Isoquinoline is a heterocyclic aromatic compound commonly used in the synthesis of many pharmaceuticals and organic compounds. However, the purity of isoquinoline is often compromised by the presence of impurities. These impurities can affect the quality and efficacy of the final product, making it important to identify and quantify them accurately. Common isoquinoline impurities include quinoline, acridine, and phenanthridine, among others. Thorough analysis and removal of these impurities is essential to ensure the safety and effectiveness of isoquinoline-based products.