Diss. (sammanfattning) Linköping : Univ., 2004. / Härtill 6 uppsatser.

Amphetamine abuse is an enduring problem in many developed nations, including Sweden. It causes lasting damage both to its users and in the form of increased strain on healthcare services. It is therefore critical that police be equipped with the tools necessary to rapidly and accurately identify any samples in order to combat this scourge. Current analysis methods rely on large complex machines such as gas-chromatographs. This causes a significant bottleneck as all samples must be sent to lab for analysis. In this report the potential application of graphene quantum dots(GQDs) as a sensor for amphetamine has been studied. These offer a potentially quick and cheap analysis method that could be integrated into an easily portable detector. It was found that GQDs synthesised by a simple method from citric acid shows increased photo-luminescence in the presence of amphetamine. The response is largely linear with increasing concentrations of amphetamine within an interval of 1mM-200mM. This indicates they may very well serve as a sensing element of an amphetamine detector. / Amfetaminmissbruk har länge varit ett problem i många industrialiserade länder, inklusive Sverige. Det skapar långvariga skador både på dess användare och i form av ökade kostnader för hälsovården. Det är därför kritiskt att polisen ges de verktyg som behövs för att snabbt och precist kunna analysera prov. Nuvarande analysmetoder använder sig av stora avancerade maskiner so som gas-kromatografer. Detta skapar en flaskhals då alla prov som tas måste skickas till labb för analys. I denna rapport har användningen av grafen kvantprickar (GQD) som en sensor för amfetamin studerats. Dessa har potentialen att ge en snabb och enkel analysmetod som skulle kunna integreras i portabel sensor. GQD:er syntetiserade med en simpel metod från citronsyra visas i dessa experiment ha ökad fotoluminiscens när de är lösta tillsammans med amfetamin. Denna respons är linjär relativt till koncentrationen av amfetamin inom intervallet 1mM-200mM. Detta indikerar att dessa GQD:er mycket väl kan användas som ett sensorelement i en amfetamindetektor.

The large-scale abuse and addiction of narcotics such as amphetamine and cocaine have become a global problem. In this project, we innovatively use graphene quantum dots (GQDs) as a fluorescent sensor to detect and quantify amphetamine and cocaine. This technology will have broad forensic application prospects. Compared with metallic quantum dots, graphene quantum dots are green and safe, with excellent bio-compatibility and low toxicity. We used undoped and N-doped GQDs as fluorescent sensing probes for the detection of amphetamine and cocaine, respectively. Using FTIR and FL as characterization methods, the fluorescence luminescence of GQDs under multiple excitation wavelength bands was studied and compared with the fluorescence after adding drugs. The experimental results show that the N-doped GQDs has a higher response to the binding substance. The detection concentration of amphetamine ranges from 5 µM to 5 mM, and the detection concentration of cocaine ranges from 10 µM-10 mM. Within this range, the fluorescence peak intensity ratio and the drug concentration have a two-stage linear negative correlation. / Storskaligt missbruk och missbruk av narkotika som amfetamin och kokain har blivit ett globalt problem. I detta projekt använder vi innovativt grafenkvantprickar (GQDs) som en fluorescerande sensor för att detektera och kvantifiera amfetamin och kokain. Denna teknik kommer att ha breda rättsmedicinska applikationsmöjligheter. Jämfört med traditionella kvantprickar är grafenkvantprickar gröna och säkra, med utmärkt biokompatibilitet och låg toxicitet. Vi använde odopade och N-dopade GQD: er som fluorescerande avkännande sonder för detektion av amfetamin respektive kokain. Med användning av FTIR och FL som karakteriseringsmetoder studerades fluorescens luminiscens hos GQD under flera exciteringsvåglängdsband och jämfördes med fluorescensen efter tillsats av läkemedel. De experimentella resultaten visar att den N-dopade GQD har ett högre svar på den bindande substansen. Detekteringskoncentrationen av amfetamin sträcker sig från 5 µM till 5 mM, och detektionskoncentrationen av kokain varierar från 10 µM-10 mM. Inom detta område har fluorescens toppintensitetsförhållandet och läkemedelskoncentrationen en tvåstegs linjär negativ korrelation.

In this project a LC-MS-method for the analysis of gamma-hydroxybutyrate, gamma-butyrolactone, 1,4-butanediol, amphetamine and methadone was developed. Initially, the efficiency of the ionisation of the analytes was evaluated with respect to the ionisation technique (ESI, APCI and APPI) and the composition of the mobile phase. In the next step a number of different columns was tested in order to find the one with the greatest potential for separation of the substances in question. Using the selected column, the separation was optimised by means of experimental design and the software The Unscrambler 7.8. The parameters studied were the flow rate, the column temperature and the mobile phase composition. The response variables were the resolution between the target compounds and the retention time of the last eluting compound. These experiments showed that, in order to obtain the best ionisation, the mobile phase should consist of 5 mM formic acid in water and acetonitrile. ESI should be used in the positive mode for all analytes except gamma-hydroxybutyrate, for which the negative mode should be applied. The Hypercarb column exhibited superior retention of the analytes and was therefore selected for further optimisation. The dimensions of this column were 2.1 x 50 mm and the particle size 5 μm, connected to a 2.1 x 10 mm precolumn containing the same packing material. The optimum of the flow rate and the column temperature were 250 μl/min and 20 ºC respectively. For the separation of gamma-hydroxybutyrate, gamma-butyrolactone and 1,4-butanediol the mobile phase consisted of 100% water with 5 mM formic acid. Thereafter a gradient, up to 70% acetonitrile with 5 mM formic acid, was used in order to elute amphetamine and methadone. Efforts were also made to find an internal standard for the method. However, none of the compounds tested was found suitable. In order to get the method usable for routine analysis, which is the goal, further work is required. A suitable internal standard needs to be added to the method and thereafter work remains with validation of the method.

<p>In this project a LC-MS-method for the analysis of gamma-hydroxybutyrate, gamma-butyrolactone, 1,4-butanediol, amphetamine and methadone was developed.</p><p>Initially, the efficiency of the ionisation of the analytes was evaluated with respect to the ionisation technique (ESI, APCI and APPI) and the composition of the mobile phase. In the next step a number of different columns was tested in order to find the one with the greatest potential for separation of the substances in question. Using the selected column, the separation was optimised by means of experimental design and the software The Unscrambler 7.8. The parameters studied were the flow rate, the column temperature and the mobile phase composition. The response variables were the resolution between the target compounds and the retention time of the last eluting compound.</p><p>These experiments showed that, in order to obtain the best ionisation, the mobile phase should consist of 5 mM formic acid in water and acetonitrile. ESI should be used in the positive mode for all analytes except gamma-hydroxybutyrate, for which the negative mode should be applied. The Hypercarb column exhibited superior retention of the analytes and was therefore selected for further optimisation. The dimensions of this column were 2.1 x 50 mm and the particle size 5 μm, connected to a 2.1 x 10 mm precolumn containing the same packing material. The optimum of the flow rate and the column temperature were 250 μl/min and 20 ºC respectively. For the separation of gamma-hydroxybutyrate, gamma-butyrolactone and 1,4-butanediol the mobile phase consisted of 100% water with 5 mM formic acid. Thereafter a gradient, up to 70% acetonitrile with 5 mM formic acid, was used in order to elute amphetamine and methadone. Efforts were also made to find an internal standard for the method. However, none of the compounds tested was found suitable.</p><p>In order to get the method usable for routine analysis, which is the goal, further work is required. A suitable internal standard needs to be added to the method and thereafter work remains with validation of the method.</p>