Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Size exclusion chromatography with UV–vis detection, combined with ultrasonication pretreatment, enables sensitive detection and quantification of back-produced polymer at very low concentrations in produced water. This approach supports reliable polymer monitoring and offers a practical route to improve surveillance of polymer flooding performance.

ABSTRACT
Polymer flooding is an oil recovery technique with environmental and operational benefits, yet accurate quantification of back-produced polymer (BPP) in produced water remains a challenge. This study reports the development and validation of a sensitive and field-applicable size exclusion chromatography method with ultraviolet detection (SEC-UV) for trace-level quantification of sulfonated polyacrylamides (S-PAM). The method achieved limits of detection and quantification of 2.1 and 6.4 mg L−1, respectively, in oilfield-produced water, significantly outperforming SEC with refractive index detection, which is limited to concentrations above 100 mg L−1. Incorporation of a controlled ultrasonication pretreatment minimized errors from polymer degradation, reducing relative errors from up to 42% to as low as 4%–14%. Intralaboratory blind tests confirmed high accuracy (relative errors < 5%), while interlaboratory comparisons demonstrated reliability for trace-level analysis. Field application further showed the method's capability to detect polymer breakthrough and monitor BPP concentration trends at the wellhead, with results aligning with predictive reservoir models. Overall, this work establishes SEC-UV as a validated reference method for low-mg L−1 S-PAM quantification, addressing matrix complexity and degradation challenges. Its demonstrated accuracy and sensitivity support both operational decision-making in polymer flooding pilots and environmental monitoring of produced water, with potential for extension to other PAM-based polymers.