CO Poisoning Question

[DandyDon]

CA, for one, requires CO detectors in new construction, at time of sale, and in rentals.

I still think that enforcement would be challenging for rentals. Ultimately, it's on the dweller to test those gadgets monthly.

 

[Bob DBF]

I still think that enforcement would be challenging for rentals. Ultimately, it's on the dweller to test those gadgets monthly.

Yeah, you can lead a horse to water... The main point is they are required to be there and operational at the time of sale or rental. Around here the rentals have to be checked by the landlord each year, and there is the random county inspection. Luckily they are pretty reliable, and set to beep if any internal check is bad.

 

[Storker]

I find it interesting that CO supposedly has 210 times the affinity to bond with heme than O2 (it would be interesting to understand how that figure is derived) yet it will give up the covalent bond based on the diffusion gradient caused by high concentration of O2....

Neither O2 nor CO bind covalently to hemoglobin. They form complexes with hemoglobin in equilibrium reactions

https://aklectures.com/lecture/respiratory-system/carbon-monoxide-and-hemoglobin

 

[DandyDon]

That low-battery beep is annoying.

I've been hearing a soft, occasional beep off to the right when I sit at my computer for a week. Tonight while in my utility room off to my left, an auxiliary smoke detector I keep hanging in there gave a loud beep. Further investigation narrowed it down as the mystery beep and the batteries did test bad so I guess my hearing direction is just out of whack.

 

[Zef]

Neither O2 nor CO bind covalently to hemoglobin. They form complexes with hemoglobin in equilibrium reactions

https://aklectures.com/lecture/respiratory-system/carbon-monoxide-and-hemoglobin

The video you linked did a great job explaining the dissociation curve, but I don't recall the lecturer discussing bond type or lack thereof.

I did some further research on the bond type between O2 and Hb and CO and Hb and found, as you suggested, info that agrees that it is not covalent (as I originally thought) or ionic, but is called a coordinate/dative bonds:

"The bonding between iron in hemoglobin and the oxygen molecule is not an ionic bond or a covalent bond. It involves coordinate bonds (also known as dative bonds). In covalent bonds between two atoms, one electron each from the two atoms are shared between them to form the bond. But coordinate bond is a type of bond in which both electrons in the bond (an electron pair) are “donated” by the same atom. Therefore such bonds are formed between atoms which have lone pair of electrons (like O, S, N etc.) and a positively charged metal atom which receives the electron pair. This type of bond is weaker than ionic or covalent bonds, and can be easily broken or formed again by adjusting conditions. You may say that this is a “temporary” kind of bond. It is indicated by an arrow from the atom donating the electron-pair towards the metal ion receiving them."

***Note: quote above attributed to Dr. Ravi Divakaran, PhD Chemistry. The quote was taken from a non-academic internet site so it is provided only for discussion purposes.

-Z

 

[Akimbo]

Neither O2 nor CO bind covalently to hemoglobin. They form complexes with hemoglobin in equilibrium reactions

https://aklectures.com/lecture/respiratory-system/carbon-monoxide-and-hemoglobin

I understood that is why terms like affinity are used instead of bond, which implies covalent bonds. Navy hyperbaric docs used analogies like electromagnets to help sailors make sense of Oxygen molecules "hitchhiking" on red blood cells.

I've been hearing a soft, occasional beep off to the right when I sit at my computer for a week. Tonight while in my utility room off to my left, an auxiliary smoke detector I keep hanging in there gave a loud beep. Further investigation narrowed it down as the mystery beep and the batteries did test bad so I guess my hearing direction is just out of whack.

No worries, it will eventually go from that soft occasional low-battery beep to the ear-splitting alarm... usually around 3:00 AM. It's a good thing we don't keep a loaded shotgun around or my sweet little bride would have "fixed" it instead of making me get a ladder and replace the battery.

 

[Storker]

I understood that is why terms like affinity are used instead of bond, which implies covalent bonds. Navy hyperbaric docs used analogies like electromagnets to help sailors make sense of Oxygen molecules "hitchhiking" on red blood cells.

Good idea. For someone versed in chemistry, bonds are bonds. Some bonds are covalent, some bonds are electrostatic. Some bonds are H-bonds, some bonds are ligand bonds. Some bonds are vdW bonds, some bonds are hydrophobic bonds.The bond strength varies by several orders of magnitude. Towards non-chemists, it's probably a good idea to avoid using the "b" word for anything weaker than a covalent bond, to avoid confusion.

 

[Storker]

I did some further research on the bond type between O2 and Hb and CO and Hb and found, as you suggested, info that agrees that it is not covalent (as I originally thought) or ionic, but is called a coordinate/dative bonds

Yep, they are coordinate AKA ligand-type (complexing) bonds.

 

[Akimbo]

I understood that is why terms like affinity are used instead of bond, which implies covalent bonds. Navy hyperbaric docs used analogies like electromagnets to help sailors make sense of Oxygen molecules "hitchhiking" on red blood cells.

Good idea. For someone versed in chemistry, bonds are bonds.

I'm sure the analogy evolved from years of trying to explain complex microbiology to diver-sailors with widely varied backgrounds. Same with "biologically inert". Finding common ground between young seaman that may have dropped out of school to officers with PhDs in physiology is almost as hard as finding common ground on the Internet.

Seriously, this kind of discussion is valuable. US Navy diving schools rarely had to communicate with different nationalities, vastly different cultures, and non-native english speakers like ScubaBoard. Discovering phrases that are understandable and technically correct can benefit everyone.

 

[Zef]

I understood that is why terms like affinity are used instead of bond, which implies covalent bonds. Navy hyperbaric docs used analogies like electromagnets to help sailors make sense of Oxygen molecules "hitchhiking" on red blood cells.

Affinity and bond are not the same in the context of this discussion.

Affinity is the likelihood/tendency that the bond will happen.

I was under the false impression/assumption that the bond between O2 and Hb and CO and Hb was covalent because it is a weak bond, and a covalent bond is weaker than an ionic bond.

I was not even aware of coordinate/dative bonds which are even weaker than covalent bonds. The weaker bond facilitates the dissociation of the O2/CO from the hemoglobin.

-Z