In our latest research endeavor, we are proud to present an innovative approach to the synthesis of carbon dots (CDs) derived from the biomass xylan, which we have termed P-CDs. These P-CDs are meticulously integrated with a state-of-the-art biomass nanofiber membrane composed of polycaprolactone (PCL) and polylactic acid (PLA), resulting in the creation of a novel solid-state fluorescent sensor, designated as NFP-CDs. This cutting-edge sensor has been meticulously engineered for the highly sensitive and specific detection of nitrite ions (NO2−), a critical parameter in various fields. The NFP-CDs sensor stands out for its user-friendly design, cost-effective production, and portable nature, making it an ideal choice for rapid and visible nitrite ion detection. It exhibits an extraordinary response time of less than 1 s, which is a testament to its high sensitivity. Furthermore, the sensor demonstrates exceptional selectivity and specificity, with a remarkably low detection threshold of 0.36 μM. This is achieved through a sophisticated dual detection mechanism that synergistically combines colorimetric and spectral analyses, ensuring accurate and reliable results. In addition to its impressive technical specifications, the NFP-CDs sensor has been rigorously tested and validated for its efficacy in detecting nitrite ions in real-world samples. These samples include a diverse range of food products such as rock sugar, preserved mustard, kimchi, and canned fish. The sensor has demonstrated a remarkable recovery rate, which varies from 99 % to 106 %, highlighting its potential for practical application in nitrite ion detection. This research not only offers a robust and effective strategy for the detection of nitrite ions but also carries profound implications for enhancing food safety and bolstering environmental monitoring efforts. The development of the NFP-CDs sensor represents a significant step forward in the field of sensor technology, providing a powerful tool for the detection of nitrite ions and contributing to the broader goals of public health and environmental stewardship.