Accumet ab15 plus ph meter

The novel designed probe featuring a hexagonal 1-in-6 fiber configuration (Scheme S1b)⁴² was fabricated as described previously with minor modifications.^{39 –41} Briefly, single-mode optical fiber (SMF-28, Corning Inc., NY) was used, and the probe was fabricated by using a home-built coaxial-twisting and gravitational-stretching system.^{40 (link)} Once the 1-in-6 fiber taper stem was fabricated, a uniform Au/Pd layer with an approximate thickness of 250 – 300 nm was sputter-coated, to optically isolate the probe tip from environmental influences. Then focused ion beam (FIBs, Helios Nanolab 600, FEI) milling was applied to remove the very tip (< 5 μm) Au/Pd layer. Immediately the tip was subjected to an organic-modified silicate (OrMoSil) sol-gel coating to introduce the embedded pH-sensing HPTS dye (excitation at488nm and emission at 525 nm). The featured small sensing tip and the designed 1-in-6 fiber configuration ensured a high spatial resolution detection and high-efficiency emission-collection. All fabricated probes were validated through measuring a series of standard pH buffer solutions with known pH, which have been pre-confirmed by an Accumet AB15 Plus pH meter (Thermo Fisher Scientific Inc., MA).

A novel optical microprobe with a hexagonal 1-in-6 fiber configuration (Figure 1 and 2, Figure S1) was fabricated as described previously with minor modifications.(Sisi Chen et al., 2017 ; Yang, Wang, Chen, et al., 2015 (link); Yang, Wang, Lan, et al., 2015 ) Briefly, single-mode optical fiber (SMF-28, Corning Inc., NY) was used and the probe was fabricated by using a home-built coaxial-twisting and gravitational-stretching system (Figure S1) (Yang, Wang, Chen, et al., 2015 (link)). Once the 1-in-6 fiber taper stem was fabricated, a uniform gold (Au)/palladium (Pd) layer with an approximate thickness of 350 – 450 nm was sputter-coated, to optically isolate the probe tip from environmental influences. Then focused ion beam (FIBs, Helios Nanolab 600, FEI) milling was applied to remove the very tip (< 5 μm) Au/Pd layer. Immediately the tip was subjected to an organic-modified silicate (OrMoSil) sol-gel coating to introduce the embedded pH-sensing HPTS dye (ex. 488nm/em. 525 nm). The featured small sensing tip and the designed 1-in-6 fiber configuration ensured a high spatial resolution detection and highly efficient emission-collection. All fabricated probes were validated through measuring a series of standard pH buffer solutions with known pH (Figure 2a), which have been pre-confirmed by an Accumet AB15 Plus pH meter (Thermo Fisher Scientific Inc., MA).