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.

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.

Electromembrane Extraction of Naphthenic Acids in Produced Water Followed by Ultra-High-Resolution Mass Spectrometry Analysis.

Naphthenic acids comprise one of the most toxic compounds of the produced water released from offshore oil platforms. Therefore, developing and applying faster, simpler, and more efficient analytical methods for analyzing naphthenic acids are urgently needed. Electromembrane extraction (EME) uses the electrokinetic migration of target ions through a porous membrane.

Direct analysis of naphthenic acids in produced water and crude oil by NH-surface-modified wooden-tip electrospray ionization mass spectrometry.

This work describes the surface coating of wooden toothpicks with amino groups (NH) for electrospray ionization mass spectrometry (MS) analysis of naphthenic acids (NAs) in produced water samples and crude oil fractions. NH was introduced into the cellulosic material through a silanization reaction using aminopropyltriethoxysilane. An NH-modified toothpick was inserted into the analyte extraction sample and was subsequently used as an electrospray emitter for MS analysis.

Communicating vessels volumeter to measure upper extremity lymphedema after breast cancer: reliability and criterion validity compared to the gold standard.

Background: The traditional overflow method for measuring limb volume remains the gold standard, but many disadvantages still inhibit its routine use in clinical practice.

Objective: To assess the intra-rater and inter-rater reliability and criterion validity of the 'communicating vessels volumeter' (CVV) for volume measurement of lymphedematous upper extremities (LUE) by using the overflow volumeter (OV) as the reference standard.

Methods: Twelve LUE of 12 women undergoing mastectomy for breast cancer were measured three times each by three raters using both methods, totaling 216 volume measurements.

Microemulsification: an approach for analytical determinations.

We address a novel method for analytical determinations that combines simplicity, rapidity, low consumption of chemicals, and portability with high analytical performance taking into account parameters such as precision, linearity, robustness, and accuracy. This approach relies on the effect of the analyte content over the Gibbs free energy of dispersions, affecting the thermodynamic stabilization of emulsions or Winsor systems to form microemulsions (MEs). Such phenomenon was expressed by the minimum volume fraction of amphiphile required to form microemulsion (Φ(ME)), which was the analytical signal of the method.

Assessment of the intraobserver and interobserver reliability of a communicating vessels volumeter to measure wrist-hand volume.

Background: Traditional volumetry based on Archimedes' principle is the gold standard for the measurement of limb volume, but the routine use of this technique is discouraged because of several disadvantages.

Objective: The purpose of this study was to evaluate intraobserver and interobserver reliability of direct measurements of wrist-hand volume using a new communicating vessels volumeter based on Pascal's law.

Design: A reliability study was conducted.