In H2SO4 solution, the arsenic was reduced to arsine (AsH3) by NaBH4, and absorbed by solution of H3PO4-HAuCl4-NH4SCN-gum arabic. The Au3+ was reduced to nanogold, which led to the absorption value at 555nm increased. Under the selected conditions, the value was linear to the concentration of As (III) in the range of 0.07-1.10 μg/mL, a detection limit of 0.03 μg/mL. The proposed method was applied to detect As (III) in water samples, with satisfactory results.

The decolored reaction between cetyltrimethyl ammonium bromide (CTMAB) and nanosilver was studied, and a simple, rapid spectrophotometric method was established to determine CTMAB. In pH 7.8 Na2HPO4-NaH2PO4buffer solution, nanosilver exhibited a maximum absorption peak at 395 nm, and it reacted with CTMAB to form larger particles that resulted in the absorption decreasing. Under the chosen conditions, the decreased absorbance was linear to the CTMAB concentration in the range of 2.5×10-7-1.0×10-5mol/L, with the regression equation of ΔA395 = 0.0431C CTMAB + 0.0182, the correlation coefficient of 0.9968 and the detection limit of 0.21μmol/L CTMAB. The proposed method was applied to detect CTMAB in water samples, with simplicity, rapidity and accuracy.

In pH 6.5 Na2HPO4-NaH2PO4 buffer solution and in the presence of stable reagent PEG10000 and aggregation reagent NaCl, nanosilvers were aggregated to form stable aggregated-nanosilvers (ANS). The molecular probe of 4-mercaptopyridine (MP) adsorbed on the surface of ANS to form MP-ANS conjugates that produce strongest surface-enhanced resonance Raman scattering (SERRS) peak at 1097 cm-1. When Au(III) was added, the SERRS intensity at 1097 cm-1 decreased. The decreased SERRS intensity was linear to Au(III) concentration in the range of 5-50 ×10-10 mol/L, with a detection limit of 2.0×10-10 mol/L Au(III).

Highly sensitive and selective surface-enhanced resonance Raman scattering (SERRS) spectral detection technique are developed by combining the functional nucleic acid (FNA) including aptamer and DNAzyme, and nanoparticle such as gold/silver (NG/NS) aggregation. The recent progress of SERRS was reviewed in this paper.

In the 0.02 mol/L HCl medium solution, berberine (BB) cationic ion and AuI2- combine to BB-AuI2 association complex molecule. These complex molecules self-aggregate to (BB-AuI2)n association particles. It exhibits a fluorescence peaks at 470 nm. A new and sensitive fluorescence method has been proposed for the determination of trace amounts of BB in the range of 10-800 ng/ml. The detection limit is 3ng/ml BB. The method has been applied to the determination of trace berberine in real samples, with satisfactory results. The cause of the fluorescence was also discussed.