To establish a method for determination the content of sorbic acid in beverages by 1H-quantitative nuclear magnetic resonance (1H-qNMR).
Nuclear magnetic resonance was used to measure the sorbic acid (SA) content in beverages. The content of SA in the sample was proportional to the signal peak of 1H nuclear magnetic resonance; deuterated water (D2O) was used as the deuterated solvent, and the methyl peak of the internal standard substance “3-(trimethylsilyl)propanoic-2, 2, 3, 3-d4 acid sodium salt” (TMSP-d4) in deuterated water was calibrated to a chemical shift of 0.00 ppm. The multiple coupling peak at δ=1.84 (±0.05) ppm was identified as the characteristic chemical shift peak of sorbic acid, and quantification was performed using the external standard method. The ‘zgpr’ pulse sequence was employed for 1H-NMR to suppress the residual water peak signal, with 16 scans acquired for each sample.
Method validation indicated a good linear relationship within the concentration range of 7.5–300.0 μg/mL: Y=0.01019X+0.36268, r2>0.99. The limits of detection and limits of quantitation were 2.5 μg/mL and 7.5 μg/mL, respectively. The recovery rates ranged from 81.8% to 102.6%, with relative standard deviations of 0.69%–5.27%.
This method features simple sample pretreatment, accurate results, and significantly reduces detection time. It is suitable for rapid, high-throughput analysis of sorbic acid in beverages and shows promising potential for practical applications.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |