evaluation and quantification of fe3o4 concentrations in deposits formed inside iraqi gas supply pipelines using a chemiluminescence method based on flow injection analysis

The accumulation of black powder deposits inside gas pipelines can lead to various issues affecting pipeline operation and integrity. the presence of black powder has the potential to contaminate the gas product, promote increased wear on pipeline internals, and cause clogging that reduces flow rates. from a safety perspective, black powder buildup may pose health and environmental concerns. previous studies have analyzed the composition of black powder deposits from pipelines using techniques like xrf, xrd, tg-dta, and ftir. their findings show that iron oxide (fe3 o4 ) is the primary component of black powder. this study developed a novel flow injection-chemiluminescence (fi-cl) method under basic conditions for determining fe3 o4 concentrations in black powder deposits because fe3 o4 can catalyze the chemiluminescence reaction. compared to traditional analytical techniques, the proposed cl-based flow injection approach is characterized by good selectivity, simplicity, low cost, and without consuming additional materials. the cl mechanism was investigated through cl spectral, revealing the involvement of fe3 o4 in enhancing the luminol-naoh-h2 o2 reaction. experimental conditions for the fi-cl system were optimized. under optimal parameters, the relative cl intensity showed a linear relationship with fe3 o4 concentration over the range of 0.5-100 µg ml^-1, and the detection limit was 0.47 µg ml^-1 with a relative standard deviation (%rsd) of 2.0% at 5.0 µg ml^-1. the method was successfully applied to black powder samples extracted from gas pipelines, showing 92.59- 107.69% recoveries and a precision of 0.8-3.1%. results agreed well with an alternative technique. the proposed fi-cl method offers a fast, convenient, and cost-effective means for iron oxide quantification in pipeline deposits and corrosion products.