Cobinamide-Based Cyanide Analysis by Multiwavelength Spectrometry in a Liquid Core Waveguide

Abstract

A novel cyanide analyzer based on sensitive cobinamide chemistry relies on simultaneous reagent and sample injection and detection in a 50 cm liquid core waveguide (LCW) flow cell illuminated by a white light emitting diode. The transmitted light is read by a fiber-optic charge coupled device (CCD) spectrometer. Alkaline cobinamide (orange, λ max = 510 nm) changes to violet (λ max = 583 nm) upon reaction with cyanide. Multiwavelength detection permits built-in correction for artifact responses intrinsic to a single-line flow injection system and corrects for drift. With optimum choice of the reaction medium, flow rate, and mixing coil length, the limit of detection (LOD, S/N = 3) is 30 nM and the linear dynamic range extends to 10 μM. The response base width for 1% carryover is <95 s, permitting a throughput of 38 samples/h. The relative standard deviations (rsd) for repetitive determinations at 0.15, 0.5, and 1 μM were 7.6% (n = 5), 3.2% (n = 7), and 1.7% (n = 6), respectively. Common ions at 250-80 000× concentrations do not interfere except for sulfide. For the determination of 2 μM CN − , the presence of 2, 5, 10, 20, 100, and 1000 μM HS − results in 22, 27, 48, 58, 88, and 154% overestimation of cyanide. The sulfide product actually has a different characteristic absorption, and in those samples where significant presence is likely, this can be corrected for. We demonstrate applicability by analyzing the hydrolytic cyanide extract of apple and pear seeds with orange seeds as control and also measure HCN in breath air samples. Spike recoveries in these sample extracts ranged from 91 to 108%.Hydrogen cyanide (HCN) is the simplest combination of the three key elements essential to all life forms, yet HCN and its common alkali metal salts (NaCN, KCN, etc.) are wellknown for their high toxicity. They are widely used in manufacturing synthetic fibers and plastics, agricultural herbicides, fumigants and insecticides, dyes and pigments, animal feed supplements, chelating agents for water treatment, plating and other specialty chemicals and pharmaceuticals, and mining and processing gold. 1,2 Cyanide binds reversibly to the iron containing heme group of cytochrome a3 with resulting inhibition of mitochondrial electron chain transport, decreased energy formation, and changes in the cellular redox state, producing metabolic acidosis. Like O 2 , HCN binds to heme Fe(II) in reduced cytochrome a3. However, in the presence of O 2 when the iron is oxidized to Fe(III), the binding increases markedly. 3 The brain and heart are immediately and readily affected by cyanide. 1 The extreme toxicity of cyanide in physiological systems as well as the continuing

Reactions of Cobinamide with Glucose and Fructose

“…Recently this compound has attracted researchers' interests due to the high efficacy of its derivatives as cyanide antidotes (sulfitocobinamide) [15][16][17] and cyanide chemosensors (monocyanocobinamide). [18][19][20] Cbi application is also of interest in the study of both Co 3+ → Co 2+ and Co…”

Light-Emitting Diodes for Analytical Chemistry

“…Blood cyanide measurement is an important rapid emergency need in smoke inhalation victims. Cobinamide forms an intensely purple product with cyanide (λ max 583 nm); this has been used for nanomolar-level cyanide measurement with a white LED-LCW cell using two additional wavelengths beside 583 nm for blank and baseline correction (93,94). The principle has also been used in an impregnated filter-based (95) and a porous membrane petri dish-based platform (96), both disposable.…”

Ultra-sensitive determination of cyanide in surface water by gas chromatography–tandem mass spectrometry after derivatization with 2-(dimethylamino)ethanethiol

“…Derivatization efficiencies were compared for 2-(dimethylamino)ethanethiol concentrations (0.1, 0.2, 0.5, 0.6, 0.7, 0.8, and 0.9 mg L À1 ), pH (4, 5, 6, 7, 8, and 9), various temperatures (40,50,60,70,80, and 90 C), and reaction times (10,15,20,30,40, and 50 min). The optimum derivatization conditions for cyanide with 2-(dimethylamino)ethanethiol were determined by peak area ratios of 2-(dimethylamino)ethyl thiocyanate to the internal standard spiked after the extraction.…”

“…Spectrophotometry has been widely employed in the determination of cyanide through the use of many types of dye [15][16][17][18][19]. Electrochemical methods using sensors have been routinely used for cyanide analysis [20][21][22]. Flow injection analysis [23], atomic absorption spectrometry [24], electrophoresis [25][26][27], and ion chromatography [28] have also been used for the determination of cyanide, but their sensitivities are not adequate to detect below mg L À1 levels in environmental water.…”