{"id":1159,"date":"2026-08-11T19:18:37","date_gmt":"2026-08-11T17:18:37","guid":{"rendered":"https:\/\/dutchpeptidelabs.nl\/blogs\/leren-over-peptiden\/aliquoteren-van-peptide-oplossingen-vries-dooicycli-voorkomen-2"},"modified":"2026-09-19T11:30:46","modified_gmt":"2026-09-19T11:30:46","slug":"aliquoteren-van-peptide-oplossingen-vries-dooicycli-voorkomen","status":"publish","type":"post","link":"https:\/\/dutchpeptidelabs.nl\/en\/blogs\/leren-over-peptiden\/aliquoteren-van-peptide-oplossingen-vries-dooicycli-voorkomen","title":{"rendered":"Aliquoting peptide solutions: avoiding freeze-thaw cycles"},"content":{"rendered":"<p>Anyone working with peptide solutions in the laboratory recognises the problem: a reconstituted stock is prepared, part of it is used for an experiment, and the rest goes back into the freezer. Next time the same vial is thawed again, used, and frozen again. Every one of those cycles costs stability. Aliquoting \u2014 dividing a solution into small, single-use portions immediately after reconstitution \u2014 is one of the simplest ways to prevent that, and yet in practice it is often skipped.<\/p>\n<h2>What happens during a freeze-thaw cycle<\/h2>\n<p>When an aqueous solution freezes, ice crystals form. As the water crystallises out, the concentration of dissolved substances in the remaining liquid phase rises \u2014 an effect known as cryoconcentration. For a peptide this means a locally much higher concentration than the nominal value, which can promote aggregation and precipitation. On thawing the situation reverses, but not always completely: aggregates once formed do not necessarily redissolve. Repeat this process a few times and the cumulative damage to the peptide structure can build up measurably, visible as deviating HPLC peaks or a falling signal intensity in mass spectrometry.<\/p>\n<p>Mechanical stress also plays a part: the growth of ice crystals can physically damage peptide bonds at the interface between ice and liquid, particularly in longer or slower freezing cycles.<\/p>\n<h2>Why one vial and multiple thaw cycles is not a good idea<\/h2>\n<p>The effect of repeated freezing and thawing is not linear. The first cycle often shows little measurable difference, but from the third or fourth cycle degradation increases visibly for many peptide sequences, particularly for peptides sensitive to oxidation or deamidation. Because this effect differs per sequence and per buffer condition, the risk is hard to predict without testing it specifically \u2014 and most laboratories have neither the time nor the budget for that. Aliquoting largely eliminates that uncertainty: each tube is thawed only once and never refrozen.<\/p>\n<h2>Setting up an aliquoting strategy<\/h2>\n<p>A practical approach starts immediately after reconstitution, not at the point of first reuse:<\/p>\n<ul>\n<li>\n<strong>Determine the volume per experiment in advance.<\/strong> Work back from typical use per session, plus a small margin, so that as little residual volume as possible is left over.<\/li>\n<li>\n<strong>Use small, low-bind tubes.<\/strong> For small volumes, adsorption to the wall of standard polypropylene tubes can capture a relatively large part of the peptide mass; low-protein-binding tubes limit that loss.<\/li>\n<li>\n<strong>Label every tube fully.<\/strong> Peptide name, concentration, buffer, date of reconstitution and lot number belong on every tube, not just on the original vial.<\/li>\n<li>\n<strong>Freeze quickly.<\/strong> Rapid freezing (for example in an ethanol\/dry ice bath or at -80 \u00b0C) limits the formation of large ice crystals compared with slow freezing in a standard -20 \u00b0C freezer.<\/li>\n<li>\n<strong>Record use per aliquot.<\/strong> Once a tube has been thawed it is marked as used and not refrozen \u2014 not even if a small remainder is left.<\/li>\n<\/ul>\n<h2>Storage temperature and shelf life of aliquots<\/h2>\n<p>For most research peptides in solution the rule is: the colder, the more stable in the long term, with -80 \u00b0C preferred over -20 \u00b0C for long-term storage. For the short term (days to a few weeks, depending on the sequence and buffer) a -20 \u00b0C freezer can suffice, provided freeze-thaw cycles are avoided. Lyophilisation of the starting material, followed by reconstitution of only the volume needed shortly before use, is for many applications more stable still than keeping a large stock of solution \u2014 see also our earlier guide to lyophilisation for the trade-offs involved.<\/p>\n<h2>Weighing cost against risk<\/h2>\n<p>Aliquoting demands more tubes, more labelling work and slightly more freezer space. Against those costs stands the assurance that every experiment starts with material of consistent quality, without the uncertainty that comes with a vial already thawed four or five times. For quantitative analyses where reproducibility counts, that difference usually outweighs the extra preparation time comfortably.<\/p>\n<p><em>The products and information of Dutch Peptide Labs are intended solely for laboratory and research purposes. They are not intended for human or animal consumption, diagnostic use or therapeutic application.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Anyone working with peptide solutions in the laboratory recognises the problem: a reconstituted stock is prepared, part of it is used for an experiment, and the rest goes back into the freezer. Next time the same vial is thawed again, used, and frozen again. Every one of those cycles costs stability. Aliquoting \u2014 dividing a [&hellip;]<\/p>\n","protected":false},"author":0,"featured_media":430,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1159","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-niet-gecategoriseerd"],"acf":[],"_links":{"self":[{"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/posts\/1159","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/comments?post=1159"}],"version-history":[{"count":1,"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/posts\/1159\/revisions"}],"predecessor-version":[{"id":1170,"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/posts\/1159\/revisions\/1170"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/media\/430"}],"wp:attachment":[{"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/media?parent=1159"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/categories?post=1159"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dutchpeptidelabs.nl\/en\/wp-json\/wp\/v2\/tags?post=1159"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}