5500 q trap hybrid triple quadrupole linear ion trap mass spectrometer

Target organic contaminants were analyzed with a 5500 QTRAP hybrid triple quadrupolelinear ion trap mass spectrometer with a turbo Ion Spray source (Applied Biosystems), coupled to a Waters Acquity Ultra-Performance TM liquid chromatograph (Milford) . The details of the target analytical method are given in Text S3 and Table S1. Free chlorine and ozone were measured in the presence and absence of 20 mM NaCl, respectively, immediately after sampling and using a diethyl-p-phenylene diamine (DPD) colorimetric method, i.e., Chlorine/Ozone/Chlorine dioxide cuvette tests LCK 310 (Hach Lange Spain Sl). The detection limit for the measurement of free chlorine (HOCl/OCl -) using the DPD method was 0.05 mg L -1 . Chloride, chlorate and perchlorate were measured by high-pressure ion chromatography (HPIC) using a Dionex ICS-5000 HPIC system. The quantification limits for the measurements of Cl -, ClO3 -and ClO4 -were 0.025 mg L -1 , 0.015 mg L -1 and 0.004 mg L -1 , respectively.
Hydrogen peroxide (H2O2) was measured by a spectrophotometric method using 0.01 M copper (II) sulphate solution and 0.1% w/v 2,9 dimethyl -1,10 -phenanthroline (DMP) solution, based on the formation of Cu(DMP) + 2 cation, which shows an absorption maximum at 454 nm (Baga et al. 1988) (link).