Microfluidic flow injection thermal lens microscopy for high throughput and sensitive analysis of sub-[mu]L samples

Mingqiang Liu (Author), Sara Malovrh (Author), Mladen Franko (Author)

Abstract

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.

Keywords

spektrometrija TLS;mikroskopija TLM;mikrofluidika;krom (VI);

Data

Language:	English
Year of publishing:	2016
Typology:	1.01 - Original Scientific Article
Organization:	UNG - University of Nova Gorica
UDC:	543.2/.9
COBISS:	4365051
ISSN:	1759-9660
Views:	4417
Downloads:	261
Average score:	0 (0 votes)
Metadata:

Other data

URN:	URN:SI:UNG
Type (COBISS):	Not categorized
Pages:	str. 5053-5060
Volume:	ǂVol. ǂ8
Issue:	ǂiss. ǂ25
Chronology:	2016
DOI:	10.1039/C6AY00932H
ID:	9148264