Microwave-assisted Solvent Extraction Research Articles

The Extraction of Oxalate Acid from Porang Flour (Amorphophallus oncophyllus) using Microwave-Assisted Solvent Extraction

Porang (Amorphophallus oncophyllus) is one of the local annual plants that contain high levels of oxalate. Oxalates are undesirable compounds in porang flour, and their levels must be removed or reduced to obtain high quality porang flour as a food ingredient. In this research, the extraction of oxalate acid was conducted using microwave-assisted solvent extraction and mechanical separation methods. This study aims to analysis the parameters that influence the extraction of oxalate acid using microwave-assisted solvent extraction such as the effect of microwave power, extraction time, feed-to-solvent ratio (F/S) and material size. The mechanical separation process will be studied the effect of material size for extraction of oxalate acid. The optimum yield obtained for oxalate acid extraction with microwave-assisted solvent extraction was microwave power of 600 W, extraction time of 30 min, feed-to-solvent ratio of 0.05 g/mL and porang size of 100 mesh obtained by oxalate acid yield of 24.78%. Porang size of 100 mesh was the optimum yield obtained for extraction of oxalate acid using mechanical separation method. The result of physical properties test using SEM-EDX and FTIR shows that extraction of oxalate acid from porang using microwave extraction method could produce oxalic acid which has good quality. In addition, extraction using microwave offers an environment-friendly extraction method, which can accelerate and increase the oxalate acid extraction yield.

A Rapid Evaluation Method for Transformer Insulation Status

A method for rapid analysis of transformer insulation status indicated by moisture content in insulation paper was developed by microwave-assisted solvent extraction coupled with Fourier transform infrared spectroscopy (FTIR). The results show that acetonitrile is the best extraction solvent, and the second derivative based on the difference spectrum is obviously better than the difference spectrum. For the acetonitrile spectrum of extracting water, the sensitivity of hoh bending vibration 1680 cm−1 is higher than that of OH stretching vibration 3615 cm−1. For all test samples, the results of this method are basically consistent with the standard method and show excellent precision. The study shows that it is feasible to rapidly analyze the moisture content of transformer insulation paper by solvent extraction coupled with FTIR.

Sample preparation for planar chromatography.

High-performance thin-layer chromatography has favorable properties for high-throughput separations with a high matrix tolerance. Sample preparation, however, is sometimes required to control specific matrix interferences and to enhance the detectability of target compounds. Trends in contemporary applications have shifted from absorbance and fluorescence detection to methods employing bioassays and mass spectrometry. Traditional methods (shake-flask, heat at reflux, Soxhlet, and hydrodistillation) are being challenged by automated instrumental approaches (ultrasound-assisted and microwave-assisted solvent extraction, pressurized liquid extraction, and supercritical fluid extraction) and the quick, easy cheap, efficient, rugged, and safe extraction method for faster and streamlined sample processing. Liquid-liquid extraction remains the most widely used approach for sample clean-up with increasing competition from solid-phase extraction. On-layer sample, clean-up by planar solid-phase extraction is increasingly used for complex samples and in combination with heart-cut multimodal systems. The automated spray-on sample applicator, the elution head interface, biological detection of target and non-target compounds, and straightforward mass spectrometric detection are highlighted as the main factors directing current interest toward faster and simpler sample workflows, analysis of more complex samples, and the determination of minor contaminants requiring high concentration factors.

Optimization of Canolol Production from Canola Meal Using Microwave Digestion as a Pre-Treatment Method.

Canola meal, the by-product of canola oil refining, is a rich source of phenolic compounds and protein. The meal, however, is primarily utilized as animal feed but represents an invaluable source of nutraceuticals. Of particular interest are the sinapates, sinapine and sinapic acid, with the decarboxylation of the latter to form canolol. Extracting these phenolics has been carried out using a variety of different methods, although there is an urgent need for environmentally safe and sustainable methods. Microwave-assisted solvent extraction (MAE), as a green extraction method, is receiving considerable interest. Its ease of use makes MAE one of the best methods for studying multiple solvents. The formation of canolol, from sinapine and sinapic acid, is primarily dependent on temperature, which favors the decarboxylation reaction. The application of MAE, using the MultiwaveTM 500 microwave system with green extractants, was undertaken to assess its ability to enhance the yield of sinapates and canolol. This study examined the effects of different pre-treatment temperature-time combinations of 140, 150, 160, and 170 °C for 5, 10, 15, 20, and 30 min on the extraction of canolol and other canola endogenous phenolic compounds. Total phenolic content (TPC), total flavonoid content (TFC), as well as metal ion chelation (MIC) and DPPH radical activity of the different extracts were assessed. The results confirmed that extractability of canolol was optimized with methanol at 151 °C and with ethanol at 170 °C with pre-treatment times of 15.43 min and 19.31 min, respectively. Furthermore, there was a strong positive correlation between TPC and TFC (p < 0.05) and a negative correlation between TFC and DPPH radical activity. Interestingly, no significant correlation was observed between MIC and DPPH. These results confirmed the effectiveness of MAE, using the novel MultiwaveTM 500 microwave instrument, to enhance the yield of canolol. This was accompanied by substantial improvements in the antioxidant activity of the different extracts and further established the efficacy of the current MAE method for isolating important natural phenolic derivatives for utilization by the nutraceutical industry.

Comparison of microwave, ultrasound and ultrasound-microwave assisted solvent extraction methods on phenolic profile and antioxidant activity of extracts from jackfruit (Artocarpus heterophyllus Lam.) pulp

This study aimed to investigate the impact of different solvents (water, 60% methanol, 60% ethanol and 60% acetone) and methods (conventional solvent extraction, ultrasound-assisted extraction, microwave-assisted extraction and ultrasound-microwave assisted extraction) on the phenolic profile and antioxidant activity of jackfruit (Artocarpus heterophyllus Lam.) pulp. The Folin-Ciocalteu assay was used to determine the total phenolic content (TPC), and antioxidant activity was measured by DPPH and ABTS assays. The phenolic profiles in different extracts were identified using the UPLC-ESI-Q-TOF-MS/MS technique. The results showed that significant differences (p < 0.05) in TPC were found among different extraction methods, the microwave-assisted extraction with 60% ethanol had the highest TPC (2.40 mg GAE/g) compared with the extracts obtained from other methods. Meanwhile, the highest DPPH radical and ABTS radical cation was found in the 60% ethanol-MAE extracts. Correlation analysis further showed a significant positive correlation between TPC and antioxidant activity (R2 > 0.8, p < 0.001). Seventy-eight phenolic compounds were identified by UPLC-ESI-Q-TOF-MS/MS analysis. The most abundant phenolic compounds in jackfruit pulp were identified in negative mode, with 60% ethanol-MAE being the most effective. The quantity of phenolic compounds extracted varied with different extraction methods indicated that the extraction methods had effects on the phytochemical characteristics.

Simulation and experimentation on parameters influencing microwave-assisted extraction of bioactive compounds from Kaempferia parviflora rhizomes

In this study, a microwave extractor was successfully developed by simulating the waves and electric fields in a heating chamber. The chamber size and positions of the magnetrons were determined to maximize the heating in the microwave extractor. The results from the COMSOL Multiphysics software were used to construct the microwave extractor. Microwave-assisted solvent extraction was then performed on Kaempferia parviflora rhizomes. The highest total flavonoid and phenolic contents of 258.81 ± 1.01 µg quercetin equivalents per ml sample and 120.69 ± 0.75 µg gallic acid equivalents per ml sample, respectively, were achieved by extraction in methanol solvent at 83 °C within 2.5 min. These values were higher than those obtained from ultrasound-assisted extraction for 30 min and Soxhlet extraction for 60 min. In addition, the extraction time of 5,7-dimethoxyflavone using the Soxhlet extractor, which was approximately 1 h, was reduced to 2 min using the microwave extractor. These results demonstrated that microwaves are an outstanding heat source for extracting bioactive compounds and exhibit potential for commercial applications. Computer simulations were performed to provide insights into microwave heating. This information could be used to overcome technical challenges in industrial processes.

Combination of microwave-assisted solvent extraction and effervescence-assisted deep eutectic solvent-based in-syringe dispersive liquid-liquid microextraction and its application in the extraction of triazine pesticides from apple samples.

In the current study, a combination of microwave-assisted solvent extraction combined with effervescence-assisted deep eutectic solvent-based in-syringe dispersive liquid-liquid microextraction has been developed as a new sample pretreatment method. The offered method was used for the extraction of five triazine pesticides (atrazine, propazine, cyanazine, ametryn, and simazine) from apple samples before their determination by gas chromatography-flame ionization detection. For this purpose, briefly, the apple sample was contacted with a suitable acidified extraction solvent and the mixture was exposed to microwave irradiations. Then, the supernatant was taken and mixed with a few microliters of a low-density deep eutectic solvent. The supernatant phase containing the extracted analytes was injected into a sodium bicarbonate solution filled into a syringe. Consequently, the effervescence reaction occurs and the analytes were extracted into the fine droplets of extractant dispersed throughout the solution. Afterward, an aliquot of this phase was analyzed by the chromatographic system. Satisfactory outcomes include high enrichment factors (228-261) and extraction recoveries (67-87%), good repeatability (relative standard deviations equal to or less than 3.2% and 5.3% for intra- and inter-day precisions), and low limits of detection (0.4-0.7 ng/g) and quantification (1.4-2.3 ng/g) were acquired under the best experimental situations.

Melatonin‐rich, erucic acid‐lean nutraceutical supplements by microwave‐assisted solvent extraction of brown and yellow mustard seeds

The microwave-assisted solvent extraction (MASE) parameters optimized by Taguchi L9 (34) orthogonal array design to obtain extracts with a favorable combination of high melatonin-cum-low erucic acid content from Brassica juncea (BJ) and Brassica campestris (BC) seeds were: seed particle diameter of 500 μm for BJ and 420 μm for BC seeds, 1:10 sample to solvent (50% ethanolic water) ratio, 180 W microwave power, and 10 min extraction time. The yield of melatonin from BC was relatively higher owing to its greater protein and/or moisture content(s). Biochemical characterization confirmed a synergistic consortium of antioxidants in the extracts, viz. melatonin along with co-extracted ascorbic acid, limonene, and linalool. At the optimized condition, the actual power absorbed by the seed-solvent matrices (21.5 W in BJ-, 24.6 W in BC-MASE extracts) was lower compared to the microwave power applied (180 W) during MASE. Our studies affirm safe consumption of the extracts as melatonin-rich nutraceutical supplements. Novelty impact statement This work is of significance since melatonin which is commercially used as a drug has been extracted from an unconventional source, that is, from an oilseed crop for use as a food antioxidant. MASE has been conducted for the first time with green solvents for obtaining “melatonin rich-cum-erucic acid-lean” extracts of brown and yellow mustard seeds embracing natural “antioxidant synergy” within. The procedure established in this work could be easily scaled up to commercial level extraction of “a synergistic consortium of antioxidants” from other oilseeds (or allied food matrices).

Study of Lignin Extracted from Rubberwood Using Microwave Assisted Technology for Fuel Additive.

Lignin is the most abundant natural aromatic polymer, especially in plant biomass. Lignin-derived phenolic compounds can be processed into high-value liquid fuel. This study aimed to determine the yield of lignin by the microwave-assisted solvent extraction method and to characterize some essential properties of the extracted lignin. Rubberwood sawdust (Hevea brasiliensis) was extracted for lignin with an organic-based solvent, either ethanol or isopropanol, in a microwave oven operating at 2450 MHz. Two levels of power of microwave, 100 W and 200 W, were tested as well as five extraction times (5, 10, 15, 20, 25, and 30 min). The extracted lignin was characterized by Klason lignin, Fourier transform infrared spectroscopy (FT-IR), 2D HSQC NMR, Ultraviolet-visible spectrophotometry (UV-vis), and Bomb calorimeter. The results showed that the yield of extracted lignin increased with the extraction time and power of the microwave. In addition, the extraction yield with ethanol was higher than the yield with isopropanol. The highest yield was 6.26 wt.%, with ethanol, 30 min extraction time, and 200 W microwave power.

Microwave assisted extraction, phytochemical and antimicrobial evaluation of ethyl acetate extracts of stem bark of Ficus exasperata (Vahl)

Stem bark of Ficus exasperata was extracted using ethyl acetate by microwave-assisted solvent extraction. Phytochemical screening and antimicrobial evaluation were carried out on the extract. Phytochemical screening revealed the presence of cardiac glycosides, tannins, flavonoids, triterpenes and steroids. Antimicrobial evaluation revealed that the extract is active against Methicillin – resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Streptococcus pneumoniae, Salmonella typhi, Proteus mirabilis, Shigella dysenteriae, Candida stellatoidea and Candida tropicalis. The zones of inhibition (mm) for the test organisms were (24 - 31) mm. Minimum inhibition concentrations (mg/L) of extract against MRSA, Staphylococcus aureus, Streptococcus pneumonia, Salmonella typhi, Proteus mirabilis, Shigella dysenteriae, Candida stellatoidea and Candida tropicalis were 2.5, 1.25,1.25, 2.5, 1.25, 1.25, 1.25 and 2.5 respectively. Minimum bactericidal concentrations (mg/L) of extract against Methicillin – resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Streptococcus pneumonia, Salmonella typhi, Proteus mirabilis Shigella dysenteriae Candida stellatoidea and Candida tropicalis were 5, 2.5, 2.5, 5, 5, 2.5,2.5 and 5 respectively. The extract showed high inhibition against MRSA and Candida tropicalis.

Ultrasound and microwave‐assisted solvent extraction of mango kernel oil and evaluation of physicochemical properties and fatty acid profile

The present study was conducted to evaluate and compare the efficacy of microwave-assisted extraction (MAE) and a combination of ultrasound and MAE (UMAE) in extracting mango kernel oil (MKO), as well as studying the physicochemical properties and fatty acid composition of the extracted oil. Oil recovery by MAE and UMAE was 88.42 ± 1.36% and 96.67 ± 1.30%, respectively. The physicochemical properties of MKO included free fatty acids (1.99%–2.18%), acid value (3.97–4.43 mg KOH/g), peroxide value (2.33–2.50 mEq/kg), saponification value (187.93–202.89 mg KOH/g), unsaponifiable matter (3.48%–3.62%), pH (5.83–6.07), melting point (29.5–32.4°C), and specific gravity (0.911–0.926). The fatty acid profile indicated that stearic acid was the most dominant, constituting 37.87%–39.59% of the total fatty acid content. Other major fatty acids included 31.51%–32.38% oleic acid and 15.74–18.88% docosahexaenoic acid. Palmitic, γ-linolenic, α-linolenic, arachidic, behenic, linoleic, and eicosadienoic are the minor fatty acids present in MKO. Novelty impact statement Mango seeds could be utilized as an inexpensive raw material for the production of commercial mango kernel oil. Ultrasound and microwave-assisted solvent extraction of mango kernel oil were optimized for oil yield and quality of extracted oil. The physicochemical properties and fatty acid profile of the extracted oil were evaluated for its industrial potential.

Development of a microwave‐assisted solvent extraction process for the extraction of high‐value carotenoids from Chlorella biomass

AbstractThe commercial production of carotenoids as bioactive commodities from microalgae has been severely limited due to the nature of the microalgal outer cell matrix. Microwave technology offers a rapid method for obtaining larger amounts of these biochemical compounds. The process facilitates cell‐wall rupture, releasing the inner cell components. Chlorella biomass, raised in an outdoor raceway pond, is used for downstream extraction of carotenoids by following the microwave‐assisted solvent extraction (MAE) approach. The response surface modeling (RSM) strategy was employed to optimize the two independent parameters, power and extraction time, with a two‐level central composite design (CCD). Acetone, hexane, methanol, hexane : acetone (1:1), hexane : ethanol (7:3) were used as solvents of choice. Acetone gave a total carotenoid yield of 0.061 ± 0.003 mg gm−1 under optimum microwave power and time; 130 W and 1.69 min. The optimized yield from hexane was 0.00173 ± 0.005 mg gm−1 with an exposure time of 1 min to 100 W. The total carotenoid yield of the methanol‐based extraction batch was 0.0371 ± 0.004 mg gm−1 with 157 W and 1 min of extraction time. The solvent mixtures of hexane : acetone gave 0.0398 ± 0.002 mg gm−1 (185 W for 1.7 min) and hexane : ethanol gave 0.0383 ± 0.004 mg gm−1 (195 W, 1.6 min), respectively. The results indicate a satisfactory outcome to the process. They also show microwave‐based extraction to be a fast, economic, reproducible, and repeatable method in comparison with the conventional strategies used for recovering the sensitive natural pigments. © 2021 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Effect of Various Extraction Methods and Solvent Types On Yield, Phenolic and Flavonoid Content and Antioxidant Activity of Spathodea nilotica Leaves

Phytochemicals are gaining interest as a new source of natural pharmaceuticals to replace synthetic ones, which are controlled owing to potential health hazards and toxicity. A comparison of extract yield, phenolic, flavonoid content and antioxidant activity in various extraction methods were studied. with different solvent polarity including chloroform (CF), ethyl acetate (EtOAc), acetone (AC), methanol (MeOH), and distilled water (DW) was prepared using maceration extraction (ME), one of the traditional methods and two methods of recent extraction techniques also known as Green Extraction techniques, ultrasound-assisted solvent extraction (UASE) and microwave-assisted solvent extraction (MASE). The antioxidant activity of the extracts was measured using the DPPH method of the antioxidant assay. Higher phenolic (194.3±1.5 and 191.7±0.4, respectively) were found in the methanolic leaf extracts in the case of MASE and UASE than maceration extraction (ME). Meanwhile, DW extract showed the highest flavonoids (174.3±1.0 and 167.4±1.0, respectively) contents by using UASE and MASE followed by methanolic extract (140.1±0.6 and 136.6±1.1, respectively) compared with the conventional extraction technique. The extraction techniques, as well as the solvent polarity and time of extraction, influenced extract yield, total phenolic and flavonoid content, and antioxidant activity.

Optimization of microwave-assisted solvent extraction of hemp (Cannabis sativa L.) seed oil using RSM: evaluation of oil quality

Optimization of microwave-assisted solvent extraction of hemp (Cannabis sativa L.) seed oil using RSM: evaluation of oil quality

Water-induced release of recalcitrant polycyclic aromatic hydrocarbons from soil organic matter during microwave-assisted solvent extraction

Polycyclic aromatic hydrocarbons (PAHs) in soil can be recalcitrant to solvent extraction after aging. We showed in this study that mixing a small amount of water in the extracting solvent during microwave-assisted extraction (MAE) can release recalcitrant PAHs, resulting in significant improvement in the analyzed concentrations. The improvement factor (F) for the total of 16 priority PAHs (∑PAH16) listed by the United States Environmental Protection Agency was 1.44–1.55 for field soils. By comparing the F values for different soil organic components, we demonstrated that the recalcitrant PAHs were primarily associated with biochar, humic acid (HA), and humin (HM), with the F values for ∑PAH16 of 1.94, 6.62, and 4.59, respectively. The results showed that the recalcitrant PAHs comprised a sequestered fraction and a desorption-limited fraction. NMR spectra showed that water worked alone at elevated temperature to promote hydrolysis of biochar and destroy the macromolecular structure, thus causing the release of the otherwise sequestered PAHs during MAE. The substantial reduction in F values for HA and HM after demineralization indicated sequestration of PAHs in organic-mineral complexes, which can be destroyed by hot water treatment. The release of the sequestered fraction was nonselective and independent of compound hydrophobicity. In comparison, the release of the desorption-limited fraction was positively affected by the hydrophobicity of PAHs and was facilitated by the presence of water in the extracting solvent. The results of this study provide important insights into the sequestration and release of recalcitrant PAHs in soil.

Study of 'Fingerprints' for Green Tea from Different Planting Areas in Eastern China

ABSTRACT Green tea is one of the main teas in China, which is unfermented and retains more natural substances of fresh tea leaves. This is the preliminary study of application of'fingerprints' based on differences in component composition of green tea. Five green teas from different areas in eastern China are analyzed, which are processed by microwave-assisted solvent (ethanol) extraction method to obtain tea polyphenols, flavonoids, polysaccharides, pigments (thearubigins, theaflavins, theabrownins). The results show that the component composition of five green teas are varied from each other; based on these contents varieties, we have constructed a 'fingerprint' and applied linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA) to assist in the identification of these five green teas. This method does not require large, expensive instruments (such as high performance liquid chromatograph, gas chromatograph, mass spectrometer, etc.), and is easy to use, which provides a new avenue for the identification of tea. Keywords: Green tea, contents varieties, identification, 'fingerprints'.

A holistic approach for microwave assisted solvent extraction of phenolic compounds from Ficus benghalensis fruits and its phytochemical profiling

AbstractFicus benghalensis is a fig species spread throughout Asia, especially India, which finds its place in the tradition Indian system of medicines for their renowned protective properties. This study explores the extraction and identification of phytochemicals from the fruits of Ficus benghalensis using a time‐saving nonconventional technique of microwave assisted solvent extraction (MASE). The influence of independent variables (viz., solid‐solvent ratio, microwave power and irradiation time) on the maximum total phenolic content (TPC) and total flavonoid content (TFC) values was analyzed and optimized using response surface methodology (RSM) with a Box–Behnken Design. The maximum values of TPC (340.14 ± 0.34 mg/g) and TFC (413.64 ± 0.19 mg/g) were found at a shorter extraction time of 5 min, solid‐solvent ratio of 1:17 g/ml and microwave power of 420 W. The GC chromatogram was used for the phenolic distribution analysis and screening of the secondary metabolites. The GC spectra showed the presence of 26 biologically active secondary metabolites. 7‐tetradecenal (Z) (42.14%) was the predominant compound followed by n‐hexadecanoic acid (20.61%) and octadecanoic acid (14.07%). These compounds, along with others reportedly exhibit anticancer, antioxidant, anti‐diabetic, and antibacterial activities, thereby validating the traditional uses of the Ficus benghalensis fruit as a pharmaceutical supplement.Practical applicationThe outcome of this work shows a time‐saving method of phytochemical extraction which can be used for extracting valuable metabolites from Ficus benghalensis fruits. Moreover, findings from this research work will aid as a baseline to facilitate future studies in the isolation and purification of the identified pharmaceutically active phytochemicals present in the Ficus benghalensis fruit extract. This can be further used to increase the fruits' bioprospecting.

Simultaneous application of deep eutectic solvent as extraction solvent and ion-pair agent in liquid phase microextraction for the extraction of biogenic amines from tuna fish samples

An efficient, simple, rapid, and repeatable sample preparation method based on microwave-assisted solvent extraction combined with dispersive liquid–liquid microextraction using in situ synthesis of a deep eutectic solvent was developed for the extraction of some biogenic amines in canned tuna fish samples. In this procedure, one carboxylic acid group of hexanedioic acid is participated in formation of the deep eutectic solvent while the other one is used to form ion pair with the analytes. Initially the analytes are extracted into deionized water sample during microwave-assisted solvent extraction. After centrifugation deep eutectic solvent synthesis and the microextraction procedure are performed simultaneously in the supernatant phase. The enriched analytes are separated and determined by high performance liquid chromatography-diode array detection. The method provided low limits of detection and quantification in the ranges of 0.25–0.50 and 0.84–1.7 ng g−1, respectively. The method had a proper repeatability with relative standard deviation less than or equal to 12%. The validated method was successfully performed on different canned tuna fish samples obtained from different producers.

Recovery of Valuable Components from Food Wastes by Microwave Assisted Extraction

Today, insufficiency of natural resources, rapidly growing world population, climate change, food losses and food waste cause significant risk for food safety. In food industries, high amounts of solid and liquid wastes are released at various stages of production. The majority of them are organic wastes left from the raw material processed. Food waste, food and nutrition safety and food quality affect the sustainability and economic development of food systems and have negative impacts on natural resources and environmental protection. In addition, these food wastes can be converted into useful products which have market value, such as polyphenols, dietary fiber and photochemistry etc. Therefore, studies on the assessment of these wastes are becoming increasingly important and quick and effective new applications are needed. Traditional extraction methods usually take a long time and require large amounts of solvent. Microwave assisted solvent extraction (MASE) is one of the modern methods which have been used more commonly in recent years, with short extraction time, less solvent usage and lower energy requirements, higher heating rates, higher extraction efficiency, higher selectivity and better quality target products. Microwave assisted solvent extraction is one of the modern methods with its increasing use in recent years. In this study, microwave extraction has been studied in general and the studies on the extraction of valuable components by microwave extraction technique from food wastes were compiled. Keywords: Food waste, Microwave assisted extraction DOI: 10.7176/JSTR/6-09-05

Microwave-assisted solvent extraction and double-shot analytical pyrolysis for the quali-quantitation of plasticizers and microplastics in beach sand samples

Pollution from microplastics (MPs) needs to be evaluated by deploying reliable analytical techniques that provide qualitative and quantitative data on the extent of contamination in the various environmental matrices. Solvent extraction of MPs followed by pyrolysis-gas chromatography-mass spectrometry (Py-GC–MS) provides data that not only regard the soluble plastics, but also the organic additives contained in MPs and the low-molecular weight degradation products of insoluble plastics. In this study, the potential of microwave-assisted solvent extraction and double-shot Py-GC–MS was investigated in order to obtain quali-quantitative information on polystyrene and on phthalate plasticizers in environmental samples. The method was validated and provided recoveries higher than 96 %, and detection limits lower than 1 ng and 1 μg for phthalates and polystyrene, respectively. We used the method to analyze samples of sand collected from a shoreline in Tuscany (central Italy) and thereby determine the content of phthalates and polystyrene at different depths and distances from the coastline. Qualitative data were also obtained regarding the presence of oxidation products derived from polyethylene and polypropylene. The different contents of plasticizers, plastics, and degradation products in the investigated samples are discussed in relation to how environmental agents affect the leaching and degradation processes of the polymers.