Eilertsen Hans Chr, Huseby Siv, Degerlund Maria, Eriksen Gunilla K, Ingebrigtsen Richard A, Hansen Espen
Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø N-9037, Norway.
MabCent-SFI, UiT The Arctic University of Norway, Tromsø N-9037, Norway.
Molecules. 2014 Oct 13;19(10):16373-80. doi: 10.3390/molecules191016373.
During normal sample preparation, storage in freezers and subsequent freeze/thaw cycles are commonly introduced. The effect of freeze/thaw cycles on the metabolic profiling of microalgal extracts using HR-MS was investigated. Methanolic extracts of monocultures of Arctic marine diatoms were analyzed immediately after extraction, after seven days of storage at -78 °C (one freeze/thaw cycle), and after additional seven days at -20 °C (two freeze/thaw cycles). Repeated direct infusion high-resolution mass spectrometry analysis of microalgae extracts of the same sample showed that reproducibility was ca. 90% when a fresh (unfrozen) sample was analyzed. The overall reproducibility decreased further by ca. 10% after the first freeze/thaw-cycle, and after one more freeze/thaw cycle the reproducibility decreased further by ca. 7%. The decrease in reproducibility after freeze-thaw cycles could be attributed to sample degradation and not to instrument variability.
在正常样品制备过程中，通常会将样品储存在冰箱中，并进行后续的冻融循环。研究了冻融循环对使用高分辨质谱（HR-MS）的微藻提取物代谢谱的影响。北极海洋硅藻单培养物的甲醇提取物在提取后、在-78°C储存7天（一个冻融循环）后以及在-20°C再储存7天（两个冻融循环）后立即进行分析。对同一样品的微藻提取物进行重复直接进样高分辨质谱分析表明，分析新鲜（未冷冻）样品时的重现性约为90%。在第一个冻融循环后，总体重现性进一步下降约10%，再经过一个冻融循环后，重现性又进一步下降约7%。冻融循环后重现性的降低可归因于样品降解，而非仪器的变异性。
