Toluene

Chemicals, reagents and buffers. The glass microscope slides used as substrates for the microarrays were obtained from Labbox Labware, S.L. (Spain). The Immobilon-P PVDF membranes were acquired from Merck (Spain). The PTFE membranes came from Wolfpack (Spain). 2-[Methoxy(polyethyleneoxy)6-9propyl]trimethoxysilane was purchased from Gelest (Germany). 1H,1H,2H,2H-Perfluorodecyltriethoxysilane and vinyltrimethoxysilane were supplied bySigma-Aldrich (Spain). Toluene was purchased from Scharlau (Spain). 3,3′,5,5′-Tetramethylbenzidine liquid substrate was acquired from SDT (Germany). Note: all the chemicals were handled following the corresponding material safety data sheets. All the chemicals were used without further purification.
Milli-Q water, with a resistivity above 18 mΩ, was used to prepare the aqueous solutions. The employed buffers, phosphate buffer saline (PBS1х, 0.008 M sodium phosphate dibasic, 0.002 M sodium phosphate monobasic, 0.137 M sodium chloride, 0.003 M potassium chloride, pH 7.5), PBS-T (PBS1х containing 0.05% Tween 20) and saline sodium citrate (SSC1х, 0.15 M sodium chloride, 0.02 M sodium citrate, pH 7) were filtered through a 0.45-µm pore size nitrocellulose membrane of the Fisher brand (Germany) before being used. Table 1. Used oligonucleotides sequences

Hexane and toluene as HPLC grade solvent were purchased from Scharlau (Barcelona, Spain). Hydrogen sulfide as gas state (>99%), ethyl mercaptan, dimethyl sulfide, carbon disulfide, butyl mercaptan and dimethyl disulfide as liquid state (>99%) were used supplied by Sigma Aldrich (Steinheim, Germany). Solid-phase support were Anasorb CSC coconut charcoal (50/100 mg) combined with sodium sulfate dryers supplied by SKC limited (Dorset, UK), Orbo-32 activated coconut charcoal (100/50 mg) (Sigma Aldrich, USA) and Tenax TEA (Sigma Aldrich, USA).