Studies of dissolved organic matter (DOM) composition have used several different methods to concentrate and extract the DOM from fresh water, but the impact of these methods on the composition of the DOM is relatively unknown, as very few studies use more than one method to compare results. The aim of this study was to use several methods, frequently used in the scientific literature, to concentrate and extract DOM from fresh water and compare the elemental and functional group composition of the extracted DOM. In addition, the cost, in terms of money, resources and time, were assessed for each method. The results showed that the elemental and functional group composition of the extracted DOM varied between methods significantly. The methods that yielded the most similar and reproducible DOM results were rotary evaporation, dry-down at 60 °C and freeze-drying. Although each of these methods required a relatively expensive piece of laboratory equipment, this was a ‘one-off’ cost, and consumables and time per sample were relatively low. This study highlights the dangers of comparing DOM data from different studies when the DOM has been extracted via different methods. In future, it is recommended that studies of DOM composition report their methods of extraction clearly and consistently, ideally using one (or more) of the methods showing reliable results here.

对溶解有机物（DOM）组成的研究已经使用了几种不同的方法来浓缩和从淡水中提取DOM，但是这些方法对DOM组成的影响是相对未知的，因为很少有研究使用一种以上的方法来比较结果。这项研究的目的是使用科学文献中经常使用的几种方法，从淡水中浓缩和提取DOM，并比较提取的DOM的元素和官能团组成。此外，还评估了每种方法的金钱，资源和时间成本。结果表明，提取的DOM的元素和官能团组成在方法之间存在显着差异。产生最相似和可重复的DOM结果的方法是旋转蒸发，在60°C下干燥，然后冷冻干燥。尽管每种方法都需要相对昂贵的实验室设备，但这是“一次性的”成本，并且每个样品的耗材和时间相对较低。这项研究强调了当通过不同方法提取DOM时比较来自不同研究的DOM数据的危险。将来，建议对DOM组成的研究清晰，一致地报告其提取方法，最好使用此处显示可靠结果的一种（或多种）方法。这项研究突出了当通过不同方法提取DOM时比较来自不同研究的DOM数据的危险。将来，建议对DOM组成的研究清晰，一致地报告其提取方法，最好使用此处显示可靠结果的一种（或多种）方法。这项研究强调了当通过不同方法提取DOM时比较来自不同研究的DOM数据的危险。将来，建议对DOM组成的研究清晰，一致地报告其提取方法，最好使用此处显示可靠结果的一种（或多种）方法。