This standard specifies a method for determining the free quinoline and isoquinoline content in dyes and textile dyeing and finishing auxiliaries. The core of the detection involves the use of a gas chromatograph equipped with a specific capillary column. After separation by the instrument, the target components in the sample are detected by a hydrogen flame ionization detector. Since quinoline and isoquinoline are toxic and can migrate with the product, posing potential hazards to human health and the environment, establishing this precise detection method is crucial for assessing the health and ecological risks of the products.