Dimethylsulfoniopropionate (DMSP) plays many important physiological and ecological roles in macroalgae. The most common method to measure DMSP is by gas chromatography analysis of the dimethylsulfide (DMS) produced after NaOH hydrolysis (pH > 12). Storage of DMS, however, is not recommended for more than a week. We investigated if acidification can be a suitable method to preserve DMSP in macroalgal samples over three months of storage, compared to widely used protocols such as drying and freezing at −20°C. The DMSP content of green (Ulva sp. and Ulva compressa), red (Chondrus crispus), and brown (Bifurcaria bifurcata) macroalgae were analyzed: 24 h after NaOH addition (control values); and after acidification (0.2 mol · L HCl⁻¹) for 24 h of fresh material, followed by NaOH addition for 24 h. These values were compared to measurements after 3‐month storage of samples that had been either dried in a heater (60°C for a night, and storage at room temperature), or frozen at −20°C, or kept in 0.2 mol · L HCl⁻¹. There was no significant difference between DMSP measurements on freshly collected material and after acidification of the samples, whether 24 h later or after 3 months of storage. This was in contrast to 3‐month storage protocols involving overnight drying at 60°C (75‐98% DMSP loss), and to a lesser degree freezing at −20°C (37‐80% DMSP loss). We thus advise to acidify macroalgal samples for preservation over long periods of time rather than drying or freezing, when assaying DMSP content.

中文翻译：

---

使用酸化技术在大型藻类中保存DMSP的新协议及其与现有协议的比较

丙酸二甲酯（DMSP）在大型藻类中起着许多重要的生理和生态作用。测量DMSP的最常用方法是通过NaOH水解（pH> 12）后产生的二甲基硫醚（DMS）的气相色谱分析。但是，建议不要将DMS存储超过一周。与广泛使用的方案（例如在-20°C下干燥和冷冻）相比，我们研究了酸化是否可以作为在大型藻类样品中保存DMSP超过三个月的合适方法。分析了绿色（Ulva sp。和Ulva compressa），红色（Chondrus crispus）和棕色（Bifurcaria bifurcata）大型藻类的DMSP含量：添加NaOH后24 h（控制值）；酸化后（0.2 mol·L HCl^-1）处理24小时的新鲜物料，然后添加NaOH 24小时。将这些值与在加热器中干燥（在60°C过夜，并在室温下保存）或在-20°C冷冻或保持在0.2 mol·的样品保存3个月后的测量值进行比较。 L HCl ^-1。无论是在24小时后还是在3个月后，对新鲜收集的材料进行的DMSP测量与酸化后的样品之间都没有显着差异。这与3个月的存储协议相反，该协议涉及在60°C过夜干燥（75-98％DMSP损失），而在-20°C下降低冷冻程度（37-80％DMSP损失）。因此，当测定DMSP含量时，我们建议酸化大型藻类样品以长时间保存，而不是干燥或冷冻。