L-Phenylalanine

Examples of using this product（for reference only）

HPLC

Thequantity of phenylalanine was determined using an highperformance liquid chromatography (HPLC) system equipped with a diode array detector (DAD) and anC18 column (250 mm × 4.6 mm, 5 μm). Quantification was conducted at 212 nm. Elution was carried out using a linear acetonitrile gradient (2% for 5 min; 2%–15% for 10 min; 15% for 5 min; and 15%–2% for 5 min). The flow rate was 1.0 mL min-1,and the injection volume was 20 μL.

References：

A S G , B Y M , B Y W ,et al.Effects of storage temperature on bisdemethoxycurcumin formation in fresh-cut yam ( Dioscorea opposita )[J].Journal of Food Composition and Analysis, 2021.DOI:10.1016/j.jfca.2021.104106.

HPLC

The SA content was determined using high-performance liquid chromatography with a 4.6 × 250 mm column . The mobile phase had a flow rate of 0.7 mL/min (isocratic elution) and was composed of acetonitrile and 0.1% phosphoric acid (97:3, v/v). The column temperature was 25 ℃, a UV–visible detector was used for detection at a wavelength of 213 nm, and the injection volume was 20 μL.

References：

Shi Y, Chen G, Chen K, Chen X, Hong Q, Kan J. Assessment of fresh star anise (Illicium verum Hook.f.) drying methods for influencing drying characteristics, color, flavor, volatile oil and shikimic acid. Food Chem. 2021 Apr 16;342:128359. doi: 10.1016/j.foodchem.2020.128359. Epub 2020 Oct 13. PMID: 33092919.

LC-MS/MS

LC-MS/MS conditions Analysis was performed using a liquid chromatographytandem mass spectrometer LC–MS/MS equipped with an ESI source. Separation was performed using a C18 column (250 mm × 4.6 mm × 5 μm). The flow rate was 0.4 ml/min, and the column temperature was maintained at 25℃. The mobile phases were formic acid: water (0.1:100, v/v) as mobile phase A, and methanol:acetonitrile (1:1) and 0.1% formic acid as mobile phase B. The binary gradient elution conditions were: (A:B): 0.01 min–5 min, 70:30→5:95; 5–8 min, 5:95; 8.01 min–16 min, 70:30. Detection was performed using multiple reaction monitoring (MRM) in positive mode, and the optimized MRM parameters for each compound are shown in Table 1. The mass condition parameters were set as: nebulizer gas, 3 L/min; drying gas, 10.0 L/min; heating gas, 10.0 L/min; interface temperature, 30℃; collision-induced dissociation (CID) gas, 230 kPa; DL temperature, 250℃; thermal block temperature, 400℃; interface voltage, ?4.5 kV. The autosampler was kept at 4℃.

References：

Xu H, Pan LB, Yu H, Han P, Fu J, Zhang ZW, Hu JC, Yang XY, Keranmu A, Zhang HJ, Bu MM, Jiang JD, Wang Y. Gut microbiota-derived metabolites in inflammatory diseases based on targeted metabolomics. Front Pharmacol. 2022 Sep 27;13:919181. doi: 10.3389/fphar.2022.919181. PMID: 36238574; PMCID: PMC9551995.

LC/MSn-IT-TOF

LC-MS/MS was used for the analysis and quantification of dopamine, phenylalanine, tyrosine, and L-dopa. LC separation was achieved using an C18 column (5 μ × 150 mm) maintained at 40℃. The mobile phase for L-dopa, dopamine, tyrosine, and phenylalanine consisted of water–formic acid (100:0.1, v/v) (A) and acetonitrile (B) with a linear gradient elution (A:B, 0 min, 90:10; 2 min, 90:10; 3 min, 5:95; 5 min, 5:95; 5.01 min, 90:10; 8 min 90:10) at a flow rate of 0.8 mL/min during the whole gradient cycle. Shimadzu LC-MS solution (Version 5.72) was used for data acquisition and processing. For positive ESI analysis, the parameters were as follows: nebulizer gas, 3 L/min; drying gas, 10.0 L/min; interface, ?4.5 kV; CID gas, 230 kPa; and DL temperature, heat block temperature were maintained at 200 ℃ and 250 ℃, respectively. Quantification was carried out using multiple reaction monitoring mode. The m/z transitions were 154.20 → 91.10 (m/z) for dopamine, 198.15 → 107.05 (m/z) for L-dopa, 165.85 → 120.20 (m/z) for phenylalanine, 182.00 → 136.10 (m/z) for tyrosine, and 108.20 → 91.10 (m/z) for the IS. The peak areas of those compounds in fluid samples and the IS were recorded, respectively.

References：

Wang Y, Tong Q, Ma SR, Zhao ZX, Pan LB, Cong L, Han P, Peng R, Yu H, Lin Y, Gao TL, Shou JW, Li XY, Zhang XF, Zhang ZW, Fu J, Wen BY, Yu JB, Cao X, Jiang JD. Oral berberine improves brain dopa/dopamine levels to ameliorate Parkinson's disease by regulating gut microbiota. Signal Transduct Target Ther. 2021 Feb 24;6(1):77. doi: 10.1038/s41392-020-00456-5. PMID: 33623004; PMCID: PMC7902645.

Remark：These protocols are for reference only. Solarbio does not independently validate these methods.

Note：

1. The products are all for scientific research use only. Do not use it for medical, clinical diagnosis or treatment, food and cosmetics, etc. Do not store them in ordinary residential areas.

2. For your safety and health, please wear laboratory clothes, disposable gloves and masks.

3. The experimental results may be affected by many factors, after-sale service is limited to the product itself and does not involve other compensation.