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PubMed2005

Comparison of ninhydrin method of detecting amine compounds with other methods of halitosis detection.

OBJECTIVES: Halitosis is a result of overactivity of Gram-negative bacteria for which protein amino acids are the major source of energy. Therefore, statistical correlation between concentrations of volatile sulphur compounds (VSCs) and low-molecular-weight amines should be expected. MATERIALS AND METHODS: Eighty-four patients suffering from halitosis and 40 healthy volunteers aged 20-62 years (average 39.7) participated in the study. In all subjects low-molecular-weight amines were evaluated by the ninhydrin method. Patients with halitosis were randomized into treatment groups. Zinc tablets, tablets and mouthwash containing chlorhexidine or lyophilized lactic acid-forming bacteria were used. RESULTS: Analysis showed that the level of amines was highest in subjects with halitosis (0.39, s.d. +/- 0.06, P < 0.001) and correlated significantly with results of VSC measurement and organoleptic scores (P < 0.001). Reduction of amine levels after treatment was statistically significant (P < 0.001). Three months following treatment the amine levels began to increase (0.37, s.d. +/- 0.05). The amine levels in healthy controls were lower (0.29, s.d. +/- 0.07) and remained at a stable level. CONCLUSION: The salivary amine levels significantly correlated with VSC levels and organoleptic scores. Therefore, the ninhydrin method of detecting salivary amines may be an alternative or additional method of diagnosing halitosis. This method may also be used to evaluate treatment efficacy.

Adolescent↗
PubMed1964

ESTIMATION OF ALPHA-AMINO NITROGEN IN PLASMA AND URINE BY THE COLORIMETRIC NINHYDRIN REACTION.

Methods are described for the estimation of plasma and urine alpha-amino nitrogen by the colorimetric ninhydrin reaction; in the method for urine, both ammonia and urea are separated by a rapid ion-exchange resin procedure. Two methods of estimation are given; one has the advantage of great simplicity, but involves the use of cyanide; in the other, cyanide is eliminated. Normal values are reported; they correspond well with those obtained by the gasometric ninhydrin method.

Amino Acids↗
PubMed1990

Visualization of sialoglycoproteins in polyacrylamide gels by acidic ninhydrin reaction.

A new method for staining sialoglycoproteins in polyacrylamide gel after disc electrophoresis is described. The method utilizes the reaction of sialic acids with an acidic ninhydrin reagent which yields a stable color with an absorption maximum at 470 nm. After electrophoresis, the polyacrylamide gel is placed in a test tube and heated with 5 ml of the acidic ninhydrin reagent for 10 min in a boiling water bath. Sialoglycoproteins are detected as brown bands. No additional procedure such as destaining is necessary. When 20 micrograms fetuin, a sialoglycoprotein, per gel is applied, the band remains visible for at least 2 h. Stained gel can be scanned with a gel scanner at 470 nm. When the stained gel was dried on a sheet of polypropylene filter, the color was stable for at least one month. The present method is superior to the method using Stains-all (3,3'-diethyl-9-methyl-4,5,4',5'-dibenzothiacarbocyanine) in specificity and simplicity for the detection of sialoglycoproteins.

Electrophoresis, Polyacrylamide Gel↗
PubMed2000

Chemical development of latent fingerprints: computational design of ninhydrin analogues.

The design of chemical compounds for development of latent fingerprints is explored computationally. Our main findings are: (a) We show why past attempts to improve the widely used ninhydrin gave relatively small improvements (referring to color only). The optical transition is connected with a "transition core" and therefore is influenced little by substitution on the aromatic rings. (b) We propose new analogues of ninhydrin with a significant potential such as thiono derivatives.

Adsorption↗
PubMed1990

Studies on the synthesis, characterisation and antimicrobial activity of new Co(II), Ni(II) and Zn(II) complexes of Schiff base derived from ninhydrin and glycine.

For the first time, Co(II), Ni(II) and Zn(II) complexes have been synthesized involving an intermediate Schiff base, indane-1,3-dione-2-imine-N-acetic acid the condensed product of ninhydrin and glycine. These coloured complexes were characterised by elemental analysis, molar conductivity, thermogravimetric analyses/differential thermal analysis, infrared, magnetic susceptibility, NMR and electronic spectral studies. Mechanisms for their formation have been proposed. The experimental studies reveal that the complexes possess octahedral stereochemistry whereas the Schiff base behaves as a monobasic tridentate ligand. A molecular structure for the metal complexes is also proposed. A comparative study of the antimicrobial activity of ninhydrin and the corresponding metal complexes against Escherichia coli, Proteus mirabilis, Staphylococcus aureus and Streptococcus faecalis has been undertaken and the results are discussed.

Anti-Bacterial Agents↗
PubMed1982

Free amino acids and ninhydrin-positive substances in fish--II. Cardio-respiratory system: plasma, erythrocytes, heart and gills of the rainbow trout (Salmo gairdnerii Richardson).

1. Free amino acids and ninhydrin-positive substances were studied in blood plasma, erythrocytes, heart and gills of rainbow trout using ion exchange automatic chromatography. 2. In comparison with plasma, only few amino acids have higher levels in red cells: aspartic and glutamic acids, glycine. 3. In heart and gills total amino acid level is greater than in blood. Levels are similar in both tissues except glutamic acid which is higher and histidine which is lower in gills. 4. The main ninhydrin positive substance is taurine which has very high level in erythrocytes, heart and gills, much more than in previously studied muscle and skin.

Amino Acids↗
PubMed2001

Enhancement of an insufficient dye-formation in the ninhydrin reaction by a suitable post treatment process.

A study of the reaction between ninhydrin and alanine has been carried out taking into account that, adhered on the surface of a dry porous medium such as paper, a quasi-heterogeneous reaction has to take place. Instead of amino acids released from human sweat glands, aqueous solutions of alanine were taken to deliver a given amount of amino acid to the sample. The dye density, obtained after using a standard development process, could noticeably be increased by setting a drop of water on the dye dot, thus indicating that not all the alanine had been used for dye formation during the usually applied process. The incomplete reaction can be explained by the problem of bringing the reactants into contact with each other when both are in the solid phase in the porous surrounding. The temporary presence of water allows a reorientation of the insoluble reactants. With fingerprints an increase in both the rate of development and the final dye density could be obtained when the sample was post treated after the developing process with the blank solvent, thus also the background coloration could be decreased. The ideas presented in this paper may form the basis for a modification of developing processes with ninhydrin in order to increase the proportion of amino acids present (in the sample) used in dye formation without data loss.

Journal Article↗
PubMedDate not supplied

Rapid optimization of the post-column fluorogenic ninhydrin reaction for the HPLC-based determination of bradykinin and related fragments.

A flow injection analysis scheme is demonstrated for the rapid optimization of reagent concentrations, flow rates, delay time and temperature using the guanidino moiety specific fluorogenic ninhydrin reaction. Using the amino acid arginine, non-arginine containing peptides, and the arginine-containing peptides, bradykinin and related fragments, specificity is demonstrated. These results serve to extend previous descriptions of the post-column reaction by offering a time efficient approach for the optimization of newly assembled post-column reactors using this chemistry. The reactor is subsequently added to a gradient elution HPLC system with the separation of bradykinin and bradykinin fragments demonstrated. Detection sensitivity in the high femtomole-low picomole mass range was achieved for these substances.

Bradykinin↗
PubMed2004

Ninhydrin sweat test: a simple method for detecting antibodies neutralizing botulinum toxin type A.

Approximately 5% of patients with cervical dystonia receiving repeated botulinum neurotoxin A (BoNT/A) injections develop secondary loss of treatment benefit. Currently available tests to directly detect neutralizing BoNT/A antibodies (BoNT/A-AB) are either expensive or time consuming. To establish a simple, clinically useful test for antibody detection, we adapted the ninhydrin sweat test (NST). Eighteen dystonic patients with secondary nonresponse and clinically suspected BoNT/A-AB formation were tested for BoNT/A-AB in the mouse diaphragm test (MDT). In addition, the size of the anhidrotic area was determined by the NST 21 days after an intradermal dose of 10 U Dysport into the hypothenar region of the left palm. In nine patients, positive BoNT-AB titers were found in the MDT. There was a significant correlation between the BoNT/A-AB titers and the anhidrotic area (Spearman's rho = -0.9, P < 0.0001). Both tests provided comparably good results with respect to qualitative antibody detection. In the clinical situation of secondary nonresponse to BoNT/A therapy, the economical NST may be a helpful tool to detect neutralizing BoNT/A-AB.

Adult↗
PubMed1982

Deuterium isotope effects in the ninhydrin reaction of primary amines.

The rate of development of Ruhemann's purple in the ninhydrin reaction of two deuterated primary amines, aa-d2-p-tyramine and aa-d2-beta-phenylethylamine, is significantly reduced. It appears to be a primary isotope effect and indicates that the cleavage of the carbon-hydrogen bond at the a-position is involved in the rate-determining step of the color reaction.

Amines↗
PubMed1980

Ascorbic acid: an unstable ninhydrin-positive urinary constituent running with valine in a commonly used screening system.

Large amounts of ascorbic acid occur occasionally in the urine of children being investigated for possible inherited metabolic disease and may give a positive ninhydrin reaction after thin-layer chromatography. As this compound is unstable in urine and runs with valine in a solvent system commonly used for preliminary screening, it is a possible source of confusion.

Ascorbic Acid↗
PubMed1985

Effect of various substances on the colorimetric amino acid-ninhydrin reaction.

The effect of salts, acids, alkali, and buffer solutions on the color development of the Cd-ninhydrin-amino acid reaction has been investigated. Of the salt solutions examined only Cu2+ and Fe3+ interfered with the color yield. Very low concentrations of these ions were sufficient to drastically inhibit color development.

Amino Acids↗
PubMed1989

Spectrophotometric determination of tryptophan in intact proteins by the acid ninhydrin method.

The interaction of tryptophan, lysozyme and tyrosine with ninhydrin in strong acid media has been investigated at 20, 25, 30, and 35 degrees C by spectrophotometry. Second-order rate constants and molar absorptivity values have been evaluated from an analytical point of view. Optimum conditions for the selective estimation of tryptophan, tryptophan residues in intact proteins, and indoles--without the disturbing effect of tyrosine--have been given. Under optimum conditions, in the concentration range from 2.5 X 10(-8) to 3.0 X 10(-7)M, molar absorptivity values and reproducibility data for various reactants have been reported. Molar absorptivity values (Am X 10(-3)/M X cm) of tryptophan (21.35), lysozyme (19.33), bovine serum albumin (21.05), human serum albumin (21.00), casein (17.85), alpha-chymotrypsin (18.28), trypsin (14.43), indole (5.03), and indole-3-acetic acid (13.75) have been measured with a standard error of 2.3% or less for any particular reactant.

Hydrogen-Ion Concentration↗
PubMed1978

Middle-sized ninhydrin-positive molecules in uraemic patients treated by repeated haemodialysis. II. Chief peptide constituents of the faction.

The fraction of middle-sized molecules obtained from haemodialysate by chromatography on Dowex 50W x 8 resolves upon thin-layer electrophoresis on Sephadex G-25 into nine ninhydrin-positive fractions and one staining only with tolidine reagent. All ten electrophoretic fractions give similar filtration profiles with Bio-Gel P-6 in the presence of SDS and 2-mercaptoethanol. The chief peptide components common to each electrophoretic fraction have molecular weight approx. 3000 and are especially abundant in lysine, glycine, glutamine acid and serine, while aromatic amino acids are in very low concentration.

Amino Acids↗
PubMed1995

Accurate determination of adjuvant-associated protein or peptide by ninhydrin assay.

Modern peptide and subunit vaccines are increasingly having to rely on the use of immunological adjuvants to achieve effective immunity. However, the only adjuvant currently approved for use in humans is aluminium hydroxide, although many adjuvants are currently under preclinical development. Determining immunogen concentration in the presence of adjuvants such as aluminium hydroxide gel, liposomes or NISV has proved to be problematic. One approach has been to use radiolabelled antigens to extrapolate concentration to a preparation using native immunogen. However, the use of a colorimetric assay would allow greater flexibility in terms of immunogen used and would reduce costs and remove safety problems. Of the colorimetric methods we have examined thus far, only the manual ninhydrin assay has produced consistent results with detection of microgram quantities of protein or peptide in the presence of NISV or Alhydrogel, but not liposomes. As the assay relies on the detection of free amino groups after protein hydrolysis, peptides as well as proteins may be effectively determined irrespective of amino acid composition, a considerable advantage over other colorimetric assay systems.

Adjuvants, Immunologic↗
PubMed1991

Rapid measurement of leucine-specific activity in biological fluids by ion-exchange chromatography and post-column ninhydrin detection.

Commonly used methods for the measurement of leucine-specific activity use either high-performance liquid chromatography (HPLC) and pre-column derivatization or conventional ion-exchange chromatography. These are time-consuming, labor-intensive, relatively costly procedures, requiring high concentrations of radioactivity for accuracy. The present paper describes a method for the measurement of plasma leucine-specific activity using HPLC equipment, a large-bore ion-exchange column and post-column ninhydrin detection. With this method, determination of leucine concentration and leucine radioactivity was found to be linear (r2 greater than 0.999) over physiological ranges for both standards and deproteinized plasma. The intra- and inter-assay coefficients of variation for leucine concentrations were 1.4 and 2.7%, respectively. The intra- and inter-assay coefficients of variation for leucine-specific activities were 1.5 and 1.9%, respectively. The automated method is relatively fast (injection to injection time approximately 45 min), economical and capable of accurately assessing relatively small amounts of radioactivity.

Chromatography, High Pressure Liquid↗
PubMed1995

Determination of amino acids in human plasma by liquid chromatography with postcolumn ninhydrin derivatization using a hydroxyapatite cartridge for precolumn deproteination.

Amino acids in human plasma were determined by liquid chromatography with postcolumn ninhydrin derivatization using a hydroxyapatite cartridge for precolumn deproteination. S-Carboxymethyl-L-cysteine, D-phenylglycine and S-aminoethyl-L-cysteine were found to be suitable internal standards. The proposed method is simple, rapid (deproteination time less than 1 min) and reproducible [relative standard deviation below 3% except for low-level aspartic acid (n = 3)]. The average recovery of 25 amino acids was above 90%. The elution time of amino acids in human plasma was approximately 2 h. Protein binding of tryptophan was also determined by the proposed method. The analytical data for amino acids in human plasma deproteinated using the proposed and published methods (5-sulphosalicylic acid and ethanol) were compared.

Amino Acids↗
PubMed2006

Identification and evaluation of antioxidant, analgesic/anti-inflammatory activity of the most active ninhydrin-phenol adducts synthesized.

Treatment of phenols with ninhydrin in acidic medium afforded 2-hydroxy-2-(ortho-hydroxy-phenyl/naphthyl)-1,3-dioxoindanes, which being unstable were isolated in their hemiketal forms. These synthesized compounds were subjected to TLC screening for radical scavenging and in vitro lipoxgenase and cycloxygenase enzyme inhibition assays. The best compound was identified and studied in detail for steady-state and time-resolved free radical kinetics, viz., DPPH, ABTS(-), *OH and rate constants for these reactions were evaluated. The best compound was also subjected to in vivo anti-inflammatory and analgesic activities in which the compound showed good promise for further structural optimization.

Analgesics↗