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Thiol Detection

The monitoring of reduced and oxidized glutathione (GSH) in biological samples is essential for evaluating the redox and detoxification status of cells and tissues in relation to the protective role of glutathione against oxidative and free-radical-mediated cell injury. Cysteine metabolism disorders include cystinosis, an autosomal recessive disease produced by a defect in lysosomal transport, and cystinuria, a common heritable disorder of amino acid transport. Cysteine is unique among the amino acids found in proteins. There are a few reagents or assay kits available for quantifying thiols in biological systems. However, all the commercial kits either lack sensitivity or have tedious protocols.

Amplite® Fluorimetric Glutathione Assay Kit (Cat# 10055) provides an ultrasensitive fluorimetric assay to quantify GSH in sample. The kit uses a proprietary non-fluorescent dye that becomes strongly fluorescent upon reacting with thiol. The kit provides a sensitive, one-step fluorimetric method to detect as little as 1 picomole of cysteine or GSH in a 100 µL assay volume. The assay can be performed in a convenient 96-well or 384-well microtiter-plate format and easily adapted to automation without a separation step. Its signal can be easily read using a fluorescence microplate reader at Ex/Em = 490/520 nm.

GSH dose responses

GSH dose responses were measured in a 96-well solid black plate with Amplite® Fluorimetric Glutathione Assay Kit (Cat# 10055). As low as 10 nM (1 pmol/well) GSH was detected with 10 minutes incubation (n=3).


The monitoring of GSH/GSSG ratio and the quantification of GSSG in biological samples are essential for evaluating the redox and detoxification status of cells and tissues in relation to the protective role of glutathione against oxidative and free-radical-mediated cell injury. There are a few reagents or assay kits available for the quantitation of thiols in biological systems. However, all the commercial kits either lack sensitivity or have tedious protocols.

Amplite® Fluorimetric Glutathione GSH/GSSG Ratio Kits (Cat# 10056 & 10060) provide robust tools to quantify GSH. The kits use proprietary non-fluorescent dyes that become strongly fluorescent upon reacting with thiol. These kits provide a sensitive, one-step fluorimetric method to detect as little as 1 picomole of cysteine or GSH in a 100 µL assay volume. The signal can be easily read by a fluorescence microplate reader at Ex/Em = 490/520 nm. For complex samples, we strongly recommend you use Kit 10060 due to its much higher reproducibility and enhanced convenience.

GSH and GSSG dose responses
GSH and GSSG dose responses

Left: GSH and GSSG dose responses were measured with Amplite® Fluorimetric Glutathione GSH/GSSG Ratio Assay Kit (Cat#10056). Blue: GSH dose responses (0.063 µ;M to 4 µ;M); Red: GSSG dose responses (0.063 µ;M to 4 µ;M GSSG which is equivalent to 0.125 µ;M to 8 µ;M GSH). Right: GSH and GSSG dose responses were measured with Amplite® Rapid Fluorimetric Glutathione GSH/GSSG Ratio Assay Kit (Cat# 10060). Blue: GSH dose responses (0.078 to 5 µ;M); Red: GSSG dose responses (0.078 to 5 µ;M GSSG which is equivalent to 0.156 to 10 µ;M GSH).