Characterization and Quantification of Naphthenic Acids in Produced Water by Orbitrap MS and a Multivariate Approach.

Naphthenic acids (NAs) naturally occur in crude oil and its associated produced water, presenting significant challenges, such as corrosion, in refinery apparatus and ecotoxicity in aquatic habitats. This study delineates a multivariate method to quantify NAs in produced water via electrospray ionization coupled with high-resolution Orbitrap mass spectrometry (ESI-Orbitrap MS). By employing liquid-liquid extraction, followed by direct infusion ESI(-)-Orbitrap MS, we characterized and quantified NAs employing a partial least-squares regression (PLS) model enhanced by the ordered predictor selection (OPS) algorithm. Thirty-six produced water samples were utilized, with 24 allocated for calibration and 12 designated for validation. The PLS-OPS model demonstrated notable accuracy in predicting NA concentrations in simulated and actual produced water samples ranging from ∼30 to 300 mg·L-1. This methodology offers a rapid yet robust alternative for quantifying NAs using mass spectrometry augmented by PLS and the OPS. Its significance is underscored by its potential to equip the petroleum industry with a swift and reliable monitoring mechanism for NAs in produced water, thereby aiding in mitigating environmental and operational risks.

Gold nanoparticles for surface-enhanced Raman scattering detection of benzyldimethyldodecylammonium chloride at low concentration.

The oil and gas industry plays a vital role in the global economy. The production process has several critical conditions and can expose metals to corrosion. Surfactants like the quaternary ammonium salt Benzyldimethyldodecylammonium Bromide (BDAC) are currently used to prevent corrosions; classical methods for determining these surfactants have problems in saline samples and usually present high costs. In this context, spectroscopic techniques become an excellent alternative for quaternary ammonium salts detection. Here, a SERS (surface-enhanced Raman scattering) sensor based on gold nanoparticles (AuNPs) synthesized through chemical reduction was used as an alternative method for BDAC detection. We detected BDAC at low concentrations in water solutions: at 5 to 30 ppm (1.47 × 10-5 mol L-1 to 8.82 × 10-5 mol L-1); and had the vibration attempt attribute analyzed. A new study of quaternary ammonium compounds using AuNPs and SERS with a different, easy, and repeatable approach to spectra acquisition is presented and shows to be a promising method applied in quaternary ammonium salt compounds detection for the oil and gas industry.