Ractopamine (RAC) is banned for use in swine to improve carcass leanness in the vast majority of countries and areas because its residue may pose health risks. This study investigated the feasibility of applying Fourier transform infrared (FT-IR) spectroscopy ranging from 4000 to 400 cm⁻¹ for analysis of RAC concentration in swine urine. RAC of 0–0.20 μg/mL was added to urine samples collected from 15 swines to prepare a total of 110 samples, which were dried at 40 °C for 48 h before spectra acquisition. By using the whole spectra pretreated by Savitzky-Golay smoothing (SGS)-spectral intensity normalization (SIN)-second derivative transformation (SDT), an optimal partial least squares regression (PLSR) model was obtained with a determination coefficient (R²) of 0.997 and a ratio of performance to deviation (RPD) of 18.756 for determining the RAC. Excitedly, 25 important wavenumbers could also be used to build a better PLSR model with R² of 0.924 and RPD of 3.68. Compounds in swine urine could cause the shifts of some vibration peaks of RAC such as NH and OH via intermolecular interactions. The satisfactory results indicated that FT-IR spectroscopy combined with sample drying and spectra pretreatment has a great potential for rapid analysis of ractopamine in swine urine.

绝大多数国家和地区都禁止在猪中使用莱克多巴胺（RAC）来改善car体的瘦度，因为其残留物可能会危害健康。这项研究调查了在4000到400 cm ^-1范围内应用傅里叶变换红外（FT-IR）光谱分析猪尿中RAC浓度的可行性。将0–0.20μg/ mL的RAC添加到从15头猪中收集的尿液样品中，以制备总共110个样品，将其在40°C下干燥48 h，然后再采集光谱。通过使用Savitzky-Golay平滑（SGS）-光谱强度归一化（SIN）-二阶导数变换（SDT）预处理的整个光谱，获得具有确定系数（R ²）的最优偏最小二乘回归（PLSR）模型。）等于0.997，而用于确定RAC的性能与偏差之比（RPD）为18.756。令人兴奋的是，还可以使用25个重要的波数来构建更好的PLSR模型，R ²为0.924，RPD为3.68。猪尿中的化合物可能通过分子间相互作用而引起RAC某些振动峰（例如N H和O H）的移动。令人满意的结果表明，FT-IR光谱结合样品干燥和光谱预处理具有快速分析猪尿中莱克多巴胺的巨大潜力。