关键词: 高效液相色谱-串联质谱, 含量水平, 激素, 燕窝

Abstract:

Edible bird's nests (EBNs), a food of animal origin, are temporary nests built by swiftlets to foster their offspring. As EBNs and their products are widely accepted by consumers, the safety of hormones in EBNs has also received increasing attention. The establishment of a method for hormone analysis in EBNs and the investigation of hormone levels based on the analytical method are the most effective measures to eliminate any safety concerns. In this study, a multi-residue method was developed for the simultaneous determination of 45 hormones in EBNs, including estrogens, progesterones, androgens, and cortical hormones. EBN samples (1.0 g) were weighed into 50 mL polypropylene centrifuge tubes and mixed with 8 mL of pure water. Then, the samples were extracted twice with 15 mL of acetonitrile and ethyl acetate (1∶1, v/v) under ultrasonic-assisted conditions for 30 min, and the protein in the EBN samples was precipitated at 4000 r/min for 5 min. The clear supernatants were loaded onto a hydrophilic-lipophilic balanced (HLB) SPE column, which was previously activated with methanol (3 mL) followed by pure water (3 mL). The cartridge was washed with 3 mL of pure water and 3 mL of 50% methanol aqueous solution. The hormones were eluted with 3 mL of methanol. A rapid analysis was performed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The hormones in the extracting solution were separated on a Phenomenex Kinetex C₁₈ column (100 mm×2.1 mm, 2.6 μm) and eluted by gradient elution with acetonitrile-0.1% formic acid aqueous solution (ESI⁺) or acetonitrile-water (ESI^-). Qualitative and quantitative analyses were performed using the multiple reaction monitoring (MRM) mode. The HPLC-MS/MS results showed good linearity in the range of 0.20-20.0 μg/L with correlation coefficients (R²) ≥0.9990. For the 45 hormones, the limits of detection (LODs, S/N≥3) were 0.04-0.70 μg/kg and the limits of quantification (LOQs, S/N≥10) were 0.16-2.00 μg/kg. The recoveries of five hormones, namely, fluorometholone, budesonide, aldosterone, fluocinonide, and ethinylestradiol, were 40.2%-63.6%. Owing to the low recoveries, this method might be suitable only for qualitative testing of the five hormones. The recoveries of the other 40 target analytes were between 72.2% and 112.3% at spiked levels of 2.0, 4.0, and 20.0 μg/kg with relative standard deviations (RSDs) of 2.5%-11.6%. The method is characterized by easy operation, rapidness, high precision, and high sensitivity for the 40 compounds. Thus, this method is suitable for determination of the 40 hormones from EBNs for qualitative testing and quantitation. The proposed method was used to analyze 1021 EBN samples from Malaysia, Indonesia, Thailand, and Vietnam from 2017 to 2021. Only three hormones, progesterone, boldenone, and androstenedione, were identified in the EBN samples, while the levels of the other hormones were lower than their individual LODs. The detected rates of progesterone, boldenone, and androstenedione were 100%, 79%, and 89%, respectively. The contents of progesterone, boldenone, and androstenedione in the EBN samples were 0.097-3.58 μg/kg, 0-0.096 μg/kg and 0-1.77 μg/kg, respectively. The levels of hormones in EBNs were compared with those in eggs, pure milk, and dairy products, which were also animal-derived foods. Androstenedione was detected in all egg samples monitored, and its content was higher than that in EBN samples, pure milk, and dairy products. The content of boldenone was similar among the four products investigated in this study. Based on risk assessment using progesterone, the dietary intake was found to be 3.54 μg/d from milk >1.09 μg/d from eggs >0.0030 μg/d from EBNs. The results showed that the levels of hormones in EBNs were much lower than those in eggs, milk, and dairy products for daily consumption. Based on this investigation, the health effect of the hormones in EBNs may be insignificant.

Key words: high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), content level, hormones, edible bird's nest (EBN)