Agilent 5973n msd

2.1. Sampling and THM analysis Kavcar et al. (2006) (link) had collected samples from 100 households in Izmir, Turkey. While tap water was drunk in 65 of the 100 sampled households, the remaining 35 consumed bottled water. Bottled water samples were directly collected from the container. Tap water samples were collected after the 3 min flushing. Ascorbic acid was used as a quenching agent for inhibition of the oxidant activity. Sampling vials were immediately closed and shaken for mixing the sample and quenching agent. All samples were transferred to the laboratory in dark in a cooler, and extracted within five days. Gas chromatography instrument (Agilent 6890N) with a mass selective detector (Agilent 5973N MSD) was used for analysis of THMs. Five-point calibration (1, 5, 25, 50, and 100 μg/L) was used. R 2 values of calibration curves were higher than 0.996. Further details can be found in the previous study (Kavcar et al., 2006) (link). Total THM concentrations measured by the local authorities at several points in the water distribution system in 2013-2017 period were obtained to validate the use of previously measured concentrations by comparing the two sets by hypothesis testing.

Extracted solutions were analysed using GC/MS instrumentation. An HP GC6890 (Agilent Technologies Inc., Palo Alto, CA, USA) and Agilent 5973N MSD (Agilent Technologies Inc., Palo Alto, CA, USA) were used for analysis of 8 phthalate metabolites and MEHP-d 4 . The column was a DB-5MS (30 m × 0.25 mm i.d. × 0.25 μm; Agilent Technologies, Inc., Santa Clarita, California, USA). Helium was used as the carrier gas (70 kPa, constant flow mode). The oven temperature was programmed as follows: 80 for 2 min, followed by 20°C/min up to 300°C for 20 min. The injector was operated in the split mode at 280°C (1 μL injection volume). The detector was operated in the selective ion mode (SIM) at a temperature of 230°C.

The chromatographic analysis were performed using an Agilent 6890A gas chromatograph, equipped with a Gerstel MPS2 autosampler (Gerstel, Maryland, USA), coupled to a single quadrupole mass spectrometer, Agilent 5973N MSD (Agilent Technologies, California, USA), operating in EI mode. The GC separation was performed using a fused silica Supelcowax 10 capillary column with a length of 30m x 0.25mm ID and a film thickness of 0.25 µm (Sigma Aldrich, Germany). The oven program was set as follows: 40ºC (3 min); 5.00 ºC/min to 160ºC (1.00 min); 40.00 ºC/min to 260ºC (1.50 min). The injection system consisted of two units; the thermal desorption unit (TDU) and the programmable temperature vaporizing (PTV)cooled injection system (CIS4) (Gerstel, Maryland, USA). The TDU parameters were set as follows; sample removal mode, splitless at an initial temperature of 40ºC (1 min equilibrium time); 60 ºC/min to 260ºC (4 min), transfer line temp 260ºC. The CIS4 PTV was equipped with a Tenax ® TA packed liner, CIS4 temperature program: 40ºC
(1 min equilibrium time); 12 ºC/s to 260ºC (4 min). A summary of the different temperature programs is graphically displayed in Figure S2.