Aerospace Toxicology Overview: Aerial Application and Cabin Air Quality - Reviews of Environmental Contamination and Toxicology - page 30

5. Visible spectrophotometry by hemolyzing red cells of blood specimens,
reducing MetHb and OxyHb to HHb, and calculating ratios of the absorbance
values of the specimens at 540 and 579 nm (Canield et al. 1998, 1999 ; Sanderson
et al. 1978 ; Winek and Prex 1981 ).
6. Headspace gas chromatography by (1) converting MetHb and OxyHb to HHb by
using sodium dithionite in two separate aliquots of blood samples, (2) saturating
one aliquot with CO (the second aliquot is not treated with CO), (3) getting the
release of CO from both aliquots by a ferricyanide or phosphoric acid solution,
(4) injecting headspace air samples of the CO-saturated and non-CO treated ali-
quots into a gas chromatograph, equipped with a column and a methanation unit
(nickel catalyst and hydrogen unit), (5) detecting methane by lame ionization,
and (6) calculating %COHb level in a blood sample by comparing methane peaks
of the CO-saturated blood sample and of the non-CO treated (original) blood
sample (Cardeal et al. 1993 ; Grifin 1979 ).
7. Headspace gas chromatography by dividing the sample into two parts, saturating
one part with CO (other used without CO-treatment), treating both parts with
sodium dithionite to reduce MetHb and OxyHb to HHb, releasing CO from the
both parts by sulfuric acid with saponin, injecting headspace air samples of the
CO-saturated and the non-CO treated samples into a micro-gas chromatograph,
and comparing gas chromatographic CO peaks of the original (non-CO treated)
blood sample and of the CO-saturated blood sample, and calculating %COHb in
a blood sample (Endecott et al. 1996 ; Lewis et al. 2004 ).
For CN − :
1. Colorimetry by the reaction of CN − present in blood with p- nitrobenzaldehyde
and o- dinitrobenzene under an alkaline condition and production of a violet
color, suggesting the presence of a potentially toxic CN − concentration (Dunn
and Siek 1990 ; Guilbault and Kramer 1966 ; Rieders 1975a ).
2. Visible spectrophotometry by the liberation of HCN from blood by acidiication
and microdiffusion, trapping of HCN in a dilute alkaline solution, conversion of
HCN to cyanogen chloride after reacting with chloramine-T, and then reacting
cyanogen chloride and pyridine to form N -cyanopyridinium chloride, followed by
a cleavage reaction to form an anil of glutaconic aldehydes and then coupling with
barbituric acid to generate a red-pinkish, highly resonant product , indicating the
presence of CN − (Blanke 1976b ; Feldstein and Klendshoj 1957 ; Rieders 1975b ).
3. Headspace gas chromatography (nitrogen-phosphorus detection) by equilibra-
tion of blood in the presence of an internal standard (acetonitrile) in a vial and
injection of the headspace of the vial onto a gas chromatograph to detect HCN
and acetonitrile (McAuley and Reive 1983 ; Zamecnik and Tam 1987 ).
4. Headspace gas chromatography (electron capture detection) by the liberation
of HCN from blood, conversion of HCN to cyanogen chloride by reaction with
chloramine-T, and injection of headspace onto a gas chromatograph (Odoul
et al. 1994 ).
5. Spectrophotoluorimetry or high-performance liquid chromatography (luo-
rescence detection) by transformation of CN − by acidiication from blood to