Ratio-fluorescence detection of tert-butylhydroquinone based on non-conjugated polymer dots and gold nanoclusters.

A novel ratiometric fluorescent probe based on non-conjugated polymer dots (NCPDs) and gold nanocluster (AuNCs) was constructed to determine tert-butylhydroquinone (TBHQ). The probe exhibited dual emission peaks at 480 nm and 630 nm under 370 nm excitation. The fluorescence of AuNCs was quenched by TBHQ due to strong electrostatic interactions, whereas the emission of NCPDs increased. The ratio of fluorescence intensity at 480 nm to 630 nm (F480 / F630) was monitored as analytical signal response. The probe have been utilized for the detection of TBHQ with good linear relationship in the range of 0.2 to 60 µg/mL. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.048 µg/mL and 0.159 µg/L, respectively. Three levels of spiked-in TBHQ concentrations were obtained with recovery rates from 80 % to 102 %. The present study provided an effective ratiometric fluorescence method for selective screening of TBHQ in food samples.

A new spot quality control for protein macroarray based on immunological detection.

Protein macroarray is a new, simple and multiple biochemistry detection system, in which the test spots are more than 1mm diameter and results directly visible and instrumentation is not necessary. This technology, however, possesses recognized problems with spot quality and uniformity, issues that can limit its application. Previous methods have been developed for spot quality control, but they are complicated or require specific instrumentation. Therefore, we have developed a spot quality control buffer supplement with Ponceau S (SQCB-PS) as a direct and visible means of monitoring spot quality on nitrocellulose membrane prior to hybridization. In this report, 1% (w/v) Ponceau S and 10% (v/v) glycerol in spotting buffer were found to be optimal for spot quality control and food-borne pathogens multiple detection. Furthermore, the sensitivity and specificity of the protein macroarray were not compromised by spotting buffer with Ponceau S. Under optimal conditions, this visible spot quality control method makes the detection more reliable, and should enhance the wider use of the technique.