Quality assessment of environmental water by a simple and fast non-ionic hydrophobic natural deep eutectic solvent-based extraction procedure combined with liquid chromatography tandem mass spectrometry for the determination of plastic migrants

Abstract

Graphical abstract A non-ionic hydrophobic natural deep eutectic solvent (HNADES) based on thymol and menthol was proposed for the liquid-liquid microextraction of fourteen phthalates and one adipate from environmental water samples. Separation, identification, and quantification were achieved by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. The main factors affecting the extraction efficiency were thoroughly studied. Sample pH of 8 and 100 μL of thymol:menthol at molar ratio 2:1 were selected as the best conditions, while ionic strength and type of dispersant solvent were not relevant for the extraction of the target compounds. The whole methodology was validated for treated wastewater, runoff, and pond water matrices, using di- n -butyl phthalate-3,4,5,6-d 4 and dihexyl phthalate-3,4,5,6-d 4 as surrogates. Recovery ranged from 70 to 127% with relative standard deviation values lower than 14%. Limits of quantification of the method were in the range 0.042–0.425 μg/L for treated wastewater, 0.015–0.386 μg/L for runoff, and 0.013–0.376 μg/L for pond water. The methodology was applied for the analysis of real treated wastewater, runoff, and pond water samples from different places of Tenerife and Gran Canaria (Canary Islands) finding the presence of diethyl phthalate, diallyl phthalate, dipropyl phthalate, benzylbutyl phthalate, di-n-butyl phthalate, bis-(2- n -butoxyethyl) phthalate, di-n-pentyl phthalate, dicyclohexyl phthalate, and bis-(2-ethylhexyl) phthalate at concentrations between 105.2 and 3414 ng/L. Supplementary Information The online version contains supplementary material available at 10.1007/s00216-021-03166-1.

Recent Applications of Deep Eutectic Solvents in Environmental Analysis

“…The unique features of DESs have boosted their applications in analytical chemistry, especially as alternative extraction solvents in sample preparation. In this sense, as can be seen in Table 1 [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], these solvents have been successfully employed for the evaluation of plastic migrants [11,16], pharmaceuticals [12,13,17,19], pesticides [14,15,18,25], dyes [15], hormones [16], ultraviolet (UV)-filters [16,21], polycyclic aromatic hydrocarbons (PAHs) [22] and explosives [24] in different environmental matrices, mainly water samples [11][12][13][14][15][16][17][18][19]21,22,24,25] and to a lesser extent in soil samples [15,24]. Among the types of DESs used with this purpose, HDESs have signif...…”

“…In addition, ChCl-based DESs have also been applied to capture CO 2 from natural gas [20] and biomass delignification [23]. Regarding the extraction procedures, the application of DESs has taken place in various microextraction techniques including liquid-liquid microextraction (LLME) [11,13,[15][16][17][18]21,22] and its dispersive mode (DLLME) [12,14,19], assisted by vortex (VA) [11,15,19], ultrasounds (UA) [14,18,22], air cycles of pulling in/pushing out [16,21], using a mechanical shaker (SA) [17], controlled by pH changes [13] and solidifying the floating organic droplet (SFOD) after the extraction process [16,22], as well as in solid-phase extraction in its magneticmicro-dispersive mode (m-µ-dSPE) [24,25]. A heating and stirring extraction has also been developed [23].…”

“…As can be seen in Figure 1, Raynie and GAPI pictograms also confirmed these results. However, other studies in which the phase separation has only been favoured by mechanical assistance (i.e., VA, SA, UA and air-assisted (AA) methods) can also be found in the literature [11,15,[17][18][19]21]. In these cases, the analytical procedures are simpler, faster and cheaper since the use of additional solvents or solutions is avoided.…”

“…These solvents are exclusively constituted by primary or secondary metabolites, as well as other compounds presented in cells that make them less-or non-toxic and assure their biocompatibility. These characteristics have enhanced the interest in the application of NaDESs for the evaluation or treatment of environmental matrices due to the low impact of these solvents in such media performing more sustainable procedures [11]. Indeed, a brief evaluation of the recent literature indicates that NaDESs make up the majority of DESs used in the field of environmental analysis for the study of organic and inorganic compounds in liquid and solid matrices.…”

A Comprehensive Review on Liquid-Liquid Extraction Based Systems in Treatment of Textile Wastewater

“…Based on the density difference between extract and raffinate phases, separation occurs. The extract phase is further separated by using distillation or any other similar unit operation to separate solute and extracting solvent (25,26) . Extracting solvent is recycled for its use in process industries.…”