Victoria Blue 4R Research Articles

TbMOF@Au catalytic determination of trace malathion with aptamer SERS/RRS/Abs assay.

Terbium metal-organic framework (TbMOF) was prepared by microwave method with 1,3,5-benzenetricarboxylic acid as ligand. With HAuCl4 as precursor and NaBH4 as reducing agent, TbMOF-loaded gold nanoparticles (AuNPs) catalyst (TbMOF@Au1) was prepared rapidly and characterized by transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. It was found that TbMOF@Au1 has a strong catalytic effect on the HAuCl4-Cys nanoreaction, and the produced AuNPs have a strong resonant Rayleigh scattering (RRS) peak and surface plasmon resonance absorption (Abs) peak at 370nm and 550nm, respectively. With the addition of the molecular probe Victoria blue 4R (VB4r), AuNPs have a strong surface-enhanced Raman scattering (SERS) effect, the target analyte molecules are trapped in between the nanoparticles and a hot spot effect created in the process resulting in an extremely high SERS signal. A new SERS/RRS/Abs triple-mode analysis method for Malathion (MAL) was established by coupling this new TbMOF@Au1 catalytic indicator reaction with MAL aptamer (Apt) reaction, and its SERS detection limit was 0.21ng/mL. The SERS quantitative analysis method has been applied to the analysis of fruit samples with the recovery of 92.6-106.6% and the precision of 2.72-8.16%.

SERS and RRS Spectral Detection of Ultratrace Sulfite Based on PtPd Nanoalloy Catalytic Amplification

At temperature of 75 °C, the ethanol-HAuCl4 reaction to generate gold nanoparticles is relatively slow (AuNPs), and the noble metal nanoparticles can catalyze this nanoreaction. Sulfite can reduce PdCl2-H2PtCl6 to generate PtPd nanoalloy (PtPd) and strong catalysis to generate red AuNPs, which has a strong RRS peak at 370 nm. When Victoria blue 4R (VB4R) is added, it produced a strong SERS peak at 1617 cm−1. We use SERS, RRS, absorption spectroscopy, electron microscopy, and other techniques to study the catalytic reaction of PtPd nanoalloy and propose a new mechanism for the nanoalloy catalytic reactions. When the SO32−concentration in the system gradually increases, the AuNPs produced by the catalytic reaction gradually increase and the RRS/SERS peak intensity increases linearly. Based on the nanoalloy catalytic amplification strategy, a new and sensitive RRS/SERS coupled dual-mode detection method for SO32− was constructed, with linear range of 0.13–12.1 μg·L−1 and a DL of 0.02 μg·L−1.

Graphene oxide nanoribbon catalysis of gold nanoreaction and its application to SERS quantitative analysis of ultratrace glucose

Catalysis of four nanostructures, including graphene oxide nanoribbons (GONR), graphene oxide, N-doped carbon quantum dot and Ca-doped carbon quantum dot is examined on the reaction HAuCl4–trisodium citrate to form nanogold (AuNP). GONR exhibited strongest catalysis and appeared a SERS peak at 1615 cm−1 in the presence of Victoria blue 4R molecular probes in the formed AuNP sol substrate. Upon addition of 4-mercaptophenylboronic acid (MPBA), it adsorbs on GONR to form MPBA–GONR conjugates that caused the SERS peak decreasing due to its catalysis decreasing. Upon addition of glucose, it reacts with MPBA to form MPBA–glucose complex to increase the SERS peak linearly owing to GONR catalysis recovering. The increased SERS signal (ΔI) is linear to glucose concentration in the range of 0.33–5.33 nM, with a detection limit of 0.13 nM. Thus, a new and highly sensitive SERS quantitative analysis method is established for detection of glucose, based on GONR catalytic amplification.

A simple gold nanoplasmonic SERS method for trace Hg2+ based on aptamer‐regulating graphene oxide catalysis

The as-prepared graphene oxide (GO) exhibited a strong catalytic effect on reduction of HAuCl4 by trisodium citrate to form gold nanoplasmons (AuNPs) with a strong surface-enhanced Raman scattering (SERS) effect at 1615cm-1 in the presence of molecular probe Victoria blue 4R (VB4r). SERS intensity increased with nanocatalyst GO concentration due to the formation of more AuNP substrates. The aptamer (Apt) of Hg2+ can bind to GO to form Apt-GO complexes, which can strongly inhibit nanocatalysis. When target Hg2+ is present, the formed stable Hg2+ -Apt complexes are separated from the GO surface, which leads to GO catalysis recovery. The enhanced SERS signal was linear to Hg2+ concentration in the range 0.25-10nmol/L, with a detection limit of 0.08nmol/L Hg2+ . Thus, a new gold nanoplasmon molecular spectral analysis platform was established for detecting Hg2+ , based on Apt regulation of GO nanocatalysis.

A sensitive SERS quantitative analysis method for Ni2+ by the dimethylglyoxime reaction regulating a graphene oxide nanoribbon catalytic gold nanoreaction.

The nanogold reaction between HAuCl4 and trisodium citrate (TCA) proceeded very slowly at 60°C in a water bath. The as-prepared graphene oxide nanoribbons (GONRs) exhibited strong catalysis during the reaction to form gold nanoparticles (Au NPs) and appeared as a strong surface-enhanced Raman scattering (SERS) peak at 1616cm-1 in the presence of the molecular probe Victoria blue 4R (VB4r). With increase in GONR concentration, the SERS peak increased due to increased formation of Au NPs. Upon addition of dimethylglyoxime (DMG) ligand, which was adsorbed onto the GONR surface to inhibit GONR catalysis, the SERS peak decreased. When Ni2+ was added, a coordination reaction between DMG and Ni2+ took place to form stable complexes of [Ni (DMG)2 ]2+ and the release of free GONR catalyst that resulted in the SERS peak increasing linearly. A SERS quantitative analysis method for Ni2+ was therefore established, with a linear range of 0.07-2.8μM, and a detection limit of 0.036μM Ni2+ .

A sensitive surface-enhanced Raman scattering method for chondroitin sulfate with Victoria blue 4R molecular probes in nanogold sol substrate.

Using silver nanoparticles (AgNPs) as the nanocatalyst, l-cysteine rapidly reduced HAuCl4 to make a stable gold nanoparticle sol (Ag/AuNP) that had a high surface-enhanced Raman scattering (SERS) activity in the presence of Victoria blue 4R (VB4r) molecular probes. Under the selected conditions, chondroitin sulfate (Chs) reacted with the VB4r probes to form associated complexes that caused the SERS effect to decrease to 1618cm-1 . The decreased SERS intensity was linear to the Chs concentration in the range 3.1-500ng/ml, with a detection limit of 1.0ng/ml Chs. Accordingly, we established a simple and sensitive SERS quantitative analysis method to determine Chs in real samples, with a relative standard deviation of 1.47-3.16% and a recovery rate of 97.6-104.2%.

SERS spectral study of HAuCl4-cysteine nanocatalytic reaction and its application for detection of heparin sodium with label-free VB4r molecular probe

In the presence of nanocatalyst, L-cysteine reduce HAuCl4 rapidly to form gold nanoparticles (AuNP), and a quick nanocatalytic preparation procedure was established for Au/AuNP sol with highly active surface enhanced Raman scattering (SERS) effect and good stability. The nanoreaction was also studied by absorption, resonance Rayleigh scattering (RRS), transmission electron microscopy (TEM) and energy spectra. In the selected conditions, the analyte heparin sodium (HS) could react with victoria blue 4 R (VB4r) to form associated complexes which have very weak SERS effect to make the SERS signals decrease. The SERS signals at 1617 cm−1 reduced linearly with HS concentration increasing. Upon addition of FeCl3, it hydrolyzed to form stable Fe(OH)3 sol platform that carried SERS active Au/AuNPs to enhance the sensitivity. Accordingly, we established a SERS quantitative analysis method in the sol substrate of Fe(OH)3-Au/AuNPs, with a linear range of 0.5–75 ng/mL HS and a detection limit of 0.2 ng/mL. HS in real samples was determined, with a relative standard deviation of 2.65–7.63% and a recovery of 99.3–101%.

A sensitive and selective Victoria blue 4R SERS molecular probe for sodium lauryl sulfate in AuNP/AgCl sol substrate

Sodium lauryl sulfate (SLS) is an important pollutant, it is urgent to develop simple and sensitive method for determination of SLS in environment. In this article, a gold nanoparticle (AuNP) sol with highly active surface enhanced Raman scattering (SERS) and good stability was prepared, based on the nanoenzyme AuNP catalysis of L-cysteine reduced HAuCl4. In the AuNP sol substrate containing the sensitized reagent of AgNO3 that formed strongly SERS active substrate of AuNP/AgCl, free-label Victoria blue 4R (VB4r) SERS molecular probes reacted with sodium lauryl sulfate (SLS) to form associated complexes with very weak SERS effect at 1617cm−1 that caused the SERS intensity decreased linearly. A new SERS quantitative analysis method was established for the determination of 0.01–15μmoL/L SLS, with a detection limit of 0.005μmoL/L. SLS in water smples was determined, with a relative standard deviation of 1.36–8.55% and a coery of 97.4–104.1%.

A novel nanocatalytic SERS detection of trace human chorionic gonadotropin using labeled-free Vitoria blue 4R as molecular probe

In pH 7.4 Na2HPO4-NaH2PO4 buffer solution containing the peptide probes for human chorionic gonadotropin (hCG), silver nanoparticles (AgNPs) were aggregated to big AgNPs clusters that exhibited very weak catalytic effect on the gold nanoparticle reaction of H2O2-HAuCl4. When hCG was present in the peptide probe solution, the AgNPs did not aggregate and it had strong catalytic effect on the gold nanoparticle reaction with a strong resonance Rayleigh scattering (RRS) peak at 370nm and a strong surface enhanced Raman scattering (SERS) peak at 1615cm−1 in the presence of molecular probe of Victoria blue 4R (VB4R). With the increase of the hCG concentration, the catalysis enhanced due to the nanocatalyst of AgNPs increasing, and the RRS intensity increased at 370nm. The increased RRS intensity was linear to the hCG concentration in 0.05–10ng/mL, with a linear regression equation of ΔI370nm=409.8C +294. And the SERS intensity at 1615cm−1 increased linearly with the hCG concentration in the range of 0.05–20ng/mL, with a linear regression equation of ΔI1615cm-1=142C+134. Based on this, two new methods of nanocatalytic SERS and RRS were proposed for the determination of trace hCG.

Direct determination of polyacrylamide in water samples by its enhancement effect on the resonance Rayleigh scattering of some basic diphenyl naphthylmethane dyes

Interaction of partially hydrolyzed polyacrylamide (HPAM) with basic diphenyl naphthylmethane dyes including victoria blue 4R (VB4R), victoria blue B (VBB) and night blue (NB), was characterized by resonance Rayleigh scattering (RRS) spectra. Accordingly a RRS method for the direct determination of HPAM at nanogram levels has been developed. The maximum RRS wavelengths (λmax) appear at 276 nm, 284 nm, and 374 nm for VB4R, VBB, and NB systems, respectively. The RRS spectral characteristics, the influencing factors, and the optimum conditions have been investigated. The RRS intensity was directly proportional to the concentration of HPAM in the range of 0.054∼3.5 µg mL−1 for VB4R system, 0.10∼5.0 µg mL−1for VBB system, and 0.10∼1.5 µg mL−1 for NB system. The methods exhibited high sensitivities. The detection limits were 16.5 ng mL−1 (VB4R system), and 31.0 ng mL−1 (VBB and NB systems). The selectivity of the method was investigated by using VB4R system owing to the highest sensitivity. Concentrations of HPAM in tap water, synthetic water and practical waste water samples were analyzed satisfactorily. The reaction mechanism and RRS enhancement reasons were discussed.

A simple method of boron determination in mineral waters using Victoria blue 4R

The reaction of the tetrafluoroborate anion with Victoria blue 4R (VB4R) reagent was investigated, and a new, simple, rapid and sensitive method was developed for the spectrophotometric determination of boron. The method is based on the reaction of boric acid with fluoride, which forms the tetrafluoroborate anion, and that is followed by the extraction of with VB4R into benzene and subsequent spectrophotometric detection. The optimum conditions for the conversion of boron to tetrafluoroborate anion as well as for complex formation and extraction of with VB4R were found. The molar absorptivity of the investigated complex is 9.6 × 104 L mol−1 cm−1 at 610 nm. The absorbance of the coloured extracts obeys Beer's law in the range 0.03–0.55 mg L−1 of B(III). The limit of detection calculated from a blank test (n = 10; P = 0.95) based on 3 s is 0.02 mg L−1 of B(III). Under appropriate extraction conditions, the majority of metals (excluding probably tantalum and some others) did not form extractable fluoride complexes with VB4R. Therefore, the presence of small quantities of metals should not interfere with the determination of boron in the presence of a sufficient surplus of fluoride. Exceptions, however, are metal ions such as Sn(IV), Ti(IV), Sn(II), Zr(IV), Hg(II), Hg(I), Tl(I), etc., which strongly hydrolysed under experimental conditions. Some anions formed complexes with the cation of VB4R and are easily extractable using benzene. Examples of such ions are , I−, SCN−, Br−, bromate, chlorate, iodate and perrhenate. These anions strongly interfere with boron determination and therefore must first be extracted with VB4R before boron determination. The boron must then be converted to and extracted with VB4R into benzene for determination. The Cl−, , , CH3COO− and anions are extracted in very small amounts or not at all, and do not interfere with boron determination. The reaction mechanism was also discussed. Quantum chemical calculations were carried out for VB4R, and the optimised molecular structure and atomic net charges were calculated. The possible position of the protonation of VB4R as well as the possible position for dipole-ion interaction (associate building) between the reagent and the anion was predicted. The method was used for the determination of boron in commercial brand mineral waters.

Catalytic determination of traces of oxalic acid in vegetables and water samples using a novel optode

A new optode has been introduced for determination of oxalic acid. The optode sensing reagent is Victoria blue 4R which is immobilized on triacetylcellulose membrane. This reagent could be oxidized by dichromate in acidic media resulting in decoloration of the membrane. Oxalic acid has a strong catalytic effect on this reaction. The difference in absorbance of the immobilized form of Victoria blue 4R at 615 nm between uncatalyzed and catalyzed reactions (Δ A) is directly proportional to the concentration of oxalic acid. Oxalic acid can be determined in the concentration range of 2–180 μg ml −1. The effect of different possible interfering species has been examined and was shown that the optode has a very good selectivity. The optode has been applied for the determination of oxalic acid in different real samples such as spinach, beet root, mushroom and river water with excellent recoveries.

Resonance Rayleigh scattering study of the interaction of heparin with some basic diphenyl naphthylmethane dyes.

In a near-neutral medium, a combination of heparin with some basic diphenyl naphthylmethane dyes such as victoria blue 4R (VB4R), victoria blue B (VBB), or night blue (NB) can result in a significant enhancement of resonance. Rayleigh scattering (RRS) and their maximum scattering wavelengths lambdamax appear at 523, 534, and 540 nm for VB4R, VBB, and NB, respectively. The characteristics of RRS spectra of the heparin-dye complexes, the influencing factors, and the optimum conditions of these reactions have been investigated. The RRS intensity is directly proportional to the concentration of heparin in the range of approximately 0 to 0.4 microg/mL for all systems. The methods exhibit high sensitivities, and the detection limits for heparin are 3.35 ng/mL for the VB4R system, 6.62 ng/ mL for the VBB system, and 6.29 ng/mL for the NB system. Because the VB4R system is the most sensitive, it was taken as an example to study the selectivity of the method. A new method for the determination of trace amounts of heparin based on RRS technique has been developed. Moreover, the enhancement reasons of RRS and the relationship between RRS spectral characteristics of the heparin-dye complex and its absorption spectra have been primarily discussed.

Care in comatose surviors of cardiac arrest

The empirical demonstration of insulin by the basic (cationic) dye Victoria Blue 4R (V4R; Ivić 1969) shows the character of a histochemical reaction (Wohlrab et al. 1985), while the chemism of the reaction is not quite understood yet. Aim of this investigation: Will the spectral behaviour of V4R in visible light be influenced by oxidized or nonoxidized insulin?Dependent on the concentration, V4R shows in aqueous solution 2 absorption maxima (λ = 697 and 558 nm), which represents monomers and dimers of the dye. With increasing dye concentration (200 μmol/l), V4R forms dimers and even higher polymers. Constant V4R concentration (200 μmol/l) results with increasing concentration of oxidized insulin (4 to 16 μmo1/l) in a reduction of extinction, while the extinction at λ = 558 nm (dimers) is more decreased than at λ = 597 nm (monomers). Nonoxidized insulin has no remarkable influence on the absorption behaviour of V4R. Extinction measurements on V4R stained B-cells of islets of Langerhans after preoxidation of the section resulted in a main absorption maximum at λ = 554 nm.Conclusion: Depending on the concentration, the dye V4R is associated with the oxidized insulin in aqueous solution, which is also indicated by the occurrence of an isosbestic point in the curve behaviour. This is expressed by the establishment of a concentration-dependent equilibrium between the dye V4R and the oxidized insulin (change in the dissociation and aggregation behaviour respectively of the dye V4R). The determined main absorption maximum (λ = 554 nm) in the biological material points in the same way to interactions between the stain and oxidized nsulin.

An Identification Scheme for Oral Non-pigmentedPrevotella(Bacteroides) Species

Three approaches were used to characterise 13 reference strains of non-pigmented Prevotella ( Bacteroides ) spp. and 91 clinical isolates from 21 adult patients with periodontal diseases. Strains were examined in tests for: (1) biochemical and morphological characters comprising microscopic and colonial appearance, biochemical and fermentation activity, tolerance of bile salts and dyes, susceptibility to antibiotic disks and fluorescence under U.V. light; (2) production of volatile and non-volatile fatty acids by gas-liquid chromatography (GLC); and (3) preformed enzymes profiles. Species were distinguished by: hydrolysis of hippurate, starch and acsculin; fermentation of lactose, sucrose, rhamnose, xylose, arabinose, cellobiose, salicin, inulin and xylan; tolerance of Victoria blue 4R; and fluorescence. In GLC analysis, production of propionic, iso-butyric, iso-valeric and phenylacetic acids gave useful discrimination between species. Discriminatory enzyme profiles were obtained with tests for β-xylosidase, β-glucuronidase, β-glucosidase, α-fucosidase, β- N -acetylglucosaminidase and α-mannosidase. Correlation between the three approaches was good and an identification scheme was designed for non-pigmented Prevotella spp. Of the 91 clinical isolates from adult periodontal diseases, 63 gave results identical with those of reference strains and 21 showed only minor variation. The commonest species were P. buccae (42 isolates), P. veroralis ( I5 isolates) and P. oralis (eight isolates). Keywords: Prevotella ; oral flora; periodontal disease; identification; gas-liquid chromatography; enzyme tests.

Spektrophotometrische Untersuchungen zur Bindung von Viktoriablau 4R an oxidiertes Insulin

The empirical demonstration of insulin by the basic (cationic) dye Victoria Blue 4R (V4R; Ivić 1959) shows the character of a histochemical reaction (Wohlrab et al. 1985), while the chemistry+ of the reaction is not quite understood yet. Aim of this investigation: Will the spectral behaviour of V4R in visible light be influenced by oxidized or non-oxidized insulin? Dependent on the concentration, V4R shows in aqueous solution 2 absorption maxima (lambda = 597 and 558 nm), which represents monomers and dimers of the dye. With increasing dye concentration (200 mumol/l), V4R forms dimers and even higher polymers. Constant V4R concentration (200 mumol/l) results with increasing concentration of oxidized insulin (4 to 16 mumol/l) in a reduction of extinction, while the extinction at lambda = 558 nm (dimers) is more decreased than at lambda = 597 nm (monomers). Non-oxidized insulin has no remarkable influence on the absorption behaviour of V4R. Extinction measurements on V4R stained B-cells of islets of Langerhans after pre-oxidation of the section resulted in a main absorption maximum at lambda = 554 nm. Depending on the concentration, the dye V4R is associated with the oxidized insulin in aqueous solution, which is also indicated by the occurrence of an isobestic point in the curve behaviour. This is expressed by the establishment of a concentration-dependent equilibrium between the dye V4R and the oxidized insulin (change in the dissociation and aggregation behaviour respectively of the dye V4R). The determined main absorption maximum (lambda = 554 nm) in the biological material points in the same way to interactions between the stain and oxidized insulin.

Sensitive flotation-spectrophotometric determination of platinum based on systems with chlorostannate(II) and basic dyes

Sensitive flotation-spectrophotometric methods are based on the ion-associates formed by the anionic chlorostannate(II) complex of platinum with the basic dyes rhodamine 6G, Victoria blue B, Victoria blue 4R and Capri blue. The ion-associates finally formed are sparingly soluble in water; when shaken with a suitable organic liquid, they accumulate quantitatively at the phase boundary or on the wall of the separatory funnel. The compound with rhodamine 6G, separated and washed, is dissolved in acetone; those ones with the other basic dyes are dissolved in methanol. In the best method, with rhodamine 6G, the molar absorptivity is 2.8 × 10 5 l mol −1 cm −1; with the other dyes, the molar absorptivities are 2.0–2.45 × 10 5. Beer's law is obeyed over the range 0.08-0.6 μg Pt ml −1. The separated ion-associate formed with rhodamine 6G (R6G) is considered to have the formula [(R6G +) 3] [Pt(SnCl 5) 3- 5]. The effects of other platinum metals on the determination of platinum with rhodamine 6G were examined; some interference was found from palladium and rhodium. Trace amounts of platinum in palladium could be determined after separation of platinum by extraction with triphenylphosphine oxide in 1,2-dichloroethane.

A scheme for the identification of clinical isolates of gram-negative anaerobic bacilli by conventional bacteriological tests

More than 1000 strains of gram-negative anaerobic bacilli, including reference strains, clinical isolates, and members of the normal flora of the mouth, lower gastro-intestinal tract and vagina of healthy human subjects, were studied by conventional bacteriological methods and by gas-liquid chromatographic analysis of metabolic products in a series of investigations. A short combined set of tests with particular discriminant value was selected, and a scheme for the identification of the species and subspecies encountered in the diagnostic bacteriological laboratory was based upon our composite results. The tests are: antibiotic-disk resistance tests with neomycin 1000 micrograms, kanamycin 1000 micrograms, penicillin 2 units and rifampicin 15 micrograms per disk; tolerance tests with sodium taurocholate, Victoria blue 4R and gentian violet; and tests for pigment production, indole production, aesculin hydrolysis and the fermentation of glucose, lactose, sucrose, rhamnose, trehalose, mannitol and xylose. Gram-negative anaerobic bacilli are divided into four groups: (1) the fragilis group with nine species, which include the five subgroups previously classified as subspecies of B. fragilis; (2) the melaninogenicus-oralis group, which includes the three saccharolytic subspecies (ss.) of B. melaninogenicus--ss. melaninogenicus, ss. intermedius and ss. levii--and four non-pigmented species; (3) the asaccharolytic group, which comprises B. asaccharolyticus (formerly B. melaninogenicus ss. asaccharolyticus), B. corrodens and other non-pigmented non-saccharolytic strains, and (4) the fusobacteria.

Thin-layer chromatography of some cationic dyes commonly used in histology

A number of cationic dyes commonly used in histology may be conveniently and effectively analysed using the thin-layer chromatographic system of Marshall and Lewis. Commercial samples of Acridine Orange, Crystal Violet, Janus Green B, Methyl Violet, Neutral Red, Pyronin B, Pyronin Y(G), Safranin, Victoria Blue B and Victoria Blue 4R have been analysed with this system. All have been found to be complex mixtures of coloured components. Chromatographic data on these components are presented.

Rapid demonstration of juxtaglomerular granules with alcoholic crystal violet.

Adult mouse kidney fixed in 9 commonly used fixatives was embedded in paraffin, sections prepared as usual, and tests made with 16 different dyes (mostly triphenyl methanes) for efficacy in staining of juxtaglomerular granules. On the basis of the tests, staining of dewaxed and hydrated sections in 0.5% crystal violet in 70% ethanol for 3 min, rinsing in tap water, blotting and completion of dehydration in a 1:1 aniline-xylene mixture, clearing in xylene, and covering in a synthetic resin, is recommended. Tissues fixed in dichromate-containing fixatives required a prestaining oxidation with acidified KMnO4, but this was optional for other fixatives. In addition to crystal violet: ethyl violet, new fuchsin, and victoria blue 4R were also found to be effective stains for the granules.