Combination of dispersive liquid-liquid microextraction using multifunctional ionic liquids with high performance chromatography for determination of phthalate ester metabolites in human urine sample

doi:10.3724/SP.J.1123.2019.09026

Abstract

Abstract:

A novel sensitive method for the determination of the five primary metabolites of phthalate esters (PAEs) in urine was developed by combining dispersive liquid-liquid microextraction (DLLME) using ionic liquids with high performance liquid chromatography (HPLC). The factors affecting the efficiency of DLLME were optimized. The types and proportions of extraction solvent and dispersants, as well the ultrasonic extraction time, cooling time, and centrifugal time, were determined. The optimal conditions were as follows:extraction solvent[C₈MIM]PF₆] 35 μL; dispersants[BSO₃HMIm]OTf] 30 μL, [C₄MIM]BF₆] 120 μL; NH₄PF₆ 0.1 g, extraction at 35℃, ultrasonic dispersion for 5 min, cooling in ice water for 5 min, centrifugation at 4000 r/min for 5 min. After optimization, the five primary metabolites of PAEs were determined. The method showed a good linear relationship within the concentration range of 0.5-1000 μg/L. The determination coefficients (R²) were greater than 0.9955. The detection limit was in the range of 0.16-0.19 μg/L. Under the optimized conditions, the extraction recoveries for the PAEs were 92.9%-105.0%, and the relative standard deviations (RSDs) of the intra- and inter-day precisions were < 5.96%. Urine samples collected from 10 diabetic patients were tested, and the exposure level of the population to the PAE metabolites was evaluated. All the PAE metabolites were detected in these samples, and the detection rate of 2-ethylhexyl hydrogen phthalate (MEHP) was 100%. In conclusion, no toxic organic reagents were added during the extraction process in this method, and multifunctional ionic liquids were used as the extraction agent, dispersant, and salting-out agent. In other words, the extraction process was demonstrated to be green, simple, and efficient. The developed method has high sensitivity and stability, and it is suitable for the determination of trace PAE metabolites in human urine.

Key words: dispersive liquid-liquid microextraction (DLLME), high performance liquid chromatography (HPLC), phthalate metabolites, urine, multiple functional ionic liquids

SUN Qian, DAI Haoqiang, CHEN Peipei, SHE Hui, WU Jia. Combination of dispersive liquid-liquid microextraction using multifunctional ionic liquids with high performance chromatography for determination of phthalate ester metabolites in human urine sample[J]. Chinese Journal of Chromatography, 2020, 38(8): 929-936.

Figures/Tables 10

References

1	Liu S S , Peng Y F , Lin Q T , et al. Environ Toxicol Chem, 2019, 38(5): 1132
2	Bo Y N , Li R , Zhang P J , et al. Chinese Journal of Chromatography, 2016, 34(9): 868
2	薄艳娜, 李蓉, 张朋杰, et al. 色谱, 2016, 34(9): 868
3	Romani F , Tropea A , Scarinci E , et al. Fertil Steril, 2014, 102: 831
4	Reyes J M , Price P S . Environ Int, 2018, 112: 77
5	Zhang X , Qiu T , Fu H , et al. Chinese Journal of Chromatography, 2018, 36(9): 895
5	张续, 邱天, 付慧, et al. 色谱, 2018, 36(9): 895
6	Frederiksen H , Skakkebaek N E , Andersson A M . Mol Nutr Food Res, 2007, 51(7): 899
7	Desvergne B , Feige J N , Casals-Casas C . Mol Cell Endocrinol, 2009, 304: 43
8	Fan Y , Wang X , Xia Y K , et al. Journal of Environmental & Occupational Medicine, 2019, 36(2): 141
8	范赟, 王旭, 夏彦恺, et al. 环境与职业医学, 2019, 36(2): 141
9	Kang L , Liu H H , Liao S C , et al. Chinese Journal of Health Laboratory Technology, 2017, 27(23): 3349
9	康莉, 刘红河, 廖仕成, et al. 中国卫生检验杂志, 2017, 27(23): 3349
10	López-Carrillo L , Hernández-Ramírez R U , Calafat A M , et al. Environ Health Persp, 2010, 118(4): 539
11	North M L , Takaro T K , Diamond M L , et al. Ann Allergy Asthma Immunol, 2014, 112(6): 496
12	Rajesh P , Balasubramanian K . Hum Exp Toxicol, 2013, 33(7): 685
13	Svensson K , Hernandez-Ramirez R U , Burguete-Garcia A , et al. Environ Res, 2011, 111(6): 792
14	Trasande L , Sathyanarayana S , Spanier A J , et al. J Pediatr, 2013, 163(3): 747
15	Lind P M , Zethelius B , Lind L . Diabetes Care, 2012, 35(7): 1519
16	Wang H X , Wang B , Zhou Y , et al. Anal Bioanal Chem, 2013, 405(12): 4313
17	Huang C N , Li Y , Peng J Y , et al. Chinese Journal of Chromatography, 2018, 37(8): 815
17	黄超囡, 李云, 彭俊钰, et al. 色谱, 2019, 37(8): 815
18	Wu C Q , Li Y , Chang S P , et al. Chinese Journal of Chromatography, 2018, 36(5): 452
18	吴翠琴, 李颖, 常淑萍, et al. 色谱, 2018, 36(5): 452
19	Wang X X , Li X , Xiao Y X , et al. Chinese Journal of Chromatography, 2018, 36(3): 292
19	王璇璇, 李潇, 肖玉秀色谱, 2018, 36(3): 292
20	Peng L , Wang L F , Zhang D B , et al. Journal of Yangtze River Scientific Research Institute, 2019, 36(1): 29
20	彭恋, 王立帆, 张德兵, et al. 长江科学院院报, 2019, 36(1): 29
21	Sun J N , Chen J , Shi Y P . Talanta, 2014, 125: 329
22	González-Sálamo J , González-Curbelo M á , Socas-Rodríguez B , et al. Chemosphere, 2018, 201: 254
23	Wu J , Ye Z H , Li X L , et al. J Chromatogr B, 2016, 1014: 1
24	Arain M S , Arain S A , Kazi T G , et al. Spectrochim Acta A Mol Biomol Spectrosc, 2015, 137: 877
25	Kranvogl R , Knez J , Miuc A , et al. Acta Chim Slov, 2014, 61: 110
26	Sha C , Sheng Z Y , Yuan C S , et al. J Sep Sci, 2011, 34: 1503
27	Zhang H , Chen X , Jiang X . Anal Chim Acta, 2011, 689: 137

Compound	Linear range/(μg/L)	Regression equation	R²	LOD/(μg/L)
y: peak area; x: mass concentration, μg/L; linear range: 0.5-1000 μg/L.
MEP	0.5-1000	y=58.166x-0.5410	0.9985	0.17
MIBP	0.5-1000	y=62.253x-0.8688	0.9963	0.19
MBP	0.5-1000	y=58.292x-0.6217	0.9979	0.16
MBZP	0.5-1000	y=61.934x-0.9530	0.9994	0.18
MEHP	0.5-1000	y=59.979x+1.8258	0.9955	0.19

Compound	Linear range/(μg/L)	Regression equation	R²	LOD/(μg/L)
y: peak area; x: mass concentration, μg/L; linear range: 0.5-1000 μg/L.
MEP	0.5-1000	y=58.166x-0.5410	0.9985	0.17
MIBP	0.5-1000	y=62.253x-0.8688	0.9963	0.19
MBP	0.5-1000	y=58.292x-0.6217	0.9979	0.16
MBZP	0.5-1000	y=61.934x-0.9530	0.9994	0.18
MEHP	0.5-1000	y=59.979x+1.8258	0.9955	0.19

Analyte	Background/(μg/L)	5 μg/L		20 μg/L		100 μg/L		Intra-day RSD	Inter-day RSD
Analyte	Background/(μg/L)	Recovery/%	RSD/%	Recovery/%	RSD/%	Recovery/%	RSD/%	Intra-day RSD	Inter-day RSD
nd: not detected.
MEP	nd	99.6	5.02	104.5	0.57	98.1	1.59	2.98	3.56
MBP	nd	105.0	7.23	101.4	4.42	93.0	1.88	2.16	3.8
MIBP	10.47±0.27	102.4	3.38	99.6	1.80	98.6	1.39	3.68	3.32
MBZP	nd	97.4	5.34	92.9	7.32	98.5	2.05	3.56	1.23
MEHP	20.68±0.58	103.9	2.94	100.5	0.49	99.0	0.16	5.96	3.52

Analyte	Background/(μg/L)	5 μg/L		20 μg/L		100 μg/L		Intra-day RSD	Inter-day RSD
Analyte	Background/(μg/L)	Recovery/%	RSD/%	Recovery/%	RSD/%	Recovery/%	RSD/%	Intra-day RSD	Inter-day RSD
nd: not detected.
MEP	nd	99.6	5.02	104.5	0.57	98.1	1.59	2.98	3.56
MBP	nd	105.0	7.23	101.4	4.42	93.0	1.88	2.16	3.8
MIBP	10.47±0.27	102.4	3.38	99.6	1.80	98.6	1.39	3.68	3.32
MBZP	nd	97.4	5.34	92.9	7.32	98.5	2.05	3.56	1.23
MEHP	20.68±0.58	103.9	2.94	100.5	0.49	99.0	0.16	5.96	3.52

Extraction method	Instrument	Sample preparation	Linear range/(μg/L)	LOD/(μg/L)(S/N=3)	Reference
SPE: solid-phase extraction; IL-DLLME: ionic liquid-based dispersive liquid-liquid microextraction; IL-CIA-DLLME: ionic liquid cold-induced aggregation dispersive liquid-liquid microextraction.
SPE	GC-MS	enzymatic hydrolysis→SPE→azeotropic distillation→derivatisation	1.0-200	0.8-1.4	[25]
SPE	LC-MS	enzymatic hydrolysis→SPE →nitrogen-blow (drying out)	0.2-200	0.06	[5]
IL-DLLME	HPLC	ionic liquid-based DLLME→ice-water bath→centrifugation	50-600	3.3	[26]
IL-CIA-DLLME	HPLC	sample was heated to 50 ℃→ionic liquid cold-induced aggregation dispersive liquid-liquid microextraction→centrifugation	2.0-100	0.7-1.4	[27]
IL-DLLME	HPLC	enzymatic hydrolysis→DLLME→sonication→cooling in ice→ centrifugation	0.5-1000	0.16-0.19	this method