Concentration Determination of Volatile Molecular Iodine and Methyl Iodide

Abstract

Appropriate and reliable methods are necessary for routine determination of the concentrations of molecular iodine (I 2 ) and methyl iodide (CH 3 I), and methods including ultraviolet-visible spectrophotometry on aqueous solution samples for I 2 detection and gas chromatography on toluene solution samples for CH 3 I detection may be used. In this study, we examined the adequacy of the existing spectrophotometric method in terms of absorption coefficients at specific light wavelengths for several pH values of the aqueous solutions and selected iodide ion concentrations, and confirmed it finding no dependence of the absorption coefficients on the solution pH and the iodide ion concentration. Additionally, we established methods for CH 3 I analysis using toluene as a sampling solvent for either capture of CH 3 I from a gaseous solution or extraction of CH 3 I from an aqueous solution, and found that using gas-tight syringes, CH 3 I could be extracted without a significant CH 3 I loss even at ambient temperature.

Detection of Halomethanes Using Cesium Lead Halide Perovskite Nanocrystals

“…Traditionally, CH3I detection relies on sophisticated instrumentation, such as gas chromatography coupled with mass spectroscopy (GC-MS) or flame ionization detector based methods (GC-FID) [7][8][9][10] . However, these techniques are restricted to the laboratory environment and require complex sample preparation.…”

“…Traditionally, CH 3 I detection relies on sophisticated instrumentation, such as gas chromatography coupled with mass spectrometry (GC-MS) or flame ionization detector (GC-FID) based methods. − However, these techniques are restricted to the laboratory environment and require complex sample preparation. An alternative approach involves the use of more affordable and portable spectroscopic methods.…”

On-site portable detection of gaseous methyl iodide using an electrochemical method

“…Different analytical techniques have been used to detect CH 3 I, 7,8 such as gas chromatography-electron capture detection (GC-ECD), gas chromatography-mass spectrometry (GC-MS), and proton-transfer-reaction mass spectrometry (PTR-MS). However, due to the complex and time-consuming operational procedures, it is impractical for on-site inspection.…”