A fully automated spectrophotometric method based on flow-batch analysis has been developed for the determination of clenbuterol including an on-line solid phase extraction using a molecularly imprinted polymer (MIP) as the sorbent.

The molecularly imprinted solid phase extraction (MISPE) procedure allowed analyte extraction from complex matrices at low concentration levels and with high selectivity towards the analyte. The MISPE procedure was performed using a commercial MIP cartridge that was introduced into a guard column holder and integrated in the analyzer system. Optimized parameters included the volume of the sample, the type and volume of the conditioning and washing solutions, and the type and volume of the eluent.

Quantification of clenbuterol was carried out by spectrophotometry after in-system post-elution analyte derivatization based on azo-coupling using N- (1-Naphthyl) ethylenediamine as the coupling agent to yield a red-colored compound with maximum absorbance at 500 nm. Both the chromogenic reaction and spectrophotometric detection were performed in a lab-made flow-batch mixing chamber that replaced the cuvette holder of the spectrophotometer.

The calibration curve was linear in the 0.075–0.500 mg L⁻¹ range with a correlation coefficient of 0.998. The precision of the proposed method was evaluated in terms of the relative standard deviation obtaining 1.1% and 3.0% for intra-day precision and inter-day precision, respectively. The detection limit was 0.021 mg L⁻¹ and the sample throughput for the entire process was 3.4 h⁻¹.

The proposed method was applied for the determination of CLB in human urine and milk substitute samples obtaining recoveries values within a range of 94.0–100.0%.

已经开发了一种基于分批分析的全自动分光光度法，用于测定盐酸克伦特罗，包括使用分子印迹聚合物（MIP）作为吸附剂的在线固相萃取。

分子印迹固相萃取（MISPE）程序允许以低浓度水平和对分析物的高选择性从复杂的基质中萃取分析物。MISPE程序是使用商业MIP盒进行的，该盒被引入保护柱固定器并集成在分析仪系统中。优化的参数包括样品的体积，调理和洗涤溶液的类型和体积，以及洗脱液的类型和体积。

使用N-（1-萘基）乙二胺作为偶合剂，基于偶氮偶合，在系统内洗脱后分析物衍生化后，通过分光光度法对盐酸克伦特罗进行定量，以得到在500 nm处具有最大吸光度的红色化合物。发色反应和分光光度检测均在实验室制造的分批混合室中进行，该室取代了分光光度计的比色杯架。

校正曲线在0.075–0.500 mg L ^-1范围内呈线性，相关系数为0.998。相对于日内精度和日间精度分别获得1.1％和3.0％的相对标准偏差，评估了该方法的精度。检出限为0.021 mg L ^-1，整个过程的样品通量为3.4 h ^-1。

该方法用于人尿和牛奶替代品样品中的CLB测定，回收率在94.0-100.0％范围内。