Lijing Lin

Ultra-performance convergence chromatography (UPC2) method for the analysis of biogenic amines in fermented foods

A rapid ultra-performance convergence chromatography (UPC(2)) method for the determination of eight biogenic amines (spermine, spermidine, putrescine, cadaverine, tryptamine, phenylethylamine, histamine and tyramine) in fermented foods was developed. The amines were pre-column derivatized with dansyl chloride and separated on UPC(2) system with a HSS C18 SB column (3.0 × 100 mm, 1.8 μm) using gradient elution with a binary system of CO2 and n-hexane:isopropanol:ammonium hydroxide (70:30:0.15, v/v/v), back pressure of 2,000 psi, flow rate of 2.0 ml/min and DAD detection at 254 nm. The result showed excellent linearity (r=0.9995-1.0000). Limits of detection (LOD) and limits of quantification (LOQ) were 21-67 ng/L and 72-224 ng/L, respectively. Relative standard deviations (RSD) for repeatability and reproducibility were 0.21-0.87% and 1.98-4.02%, respectively. Furthermore, this method was successfully applied to analysis of biogenic amines in Yulu and Sufu samples.

Simultaneous analysis of eight vitamin E isomers in Moringa oleifera Lam. leaves by ultra performance convergence chromatography

A new method for simultaneous determination of eight vitamin E isomers including α-, β-, γ-, and δ-tocopherol and α-, β-, γ-, and δ-tocotrienol by ultra-performance convergence chromatography (UPC(2)) equipped with a diode array detector was reported. They were separated on a BEH 2-EP column (3.0 mm × 100 mm, 1.7 μm) using gradient elution (95:5-80:20) with a mobile phase consisted of CO2 and methanol:isopropanol (1:1, v/v), back pressure of 1800 psi, flow rate of 1.5 ml/min and detection at 294 nm. The results showed good linearity (R(2)=0.9990-0.9998) and high resolution (1.48-7.67). Limits of detection (LOD) and quantification (LOQ) ranged from 23-49 ng/L and 70-150 ng/L, respectively. Relative standard deviations (RSD) for repeatability and reproducibility were 0.62-3.16% and 0.82-3.34%, respectively. Moreover, this method was successfully applied to analysis the vitamin E isomers in Moringa oleifera leaf samples.

Determination of biogenic amines in traditional Chinese fermented foods by reversed-phase high-performance liquid chromatography (RP-HPLC)

A survey of biogenic amine content of traditional Chinese fermented foods (douchi, sufu, fermented sausage, yulu, and shrimp paste) was carried out. Eight major biogenic amines including putrescine, cadaverine, histamine, phenylethylamine, tyramine, spermine, spermidine and tryptamine were separated by reversed-phase HPLC-DAD on Inertsil ODS-SP column after pre-column derivatisation with dansyl chloride. The results showed that spermine (1.65–3.96 mg 100 g−1), putrescine (0.20–10.89 mg 100 g−1), cadaverine (3.60–12.14 mg 100 g−1), and histamine (0.57–20.24 mg 100 g−1) were the most represented amines. All amines were detected in yulu, while sufu showed a much higher content of most amines. Shrimp paste showed the lowest level of total biogenic amines. Moreover, the composition and content of eight biogenic amines in the selected samples varied among different food types, origins and batches. Although the average content for each amine is within the range that may elicit direct adverse reactions, consumers should be aware of the potential synergistic effect among different amines and limit their consumption at each meal.