\n\tThere are many ways to improve the\u00a0stability\u00a0of the analyte. Let us look at some of them.\n<\/p>\n
| \n \n\t\t\t\t\tMeasure\n\t\t\t\t<\/p>\n<\/td>\n | \n \n\t\t\t\t\tChallenge\n\t\t\t\t<\/p>\n<\/td>\n<\/tr>\n |
| \n \n\t\t\t\t\tpH control\n\t\t\t\t<\/p>\n<\/td>\n | \n \n\t\t\t\t\tSample\u00a0extract pH may be crucial and therefore has to be monitored carefully.\n\t\t\t\t<\/p>\n \n\t\t\t\t\tA possible problem may be esterification of alcohols. If a low pH is used for sample preservation, then the alcohols in the sample may partially be esterified if there are also carboxylic acids present. This can be a problem if some of the analytes are alcohols.\n\t\t\t\t<\/p>\n<\/td>\n<\/tr>\n |
| \n \n\t\t\t\t\tAddition of stabilizers\n\t\t\t\t<\/p>\n \n\t\t\t\t\t\u00a0\n\t\t\t\t<\/p>\n<\/td>\n | \n \n\t\t\t\t\tSome additives\u00a0themselves are not stable and therefore their concentration and thus also stabilizing efficiency changes in time.\n\t\t\t\t<\/p>\n \n\t\t\t\t\tThe precise quantity of stabilizers in the sample is required to enable the optimal stabilizing effect [ref 62].\n\t\t\t\t<\/p>\n<\/td>\n<\/tr>\n |
| \n \n\t\t\t\t\tProtecting samples and standards from the light\n\t\t\t\t<\/p>\n<\/td>\n | \n \n\t\t\t\t\tKeeping samples and standards on the bench for minimum time possible. Working in the dark or under the yellow\/red light.\n\t\t\t\t<\/p>\n<\/td>\n<\/tr>\n |
| \n \n\t\t\t\t\tReducing sample processing time\n\t\t\t\t<\/p>\n<\/td>\n | \n \n\t\t\t\t\tTime-critical processes have to be managed \u2013 e.g. optimization of the time during each sample preparation step.\u00a0\n\t\t\t\t<\/p>\n<\/td>\n<\/tr>\n |
| \n \n\t\t\t\t\tCold storage and handling of samples and standards\n\t\t\t\t<\/p>\n<\/td>\n | \n \n\t\t\t\t\tIf analyte requires cooling, then all steps in the processing have to be carried out under cooling.\n\t\t\t\t<\/p>\n<\/td>\n<\/tr>\n |
| \n \n\t\t\t\t\tLong-term storage in cold (e.g. -70 \u00b0C; -80 \u00b0C)\n\t\t\t\t<\/p>\n<\/td>\n | \n \n\t\t\t\t\tAvailability of -70 \u00b0C or -80 \u00b0C freezers.\n\t\t\t\t<\/p>\n<\/td>\n<\/tr>\n |
| \n \n\t\t\t\t\tDerivatization in an as early as possible stage (e.g. already at sample collection)\n\t\t\t\t<\/p>\n \n\t\t\t\t\t\u00a0\n\t\t\t\t<\/p>\n<\/td>\n | \n \n\t\t\t\t\tTime-critical and time-consuming.\n\t\t\t\t<\/p>\n \n\t\t\t\t\tAchieving completeness of reaction.\n\t\t\t\t<\/p>\n \n\t\t\t\t\tDifferent matrix effects when derivatization reagents are used compared to the initial method. Reproducibility issues during the derivatization that can be taken into account with usage of IS or ILIS. Derivatization often increases s<\/em>r<\/sub> and s<\/em>RW<\/sub>. IS and ILIS help reducing s<\/em>r<\/sub> and s<\/em>RW<\/sub>.\n\t\t\t\t<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \n\t\u00a0\n<\/p>\n |