The determination of total arsenic and its chemical species is crucial for assessing toxicity, bioavailability, and stability in various contexts, including environmental and clinical settings. This study presents two validated methodologies for arsenic speciation using a single automated platform that integrates sample introduction and chromatographic separation – prepFAST IC, enhancing efficiency and reducing potential errors and contaminations associated with manual handling of samples. The first method uses a one-column approach for the quantification of six arsenic species—AsB, DMA, MMA, As(III), As(V), optimized for rapid analysis within 2 minutes. The second method, utilizing a two-column setup, includes TMAO, allowing for effective separation of AsB and TMAO. Both methods demonstrated good recoveries (94-107%), exceptional accuracy, and precision, validated through proficiency testing samples from the Centre de Toxicologie du Québec and the New York Department of Health. Limits of detection were determined to be in line with existing methodologies, confirming the reliability of both approaches.