Molybdenum disulfide-graphene oxide composites as dispersive solid-phase extraction adsorbents for the enrichment of four paraben preservatives in cosmetics

Molybdenum disulfide-graphene oxide composite (MoS2/GO) was synthesized and used as the adsorbent in dispersive solid-phase extraction. Four paraben preservatives, namely, methylparaben, ethylparaben, propylparaben, and butylparaben, were enriched with MoS2/GO and determined by ultra-high-performance liquid chromatography. Molybdenum disulfide was intercalated into graphene oxide layers to reduce self-aggregation by using the solvothermal method. The experimental results indicated that the as-prepared MoS2/GO composite exhibited great enrichment capability toward those four paraben preservatives, and the adsorption time was 10 min and the elution time was as short as 1 min. The mechanism of MoS2/GO composite and parabens is attributed to hydrogen bonding and electrostatic attraction. The relative standard deviation (RSD, n=9) of this method was below 7.6%. Limits of detection and limits of quantification were in the range 0.4-2.3 ng/mL and 1.4-7.6 ng/mL, respectively. The recoveries obtained from the parabens of cosmetic sample were in the range 91.3-124% with RSDs below 10%. The developed method has great potential for the determination of emerging contaminants with low cost and high sensitivity.Graphical abstract

Automated summary

A MoS2/GO composite was synthesized and used as an adsorbent for the determination of four paraben preservatives, showing great enrichment capability. The method has potential for the detection of emerging contaminants with low cost and high sensitivity.