Analysis in paper devices: synthesis of carbon dot for determination of clinical interesting compounds and paper-spray ionization for direct detection of doping in sport

Author(s)

Eduardo Luiz Rossini

• Document type: Doctoral Thesis
• Press: Araraquara. 2020-03-02.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Química. Araraquara
• Defense date: 2020-02-14
• Advisor: Helena Redigolo Pezza

Abstract

The first part of this work was developed on the Fritz Feigl-UNESP/CAr laboratory, in which a novel carbon dot synthesized from citric acid and tyramine was described using a one-step microwave heating route. Under UV irradiation, the CD displayed blue emission that was quenched in the presence of H2O2 and peroxidase. This property was used to develop a method to quantify glucose in biological samples using a paper platform. The method developed was applied in the analysis of certified serum and urine samples, and there were no statistically significant differences between the certified concentrations and the results obtained using the paper device with standard additions. In addition, it was developed method using 3D-µPAD, the CD fluorescence reagent and oxidase enzymes to quantify glucose and lactate in saliva samples. The sample preparation used was simple and fast. The method was validated in saliva samples utilizing standard addition and recovery, and applied in the analysis of certified serum samples, and there were no statistically significant differences between the certified concentrations and the results obtained using the 3D-µPAD. The second part of this work was developed at the Badu’s research group at The Ohio State University during the internship period funded by FAPESP, in which a direct quantification of doping agents in urine samples with no sample preparation by PS-MS was developed. Paper-spray mass spectrometry (PS-MS) is an ambient ionization method that combines the advantages of the paper platform with the reliability of MS analysis, reducing the consumption of time, reagent, and organic solvent. The use of illicit substances to improve enhance athletic performance in sport is forbidden and considered doping. The paper surface was treated with trichloromethylsilane (TCMS) using a gas-phase reaction to increase the target compounds ionization. This approach was applied for the analysis of two anabolic agents (trenbolone and clenbuterol) and two diuretics (furosemide and hydrochlorothiazide) in urine samples. Under optimized conditions, the developed methods presented satisfactory repeatability and a good correlation between concentration and absolute intensity. Highly sensitive detections as low as sub-ng mL 1 which is below the minimum required performance levels (MRPL) proposed by the WADA has been reached using the hydrophobic PS-MS without any pre-concentration and clean-up step. The proposed methods were applied in fortified urine samples with doping agents and showed to be fast, simple, sensitive, accurate and precise. (AU)

• FAPESP's process: 16/20847-6 - Development of microfluidic paper-based analytical device for clinical interest analysis with fluorescence detection
• Grantee: Eduardo Luiz Rossini
• Support Opportunities: Scholarships in Brazil - Doctorate