Novel methods for the detection of glutathione by surface enhanced Raman scattering: A perspective review ScienceDirect Colorimetric detection and determination of glutathione based on superoxide radical assisted etching approach ScienceDirect Monitoring of glutathione using ratiometric fluorescent sensor based on MnO2 nanosheets simultaneously tuning the fluorescence of Rhodamine 6G and thiamine hydrochloride ScienceDirect Rapid Quantification of Oxidized and Reduced Forms of Glutathione Using Ortho phthalaldehyde in Cultured Mammalian Cells In Vitro