Development of LC-QTOF method for analysis of extracts from urinary catheters

Sammanfattning: Urinary catheters are made of polymers which in some cases contain a number of additives in order to get certain properties such as mechanical flexibility and prolonged shelf-life. To prove costumer safety, a manufacturer need to extract and analyse  these additives by a number of different methods. This master thesis presents the method development of a liquid chromatography-quadrupole time-of-flight instrument (LC-QTOF). The aim of the study was to produce a method that could separate and characterize five known additives in extracts from urinary catheters. The extraction of catheters was performed with 2-propanol according to International Organization of Standards, ISO 10993-12:2007. Starting with an already established liquid chromatography method with UV detection (LC-UV), known to separate the additives, two different columns were tested with a water-acetonitrile gradient. Early in the study, two different ion sources, the Electrospray (ESI) and Atmospheric pressure chemical ionization (APCI) were evaluated based on their ability to ionize the five additives. APCI turned out to be the superior ion source which also was supported by the literature. Therefore the method development was performed with APCI in positive mode. A study on how acid addition to the mobile phase affected the ionization was also conducted. The evaluation however indicated no improvement in ion signal for any of the additives. When evaluating the flow rate, it showed that the APCI ion source perform better at flow rates greater than or equal to 0.5 ml/min. To optimize the ion source six different parameters were varied in an experimental design using the software MODDE. The results showed that in order to increase the ionization of all five additives the method needed to be divided into two time segments with different parameter settings.   The final method proved successful when analysing extracts from three different types of catheters. The aimed additives could be identified along with a number of unknown peaks. Some of the unknown peaks were later identified as Erucamide fragments by their masses and isotopic pattern.