||The worldwide market is around 100,000 different chemicals, including over 1000 different
drugs. Most of these substances when the environment as chemical or drug residues via WWTP. The drugs effective and fate is described to be polluting and sometimes dangerous to humans and the environment at very low concentration.
In this master project there is focused on a special group of pharmaceutical substance, namely the selective serotonin reuptake inhibitor (SSRI). This group of drugs includes Citalopram (CIT), Fluoxetin (FLU) and Sertaline (SER). SSRIs are mainly used to treat despression and several other mental illnesses. The consumption of antidepressant in Denmark has been rising since 1994. The number of people treated with SSRIs has increased by more than 170,000 persons.
This master project deal with the determination of CIT concentration in wastewater treatment plant (water sample provided by Lyngby purification) using SPE-GC-MS method. The literature is focused on the determination of CIT concentration and wastewater treatment plant and wasterwater in ng/mL range. I have therefore decided to determine the CIT standard in ng/ml range, but I could not get in this concentration range.
I have tried to optimize the GC-MS by changing some parameters such as temperature, flow rate, injector temperature, ion source temperature, transfer line temperature.
This did not gave measure results, then I switch kapilar column AQuality GCBP-1(30m × 0,25mm × 0,25μm) to the column Aglient HP-5MS (30m × 0,25mm × 0,25μm) This gave no measurable results. Finally I performed the experimental measurements for CIT standard concentration in environmental institute by GC-MS (triple quadrupole), which was programmed differently compared to GC-MS (ion trap). This has not resulted in measurable outcome.
The conclusion is that CIT standard concentration is not measured in ng/ml range by GC-MS (ion trap) and GC-MS (triple-quadrupol) method.
I have been examined the melting point of CIT and FLU, because these can be easily destroyed. The measured melting point was 130-132ºC for fluoxetion hydrochloride, but for the literature value for melting point fluoxetion hydrochloride is 158.4ºC to 158.9ºC . The measured melting point was 140ºC for citalopram hydrobromide, but for the literature value for melting point of citalopram hydrobromide is 185-188ºC . This may be a sign of impurity standard. Given I could not measure CIT standard concentrations in ng/ml, I have chosen to measure CIT standard concentration in mg/L using GC-MS method.
The reason that I cannot analyze CIT concentration in water sample is calibration curve with experimental measurements for CIT found in mg/L range. But calibration curve of CIT from the literature study is found in ng/ml range.
I calculate the ratio between the calculated detection limit (mg/L) and the theoretical limit of detection (ng/ml). This show, that it should perconcentration one million times approximately by SPE method. Opconcentration process is provided to measure CIT concentration in water sample by GC-MS method. Due to the above consideration, I opted to take CIT concentration (300 mg/L) from CIT standard calibration curve for a day and is assumed as a test for experiment work. The rest of the calibration data plotted in the calibration curve. The tests are carried out both in one day and on several days.
To calculate the uncertainty on the concentration of unknown (CIT standard) using F-test and t-test to estimate the uncertainty of experimental measurements. This has shown that the uncertainty of the sample (300 mg/L) is not significant.