Nucleic acid-based medicines have achieved significant advancements in recent years, with lipid nanoparticles (LNPs) being a pivotal platform for their delivery. However, the complexity of LNP presents significant challenges, requiring analytical methods to identify and quantify individual components to guide formulation development and ensure quality and safety. Current approaches often perform nucleic acid and lipid analysis separately and focus on a single type of formulation, highlighting the need for a simple platform method that can be applied to diverse formulations. We present a platform ion-pair reversed-phase HPLC method with UV and charged aerosol detection (CAD) to simultaneously separate and quantify lipid and nucleic acid components in LNPs. The method separated and quantified 12 lipid species and three types of nucleic acids (antisense oligonucleotide, single-guide RNA, and mRNA), covering a broad range of therapeutic cargoes. Notably, this can be achieved for the first time by one HPLC run with one-step facile sample preparation. Specifically, we used a simple buffer containing Triton and heparin to enable the single-step, simultaneous extraction of both nucleic acid and lipid components from LNPs, achieving quantification recoveries of 90-110 %. We further applied this method and addressed process and quality control challenges of LNPs, including the recovery rate of individual LNP components after purification and simultaneous quantification of co-loaded, different nucleic acid species for potential gene editing applications. This new platform method offers a robust and widely applicable tool to assess the quality of lipid-based nucleic acid therapies.