滴眼液中的硫柳汞
AN-V-057
2021-09
zh
Voltammetric determination of preservative in vaccines and various pharmaceutical and cosmetic solutions
硫柳汞(又称硫柳汞)是一种含汞的有机分子,被广泛用作疫苗和滴眼液的防腐剂。即使浓度很低,它对多种微生物和病毒也非常有效。为了降低对消费者的风险,有关部门限制了产品中汞的最大浓度。 极谱法或伏安法可用于准确测定疫苗或其他化妆品和药品溶液(如滴眼液)中的硫柳汞浓度。该方法操作简单、特异性强、无干扰。
Thiomersal (also called thimerosal) is a mercury containing organic molecule that has been widely used as preservative for vaccines and eye drops. Other applications of this substance have been for ear drops, storage and cleaning solutions for contact lenses, and in tattoo inks. It is very effective, even in very low concentrations, against a wide range of microorganisms and viruses.
To reduce the risk for consumers the maximum concentration of mercury in the products is limited by the authorities. Typical limit values in the European Union are 0.007% (as Hg) in eye products (EU Commission Regulation 1223/2009) or up to 25 μg thiomersal per vaccine injection dose if vaccines are distributed in multi-vaccine containers.
Polarography or voltammetry can be used to accurately determine the concentration of thiomersal in vaccines or other cosmetic and pharmaceutical solutions (such as eye drops). The method is simple to perform, specific, and free of interferences.
Vaccine against diphtheria, tetanus, pertussis
The sample and the supporting electrolyte are pipetted into the measuring vessel. The determination of thiomersal is carried out with an 884 Professional VA using the parameters specified in Table 1. The concentration is determined using external calibration with a calibration curve recorded from five standard concentrations.
| Parameter | Setting |
|---|---|
| Working electrode | HMDE or DME |
| Mode | DP – Differential Pulse |
| Deposition | none |
| Start potential | -0.2 V |
| End potential | -0.6 V |
| Peak potential thiomersal | -0.45 V |
- Working electrode: Multi-Mode Electrode pro with standard glass capillaries
- Reference electrode: Ag/AgCl/KCl (3 mol/L) reference electrode with electrolyte vessel. Bridge electrolyte: KCl (3 mol/L)
- Auxiliary electrode: Platinum rod electrode
The determination of thiomersal can be carried out in a simple and straightforward manner with voltammetry. The method is selective and free of interferences.
| Sample | Thiomersal [mg/L] |
|---|---|
| DTP vaccine | 102 |
Internal reference: AW BR4-0002-072011