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Abstract: The noble metal nanoparticles (NPs), including gold nanorods (AuNRs), gold nanospheres (AuNSs) and silver nanoplates (AgNPTs), were synthesized and Tween 20 stabilized NPs (Tween 20-NPs) were used as the probes for determining Hg2+. Hg2+ was determined based on the strong affinity between Au (Ag) and Hg. Hg2+ was reduced to Hg in the presence of sodium borohydride. Hg interacts with the NPs and the diameter of the NPs decreases with the increase of Hg2+ concentration, which causes the shift in absorption peak of Tween 20-NPs. The peak shifts are linearly related to Hg2+ concentrations. Compared with AuNSs and AgNPTs, when the AuNRs was used, the sensitivity for determining Hg2+ was higher. The developed method shows a good selectivity for Hg2+ and can be applied to the determination of Hg2+ in water samples. [Copyright &y& Elsevier]

Abstract: Based on the surface-enhanced Raman scattering (SERS) sodium 2-mercaptoethanesulfonate (mesna) was determined using unmodified gold colloid as the probe. The Raman scattering intensity was obviously enhanced in the presence of sodium chloride. The influence of experimental parameters, such as incubation time, sodium chloride concentration and pH value on SERS performance was examined. Under the optimum conditions, the SERS intensity is proportional to the concentration of mesna in the range of 9.0×10−8 to 9.0×10−7 mol/L and detection limit (S/N=3) is 1.16×10−8 mol/L. The corresponding correlation coefficient of the linear equation is 0.996, which indicates that there is a good linear relationship between SERS intensity and mesna concentration. The experimental results indicate that the proposed method is a viable method for determination of mesna. The real samples were analyzed and the results obtained were satisfactory. [Copyright &y& Elsevier]

Abstract: As a resonance light scattering (RLS) probe, the polyelectrolyte polymethacrylic acid (PMAA) was applied in this assay. The bovine serum albumin (BSA) and human serum albumin (HSA) were determined by the electrostatic interaction of PMAA and proteins. At pH 3.8 Na2HPO4–citric acid buffer solution, the RLS intensities of PMAA–BSA (HSA) system were greatly enhanced. The characteristic peaks were appeared at the wavelength 320, 546 and 594nm. The optimization conditions of the reaction were also examined and selected. Under the selected conditions, the RLS intensities were proportional to the protein concentrations in the range of (0.0200–2.00)×10−6 mol/L for BSA and (0.0200–2.40)×10−6 mol/L for HSA. The influences of some foreign substances were also examined. The synthetic samples containing proteins and some real samples were analyzed and the results obtained were satisfactory. [Copyright &y& Elsevier]

Abstract: By means of the resonance light scattering (RLS) technique, a new method was developed to determine the bovine serum albumin (BSA) and human serum albumin (HSA) by the interaction of serum albumin with poly(diallyldimethylammonium chloride) (PDDA). At Tris–NaOH buffer solution, the RLS intensity of serum albumin at the wavelength 320, 550 and 590nm was obviously enhanced in the presence of PDDA. The influences of some experimental factors, including incubation time, addition sequence of reagents, pH value, concentration of PDDA and foreign substances, on the enhancement of the RLS intensity were examined. The optimum conditions of the experiment were selected. Under the selected experimental condition, the enhanced RLS intensities were directly proportional to the concentrations in the range of (0.0250–2.75)×10−6 mol/L for BSA and (0.0235–1.17)×10−6 mol/L for HSA. The detection limits (S/N=3) were 8.40×10−9 mol/L for BSA and 7.39×10−9 mol/L for HSA. The synthetic samples were analysed and the results obtained were satisfactory. [Copyright &y& Elsevier]

Abstract: The DNA was determined based on resonance light scattering (RLS) spectrometry and the localized surface plasmon resonance. The gold bipyramids were used as the probes and synthesized by a seed-mediated method. Cetyltrimethylammonium bromide was used as stabilizing agent. DNA can be bound to the gold bipyramids due to electrostatic interaction and aggregates, which results in a strong enhancement of the RLS intensity. Under the optimal conditions, the intensity of RLS is directly proportional to the concentration of DNA in the range from 0.1 to 2.0μgmL−1. [Copyright &y& Elsevier]

Abstract: In this paper, the anionic surfactant sodium dodecylbenzene sulphonate (SDBS) and cationic surfactant cetyltrimethylammonium bromide (CTMAB) were used as resonance light scattering (RLS) probe to determine bovine serum albumin (BSA). Based on the weak RLS intensity of SDBS–CTMAB probe and the enhancement of RLS intensity of BSA in the presence of the probe, a simple assay for BSA was developed. The experimental results showed that the formation of three component complex BSA–SDBS–CTMAB is the main reason for the enhancement of RLS intensity of BSA, in which SDBS as a bridge can interact with both BSA and CTMAB. The effects of pH value, incubation time, concentrations of SDBS and CTMAB on the enhanced RLS intensity of BSA were investigated. Under the optimum conditions, the enhanced RLS intensity is proportional to the concentration of BSA in the range from 2.5×10−8 to 2.0×10−6 molL−1. The detection limit is 9.7×10−9 molL−1 for BSA. The study of foreign substance effect on the determination of BSA indicated that most of metal ions have little effect on the determination of BSA. The results of assay for BSA in synthetic samples were satisfactory. [Copyright &y& Elsevier]

Abstract: A simple, highly sensitive assay for fibronectin (Fn) was reported using resonance light-scattering (RLS) technique based on the enhanced RLS intensity of hyperin–cetyltrimethylammonium bromide (CTMAB)–Fn system. The interaction system of hyperin–CTMAB–Fn was investigated using spectral methods. Mechanistic investigations show that the main reason of the enhanced RLS intensity of Fn is the formation of three-component complex (hyperin–CTMAB–Fn), in which CTMAB acts as a bridge between hyperin and Fn. The effects of pH, surfactant, concentration of CTMAB and hyperin, incubation time and foreign substances on the enhancement of RLS intensity were studied. Under the optimum conditions, the enhancement of RLS intensity is in proportion to the concentration of Fn in the range of 1.9–248ng/ml. The synthetic samples containing Fn were analyzed and results obtained were satisfied. [Copyright &y& Elsevier]

Abstract: Based on the interaction between human complement factor C4 (human C4) and sodium dodecylbenzene sulphonate (SDBS) and the resonance light-scattering (RLS) technique, a highly sensitive assay for human C4 using resonance light-scattering technique was developed. At pH 2.8 Na2HPO4–citric acid buffer solution, the RLS intensities of SDBS system at 283, 503 and 600nm were obviously enhanced in the presence of human C4. The effects of surfactant, pH, incubation time, concentration of SDBS and foreign substances on the enhanced RLS intensity of system were investigated. Under the optimum conditions, the enhanced RLS intensity is directly proportional to the concentration of human C4 in the range of (0.5–120) ×10−6 gl−1 and the linear regression equation was obtained with high correlation coefficient. This RLS technique was applied to the determination of human C4 in some synthetic samples with good recovery. Moreover, it was found that the electrostatic interaction is the main binding force between SDBS and human C4. [Copyright &y& Elsevier]

Abstract: The interactions of colloidal gold and serum albumins, including bovine serum albumin (BSA) and human serum albumin (HSA), were studied by fluorescence and absorption spectrometry. Fluorescence quenching spectrometry was applied to study the interactions between colloidal gold and serum albumins. At pH 7.4 phosphate-buffered saline (PBS), the intensity of fluorescence emission spectrum of serum albumins decreased in the presence of colloidal gold, which indicated that colloidal gold quenched the fluorescence of serum albumins. Experimental results indicated that the combination reactions of colloidal gold and serum albumins were static quenching processes. Based on the effect of colloidal gold on fluorescence intensity, the binding constants, the numbers of binding sites and the acting forces between colloidal gold and serum albumins were found. [Copyright &y& Elsevier]