Ch3cooh

The electrochemical experiment was carried out based on the CHI660 electrochemical analyzer of Shanghai Chenhua Instrument Co., Ltd. A three-electrode system was used, in which a 3 mm GCE was used as the working electrode and a platinum wire was used as the counter electrode. The saturated calomel electrode is the auxiliary electrode. Sigma HD scanning electron microscope (SEM) was used to observe the morphology of the modified electrodes. The polytetrafluoroethylene liner reactor, electronic analytical balance, suction filter device, ultrasonic cleaning machine, electric heating blast drying oven, and high-speed centrifuge are all from Shanghai Chenhua Instrument Co., Ltd.
The drugs used in the experiment were Na₂MoO₄·2H₂O, CH₄N₂S, C₂H₅OH, FeCl₃·6H₂O, FeCl₂·4H₂O, NH₃·H₂O, CH₃COOH, Nafion (5 wt%) solution, C₂H₃NaO₂, Cd²⁺ standard solution and other reagents, all purchased from Sinopharm Chemical Reagent Co., Ltd. The purity used was either analytical reagent (AR) or guaranteed reagent (GR). The experimental water was ultrapure water with a resistivity of 18.0 MΩ cm. The actual water samples were taken from the seawater of the Maowei Sea in Qinzhou.

Graphene was purchased by Ningbo Moxi Tech. Co., Ltd. (China). 3, 4, 9, 10-Perylene tetracarboxylic anhydride (PTCDA) was purchased from the Xiya Chemical Reagent Company (Chengdu, China). 6-Aminocaproic acid, imidazole, triphenylphosphine (TPP) and Calcium chloride anhydrous were all purchased from Aladdin Chemistry Co., Ltd, China. Ethanediamine (EDA), Pyridine (Py), methanol, 30% hydrochloric acid, the solvent N-methyl-2-pyrrolidone (NMP) and N, N-dimethylformamide (DMF) were analytical grade, provided by Guangdong Guanghua Sci-Tech Co., Ltd, China. Sisal fibers were bought from Guangxi Sisal Company, China. NaClO₂, CH₂ClCOOH, anhydrous ethanol, Na₂SO₄•10H₂O, CH₃COOH, NaOH, H₂SO₄ and H₂O₂ were purchased from Sinopharm Chemical Reagent Co., Ltd China. All other reagents and solvents were used without further purication.

D-ribose, L-ribose, AgNO₃, H₃BO₃, CH₃COOH, H₃PO₄, NaOH, HCl were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). β-cyclodextrin (β-CD, C₄₂H₇₀O₃₅, molecular weight is 1134.99) composed of D-glucose was purchased from Sangon Biotechnology Inc. (Shanghai, China). High-purity water was used in this study. All the chemicals were used as received without further purification.

5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin (TMPyP) was purchased from Sigma-Aldrich (St. Louis, MO, USA). The oligonucleotides (ODNs), such as polyadenine dA₁₃, polycytosine dC₁₃, polyguanine dG₆TG₆ and polythymine dT₅, dT₁₀, dT₁₃, dT₁₅, dT₂₀, dT₃₀, dT₄₀, dT₅₀ were synthesized by Sangon Biotechnology Co., Ltd. (Shanghai, China). Hg(NO₃)₂, Cd(NO₃)₂·4H₂O, Cr(NO₃)₃·9H₂O, Cu(NO₃)₂·3H₂O, Fe(NO₃)₃·9H₂O, FeSO₄·7H₂O, Mn(CH₃COO)₂·4H₂O, MgCl₂·6H₂O, NiCl₂·6H₂O, Pb(NO₃)₂, ZnCl₂, Tris-HCl, CH₃COOH, NaCl and NaOH were acquired from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). All the ODNs were prepared with Tris-HCl buffer (10 mM Tris, 100 mM NaCl, pH 7.4). All reagents were of analytical grade and used as received. Ultrapure water was obtained from a Millipore water purification system (≥18 MΩ, Milli-Q, Millipore).

Betaine, dimethylglycine, l-proline, sarcosine, TMAO, and methylene blue were obtained from Shanghai Titan Technology. AA and semixylenol orange were purchased from Aladdin Chemical. Irgacure 2959 was purchased from TCI chemical. PAA (average M_W ≈ 100,000 g mol⁻¹, 35 wt% in H₂O), acrylamide, N,N′-methylene bisacrylamide, ammonium persulfate, N,N,N′,N′-tetramethylethylenediamine, and LiBr were purchased from Sigma-Aldrich. NaCl and CH₃COOH were purchased from Sinopharm Chemical Reagent. RPMI-1640 and DMEM (high glucose) culture media were purchased from Genom Co. Ltd. PBS and normal saline solutions were freshly prepared in the laboratory.