a new disposable glass cuvette for visible spectrophotometry of carboxyhemoglobin detection in postmortem blood

Abstract: carbon monoxide (co) is a colorless, odorless, and highly toxic gas that results from incomplete combustion of fossil fuels or contact with dichloromethane vapors [1]. due to the tendency of co to hemoglobin (hb), which is 250 times more than oxygen, its poisoning is one of the major causes of death in developed countries. one of the methods for co diagnosis is qualitative and quantitative detection of carboxyhemoglobin (cohb) in blood samples using the uv-vis spectrophotometry. the basis of this method is based on the difference between the absorption peak of the visible spectra of oxygenated forms of hemoglobin (hbo2) and methemoglobin in the blood after reduction (deoxyhemoglobin) with the pattern related to cohb. in this study, a new zero cell (zc) for visible (vis) spectrophotometric measurements was designed and the visible spectra at 450 to 650 nm was compared with conventional 1 cm glass cells before and after addition of the reducing agent. to make zero cells (zcs), a lamel (cover glass) with dimensions of 0.15 × 50 × 24 mm was used. each lamel was cut into six smaller lumens (zcs) with a diamond pen, and for each sample, two zcs were used (blank form also consisted of two empty (zcs). to examine the blood sample, 6 μl of blood sample was placed by the dispenser on two sheets of zc, and then 0.01 g sodium dithionite was added on the second sheet. as soon as the second slide was placed, the blood sample was automatically spread on the slide. two cells with a uniform layer of blood were prepared for the detection of pre- and post-regenerated hemoglobin for every single examination. the resulting spectra were recorded at the mentioned wavelengths. the oxyhemoglobin and methemoglobin related peaks appear in the form of a double-wave spectra, and after addition of sodium dithionite to the blood, hemoglobin is reduced. thus, in negative cases, the twin peaks in the regions of 535-545 and 570-585 nm are changed to a single peak after reduction, and in positive cases, it remains unchanged with two peaks because of stronger binding of co to hemoglobin. the advantages of the proposed method are the disposable use of vis-cell, prevention of carryovers and measuring the carboxyhemoglobin without dilution of the blood sample.