A hierarchically porous structured composite monolith sorbent of polypyrrole-coated graphene oxide and octadecyl silica incorporated in chitosan cryogel (PPY/GOx/C18/chitosan) was synthesized and used as solid-phase extraction sorbent for the determination of carbamate pesticides. Various factors affecting the characteristics of the adsorbents (chemistry of the sorbent, polymerization time, concentrations of graphene oxide and octadecyl silica) and the extraction efficiency using the prepared sorbents, such as sample loading, desorption conditions, sample volume, sample flow rate, sample pH, and ionic strength, were investigated and optimized. Under the optimal conditions of sorbent preparation and extraction, the developed composite monolith sorbent provided wide linear responses from 1.0 to 500 μg L⁻¹ for carbofuran and diethofencarb, from 0.5 to 500 μg L⁻¹ for carbaryl, and from 2.0 to 500 μg L⁻¹ for isoprocarb. The limits of detection using HPLC-UV at 203, 220, and 208 nm were in the range of 0.5–2.0 μg L⁻¹. When the composite monolith sorbent was applied for the pre-concentration and determination of carbamate in fruit juices, good recoveries (84.1–99.5%) were achieved. The developed sorbents were porous and exhibited low back pressure enabling their use at high flow rates during sample loading. Extraction and clean-up were highly efficient, and the good physical and chemical stability of the sorbent enables reuse up to 13 times.

中文翻译：

---

分级多孔复合整体式聚吡咯/十八烷基二氧化硅/氧化石墨烯/壳聚糖冷冻凝胶吸附剂，用于果汁中氨基甲酸酯类农药的提取和预浓缩

合成了掺入壳聚糖冷冻凝胶（PPY / GOx / C18 /壳聚糖）中的聚吡咯涂层氧化石墨烯和十八烷基二氧化硅的多孔结构复合整体吸附剂，并将其用作固相萃取吸附剂，用于测定氨基甲酸酯类农药。影响吸附剂特性（吸附剂的化学性质，聚合时间，氧化石墨烯和十八烷基二氧化硅的浓度）和使用制备的吸附剂的萃取效率的各种因素，例如样品上样量，解吸条件，样品量，样品流速，样品对pH和离子强度进行了研究和优化。在吸附剂制备和提取的最佳条件下，开发的复合整体吸附剂可提供1.0至500μgL ^-1的宽线性响应对于呋喃丹和二氢呋喃威，对甲萘威为0.5至500μgL ^-1，对异丙威为2.0至500μgL ^-1。使用HPLC-UV在203、220和208 nm处的检出限为0.5–2.0μgL ^-1。当将复合整体吸附剂用于果汁中氨基甲酸酯的预浓缩和测定时，可实现良好的回收率（84.1–99.5％）。所开发的吸附剂是多孔的，并且表现出较低的背压，从而使其能够在样品上样期间以高流速使用。萃取和净化非常高效，吸附剂良好的物理和化学稳定性使其可重复使用多达13次。