电子液体中的尼古丁
AN-T-208
2020-08
zh
Reliable and affordable determination by potentiometric titration
在过去的十年中，电子烟和电子烟行业取得了令人瞩目的发展。这些产品中使用的混合物通常被称为 “电子液体”、“电子流体 ”或 “电子果汁”。为确保这些电子液体的质量，需要对尼古丁含量等非常重要的质量参数进行检测。 烟草中的尼古丁通常通过气相色谱法或液相色谱法测定。水性酸碱滴定法是更经济实惠的测定方法。由于电子烟不含有可能干扰滴定的其他成分，本应用说明中介绍的酸碱水溶液滴定法可用于尼古丁测定。 这种方法是测定电子液体及其尼古丁起始原料中尼古丁含量的一种经济可靠的方法，可确保这些产品的质量。
The vaping and electronic cigarette industries have grown impressively in the past decade. Usage among youths has increased from around 1% in 2011 to 10.5–27.5% in 2019 (pre-teens vs. older teenagers) mainly due to the vast array of flavor options available (Truth Initiative, 2020). The mixtures used in these products are usually called «e-liquid», «e-fluid», or «e-juice». To ensure the quality of these e-liquids, testing the most important quality parameters is required. One important quality control parameter is the nicotine content available in these products.
Nicotine in tobacco is usually determined by gas chromatography or liquid chromatography. Aqueous acid base titration is a much more affordable alternative for this determination. As e-liquids do not contain other components which might interfere with the titration, the aqueous acid base titration presented in this Application Note can be applied for nicotine determination.
This method is an affordable and reliable way to determine the nicotine content in e-liquids and their nicotine starting material, ensuring the quality of these products.
Nicotine starting material for e-liquids as well as e-liquids are analyzed. No sample preparation is required.
The analyses are carried out on a 905 Titrando system with a rod stirrer and a Unitrode easyClean for indication of the equivalence point.
A suitable amount of sample is transferred into a disposable beaker and deionized water is added. The solution is stirred to ensure complete dissolution and mixing. Afterwards, the solution is titrated with standardized hydrochloric acid until after the first equivalence point is reached.
Steep and smooth titration curves are obtained for all analyses. An example titration curve is displayed in Figure 2. The automated analysis leads to reproducible results with low RSDs as shown in Table 1.
| Mean value / g/L | SD(abs) / g/L | SD(rel) /% | |
|---|---|---|---|
| Nicotine starting material | 31.39 | 0.01 | 0.03 |
| E-liquid 1 | 5.64 | 0.01 | 0.24 |
| E-liquid 2 | 2.82 | 0.001 | 0.04 |
| E-liquid 3 | 15.32 | 0.08 | 0.53 |
| E-liquid 4 | 10.15 | 0.04 | 0.35 |
This method is an affordable and reliable way to determine the nicotine content in e-liquids and their nicotine starting material, ensuring the quality of these products. Additionally, no harmful chemicals and no sample preparation are required for the determination.
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Internal reference: AW TI US1-0073-092018