Electronic Supplementary Material

Evaluation of Graphene Aerogel Monolith Based Solid-Phase Extraction for the Separation of Pyrethroids from Water Samples

Liu Yang a, *,†, Qiang Han b,†, Shaoai Sun b, Mingyu Ding b, *

a State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China

b The Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China

* Corresponding author:

Postal address: State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China (Liu Yang)

E-mail address: (Liu Yang)

(Mingyu Ding)

Tel: +86-13601262107

† Liu Yang and Qiang Han contribute equally to this study and share first authorship.

Experimental

Instrumental and analytical conditions

Scanning electron microscopy (SEM) images were collected on a field emission SU8010 system (Hitachi, Japan). The equipment used for SPE experiments, including Win-SPE 12 SPE, VP30 vacuum pump as well as empty SPE cartridges (6 mL, polypropylene) and frits (10 μm, polypropylene) were all provided by LabTech (Bejing, China).

Preparation of graphene oxide (GO)

The preparation of GO dispersion was from expanded graphite according to a modified Hummers' method [1]. The procedure is briefly described as follows. The mixture of concentrated H2SO4 (720 mL) and H3PO4 (80 mL) was frozen to about 0 ℃. Potassium permanganate (36 g) and expanded graphite (6 g) was added into the above mixture slowly with vigorous agitation to avoid a sudden increase of the temperature. After kept at 50℃ for 12 h, the mixture was poured into an ice-water mixture with the identical volume. 30% H2O2 was added dropwise to all the slurry turn to golden yellow. The obtained slurry was rinsed with 10% HCl and water by centrifugation. Finally, it was purified by dialysis for one week to remove the remaining metal species. The slurry was transferred subsequent to the ultrasonication for 2 h, and the mass concentration of the as-prepared GO aqueous dispersion (13.3 mg mL-1) was confirmed by drying certain volume of the above solution.

Fig. S1 The effect of sample volume on the recoveries of pyrethroids. Experimental conditions, loading: 1 μg each analyte in different volume of aqueous solution; elution: 2 mL ethyl acetate.

Fig. S2 The effect of sample pH on the recoveries of pyrethroids. Experimental conditions, loading: 1 μg each analyte in 10 mL different pH of aqueous solution; elution: 2 mL ethyl acetate.

Compound / structure / Molecular weight / Kowa / Qualitative ion / Quantitative ion
fenpropathrin / / 349.4 / 1.000×106 / 97, 125, 181 / 97
γ-cyhalothrin / / 449.9 / 1.000×107 / 181, 197, 208 / 181
permethrin / / 391.3 / 1.259×106 / 127, 163, 183 / 183
cypermethrin / / 416.3 / 3.981×106 / 163, 165, 181 / 163
fenvalerate / / 419.9 / 1.023× 105 / 125, 167, 225 / 125

Table S1 The GC-MS analysis conditions for pyrethroids

a Kow: octanol-water partition coefficient [2]

References

[1] D.C. Marcano, D.V. Kosynkin, J.M. Berlin, et al., Improved synthesis of graphene oxide, ACS Nano 4 (2010) 4806-4814.

[2] R.J.B. da Silva, P.M. Dias, M.F.G. Camões, Development and validation of a grouping method for pesticides analysed in foodstuffs, Food Chem. 134 (2012) 2291-2302.