Study on the resonance light-scattering spectrum of anionic dye xylenol orange-cetyltrimethylammonium-nucleic acids system and determination of nucleic acids at nanogram levels

The interaction of xylenol orange (XO) and nucleic acids in the presence of cetyltrimethylammonium bromide (CTMAB) in aqueous solution has been studied by a resonance light-scattering (RLS) technique with a common spectrofluorometer. In hexamethylenetetramine (HMTA) buffer (pH7.30), XO and nucleic acids react with cetyltrimethylammonium bromide to form large particles of three-component complex, which results in strong enhanced RLS signals characterized by three peaks at 295.9, 335.5 and 542 nm, Mechanistic studies showed that the enhanced RLS stems from the aggregation of XO on DNA through the bridged and synergistic effect of CTMAB. With the enhanced RLS signals at the three wavelengths, the enhanced RLS intensity is proportional to the concentration of nucleic acids in an appropriate range. The lowest limit of determination was 5.31 ng ml(-1), three synthetic samples of yDNA were analyzed satisfactorily.     

Spectral studies on the interaction of acid chrome blue K with nucleic acids in the presence of cetyltrimethylammonium bromide and the confirmation of combined points

The interaction of Acid chrome blue K (ACBK) with nucleic acids in weak basic medium was studied in the presence of cetyltrimethylammonium bromide (CTMAB) based on the measurements of resonance light scattering (RLS), UV-vis, NMR spectra, etc. In hexamethylene tetramine (HMTA) buffer (pH 7.45), ACBK and nucleic acids react with CTMAB to form a ternary complex, which results in strong enhanced RLS signals characterized by four peaks at 285, 335, 405.5 and 548nm. Mechanistic studies show that the enhanced RLS stems from the aggregation of ACBK on nucleic acids through the bridged and synergistic effect of CTMAB. With the enhanced RLS signals at the best wavelength at 335nm, the enhanced RLS intensity is proportional to the concentration of nucleic acids in a wide range. The lowest limit of determination was 7.52ngml(-1), three synthetic samples were analyzed satisfactorily. And the combined points of the anionic dye ACBK with nucleic acids-CTMAB have been tentatively confirmed through the measurement of 1H NMR spectra.     

Study on naringenin-CTMAB-DNA system by resonance light scattering technique and its analytical application

A new high-sensitivity determination method of deoxyribonucleic acid (DNA) with detection limit at nanogram levels was proposed. Based on the measurement of resonance light scattering (RLS), it was found DNA could combine with naringenin and cetyltrimethylammonium bromide (CTMAB) in basic Tris-HCl buffer and produce enhanced RLS signal. The optimum conditions for this system were studied in detail. The enhanced intensity of RLS of naringenin-CTMAB at 353 nm was directly proportional to the concentration of DNA in the range of 0.017-1.7 μg mL(-1). The detection limit was 5.06 ng mL(-1). Using the proposed method, the synthetic samples were analyzed with satisfactory results, the recovery was 99.3-105.0% and RSD was 0.7-3.7%.     

Determination of nucleic acids with tetra-(N-hexadecylpyridiniumyl) porphyrin sensitized by cetyltrimethylammonium bromide (CTMAB) using a Rayleigh light-scattering technique

Using a common spectrofluorometer to measure the intensity of Rayleigh light-scattering (RLS), a method for determination of nucleic acids has been developed. At pH 10.24 and ionic strength 0.01 mol l-1 (NaCl), the Rayleigh light-scattering of the tetra-(N-hexadecylpyridiniumyl) porphyrin (TC16PyP) is greatly enhanced by nucleic acids in the presence of cetyltrimethylammonium bromide (CTMAB), with the scattering peak located at 311.8 nm. The enhanced RLS intensity is in proportion to the concentration of calf thymus DNA (ctDNA) in the range 0.2-6.0 microg ml-1 and to that of fish sperm DNA (fsDNA) in the range 0.05-3.0microg ml-1. The limits of detection are 0.016 microg ml-1 for calf thymus DNA and 0.023 microg ml-1 for fish sperm DNA when the concentration of TPP was chosen 2.0 x 10(-6) mol l-1. Four synthetic samples were determined satisfactorily.     

Cetyltrimethylammonium bromide sensitized resonance light-scattering of nucleic acid--Pyronine B and its analytical application

This is the first report on the determination of nucleic acids with Pyronine B (PB) sensitized by cetyltrimethylammonium bromide (CTMAB) with resonance light-scattering (RLS) technique. Under the experimental conditions (1 x 10(-5) mol l(-1) PB, 1 x 10(-5) mol l(-1) CTMAB, pH 7.4, at room temperature, ionic strength 0.02 mol l(-1) NaCl), the interaction of PB with DNA sensitized by CTMAB results in enhanced RLS signals at 328 and 377 nm in the enhanced regions. It was found that the enhanced RLS intensity at 328 nm was proportional to the concentration of DNA in the suitable ranges. The linear range of this assay is 0.0-1.2 microg ml(-1) for calf thymus, 0.0-0.8 microg ml(-1) for fish sperm DNA (fsDNA), and 0.04-1.4 microg ml(-1) for yeast RNA, respectively. The detection limits (3 sigma) are 6.1 ng ml(-1) for calf thymus DNA (ctDNA), 11.2 ng ml(-1) for fish sperm DNA, and 8.6 ng ml(-1) for yeast RNA, respectively. Six synthetic samples were determined satisfactorily. This method is simple, rapid and the dye is inexpensive and stable.     

Simple and sensitive assay for nucleic acids by use of the resonance light-scattering technique with the anionic dye methyl blue in the presence of cetyltrimethylammonium bromide

This is the first report on the determination of nucleic acids based on the enhancement of resonance light scattering (RLS) of the anionic dye methyl blue (MB) in the presence of cetyltrimethylammonium bromide (CTMAB). In tris(hydroxymethyl) aminomethane buffer of pH 9.0, MB and nucleic acids react with CTMAB to form large particles of complex, which results in strong enhanced RLS signals characterized by three peaks at 334 nm, 393.5 nm and 548 nm. Mechanistic studies show that the enhanced RLS stems from the aggregation of MB on nucleic acids through the bridged and synergistic effect of CTMAB. With the enhanced RLS signals at the best wavelength at 334 nm, the enhanced RLS intensity is proportional to the concentration of nucleic acids in a wide range. The lowest limit of determination was 2.1 ng mL⁻¹, three synthetic samples were analyzed satisfactorily.     

Determination of DNA with cetyltrimethylammonium bromide by the measurement of Resonance Light Scattering.

A simple assay of DNA was developed based on the measurements of enhanced signals of Resonance Light Scattering (RLS) of cetyltrimethylammonium bromide (CTMAB) by DNA. The enhanced RLS signals, measured by simultaneously scanning the excitation and emission monochromators of a common spectrofluorometer with lambda ex = lambda em, was optimized for the DNA assay with CTMAB. On the conditions of pH 2.21 and ionic strength 0.002, the enhanced RLS intensity at 470.0 nm, delta I, was found to be proportional to the concentration of DNA in the range 0-2.5 micrograms/ml if 1.5 x 10(-5) M CTMAB was used. Limits of determination for calf thymus DNA and fish sperm DNA were 4.9 ng/ml and 9.2 ng/ml, respectively. Synthetic samples were determined with the recovery ratio ranging from 93.2% to 105.1%, and the RSD is lower than 2.7%.     

Spectral studies on the interaction of Amido black 10B with DNA in the presence of cetyltrimethylammonium bromide

The interaction of Amido black 10B (AB) with DNA in basic medium was studied in the presence of cetyltrimethylammonium bromide (CTMAB) based on the measurements of resonance light scattering (RLS), UV–vis, CD spectra, and RLS imaging. The interaction has been proved to give a ternary complex of CTMAB–DNA–AB in Britton–Robinson buffer of pH 11.55, which exhibits strong negative Cotton effect at 233.3 nm and 642.8 nm, and strong RLS signals characterized at 469 nm. Experiments showed that the enhanced RLS intensities (ΔI_RLS) against the mixture of AB and CTMAB are proportional to the concentration of fish sperm DNA (fsDNA) and calf thymus DNA (ctDNA), respectively over the range of 0.03–1.0 and 0.05–1.5 μg ml⁻¹, with the limits of determination (3σ) of 7.3 ng ml⁻¹ for fsDNA and 7.0 ng ml⁻¹ for ctDNA.     

Simple and sensitive assay for nucleic acids by use of the resonance light-scattering technique with copper phthalocyanine tetrasulfonic acid in the presence of cetyltrimethylammonium bromide

On the basis of enhancement of resonance light scattering (RLS) of copper phthalocyanine tetrasulfonic acid (CuTSPc) by nucleic acids and cetyltrimethylammonium bromide (CTMAB) under suitable conditions, a new RLS method for determination of nucleic acids in aqueous solutions has been developed. At pH 9.80–10.95 and ionic strength 0.01 mol L^–1 (NaCl), the interaction of copper phthalocyanine tetrasulfonic acid with nucleic acids in the presence of cetyltrimethylammonium bromide results in enhanced RLS signals at 282.0 nm, 383.6 nm, and 616.2 nm in the enhanced regions. It was found that the enhanced RLS intensity at 383.6 nm was proportional to the concentration of nucleic acids within suitable ranges. The limits of detection were 10.6 ng mL^–1 for fish sperm DNA and 32.4 ng mL^–1 for calf thymus DNA when the concentration of copper phthalocyanine tetrasulfonic acid was 2.0×10^–6 mol L^–1. This method is rapid, simple and sensitive. In addition, the reagents used are relatively inexpensive, stable, and easily synthesised. The method can be applied to the determination of nucleic acids in the presence of coexisting substances, and we have applied it to the determination of DNA in synthetic samples, with satisfactory results.     

Application of Cationic Gemini Surfactant 12-3-12 and Methylene Blue in Simple Detection of DNA and Investigation of Interaction Mechanism

The present work aims to propose a new simple assay for deoxyribonucleic acids (DNA) by applying cationic Gemini surfactant 12-3-12 and cationic dye methylene blue (MB) as resonance light scattering (RLS) probes. The formation of MB-DNA-12-3-12 complex at pH 3.99 results in enhanced RLS signals at 369 nm, which is proportional to the concentration of DNA from 0 to 0.88 mg L^?1, with determination limit of 0.014 mg L^?1. Most foreign substances do not interfere in the detection and three synthetic samples are analyzed satisfactorily. transmission electron microscopy (TEM), FTIR, and ultraviolet spectra are used to investigate the interaction mechanism.     

十六烷基溴化吡啶与脱氧核糖核酸作用的共振光散射光谱及其分析应用

在碱性条件下，十六烷基溴化吡啶(CPB)与脱氧核糖核酸(DNA)共存时，体系产生较强的共振光散射，其强度与DNA浓度呈线性关系，据此提出了基于阳离子表面活性剂的共振光散射法定量测定DNA。在最佳实验条件下，测得小牛胸腺DNA(ctDNA)和鱼精子DNA(fsDNA)的线性范围分别为0．2-2．0mg／L和0．2—1．25mg／L，检出限分别为0．07mg／L和0．05mg／L。该方法已应用于合成样品及实际样品中DNA含量的测定。     

Determination of cationic surfactants in water samples by their enhanced resonance light scattering with azoviolet

A simple assay of cationic surfactants in water samples was developed based on the measurements of enhanced resonance light scattering (RLS). At pH 6.09 and ionic strength 0.03 M, the interactions of azoviolet (AV) with cationic surfactants, including zephiramine (Zeph) and cetyl trimethyl ammonium bromide (CTMAB), result in enhanced RLS signals characterized by the peaks of 470.0, 485.0 and 495.0 nm. The enhanced RLS intensity is proportional to the concentration of cationic surfactant of Zeph in the range of 0.2~6.0x10(-6) M, and to that of CTMAB in the range of 0.4~4.8x10(-6 )M. The limit of determination (3 sigma) is 2.1x10(-8) M and 3.8x10(-8) M for the two surfactants, respectively. Determinations of cationic surfactants in synthetic and tap water samples were successfully made with a recovery of 90.5~108.6%.     

Determination of nucleic acids with crystal violet by a resonance light-scattering technique

For the first time, Crystal Violet (CV) was used to determine nucleic acid concentrations using the resonance light-scattering (RLS) technique. Based on the enhancement of the RLS of CV by nucleic acids, a new quantitative determination method for nucleic acids in aqueous solutions has been developed. At pH 5.03 and ionic strength 0.005 mol kg-1, the interaction of CV with nucleic acids results in three characteristic RLS peaks at 344.0, 483.0 and 666.0 nm. With 4.0 x 10(-5) mol l-1 of CV, linear relationships were found between the enhanced intensity of RLS at 666.0 nm and the concentration of nucleic acids in the range 0-2.5 micrograms ml-1 for herring sperm DNA, 0-4.0 micrograms ml-1 for calf thymus DNA and 0-4.5 micrograms ml-1 for yeast RNA. The limits of determination were 13.8 ng ml-1 for herring sperm DNA, 36.8 ng ml-1 for calf thymus DNA and 69.0 ng ml-1 for yeast RNA. The assay is convenient, rapid, inexpensive and simple.     

Determination of nucleic acids with a near infrared cyanine dye using resonance light scattering technique

A new method for the determination of nucleic acids has been developed based on the enhancement effect of resonance light scattering (RLS) with a cationic near infrared (NIR) cyanine dye. Under the optimal conditions, the enhanced RLS intensity at 823 nm is proportional to the concentration of nucleic acids in the range of 0-400 ng mL-1 for both calf thymus DNA (CT DNA) and fish sperm DNA (FS DNA), 0-600 ng mL-1 for snake ovum RNA (SO RNA). The detection limits are 3.5 ng mL-1, 3.4 ng mL-1 and 2.9 ng mL-1 for CT DNA, FS DNA and SO RNA, respectively. Owing to performing in near infrared region, this method not only has high sensitivity endowed by RLS technique but also avoids possible spectral interference from background. It has been applied to the determination of nucleic acids in synthetic and real samples and satisfactory results were obtained.     

Molecular spectroscopy study of the reaction of nucleic acids with brilliant cresol blue

The interaction of brilliant cresol blue (BCB) with nucleic acids in aqueous solution has been studied by spectrophotometry and Rayleigh light scattering (RLS) spectroscopy. Under suitable conditions, the RLS spectra of BCB changed significantly due to the presence of nucleic acids. RLS intensity of BCB at 364 nm is greatly enhanced with the addition of nucleic acids, and a new RLS peak is observed at 552 nm. This peak is about half the intensity of that at 364 nm. The results of this study show that BCB interacts with DNA possibly due to the cooperative effect of electrostatic attraction, intercalation, coordination and hydrophobic effect. Under optimum conditions, the increase of RLS at 364 nm of a BCB solution is proportional to the concentration of nucleic acids added. This result is the basis for a new RLS method for determination of nucleic acids. The linear range of ctDNA, fsDNA and yRNA is 0.12-4.70, 0.11-4.64 and 0.43-7.07 microg ml(-1), respectively.     

Study on the interaction between silver nanoparticles and nucleic acids in the presence of cetyltrimethylammonium bromide and its analytical application

A novel method is proposed in this paper, that is the silver nanoparticle (nanoAg)-cetyltrimethylammonium bromide (CTMAB) is used as the probe of resonance light scattering (RLS) for the determination of nucleic acids. Under optimum conditions, there are linear relationships between the quenching extent of RLS and the concentration of nucleic acids in the range of 4.0x10(-9)-2.0x10(-6)gmL(-1) for fish sperm DNA (fsDNA), 7.0x10(-9)-1.8x10(-6)gmL(-1) for calf thymus DNA (ctDNA) and 6.0x10(-9)-1.0x10(-6)gmL(-1) for yeast RNA (yRNA). The detection limits (S/N=3) of fsDNA, ctDNA and yRNA are 2.7x10(-10)gmL(-1), 4.8x10(-10)gmL(-1) and 7.2x10(-10)gmL(-1), respectively. The studies indicate that there are interactions among nanoAg, CTMAB and fsDNA through electrostatic and chemical affinity, and the nanoAg-CTMAB complex can induce the structural change of base stacking and helicity of fsDNA.     

花菁-脱氧核糖核酸的共振光散射光谱及其分析应用

研究了一种苯并噻唑阳离子花菁与脱氧核糖核酸(DNA)作用的共振光散射光谱,在pH 6.0的六次甲基四胺-HCl缓冲介质中,痕量DNA的加入使花菁在590nm的共振光散射强度显著增强。在最佳实验条件下,增强的共振光散射强度与DNA浓度具有良好的线性关系,据此建立了一种测定DNA的共振光散射光谱法。方法的线性范围为:小牛胸腺DNA(CT DNA),0～20μg/mL,鱼精子DNA(FS DNA),0～15μg/mL;检出限分别为0.005μg/mL和0.008μg/mL。该方法已用于合成样品中DNA的测定。     

灿烂甲酚蓝共振光谱散射法测定脱氧核糖核酸

研究了灿烂甲酚蓝与脱氧核糖核酸（DNA）作用的共振光散射光谱,在pH＝10．8－11．5的范围内,DNA的加入导致灿烂甲酚蓝共振光散射的增强,在347nm处,存在一共振光散射增强峰,其强度与DNA的浓度呈线性关系,据此建立了一种测定DNA的共振光谱散射法。该方法的线范围为80－100μg/L,检出限为23．3μg/L.     

Interactions of Janus Green B with double stranded DNA and the determination of DNA based on the measurement of enhanced resonance light scattering

A novel assay of DNA with a sensitivity at the nanogram level is proposed based on the measurement of enhanced resonance light scattering (RLS) signals resulting from the interaction of Janus Green B (JGB) with DNA. At pH 6.37 and ionic strength < 0.20, the RLS signals of JGB were greatly enhanced by DNA in the region of 300-650 nm characterized by three peaks at 416.0, 452.0 and 469.2 nm. The binding properties were examined using a Scatchard plot based on the measurement of the enhanced RLS data at 416.0 nm at a high JGB: DNA molar ratio (R > 2.22), and an aggregation mechanism of JGB in the presence of DNA at the nanogram level is proposed. Linear relationships can be established between the enhanced RLS intensity and DNA concentration in the range 0-3.5 micrograms ml-1 for both calf thymus DNA (ctDNA) and fish sperm DNA (fsDNA) if 2.0 x 10(-5) M JGB is employed. The limits of determination were 8.7 ng ml-1 for ctDNA and 9.9 ng ml-1 for fsDNA, respectively. Synthetic samples were analysed satisfactorily.     

Study on the resonance light scattering spectrum of berberine-cetyltrimethylammonium bromide system and the determination of nucleic acids at nanogram levels

The interaction of berberine with nucleic acid in the presence of cetyltrimethylammonium bromide (CTMAB) in aqueous solution has been studied by spectrophotometry and resonance light scattering (RLS) spectroscopy. At pH 7.30, the RLS signals of berberine were greatly enhanced by nucleic acid in the region of 300-600 nm characterized by four peaks at 324.0, 386.5, 416.5 and 465.0 nm. The binding properties were examined by using a Scatchard plot based on the measurement of enhanced RLS data at 416.5 nm. Under optimum conditions, the increase of RLS intensity of this system at 416.5 nm is proportional to the concentration of nucleic acid. The linear range is 7.5 x 10(-9)-7.5 x 10(-5) g ml(-1) for calf thymus DNA, 7.5 x 10(-9)-2.5 x 10(-5) g ml(-1) for herring sperm DNA, and 5.0 x 10(-9)-2.5 x 10(-5) g ml(-1) for yeast RNA. The detection limits (S/N = 3) are 2.1 ng ml(-1) for calf thymus DNA, 6.5 ng ml(-1) for herring sperm DNA and 3.5 ng ml(-1) for yeast RNA, respectively. Three synthetic samples were analyzed satisfactorily.