Five hundred microliter of the metabolite extract was dried using a speedvac. Samples were derivatized by re-suspending the extract in 50 μL of pyridine containing 15 mg/mL of methoxyamine hydrochloride, incubating at 60⋅C for 45 min, sonicating for 10 min, and incubating again at 60⋅C for an additional 45 min. Next, 50 μL of N-methyl-N-trimethylsilyltrifluoroacetamide with 1% trimethylchlorosilane (MSTFA+1% TMCS, Thermo Scientific) was added and samples were incubated at 60⋅C for 30 min, centrifuged at 3000 × g for 5 min at 4⋅C, cooled to room temperature, and 80 μL of supernatant was transferred to a 150 μL glass insert. Metabolites were detected with a Trace GC Ultra coupled to a Thermo DSQ II (Thermo Scientific), acquiring mass spectra of 50–650 m/z at 5 scans s−1 in electron impact mode after separation on a 30 m TG-5MS column (Thermo Scientific, 0.25 mm i.d., 0.25 μm film thickness). Both inlet and transfer lines were set at 280⋅C. Samples were injected in a 1:10 split ratio twice in discrete randomized blocks with a 1.2 ml min−1 flow rate, following a program of 80⋅C for 30 sec, a ramp of 15⋅C per min to 330⋅C, and holding at 330⋅C for 8 min.
Thermo dsq 2
Manufactured by Thermo Fisher Scientific
Sourced in United States
The Thermo DSQ II is a high-performance quadrupole mass spectrometer designed for a variety of analytical applications. It provides accurate and reliable mass analysis capabilities.
Automatically generated - may contain errors
4 protocols using thermo dsq 2
1
Metabolite Derivatization and GC-MS Analysis
2
Quantification of Squalene in Lipid Extracts
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
Extraction of neutral, nonsaponifiable lipids was performed as previously described (5 (link)). Dried lipid extracts were silylated with N,O-bis(trimethylsilyl)trifluoroacetamide and analyzed by gas chromatography–mass spectrometry (GC-MS) in selective ion monitoring mode using a Thermo Trace gas chromatograph coupled with a Thermo DSQII mass spectrometer and Thermo Triplus autosampler (Thermo Fisher Scientific). The peak area of squalene was normalized to that of the 5α-cholestane internal standard, and quantification was performed using a squalene standard curve. See SI Appendix, Materials and Methods for details.
3
GC-MS Analysis of Endocrine-Disrupting Chemicals
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
EDCs were analyzed using a GC-MS system (Thermo DSQ II, ThermoFisher, Waltham, MA, USA) operating in the electron capture negative ionization mode. The column was an HP-5MS capillary column (30 m × 0.25 mm, 0.25 mm film thickness). The carrier gas was high-purity helium at a flow rate of 1 mL/min. One microliter of the derivatized sample was injected into the gas chromatograph in splitless mode [1 (link)]. The injection port and transfer line were held at 280 °C. The ion source temperature was 300 °C. The GC oven temperature program started at 100 °C for 1 min, then increased by 10 °C/min to 200 °C. Afterwards, the oven temperature increased by 5 °C /min to 280 °C, and then was maintained for 2 min. The limits of detection (LOD) of BPA and NP were respectively 0.01 and 0.1 ng/L. The limits of quantification (LOQ) of BPA and NP were respectively 0.2 and 0.3 ng/L. The recoveries of BPA and NP were respectively 95.1% and 93.6%.
4
Measuring TCIPP Concentration in Cells
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
To measure the concentration of TCIPP in the test cells, air samples were simultaneously taken on a regular base from the outlet on each of the cells. An active air sampling on mixed bed (polydimethylsiloxane (PDMS) / Tenax TA) sorption tubes with a constant sampling flow of 80 mL min -1 for 4 hours (20 L sampling volume)
were used for the collection of both (gas and particulate) phases. Programmable personal air pumps SG 350 (GSA Messgerätebau GmbH, Germany) were used to sample a defined air volume of 19.2 L. After sampling, the PDMS/Tenax TA sorbent tubes were sealed with end caps and stored under nitrogen atmosphere until analysis. All samples were taken in duplicate and analyzed within seven days after the collection.
Analysis of TCIPP was performed on a TD-GC-MS system, which consisted of a TD100™ automatic thermal desorber (Markes International Ltd., UK) coupled with a gas chromatograph Thermo Trace GC Ultra and mass selective detector Thermo DSQII (Thermo Fisher Scientific Inc., USA). The parameters, performance and validation of the system for analysis of TCIPP are described in (Lazarov et al. 2015) .
To ensure that there was no TCIPP associated with the air and particles entering the cells, a blank test (FLECs placed on a precleaned glass plate) was done prior each experiment.
were used for the collection of both (gas and particulate) phases. Programmable personal air pumps SG 350 (GSA Messgerätebau GmbH, Germany) were used to sample a defined air volume of 19.2 L. After sampling, the PDMS/Tenax TA sorbent tubes were sealed with end caps and stored under nitrogen atmosphere until analysis. All samples were taken in duplicate and analyzed within seven days after the collection.
Analysis of TCIPP was performed on a TD-GC-MS system, which consisted of a TD100™ automatic thermal desorber (Markes International Ltd., UK) coupled with a gas chromatograph Thermo Trace GC Ultra and mass selective detector Thermo DSQII (Thermo Fisher Scientific Inc., USA). The parameters, performance and validation of the system for analysis of TCIPP are described in (Lazarov et al. 2015) .
To ensure that there was no TCIPP associated with the air and particles entering the cells, a blank test (FLECs placed on a precleaned glass plate) was done prior each experiment.
About PubCompare
Our mission is to provide scientists with the largest repository of trustworthy protocols and intelligent analytical tools, thereby offering them extensive information to design robust protocols aimed at minimizing the risk of failures.
We believe that the most crucial aspect is to grant scientists access to a wide range of reliable sources and new useful tools that surpass human capabilities.
However, we trust in allowing scientists to determine how to construct their own protocols based on this information, as they are the experts in their field.
Ready to get started?
Sign up for free.
Registration takes 20 seconds.
Available from any computer
No download required
Revolutionizing how scientists
search and build protocols!