BACKGROUND Visual assessment of cerebrospinal fluid (CSF) for xanthochromia (yellow color) is practiced by the majority of laboratories worldwide as a means of diagnosing intracranical bleeds. METHODS Colorimetric and spectrophotometric analysis of CSF samples for recognizing the presence of bilirubin either in low concentrations or in the presence of hemolysed blood. RESULTS The experiment...

Episulfides were determined by a simple colorimetric assay using 4-(p-nitrobenzyl)-pyridine, which has been used previously for the detection and analysis of epoxides, organophosphates, and other alkylating agents. With episulfides, absorbance was directly proportional to concentration up to an absorbance of at least 1.0. No interference was observed with a variety of non-episulfide sulfur-cont...

High-throughput genomic mutation screening for primary tumors has characteristically been expensive, labor-intensive, and inadequate to detect low levels of mutation in a background of wild-type signal. We present a new, combined PCR and colorimetric approach that is inexpensive, simple, and can detect the presence of 1% mutation in a background of wild-type. We compared manual dideoxy sequenci...

An indole-azadiene conjugate (1), synthesized by facile one-step condensation, behaves as a highly selective probe for detection of fluoride ion both in colorimetric and fluorometric analyses. The probe 1 shows F(-)-selective color change from colorless to yellow and appearance of green fluorescence. 1H NMR analysis and ab initio calculation reveal that the F(-)-induced colorimetric and fluorom...

In this paper, we propose a new method to predict the images on a CRT and a hardcopy of skin color under various illuminants. Spectral reflectance of human skin is analyzed by principal component analysis and it is shown that the spectral reflectance can be estimated by three basis functions. The estimation allows colorimetric color reproduction without colorimetric measurements for each illumi...

In commonly used procedures for colorimetric assay of orotic acid in biological materials, certain substances interfere, positively or negatively. Some that interfere negatively are ornithine, cysteine, citrulline, tyrosine, proline, hydroxyproline, and polyamines. Protein and interfering agents are easily removed by first isolating the total organic acid fraction. The orotic acid in this fract...

Fourteen commercial soft drinks have been analyzed using colorimetric sensor arrays made from a set of 25 chemically responsive dyes printed on a hydrophobic membrane. Digital imaging of the dye array before and after immersion provides a color change profile as a unique fingerprint for each specific analyte. The digital data library generated was analyzed with statistical and chemometric metho...