关键词: 超高效液相色谱-紫外检测法；液相色谱-串联质谱法；乳铁蛋白；乳制品；特征肽段

Abstract: Lactoferrin, a key functional protein in dairy products, serves the dual functions of nutritional supply and physiological regulation. Its accurate quantification serves as a critical link in the quality control and quality evaluation of dairy products. This study systematically compared the detection performances, operational procedures and application scopes of two mainstream analytical techniques for lactoferrin determination in dairy products, namely ultra-high performance liquid chromatography with ultraviolet detection (UPLC-UV) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The UPLC-UV method adopted a C4 column for chromatographic separation, with 280 nm set as the characteristic detection wavelength. The pretreatment was accomplished by phosphate buffer extraction followed by heparin affinity column purification, and quantification was performed using the external standard calibration curve method. This method featured high instrument availability, with spiked recoveries ranging from 82.32% to 98.07%, a limit of quantification (LOQ) of 1 mg/100 g, and a correlation coefficient above 0.999, indicating good reproducibility. It was suitable for routine testing of batch samples in dairy enterprises. Nevertheless, it presented moderate anti-matrix interference capability and insufficient sensitivity for the detection of trace lactoferrin in complex matrices, and was incapable of determining denatured lactoferrin. In contrast, the LC-MS/MS method involved sample dissolution and enzymatic hydrolysis to screen for signature peptides. Quantification was performed in multiple reaction monitoring (MRM) mode using the internal standard calibration curve method. It possessed excellent anti-matrix interference capacity, with a LOQ as low as 0.2 mg/100 g, and enabled the determination of total lactoferrin. This approach was applicable to the detection of low-abundance lactoferrin in complex matrix samples such as infant formula powder and high-temperature sterilized milk. However, it was constrained by high instrument cost, insufficient supporting reference materials, cumbersome operation and relatively low detection efficiency.

Key words: ultra-high performance liquid chromatography with ultraviolet detection; liquid chromatography-tandem mass spectrometry; lactoferrin; dairy products; signature peptides