A disposable blood cyanide sensor

Abstract

Deaths due to smoke inhalation in fires are often due to poisoning by HCN. Rapid administration of antidotes can result in complete resuscitation of the patient but judicious dosing requires the knowledge of the level of cyanide exposure. Rapid sensitive means for blood cyanide quantitation are needed. Hydroxocyanocobinamide (OH(CN)Cbi) reacts with cyanide rapidly; this is accompanied by a large spectral change. The disposable device consists of a pair of nested petri dish bottoms and a single top that fits the outer bottom dish. The top cover has a diametrically strung porous polypropylene membrane tube filled with aqueous OH(CN)Cbi. One end of the tube terminates in an amber (583 nm) light emitting diode; the other end in a photodiode via an acrylic optical fiber. An aliquot of the blood sample is put in the inner dish, the assembly covered and acid is added through a port in the cover. Evolved HCN diffuses into the OH(CN)Cbi solution and the absorbance in the long path porous membrane tube cell is measured within 160s. The LOD was 0.047, 1.0, 0.15, 5.0 and 2.2 μM, respectively, for water (1 mL), bovine blood (100 μL, 1 mL), and rabbit blood (20μL, 50 μL). RSDs were < 10% in all cases and the linear range extended from 0.5 to 200 μM. The method was validated against a microdiffusion approach and applied to the measurement of cyanide in rabbit and human blood. The disposable device permits field measurement of blood cyanide in < 4 min.

Comment on “Rapid visual detection of blood cyanide” by C. Männel-Croisé and F. Zelder, Analytical Methods, 2012,4, 2632

“…The blood sample (0.5 mL) taken is spiked with up to 100 µM CN − ; with a final volume of 1 mL, in the absence of any reaction the cyanide concentration will be 50 µM, in addition to endogenous cyanide already present in any blood sample (this is typically in the low single digit µM level 20 ). Regardless of the value of the equilibrium constant of the reaction $$\mathrm{bold1}+{\text{CN}}^{-}\leftrightharpoons \mathrm{bold1}bold-\text{boldCN}+{\text{OH}}^{-}$$ …”

“…1 has R = −OCH 3 , X = −CN, hereinafter called compound 1 , as in the original paper), have emerged in recent years as excellent colorimetric reagents for measuring cyanide, the hydroxo group is replaced with a second cyano group, a change in color also results.. Independently, Boss et al have been interested in aquahydroxocobinamide (OH(H 2 O)Cbi + ) as an antidote for cyanide poisoning, 8–91011121314 and Boss et al independently 15–17 or in collaboration with Dasgupta et al 18–20 have used cobinamide based reagents (both OH(H 2 O)Cbi + and CN(H 2 O)Cbi + ) for the determination of cyanide. Spectrally (CN(H 2 O)Cbi + is very similar to (OH(H 2 O)Cbi + ) while (CN) 2 Cbi is very different.…”

“…In most other previous efforts in blood determination involving cobinamide or derivatives, 15,17,19,20 HCN had to be first released from the cyanide bound to blood by strongly acidifying the sample, prior to capturing the gaseous HCN and measuring the resulting cyanide. In fact, it was pointed out 1 that a paramount advantage of the proposed approach, regardless of the technique or reagent used, is that this release of HCN along with a matrix isolation step (e.g., microdiffusion/microdistillation), common to all other approaches, is not necessary.…”

Conductometric determination of ammonium ion with a mobile drop

“…Generation of H 2 S from an aqueous sample and measurement with a micro gas analysis system was used for the determination of sulfide in natural waters [15]. Cyanide in a blood sample was converted to gaseous HCN and collected in a porous membrane containing a chromogenic reagent to permit measurement using disposable platforms [16]. A membraneless setup avoids membrane fouling problems [17,18].…”

A direct and rapid method to determine cyanide in urine by capillary electrophoresis

“…Tobacco smoking also produces cyanide thus increasing cyanide levels in blood and urine of smokers but rarely intoxicating. On the other hand, cyanides have important industrial applications including pesticides, electroplating, mineral refinery, and polymer synthesis [1,6], in which cyanides are possibly released into environments. Therefore, cyanide exposureis difficult to avoid, and thus quick identification of potential cyanide intoxication is valuable for forensic lab testing, determining chronic low-level cyanide exposure, and chemical warfare monitoring.…”