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Cited by 6Analytical chemistry methods developmentIonic liquids properties and applicationsAnalytical Chemistry and Chromatography

Thermo‐Assisted Deep Eutectic Solvent Based on Dispersive Liquid‐Liquid Microextraction for Preconcentration of Phthalate Esters in Water Samples and Determination by Gas Chromatography With Flame Ionization Detection

Open access
Abdi, Khosrou, Ezoddin, Maryam, Novasari, Venous, Lamei, Navid·2024·Journal of Separation Science
DOI 10.1002/jssc.202300878
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Abstract

A thermo‐assisted deep eutectic solvent (DES) based on dispersive liquid‐liquid microextraction followed by gas chromatography with flame ionization detection was developed for the analysis of five phthalate esters in different water samples. In the procedure involved, a DES composed of lidocaine, an amphiphilic amine, and oleic acid, was mixed with the sample assisted by ultrasound, and phase separation was achieved with increasing temperature. The heating of the extraction system induced the change of acid‐base properties of the DES components. Thus, the formation of microdroplets of DES in the sample was provided, and two phases were separated. The structure of the upper hydrophobic layer was characterized by Fourier‐transform infrared spectroscopy. Also, the amount of water in the DES phase was analyzed by mass spectrometer and Karl Fischer titration. Some critical variables on the extraction yield were assessed. The proposed method achieved 1.2–1.3 and 4.1–4.3 µg/L for limits of detection and limits of quantification, respectively. The intra‐day and inter‐day percentage relative standard deviations (n = 5) were determined to be in the range of 4.2–6.2% and 5.1–7.2%, respectively. Ultimately, this method analyzed the five phthalate esters in different water samples with high recoveries.

AI snapshot

Written from the paper’s full text.

TL;DR

A thermo-assisted deep eutectic solvent dispersive liquid–liquid microextraction method was developed to preconcentrate five phthalate esters from water before GC-FID analysis. Using a lidocaine/oleic acid DES with ultrasound, salt, and heating, the method achieved low µg/L detection limits and high recoveries in tap, bottled, and seawater samples.

Key findings

  • LODs were 1.2–1.3 µg/L and LOQs were 4.1–4.3 µg/L; calibration was linear from 4.5 to 1000 µg/L with R² values above 0.9950.
  • Enrichment factors ranged from 117.7 to 119.5, extraction recoveries from 94.2% to 95.6%, intra-day RSDs from 4.2% to 6.2%, and inter-day RSDs from 5.1% to 7.2% (n = 5).
  • In spiked real water samples, recoveries were 92.6%–101.2%, matrix effects were 93.3%–99.8%, and same-day RSDs were 2.7%–6.5% (n = 3).
  • The optimized conditions were a 1:1 oleic acid/lidocaine DES, 100 µL DES, 12% NaCl, 1 min ultrasound at 20°C, 3 min heating at 40°C, and pH 7 without pH adjustment; the analytical eco-scale score was 83.

Methods

  • The DES was prepared by mixing oleic acid as hydrogen bond donor and lidocaine as hydrogen bond acceptor in a 1:1 molar ratio. Extraction used 10 mL water sample containing 100 µg/L PAEs, 100 µL DES, ultrasound for 1 min, 12% NaCl, and a 40°C water bath for 3 min; the floated phase was injected into GC-FID.
  • Five PAEs were studied: dimethyl phthalate, diethyl phthalate, di-iso-butyl phthalate, di-n-butyl phthalate, and bis(2-ethylhexyl) phthalate. Samples included tap water from Tehran, bottled Damavand mineral water, and seawater from Chabahar Beach and Velasht Lake.
  • Characterization used FT-IR, GC-MS, and Karl Fischer titration; validation covered LOD, LOQ, linearity, enrichment factor, extraction recovery, and RSD, with real-sample spiking at 10 and 100 µg/L and greenness assessed by analytical eco-scale and green analytical procedure index.

Limitations

  • The paper does not state explicit limitations.
  • Evident from the text: only five phthalate esters and water matrices were tested, so applicability to more complex matrices such as food or biological samples is not shown.
  • Evident from the comparison table: the method’s LODs (1.2–1.3 µg/L) are higher than several cited alternative methods (e.g., 0.026–0.5 µg/L), although the proposed method is presented as greener and faster.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1002/jssc.202300878

Cites

30 of 33 references verified0 citation errors · 3 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

3 of 15 cited sources checked · 0 supported · 0 flagged · accuracy not yet measured

  • Findingown data

    For all spiked sample groups, the recovery of PAEs ranged from 92.6% to 101.2%.

    “As shown in Table 3, the recovery of PAEs and ME% in all groups of the spiked samples were in the range of 92.6%-101.2% and 93.3%-99.8%.”
    Quote in the paperSubstantial claim
  • Findingown data

    A DES volume of 100 μL was chosen as optimal.

    “Hence, to obtain higher extraction recoveries, 100 µL of the extraction solvent was opted as the optimal volume.”
    Quote in the paperSubstantial claim
  • Findingreasoning

    Extraction recoveries decreased in strongly acidic or alkaline solutions.

    “On the contrary, the extraction recoveries were diminished in strong acidic or alkaline solutions.”
    Quote in the paperSubstantial claim
  • Findingown data

    The proposed method gave limits of detection of 1.2-1.3 μg/L and limits of quantification of 4.1-4.3 μg/L for the five phthalate esters.

    “The proposed method achieved 1.2-1.3 and 4.1-4.3µg/L for limits of detection and limits of quantification, respectively.”
    • Also stated in: § 3.7 Validation of the Method · plain
      “LODs and LOQs were in the range of 1.2-1.3 and 4.1-4.3µg/L, respectively.”
    Quote in the paperSubstantial claim
  • Findingown data

    An ultrasonic time of 1 min was optimal.

    “Based on the observed results, the ultrasonic time of 1 min was selected as an optimal time to attain the best output.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 5
  • May combine two claims. 17
  • The quote only partly states this claim. 2

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Amphiphilic amines like lidocaine have been suggested as hydrogen bond acceptors, while medium- or long-chain carboxylic acids act as hydrogen bond donors for temperature-responsive DES formation.

    “Amphiphilic amines such as lidocaine (LD), have been proposed as HBAs, while mediumor long-chain carboxylic acids serve as HBDs for the TRDES formation [20].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [20] 20. J. Castaneda Corzo, K. Ballerat-Busserolles, J. Y. Coxam, A. Gautier, and J. M. Andanson, "Thermo-switchable Hydrophobic Solvents For- mulated With Weak Acid and Base for Greener Separation Processes," Journal of Molecular Liquids 377 (2023): 121468, https://doi.org/10.1016/ j.molliq.2023.121468. source

      The Introduction (p. 4) describes lidocaine as an amphiphilic amine combined with hydrophobic carboxylic acids, and Section 3.1.1 (pp. 8–9) reports temperature-dependent phase separation in aqueous DES made from lidocaine and linear aliphatic acids. The paper treats these as weak-base/weak-acid systems, but our copy does not describe lidocaine and the acids specifically as hydrogen-bond acceptors and donors. (LLM, conf=0.82)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Ultrasonic extraction works through acoustic cavitation in the sample solution.

    “As a new supplemental extraction method, ultrasonic extraction utilizes the cavitation effect by forming acoustic cavitation in the sample solution [21].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [21] 21. E. Roselló-Soto, M. Koubaa, A. Moubarik, et al., "Emerging Opportu- nities for the Effective Valorization of Wastes and by-products Generated During Olive Oil Production Process: Non-Conventional Methods for the Recovery of High-added Value Compounds," Trends in Food Science and Technology 45 (2015): 296-310, https://doi.org/10.1016/j.tifs.2015.07.003. source

      No full text of Roselló-Soto et al. (2015) is available here, and two searches scoped to that paper returned no snippets. An unscoped result about olive-oil extraction cites Roselló-Soto et al. when discussing ultrasound-assisted extraction, so the citation is plausible, but it does not establish that their paper explains acoustic cavitation. The suggested Jyoti source describes a general cavitation effect; it does not show that the claim was misattributed. (LLM, conf=0.68)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    DLLME offers high efficiency, simple operation, and low consumption of extraction and dispersion solvents.

    “DLLME has advantages such as high efficiency, simple operation, and low consumption of extraction and dispersion solvents [12].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [12] 12. E. Pourbasheer, F. Qasemi, M. Rouhi, Z. Azari, and M. R. Ganjali, "Preconcentration and Determination of 2-Mercaptobenzimidazole by Dispersive Liquid-liquid Microextraction and Experimental Design," Journal of Separation Science 40 (2017): 2467-2473, https://doi.org/10. 1002/jssc.201601453. source

      The cited paper’s title establishes that it uses DLLME, but two paper-scoped searches returned no passages about the stated advantages, so the attribution cannot be verified from its text. A different review, “Green Extraction Techniques as Advanced Sample Preparation Approaches in Biological, Food, and Environmental Matrices,” describes DLLME as efficient, simple, and low in solvent consumption (score 0.725). Those are general properties of the method, not evidence that the claim was taken from that review rather than the cited paper; misattribution is not established. (LLM, conf=0.66)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data

    Extraction recovery of the phthalate esters increased as sample pH rose from 2 to 6, then stayed constant from pH 7 to 8.

    “The results in Figure 7 indicated that the extraction recovery of PAEs increased when the sample pH increased from 2 to 6 and then the extraction recoveries remained constant with the pH increase from pH 7 to 8.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Extraction recovery increased as NaCl concentration rose from 0% to 12% w/v, but from 12% to 20% w/v there was no significant difference.

    “The results illustrated that with rising NaCl concentration from 0% to 12%, the extraction recovery increased, and then, from 12% to 20% w/v, there was no significant difference in the extraction recoveries.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    At 20°C the system was a single liquid phase, while increasing temperature produced droplets of extraction solvent.

    “The results presented a single liquid phase at 20 • C, while with increasing temperature droplets of the extraction solvent appeared.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The method's enrichment factors were 117.7-119.5, and its extraction recoveries were 94.2-95.6%.

    “EFs and ERs were obtained in the range of 117.7-119.5 and 94.2%-95.6%,respectively.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    At 100 μg/L, intra-day and inter-day relative standard deviations with n = 5 were 4.2-6.2% and 5.1-7.2%, respectively.

    “The intra-day and inter-day percentage relative standard deviations (n = 5) were determined to be in the range of 4.2-6.2%and 5.1-7.2%,respectively.”
    • Also stated in: § 3.7 Validation of the Method · plain
      “Furthermore, RSDs% at a concentration of 100 µg/L of each analyte were obtained in the range of 4.2%-6.2%and 5.1%-7.2%for intra-day (n = 5) and inter-day (n = 5) precision, respectively.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    Calibration curves for the five phthalate esters were linear from 4.5 to 1000 μg/L.

    “The calibration curves were plotted using a series of solutions with different concentrations of five PAEs in the range of 4.5-1000 µg/L being extracted with the developed method.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    A DES made from oleic acid as hydrogen bond donor and lidocaine as hydrogen bond acceptor was selected and gave the highest extraction recovery.

    “In this research, a DES composed of OA as the HBD and LD as the HBA was selected and demonstrated the highest extraction recovery.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    pH 7 was selected as optimal.

    “According to the results, pH 7 was selected in this work.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    DESs are highly biodegradable, biocompatible, switchable, easy to synthesize, and low in toxicity, and they extract organic and inorganic compounds well.

    “DESs have become one of the best replacements for toxic organic solvents because they demonstrate some specific characteristics such as high biodegradability, biocompatibility, switch ability, easy synthesis, and low toxicity as well as the excellent ability for extraction of organic and inorganic compounds [15][16][17][18].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15][16][17][18]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Temperature change shifts the pKa, which alters the system's ionic strength and the water solubility of the DES.

    “Temperature change provides the change of pKa, which will affect the system's ionic strength and then change DES's solubility in water [19].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [19] 19. J. Zhang, S. Li, L. Yao, L. Yi Yuexing Shen, Z. Li, and H. Qiu, "Responsive Switchable Deep Eutectic Solvents. A Review," Chinese Chemical Letters 34 (2023): 107750, https://doi.org/10.1016/j.cclet.2022. 107750. source
    • Rests on an assumption: Lidocaine has a highly temperature-sensitive pKa value of 8.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A DES is made by combining two or more non-toxic hydrogen bond donors and acceptors in a specific molar ratio, producing a eutectic mixture via hydrogen bonding.

    “DESs are obtained by mixing two or more non-toxic hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs) at a specific molar ratio, which can result in a eutectic mixture through hydrogen bond interactions [15].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] 15. O. Longeras, A. Gautier, K. B-Busserolles, and J.-M. Andanson, "Deep Eutectic Solvent With Thermo-switchable Hydrophobicity," ACS Sustainable Chemistry & Engineering 8 (2020): 12516-12520, https://doi. org/10.1021/acssuschemeng.0c03478. source

  • May combine two claims.

    Interpretationreasoning

    The developed method enhanced DES dispersion without a dispersive solvent, whereas other methods required dispersive solvents.

    “Dispersion of DES was enhanced by the developed method without any dispersive solvent while other methods required dispersive solvents.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Using TADES-DLLME without additional components allowed effective extraction of phthalate esters while avoiding toxic solvents.

    “The use of TADES-DLLME without using additional components allowed the effective extraction of PAEs, avoiding the usage of toxic solvents.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Traditional DLLME uses hazardous organic solvents.

  • May combine two claims.

    Premisecitation

    Temperature control and bath heating time are needed because oleate becomes hydrophobic oleic acid in the DES as temperature rises.

    “Furthermore, temperature control and bath heating time are necessary because the oleate changes to hydrophobic OA in the DES with increasing temperature [24].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [24] 24. Q. Liu, Z. Li, L. Wei, X. Chen, Y. Xu, and J. Zhao, "Fast Dispersive Liquid-liquid Microextraction of Pesticides in Water Based on a Thermo Switchable Deep Eutectic Solvent," Environmental Chemistry Letters 20 (2022): 2271-2276, https://doi.org/10.1007/s10311-022-01431-y. source

  • May combine two claims.

    Premisecitation

    Ultrasonic time helps disperse the extraction solvent into the aqueous sample and increases mass transfer of target compounds into the extraction solvent.

    “It helps to spread the extraction solvent into the aqueous sample and increase the mass transfer of the target compounds to the extraction solvent [21].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [21] 21. E. Roselló-Soto, M. Koubaa, A. Moubarik, et al., "Emerging Opportu- nities for the Effective Valorization of Wastes and by-products Generated During Olive Oil Production Process: Non-Conventional Methods for the Recovery of High-added Value Compounds," Trends in Food Science and Technology 45 (2015): 296-310, https://doi.org/10.1016/j.tifs.2015.07.003. source

  • May combine two claims.

    Premisecitation

    In temperature-responsive DES methods, heating or cooling the aqueous phase alters the DES acid-base properties and causes in situ microdroplet formation.

    “In TRDES-based procedures, the heating or cooling of the aqueous phase induced the change of their acidbase properties of DES, and thus it attributed to the in situ formation of microdroplets of TRDES.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [19] 19. J. Zhang, S. Li, L. Yao, L. Yi Yuexing Shen, Z. Li, and H. Qiu, "Responsive Switchable Deep Eutectic Solvents. A Review," Chinese Chemical Letters 34 (2023): 107750, https://doi.org/10.1016/j.cclet.2022. 107750. source

  • May combine two claims.

    Premisecitation

    The salting-out effect lowers the diffusion coefficient in the aqueous solution and raises extraction recovery of the analytes.

    “Theoretically, the salting out effect reduces the diffusion coefficient in the aqueous solution and increases the extraction recovery of the analytes [22].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [22] 22. I. C. Stratigou, A. Tsiasioti, P. D. Tzanavaras, C. K. Markopoulou, K. Fytianos, and C. K. Zacharis, "Homogeneous Liquid Liquid Extraction Using Salt as Mass Separating Agent for the Ultra High Pressure Liquid Chromatographic Determination of Doxorubicin in Human Urine," Microchemical Journal 158 (2020): 105260, https://doi.org/10.1016/ j.microc.2020.105260. source

  • May combine two claims.

    Interpretationown data

    The method is effective and simple for analyzing PAEs in various matrices.

    “In conclusion, the results confirmed that this method can be effective and easy for analyzing PAEs in different matrices.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Ultrasonic treatment improves the dispersion of the extraction solvent and increases the surface area in a short time.

  • Classified as probably not a substantial claim.

    Premisecitation

    An analytical eco-scale score above 75 represents an excellent green analysis.

    “The scores of more than 75 represent an excellent green analysis.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [30] 30. A. Gałuszka, Z. M. Migaszewski, P. Konieczka, and J. Namieśnik, "Analytical Eco-Scale for Assessing the Greenness of Analytical Proce- dures," Trends in Analytical Chemistry 37 (2012): 61-72, https://doi.org/ 10.1016/j.trac.2012.03.013. source
22 of 22

  • The paper relies on this without support.

    Traditional DLLME uses hazardous organic solvents.

    “Unfortunately, the traditional DLLME method uses hazardous organic solvents.”

  • The paper relies on this without support.

    Lidocaine has a highly temperature-sensitive pKa value of 8.

    “LD has a highly temperature-sensitive pKa value (pKa = 8).”

  • The paper relies on this without support.

    At ambient conditions, an acid-base reaction between lidocaine and carboxylic acid occurs in the aqueous phase.

    “At ambient conditions, an acid-base reaction between LD and carboxylic acid occurs in the aqueous phase.”

  • The paper relies on this without support.

    The formation of hydrogen bonds between components is an important factor in forming a DES.

    “The formation of hydrogen bonds between the components is an important factor in forming a DES.”

  • The paper relies on this without support.

    The eutectic point of a DES is related to the molar ratio of its components.

    “Also, the eutectic point of a DES is related to the molar ratio of its components.”

  • The paper relies on this without support.

    The DLLME method needs a dispersant or auxiliary device to disperse the extraction solvent in the sample solution and enhance the rate and time of the extraction.

    “The DLLME method needs a dispersant or auxiliary device to disperse the extraction solvent in the sample solution and enhance the rate and time of the extraction.”

  • The paper relies on this without support.

    Ultrasonic treatment improves the dispersion of the extraction solvent and increases the surface area in a short time.

    “Ultrasonic was applied to elevate the dispersion of the extraction solvent in the sample solution and increase the surface area in a very short time (1 min).”
7 of 7

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Heating-time and temperature figure references are reversed

    Minor

    The text assigns temperature to Figure 5 and heating time to Figure 6, but Figure 5's caption identifies it as the heating-time experiment.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. 10.1002/1615‐9314(20020101)25:1/23.0.CO;2‐3 · DOI

Cited by

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Related

Authors
Abdi, K., Ezoddin, M., Novasari, V., & Lamei, N.
Affiliations
  • Tehran University of Medical Sciences (IR)
  • Payame Noor University (IR)
Corresponding author
Ezoddin, Maryam
ORCID
Venue
Journal of Separation Science
Publisher
Wiley
Published
2024-09
Volume
47
Issue
18
Pages
e202300878-e202300878
ISSN
  • 1615-9306 (ISSN-L)
  • 1615-9314
DOI
10.1002/jssc.202300878
OpenAlex
W4402711704
Cited by
6
References
30
Citations by year
2026: 2 · 2025: 3 · 2024: 1
FWCI
1.03
Type
journal article
Language
en
Open access
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor, 19 d)
Locations
  • Journal of Separation Science (publishedVersion)
  • PubMed (publishedVersion)
Funders
Payame Noor University
Topics
  • Physical Sciences › Chemistry › Analytical Chemistry › Analytical chemistry methods development
  • Physical Sciences › Chemical Engineering › Catalysis › Ionic liquids properties and applications
  • Physical Sciences › Chemistry › Spectroscopy › Analytical Chemistry and Chromatography
Keywords
phthalates, deep eutectic solvents, dispersive liquid-liquid microextraction, water samples, lidocaine, oleic acid, ultrasound-assisted extraction, preconcentration, microdroplets, acid-base properties

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