Microfluidic flow injection thermal lens microscopy for high throughput and sensitive analysis of sub-μL samplesLiu, Mingqiang (Avtor)
Malovrh, Sara (Avtor)
Franko, Mladen (Avtor)
Spektrometrija TLSmikroskopija TLMmikrofluidikakrom (VI)An analytical method combining microfluidic flow injection analysis (μFIA) with thermal lens microscopy (TLM) was developed for high throughput and sensitive analysis of sub-μL samples. Performance of the μFIA-TLM was validated for detection of hexavalent chromium [Cr(VI)] in water samples. At different sample injection volumes, detection positions and flow rates, influences of the reaction time and the diffusion of Cr-diphenylcarbazone (DPCO) complexes on the μFIA-TLM signal were investigated. Photodegradation of the Cr-DPCO complex was clearly observed when the absorbed photons per Cr-DPCO is above 1600. After optimization of the TLM with respect to rapid flows (up to 10 cm/s), we achieved a limit of detection of 0.6 ng/mL for Cr(VI) in a 50-μm deep channel. Impacts of interfering ions [V(V), Mo(VI), Fe(III)] on the Cr(VI) determination were found to be small. Cr(VI) in real samples from a cement factory were determined and found in good agreement with results of spectrophotometry. This μFIA-TLM shows advantages over its conventional counterpart, such as eliminating additional sample conditioning, reducing over 100 times the sample consumption to sub-μL and over 10 times the time required for one sample injection to a few seconds (up to 20 samples/min). The optimized μFIA-TLM setup can be applied for fast and sensitive analysis of nonfluoresent sub-μL samples in rapidly flowing mediums.20162016-06-01 08:22:27Delo ni kategorizirano2328COBISS_ID: 4365051DOI: 10.1039/C6AY00932HNUK URN: URN:SI:UNG:REP:GJHFAC3Asl