A new ion chromatography coupled with tandem mass spectrometry(IC-ESI-MS/MS) method,with automated sampling and on-line preconcentration,has been developed for the determination of perchlorate in Antarctic snow and ice at low part-per-trillion(ng/L) levels.To the best of our knowledge, this is the first time that an analytical method is used for the determination of perchlorate in Antarctic snow and ice.The IC-ESI-MS/MS instrumentation consisted of an ICS2000 ion chromatography(IC) system coupled to an API3200 electrospray tandem mass spectrometer(ESI-MS/MS).On-line preconcentration was realized through a six-port injector valve,a TAC-ULP1 concentrator column and an AS auto-sampler.Multiple reaction monitoring(MRM) mode was used to quantify the perchlorate anion.The transition of ~(35)Cl~(16)O_4~-(m/z 98.9) into ~(35)Cl~(16)O_3~-(m/z 82.9) was monitored for quantifying the main analyte,and the transition of ~(37)Cl~(16)O_4~-(m/z 100.9) into ~(37)Cl~(16)O_3~-(m/z 84.9) was monitored for examining a proper isotopic abundance ratio of ~(35)Cl to ~(37)Cl,which was used as a confirmation tool.The limit of detection(LOD) and limit of quantitation(LOQ) for the method was 0.2 ng/ L and 0.5 ng/L,respectively.And this new method exhibited acceptable accuracy and precision for samples at ng/L levels.All the tested snow and ice samples were found to contain measurable amount of perchlorate,ranging from 10 ng/L to 340 ng/L. A new ion chromatography coupled with tandem mass spectrometry (IC-ESI-MS / MS) method, with automated sampling and on-line preconcentration, has been developed for the determination of perchlorate in Antarctic snow and ice at low part-per-trillion ng / L) levels.To the best of our knowledge, this is the first time that an analytical method is used for the determination of perchlorate in Antarctic snow and ice. The IC-ESI-MS / MS instrumentation consisted of an ICS 2000 ion chromatography (IC) system coupled to an API 3200 electrospray tandem mass spectrometer (ESI-MS / MS) .On-line preconcentration was realized through a six-port injector valve, a TAC-ULP1 concentrator column and an AS auto-sampler. (MRM) mode was used to quantify the perchlorate anion. The transition of ~ (35) Cl ~ (16) O_4 ~ (m / z 98.9) into ~ (35) Cl ~ (16) O_3 ~ - 82.9) was monitored for quantifying the main analyte, and the transition of ~ (37) Cl ~ (16) O_4 ~ (m / z 100.9) into ~ (37) Cl ~ (16) O_3 ~ (m / z 84.9 ) was monitored for examining a proper isotopic abundance ratio of ~ (35) Cl to ~ (37) Cl, which was used as a confirmation tool. Limit of detection (LOD) and limit of quantitation (LOQ) for the method was 0.2 ng / L and 0.5 ng / L, respectively. And this new method was evaluated acceptable and precision for samples at ng / L levels. All the tested snow and ice samples were found to contain measurable amount of perchlorate, ranging from 10 ng / L to 340 ng / L.