[Determination of 10 carbamate pesticide residues in liquid milk by ultra performance liquid chromatography-tandem mass spectrometry with pass-through solid-phase extraction purification].

Carbamates are used in broad-spectrum insecticides and herbicides, and have highly efficient, low-residue, and long-lasting characteristics. However, this type of pesticide exerts mutagenic, teratogenic, carcinogenic, and other adverse effects, and its frequent use can exceed the recommended scope and limits. Research on the determination of carbamate pesticides mainly focuses on foods of plant origin and pays less attention to foods of animal origin. The methods for carbamate determination described in the current national standards have complicated operating procedures and low efficiency. Therefore, highly efficient and accurate methods for carbamate detection in milk must be established. In this work, a rapid method based on pass-through solid-phase extraction (SPE) purification coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of 10 carbamate pesticides in liquid milk. The pretreatment and instrument methods were systematically optimized. The milk sample was extracted with acetonitrile, and then purified using a Captiva EMR-Lipid filtration kit. The purified extract was separated on an ACQUITY UPLC BEH C18 column with mobile phase of methanol and 0.1% formic acid aqueous solution in gradient elution. The flow rate was 0.3 mL/min. Column temperature was 35 ℃. Quantitative analysis was performed using the external standard method with matrix matching curves. The 10 carbamate pesticides showed good linear relationships in the mass concentration range of 2-200 µg/L, with correlation coefficients greater than 0.999. The limits of detection (LODs) and quantification (LOQs) for the 10 carbamate pesticides were 0.045-0.23 and 0.15-0.77 µg/kg, respectively. Recovery tests were conducted using the blank-matrix method at three spiked levels of 15, 50, and 100 µg/kg, and good recoveries for the 10 carbamate pesticides were obtained. In particular, the recoveries for the three spiked levels of 15, 50, and 100 µg/kg were 68.7%-93.3% with relative standard deviations (RSDs) of 1.8%-8.0%. The proposed method is efficient, convenient, accurate, and suitable for the rapid detection of the 10 carbamate pesticides in liquid milk. Compared with the conventional NH2 and ENVITM-18 SPE columns used in the national standard determination method, the proposed method demonstrated better purification effects. The recoveries for aldicarb sulfoxide, aldicarb sulfone, methomyl, and carbaryl after purification using the Captiva EMR-Lipid kit increased from 60% to 80%. Thus, the proposed method is suitable for targets with strong polarity and gives measurement results with good repeatability and accuracy.

Controllable construction of multifunctional superhydrophobic coating with ultra-stable efficiency for oily water treatment.

Designing interfacial coating with tailored characteristics is a crucial step in regulating the wetting properties of oil/water separation materials; however, the controllable fabrication of multifunctional layer with long-term durability in harsh environments remains challenging. Fabrication of raised dots based on magnetic Fe3O4 particles on micro-nanometer units, inspired by mussel chemistry, under the adhesion behavior of dopamine (DA) self-polymerization covalent deposition of Fe3O4 particles and hydrophobic polydimethylsiloxane (PDMS) modification to synthesize magnetic superhydrophobic cotton composites (Cotton-P). Due to the unique magnetic and superhydrophobic surface composition, the synthetic Cotton-P possesses superhydrophobic (155.4°) and magnetic properties and still exhibits these excellent properties after 10 cycles. In addition, the hydrophobicity of magnetic monolithic cotton is virtually unaffected in harsh environments. The chemical/thermal stability of the Cotton-P composite is improved due to the rigid silane coating on the skeleton. Moreover, the Cotton-P revealed excellent oil/water separation efficiency of over 98 % after 10 cycles. Based on these outstanding properties, Cotton-P has the potential to develop in the treatment of oil-water mixtures.