In the present work, micellar electrokinectic capillary chromatography (MECC) and solid surface room-temperature phosphorimetry (SSRTP) were used as analytical techniques for the determination of two strobilurins (picoxystrobin and pyraclostrobin) and of one fluoroquinolones (enrofloxacin), respectively. The experimental conditions for MECC have been optimized using an univariate approach for the following experimental and instrumental parameters: pH of the working electrolyte, concentration of the buffer, concentration of surfactant (sodium dodecyl-sulphate - SDS), type and amount of organic modifier, working temperature and applied potential. After defined the best conditions (borate buffer 40 mmol L(-1) pH=8.5; 30 SDS mmol L(-1); acetonitrile 15% in volume, 25 ºC and 25 kV), a study was carried through to improve the limit of detention (LD) and the limit of quantification (LQ) of the method. In order to do that, an on-line analyte pre-concentration called normal stacking mode (NSM) was used. In such approach, the standards and samples have been dissolved in a solution of higher impedance (water: borate 40 mmol L(-1) pH=8.5 50:50% v/v). A high sensitivity detection cell also was used to attempt the increasing of the sensitivity of the method. The analytical curves have been constructed with the use of an internal standard (azoxystrobin) and a linear response and homocedastic behavior were observed with R2 values of at least 0.999. The NSM mode allowed the values of LD (x(b) + 3(sb)) and of LQ (x(b) + 10(sb)) in the order of 10(-7) mol L(-1) for picoxystrobina and pyraclostrobina. The precision of the method (repeatability and intermediate precision) was characterized by values between 5 and 8%. The method was applied in the analysis urine and stream water, both type of samples fortified with the strobilurins. The urine sample was previously passed through a solid phase extraction column (C-18). The recoveries achieved for pyraclostrobina were 75  +- 4% for urine and 94  +- 10% for stream water samples. For picoxystrobin, the recovery values were 109  +- 9% and 102  +- 9% respectively for urine and stream water samples. The phosphorimetric characteristics of enrofloxacin have been studied in an unvaried way for experimental parameters such as the type and quantity of phosphorescence inducer (heavy atom salt), surfactant used as cellulose surface modifier, influence of the hidrogenionic concentration in the analyte solution and study of the UV exposition time for the formation of a more signal stable photoproduct. The best conditions for the phosphorimetric method for enrofloxacin were the use of basic solution (solution acetone: NaOH 0.05 mol L-1 50:50% v/v) irradiated with UV for 30 min and cellulose substrates containing 80 Vg of TlNO3. The method was applied in pharmaceutical formulations containing enrofloxacin employed in veterinary medicine (solution and pills). A method based on high efficiency liquid chromatography (HPLC), adapted from literature, was used as a reference method and the the results obtained for enrofloxacin was comparable to the ones achieved by SSRTP. The analytical curve presented linear and homocedastic behavior with R2 values higher than 0.99. The LD (x(b) + 3(sb)) and the LQ (x(b) + 10(sb)) values were 2.1 and 4.8 ng respectively. The precision (repeatability and intermediate precision with change of analyst) of the method presented values between 2 and 19%. The uncertainty of the phosphorescence measurement was calculated using the systematic method indicated in the ISO GUM. Values between 18 and 26% had been achieved, with the repeatability with substrate change the most important source uncertainty. In the validation procedure, enrofloxacin concentration values found in the medicine samples analyzed by SSRTP and HPLC were statistically similar ( t(experimental) value of 0.48 and 1.04 smaller than the t(critic) value of 2.23).