4 nitroaniline

Graphite powder (99.99% -trace metal basis), sodium nitrate (99%), potassium permanganate (99%), 4-nitroaniline (≥99%), 4-aminophenol (≥99%) and 4-nitro-ο-phenylenediamine (≥99%) were purchased from Sigma-Aldrich, Johannesburg, South Africa. These chemicals were of analytical grade and were used without further purification. Hydrogen peroxide (100%) was purchased from Merck Laboratory Supplies, Johannesburg, South Africa. Sulfuric acid (98%) was purchased from Promark Chemicals, Johannesburg, South Africa. Double distilled water was obtained from a double distiller, Glass Chem water distiller model Ws4lcd was supplied by Shalom Laboratory Supplies, Durban, South Africa. A gas mixture of 10% hydrogen in argon (v/v) was purchased from Afrox Limited Gas Co., Durban, South Africa. Weighing of N-rGO was done on an electronic weighing balance, Mettler AE 200, Mundelein, IL USA. Ultrasonication was performed in a digital ultrasonic water bath (400 W) obtained from Shalom Laboratory Supplies, Durban, South Africa.

Chemicals including CA (≥97%), RA (≥97%), BL (98%), and ML (97%) were purchased from Aladdin Biochemical Technology Co., Ltd. (Shanghai, China). Polyethylene glycol (number average molecular weight, 400) (PEG-400) was supplied by Yantian Biotechnology Co., Ltd. (Shanghai, China). The IL, [C₄mim]PF₆ (99%) was obtained from the Lanzhou Institute of Chemical Physics of the Chinese Academy of Sciences (Lanzhou, China). Reichardt’s dye (RD, 90%) and 4-nitroaniline (NA, ≥99%) were supplied by Sigma-Aldrich Co., (St. Louis, MO, USA); N,N-diethyl-4-nitroaniline (DENA, 97%) was obtained from Fluorochem Ltd., (Hadfield, UK). The macroporous resins CAD-40 (polar resin, specific surface area: 450–500 m² g⁻¹, particle size: 60–16 meshes) and HP-20 (non-polar resin, specific surface area: 550–600 m² g⁻¹, particle size: 60–16 meshes) were supplied by Xinhu Laboratory Equipment Co., Ltd. (Shanghai, China). All the other reagents are of analytical grade and were used as received. Dried ROLs were supplied by Haoruijia Biotechnology Co., Ltd. (Chengdu, China) and crushed into fine powers (100 meshes) before use. The extract of the ROLs was prepared using 45% PEG-400 as the extraction solvent containing 4.3% H₃PO₄ [13 (link)].

NIC, 4-nitroaniline, 2-nitroaniline, 3-nitroaniline, N-(4-nitrophenyl) propionamide, H-Val-pNA HCl, L-argininep-nitroanilide dihydrochloride, 4-nitrophenethylamine hydrochloride, N-methyl-4-nitrophenethylamine hydrochloride, H-Ala-pNA HCl, N, N-dimethyl-4-nitroaniline, H-Glu-pNA, halofuginone, toltrazuril, 1,3-diphenylguanidine, ronidazole, and dinitolmide were obtained from Sigma-Aldrich (St. Louis, MO, USA) (Figure 1). The coating antigen (DNC-4-BSA) and mAb 3B4 were acquired from China Agricultural University (Qianqian Tang May 2018). For other reagents materials were shown in the Supplementary Materials part.