importance. The samples for analysis of BTEX and PAHs need to be suitable for the various detection methods after pretreatment, which include Soxhlet extraction, ultrasonic extraction, solid-phase microextraction, supercritical extraction, and needle trap. The detection techniques mainly consist of gas chromatography (GC), mass spectrometry (MS), and online sensors, and provide comprehensive information on contaminants in the soil. Their performance is evaluated in terms of sensitivity, selectivity, and recovery. Recently, there has been rapid progress in the pretreatment and analysis methods for the quantitative and qualitative analyses of BTEX and PAHs. Therefore, it is necessary to produce a timely and in-depth review of the emerging pretreatment and analysis methods, which is unfortunately absent from the recent literature. In this work, state-of-art extraction techniques and analytical methods have been summarized for the determination of BTEX and PAHs in soil, with a particular focus on the potential and limitations of the respective methods for different aromatic hydrocarbons. Accordingly, the paper will describe the basic methodological knowledge, as well as the recent advancement of pretreatment and analysis methods for samples containing BTEX and PAHs.

QuEChERS with Ultrasound-Assisted Extraction Combined with High-Performance Liquid Chromatography for the Determination of 16 Polycyclic Aromatic Hydrocarbons in Sediment

Background

Polycyclic aromatic hydrocarbons (PAHs) have attracted worldwide attention due to their carcinogenic, teratogenic, and mutagenic effects, environmental persistence, and bioaccumulation characteristics. Therefore, the sensitive, reliable, and rapid detection of PAHs in sediment is of great importance.

Objective

To develop a high-performance liquid chromatography (HPLC) with fluorescence and ultraviolet detection after Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) treatment for simultaneous determination of 16 U.S. Environmental Protection Agency priority PAHs in sediment samples.

Method

The samples were ultrasonically extracted with acetone and then the supernatant was purified with a modified QuEChERS method. After centrifugation, the supernatant was injected into the HPLC system for analysis. The separation was accomplished on a ZORBAX Eclipse PAH column (150 × 4.6 mm, 3.5 μm) and the column temperature was set at 30 °C. The flow rate of the mobile phase consisting of water and acetonitrile in gradient elution mode was fixed at 0.9 mL/min. Detection was conducted on an ultraviolet detector and a fluorescence detector simultaneously. The qualitative analysis was based on retention time and the quantification was based on standard curves.

Results

Under the optimal conditions, this method showed good linearities in the range of 10–200 μg/L with correlation coefficients greater than 0.9993. The method had LODs ranging from 0.00108 to 0.314 ng/g. The mean recoveries ranged from 78.4 to 117% with intra-day and inter-day RSDs of 0.592–10.7% and 1.01–13.0%, respectively. The proposed method was successfully applied to the detection of 16 PAHs in sediment samples collected from the Funan River in Chengdu, China with total contents of 431–2143 ng/g·dw.

Conclusions

The established method is simple, rapid, environmentally friendly, and cost-effective. It can be applied to the analysis of 16 PAHs in sediment samples.

Highlights

A method of QuEChERS with ultrasound-assisted extraction combined with HPLC has been established for the analysis of 16 PAHs in sediment samples and the proposed method has been successfully applied to the analysis PAHs in real sediment samples.

Hasse diagram as a green analytical metrics tool: ranking of methods for benzo[a]pyrene determination in sediments

This study presents an application of the Hasse diagram technique (HDT) as the assessment tool to select the most appropriate analytical procedures according to their greenness or the best analytical performance. The dataset consists of analytical procedures for benzo[a]pyrene determination in sediment samples, which were described by 11 variables concerning their greenness and analytical performance. Two analyses with the HDT were performed—the first one with metrological variables and the second one with “green” variables as input data. Both HDT analyses ranked different analytical procedures as the most valuable, suggesting that green analytical chemistry is not in accordance with metrology when benzo[a]pyrene in sediment samples is determined. The HDT can be used as a good decision support tool to choose the proper analytical procedure concerning green analytical chemistry principles and analytical performance merits.

Simultaneous synthesis of a deep eutectic solvent and its application in liquid–liquid microextraction of polycyclic aromatic hydrocarbons from aqueous samples

New generation of solvents, named deep eutectic solvents, were simultaneously synthesized and used as an extraction solvent in a liquid–liquid microextraction method for the extraction and preconcentration of some polycyclic aromatic hydrocarbons.

Origin, distribution and toxicological potential of polycyclic aromatic hydrocarbons in surface sediments from the Bushehr coast, the Persian Gulf

To evaluate the hazards of polycyclic aromatic hydrocarbons (PAHs) in the Bushehr coastal zones, 12 surface sediments were analyzed. The ∑14PAHs concentrations varied from 371 to 611 ng g(-1) dw. The primary sources of the observed PAHs were pyrolytic processes, demonstrating the dominance of petroleum-related combustion inputs. The ERL/ERM and TEL/PEL values showed that there was a moderate level of toxicity risk for some PAHs. The toxicological significance of the pollutants was assessed using the toxic equivalency factor (TEF) to calculate both the toxic equivalent for dioxins (TEQTCDD) and the TEQ carcinogenic risks. Dibenz(a,h)anthracene exhibited the highest proportion in the TEQs, ranging from 49% to 56% (TEQcarc) and from 29% to 39% (TEQTCDD) regarding the overall toxicity in the sampled sediments. This result suggests that the ambient dibenz(a,h)anthracene concentration represents the risk posed by PAHs in the sediments. Moreover, using a specific sediment criterion demonstrated the bioaccumulation potential of benzo(a)pyrene for humans in the sampled sediments.

Extraction and determination of polycyclic aromatic hydrocarbons in water samples using stir bar sorptive extraction (SBSE) combined with dispersive liquid–liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) followed by HPLC-UV

The proposed method offers advantages, such as low consumption of organic solvents, high enrichment factors and good linearity, over the investigated concentration range.

Recent advances in unique sample preparation techniques for bioanalysis

The extraction and/or purification of drugs and medicines from biological matrices are important objectives in investigating their toxicological and pharmaceutical properties. Many widely used methods such as liquid–liquid extraction or SPE, used for extracting, purifying and enriching drugs and medicines found in biological materials, involve laborious, intensive and expensive preparatory procedures, and they require organic solvents that are toxic to both humans and the environment. Recent trends are focused on miniaturization, high-throughput and automation techniques. All the advantages and disadvantages of these techniques and devices in biological analysis are presented, and their applications in the extraction and/or purification of drugs and medicines from biological matrices are discussed in this review.

Determination of light-medium-heavy polycyclic aromatic hydrocarbons in vegetable oils by solid-phase extraction and high-performance liquid chromatography with diode array and fluorescence detection

A new method for determination of 16 polycyclic aromatic hydrocarbons (PAHs)-naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene-in vegetable oils was developed. Solid-phase extraction (SPE) prior to high-performance liquid chromatography with fluorescence detection could be used for all those PAHs except acenaphthylene. Acenaphthylene could be detected using a diode array detector at 228 nm. The parameters and variables that affect the extraction were investigated. Under optimum conditions: the extract reagent was centrifuged at 4 °C and evaporated. After that a SPE procedure was used for further cleanup. The limits of detection and limits of quantification were in the range of 0.01-2.35 and 0.04-7.00 μg kg(-1) in vegetable oil, respectively. The relative standard deviations were under 5%.

Rapid and simple low density miniaturized homogeneous liquid-liquid extraction and gas chromatography/mass spectrometric determination of pesticide residues in sediment

A simple, rapid and environmentally friendly analytical methodology is developed for extraction of pesticides (diazinon, chlorpyrifos and trifluralin) from sediment samples based on a technique called low density miniaturized homogenous liquid-liquid extraction (LDMHLLE) prior gas chromatography mass spectrometry determination. The method based on homogeneous liquid-liquid extraction with methanol containing n-hexane as a solvent of lower density than water (n-hexane). After addition of water, n-hexane solvent immediately forms a distinct water immiscible phase at the top of the vial, which can be easily separated and injected to the GC/MS instrument for quantification. Acquisition was performed in the selected ion monitoring mode. The limits of detection were estimated for the individual pesticides as 3S(b) (three times of the standard deviation of baseline) of the measured chromatogram for pesticides. The proposed method is very fast, simple, and sensitive without any need for stirring and centrifugation and applied to real sediment samples, successfully.