ABSTRACT
The diffusion coefficient ((4. 11±0. 78)×10-11 m2/s) and hydrated radius ((6. 12±1. 21) nm) of FITC-DSA ( fluorescein isothiocyanate conjugate dog albumin ) were investigated and measured by combining Taylor dispersion analysis with laser induced fluorescence in microchip. The influence of size of gold nanoparticles (15, 30 and 50 nm) on the interactions between FITC-DSA and gold nanoparticles was studied. The preliminary result demonstrated that the binding of protein and gold nanoparticle displayed a size-dependent relationship. It was interesting that the 50-nm gold nanoparticles could enhance the FITC-DSA fluorescence in microchannel driven with pressure. This method was simple, fast, low sample consumption and high throughput and could be used to study the interaction of nanoparticles and proteins. Systematical study using this method would enable us to have a deep understanding of the toxicity of nanomaterials, and promote the development of safe nanomedicine.
ABSTRACT
Objective To measure the fluorescence spectral information of UVRF in the facial skin of patients with acne vulgaris and seborrheic dermatitis and to comprehend the optical properties of UVRF.Methods The lesions were squeezed to extract the sebaceous secretions containing UVRF in the facial skin.Ocean Optics USB2000 +F02243 Spectrometer and the 308nm excimer laser were used as an excitation light source to measure the signal of the LIF spectrum of UVRF in 6 acne vulgaris and 4 seborrheic dermatitis patients' facial part,compared with protoporphyrin Ⅸ.Results 1-4 peaks were detected in 10 patients' UVRF specimen respectively.The fluorescence spectra's characteristic peak of UVRF in 10 patients was at 680 nm.Protoporphyrin Ⅸ was at 688 nm and more gentle and generous than UVRF's characteristic peak.Conclusions LIF system can be used to detect the fluorescence spectroscopy of UVRF.UVRF has similar spectral characteristics to protoporphyrin Ⅸ,but it is not the same species.
ABSTRACT
A rapid, reliable and sensitive pressurized capillary electrochromatography-Laser induced fluorescence ( pCEC/LIF ) method with trifluoroacetic acid ( TFA ) pre-column derivation for simultaneous determination of four aflatoxin ( AFB1 , AFB2 , AFG1 , AFG2 ) was developed. This method included separation on a capillary column packed with 1. 8μm C18 particles using 0. 05% FA aqueous solution/methanol (55:45, V/V) as mobile phase at a pump flow rate of 0. 05 mL/min when the split ratio was 1:300. Under the optimum conditions including running voltage of 15 kV, excitation wavelength of 375 nm and emission wavelength of 450 nm, the baseline separation of four aflatoxins was achieved within 10 minutes. The limits of detection (LODs) were 0. 02, 0. 016, 0. 008 and 0. 01 μg/L for AFG1, AFB1, AFG2, AFB2(S/N=3), respectively. The linear detection ranges of AFG1 , AFB1 , AFG2 , AFB2 were 0. 1-10, 0. 1-10, 0. 1-3 and 0. 1-3 μg/L with correlation coefficients (R2) of 0. 9999, 1. 0000, 0. 9995 and 0. 9997, respectively. The established method was applied to analyze the peanut butter, and the recoveries of standard addition experiment were between 90 . 0% and 112 . 0% for all analytes ( RSDs=0 . 5%-1 . 9%) .