Determination of 16 Polycyclic Aromatic Hydrocarbons in Tea by Simultaneous Dispersive Solid-Phase Extraction and Liquid–Liquid Extraction Coupled with gas Chromatography–Tandem Mass Spectrometry

Development of a polyurethane-coated thin film solid phase microextraction device for multi-residue monitoring of pesticides in fruit and tea beverages

A novel solid-phase microextraction device coated with an efficient and cheap thin film of polyurethane was developed for trace determination of 13 widely used pesticides in fruit and tea beverages. A round-shaped polyurethane film covering the bottom of a glass vial was fabricated as the sorbent to exhibit a superior capacity for preconcentrating target compounds and reducing matrix interferences. After optimization of the key parameters including the film type, extraction time, solution pH, ionic strength, desorption solvent, and conditions, this device allowed an efficient adsorption-desorption cycle for the pesticides accomplished in one vial. Coupled with gas chromatography-electron capture detection, the polyurethane-coated thin film microextraction method was successfully established and applied for the analysis of real fruit and tea drinks, showing low limits of detection (0.001-0.015 μg/L), wide linear ranges (1.0-500.0 μg/L, r²  > 0.9931), good relative recoveries (77.2%-106.3%) and negligible matrix effects (86.1%-107.5%) for the target pesticides. The proposed approach revealed strong potential of extending its application by flexibly modifying the type or size of the coating film. This study provides insights into the enrichment of contaminants from complex samples using inexpensive and reusable microextraction devices that can limit the environmental and health impact of the sample preparation protocol.

Development of a syringe membrane-based microextraction method based on metal-organic framework mixed-matrix membranes for preconcentration/extraction of polycyclic aromatic hydrocarbons in tea infusion

Inevitably, the residues of polycyclic aromatic hydrocarbons (PAHs) in tea leaves will be transferred to hot tea infusion, constituting a certain drinking risk; consequently, it is imperative to develop rapid, sensitive, and robust approaches for their trace-level detection. Herein, we developed a syringe membrane-based microextraction (SMME) method for preconcentration/extraction of PAHs in tea infusions. This method utilized metal-organic framework-mixed matrix membranes (MOF-MMMs) as adsorbents, which anchored the nanoparticles of MOFs onto the surface of PVDF membrane. The UiO-66 (Zr)-based MMM possessed high Brunauer-Emmett-Teller (BET) surface area (320.5 m² g^-1) and pore volume (0.18 cm³ g^-1), thus enhancing extraction/adsorption efficiency. Under optimized conditions, the limits of detection for PAHs reached as low as 0.02-0.08 μg L^-1 with extraction recoveries of 85.5-102.1%, and the inter-day and intra-day precision was lower than 8.4% in tea infusions. Consequently, the SMME/HPLC-DAD method shows a great potential in conventional monitoring of PAHs in tea samples.

A density-tunable liquid-phase microextraction system based on deep eutectic solvents for the determination of polycyclic aromatic hydrocarbons in tea, medicinal herbs and liquid foods

A novel density-tunable liquid-phase microextraction (DT-LPME) system was developed with high-density deep eutectic solvents (DESs) as extractant and low-density organic solvents as emulsifier and density regulator. DES-rich phase was induced to form in the bottom or in the top by adjusting the emulsifier amount. This system was used to directly extract polycyclic aromatic hydrocarbons (PAHs) from liquid and solid foods, and the obtained DES-rich phase was easy to be collected for quantification. The method (LPME with HPLC-fluorescence detector) has linearity (R² > 0.9974), detection limits of 0.6-4.2 ng L^-1 for liquid foods and 0.05-0.35 ng g^-1 for solid foods, recoveries of 86.2-114.9%, and intra-day/inter-day RSDs below 6.6%. The method was applied to detect PAHs in real samples, and the PAHs residue was found in honey and five solid foods. The DT-LPME method is simple, fast, green and suitable for direct extraction of analytes from both liquid and solid samples.

Persistent organic pollutants (PCBs and PCDD/Fs), PAHs, and plasticizers in spices, herbs, and tea - A review of chromatographic methods from the last decade (2010-2020)

Edible and highly demanded plant-derived products such as herbs, spices, and tea may be subjected to exogenous contamination of well-known chemical hazards such as persistent organic pollutants (POPs), and emerging ones such as plasticizers, affecting negatively the safety of these food commodities. This fact has led to the increasing analysis of exogenous compounds including priority POPs such as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs), as well as highly persistent polycyclic aromatic hydrocarbons (PAHs). Currently, plasticizer residues are also considered an emerging issue because of the extensive use in food packaging and potential migration into foodstuffs. In this review, the studies published from 2010 to 2020 were discussed, including the main extraction methods applied for these contaminants from herbs, spices, and tea, and it was revealed the trend toward the use of less solvent-consuming and time-effective methods. Chromatographic methods were also described, which were mainly combined with detection techniques such as classical or mass spectrometry (MS) detection. Finally, a comprehensive overview of the occurrence of these selected exogenous compounds was presented in the studied matrices, showing that their monitoring should be further investigated to ensure food safety of highly consumed condiments and tea.

Concentration and health risk assessment of polycyclic aromatic hydrocarbons in commercial tea and coffee samples marketed in Iran

The aim of the current study was to evaluate the probabilistic health risk and the concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in commercial tea and coffee samples. For determining the mentioned contaminants in sixty-four samples, a reliable and sensitive technique was validated and developed. The technique is established on magnetic solid-phase extraction and gas chromatography-mass spectrometry analysis (MSPE/GC-MS). The maximum mean of ƩPAHs in coffee samples was 13.75 ± 2.90 μg kg^-1, while the minimum mean ƩPAHs in tea samples was 4.77 ± 1.01 μg kg^-1. The mean concentration of benzo(a)pyrene (BaP) in samples ranged from 0.64 to 2.07 μg kg^-1 which was lower than that of standard levels (10 μg kg^-1) established by the European Union (EU). The Monte Carlo simulation results showed that the actual target hazard quotient (THQ) for the adult and children was equal to 1.63E-04 and 1.67E-04, respectively; hence, non-carcinogenic health risk for consumers is negligible. The result of actual incremental lifetime cancer risk (ILCR) was lower than the limits of safe risk (1E-4), indicating no notable possibility of cancer risk due to the digestion of tea and coffee for children and adults. Therefore, it can be concluded that the amount of contamination of popular commercial coffee and tea available in the Iranian market with PAHs is often similar to that found in other countries and was lower than the standard of EU. Thus, the processing conditions of these products must be controlled to prevent the formation of PAHs due to the suspicion of carcinogenicity and mutation.

A novel dispersive liquid-liquid microextraction using a low density deep eutectic solvent-gas chromatography tandem mass spectrometry for the determination of polycyclic aromatic hydrocarbons in soft drinks

Ready-to-drink teas can provide, if properly packaged, the taste and wellness character of traditional teas. Nevertheless, in tea processing, there may be several contaminations, among which polycyclic aromatic hydrocarbons (PAHs), anthropogenic contaminants that can present carcinogenic and mutagenic properties. In this work, a novel low-density deep eutectic solvent-based dispersive liquid-liquid microextraction (LDDES-DLLME) procedure followed by gas chromatography tandem mass spectrometry (GC-MS/MS) was optimized for analysis of 15 polycyclic aromatic hydrocarbons (PAHs) in ready-to-drink herbal-based beverages. The new deep eutectic solvent (DES) was synthesized with natural compounds (camphor and hexanoic acid). Several parameters of the extraction procedure such as type and volume of extraction solvent, type, volume of dispersive solvent, and time of extraction were evaluated to achieve the highest yield and to attain the lowest detection limits. The validated method showed very low limits of detection (0.01 μg L^-1) and quantification (0.2 μg L^-1), good inter- and intra-day precisions (RSD<16.87%), and recoveries higher than 69%. The method was applied to 16 type of samples and it was found total PAHs levels ranging from 0.20 to 1.82 μg L^-1. The developed LDDES-DLLME showed a reliable and innovative alternative for the extraction of PAHs from beverages, cost-effective and environmentally friendly, and providing a satisfactory throughput.