Acid base identification in household products

[Edde]

My laboratory sometimes receives samples from patients accidentally poisoned by taking household products such as bleach, suspected hydrofluoric acid containing air conditioner cleaning agent, hydrochloric acid, other household multi-purpose cleaning agents, etc. We now use chemical methods to detect suspected acid / bases. Besides acid or base, there should be other ingredients in household products that are not as toxic but whose identification can give clues to which household product the patient has taken. I am trying to look for more sensitive and specific methods for confirmation. My lab has Agilent HPLC-DAD, GCMS, GC-FID, GC-ECD, LC-MS/MS, LC-IT-TOF/MS instruments. And my boss asked me to suggest additional equipment to purchase if required.

I don't know if my logic is correct. Please kindly comment.

As acid or base ionizes in water, I will detect the pH and then the respective anion or cation. I shall purchase a conductivity detector and suppressor to link to the existing HPLC-DAD. Is this the best choice? Can it cover as much cations and anions as possible? Is ICP-MS suitable for household products analysis? I mean the acid or base for analysis may have extreme pH values and may be corrosive.

Also, I have a difficulty. If chloride ion and sulphate ion were detected in an acidic liquid, I can't say if this is hydrochloric acid or sulphuric acid. Right?

In addition, household products usually contain surfactant and solvents. Can I use Acclaim surfactant column with ELSD? Is this the best combination? Can I connect a suppressor, conductivity detector and ELSD to the existing DAD?

I heard that HPLC for running ion chromatography needs to be thoroughly washed with buffer before analysis. Is this true?

I appreciate all comments and suggestions. Thanks.

[Consumer Products Guy]

You need to supply more information: are you receiving consumer products submitted as possible source of the "poison", or are you analyzing stuff like stomach contents?

I think you need to get a background as to what ingredients are commonly used in which consumer products. For example, I doubt that hydrofluoric acid is used in consumer products as it is so toxic. Low pH toilet cleaners commonly contain hydrochloric acid, which is also called muriatic acid for swimming pool use. Household cleaners which are high pH might contain hypochlorite, and swimming pool test indicators do a decent job there. Other household cleaners can contain citric, malic, or lactic acid; we use ion chromatography with conductivity or low-UV detector with a specialty "organic acid" column and dilute sulfuric acid eluent for those and similar organic acids. We don't use suppressors for these.

I have used Acclaim surfactant column with ammonium acetate in the mobile phase, so that might be amenable to ELSD detection.

Also, I have a difficulty. If chloride ion and sulphate ion were detected in an acidic liquid, I can't say if this is hydrochloric acid or sulphuric acid. Right?

Not really. I'd quantitate the chloride and sulfate (e.g ion chromatography, or maybe even titration with silver nitrate for the chloride) to determine their relative levels, and go with the one that's higher in level, as you'll find low levels of sulfate and chloride in most products like this. Maybe acidic drain cleaners contain sulfuric acid, and powdered Drano has typically been sodium hydroxide and aluminum.

[HW Mueller]

Obviously, if you have Cl- and S04-- in an acidic solution you have hydrochloric and sulfuric acid there (maybe partially to completely dissociated).

[Edde]

You need to supply more information: are you receiving consumer products submitted as possible source of the "poison", or are you analyzing stuff like stomach contents?

Yes, I receive non-biological samples whose identity is totally unknown and may be in container without label, plus biological samples such as gastric lavage, serum, urine.

I am performing a market survey and look at ingredients on package of household products sold in supermarket. However, in most products, no ingredient is specified. The law in this locality does not require listing of ingredients in household products. In the minority of products with listed ingredients, I just find hydrochloric acid and hypochlorite, surfactant (anion, cation, non-ionic, amphoteric) and "solvent".

we use ion chromatography with conductivity or low-UV detector with a specialty "organic acid" column and dilute sulfuric acid eluent for those and similar organic acids. We don't use suppressors for these.

Low UV isn't selective, is it? Is a conductivity detector more selective? What type of "specialty organic acid column" is available? Could you please recommend?

I am totally unfamiliar with ELSD. Is it selective and specific for surfactant?

Does ICP-MS has a place in household product detection?

Thank you in advance.

[Peter Apps]

What you are getting into here is forensic chemistry, which is a specialist field all of its own, not least because of the legal implications. Forensic chemists make a lot if use of screening tests, small scale wet chemistry, specific test reagents etc etc etc before they run samples through instrumental analyses. This process is tried and tested, and has a long history that makes the courts look at it as being reliable. There are some specialist forensic chemistry journals, and various handbooks that get into the different tests - start with those.

And just in case you are thinking of asking me for details, forensics is not my area.

Most common household products use generic recipes, and I have very often found that if I want to know what is in something that a friendly phone call to the manufacturer with a good reason why I want to know saved many hours or analytical work !

Peter

[yangz00g]

Try to search Homeland Security, CDC, chemical terrorism and unknown analysis, you may have the luck to find a comprehensive decision tree for totally unknown analysis. I agree with Peter that you should start with some wet chemistry based screening kits (search first responder chemical kits you may find something useful). I used to part of the effort to develop such a matrix with my previous employer, but unfortunately, I don't have one with me after changing jobs.

Some handhold IR manufactures may have spectrum library for your targets.

Good luck

[Edde]

Thanks Peter for your advice. Some manufacturers (especially the European ones) do provide ingredients in their websites. But still, many of them do not. I am going to contact the manufacturers as you suggested.

Thanks yangz00g. I've searched the web for information. Unfortunately, I cannot find protocol yet. Anyway, I'll keep searching and thanks for your idea.

[Consumer Products Guy]

Low UV isn't selective, is it?
NO

Is a conductivity detector more selective?
NOT NECESSARILY
What type of "specialty organic acid column" is available? Could you please recommend?
Grave Davison Prevail organic acid column or Restek organic acid column, with dilute acidic eluent such as sulfuric acid

I am totally unfamiliar with ELSD. Is it selective and specific for surfactant?
No, but solvents and volatile compnents are flashed off. A surfactant like lineralkylbenzenesufonate is UV-absorbing, but sodium laureth sulfate is not, why oftentimes ELSD is used for surfactants.

Does ICP-MS has a place in household product detection?
I would say ICP has a place, ICP-MS may be overkill for its price for this application

I believe Wal-Mart web site lists MSDS documents for all the stuff it sells. In US, most personal care products list their ingredients, but don't think it's a regulation, just the companies decided to do this so government didn't take next step and make them put ingredients and percents.

[DSP007]

You equipment good, but logic...
This question - is question of clinicist (or patalogoanatom ,if we are dealing with a corpse).
Moreover, need a very experienced clinician. Damage to the sphincter of the esophagus by gastric juice with heartburn resemble damage from taking hydrochloric acid.
By the way if the client drank hydrochloric acid - you very little prove the by chemistry - it is in the gastric juice. Is that you will find some traces of inhibitor or ppm admix non characeristic for gastic juise heavy metals ( include arsenic ) ions .
On the other detergents easier, but not by much.
For example, found in the stomach of citric and oxalic acid, you must be sure that the client drank a cure for rust. And not drink a glass of orange juice ... But he could drink and then and another.

[Alex Buske]

My laboratory sometimes receives samples from patients accidentally poisoned by taking household products such as bleach, suspected hydrofluoric acid containing air conditioner cleaning agent, hydrochloric acid, other household multi-purpose cleaning agents, etc.

Poor guy.

We now use chemical methods to detect suspected acid / bases. Besides acid or base, there should be other ingredients in household products that are not as toxic but whose identification can give clues to which household product the patient has taken.

That makes sense. I would add some oxidation test

I am trying to look for more sensitive and specific methods for confirmation. My lab has Agilent HPLC-DAD, GCMS, GC-FID, GC-ECD, LC-MS/MS, LC-IT-TOF/MS instruments. And my boss asked me to suggest additional equipment to purchase if required.

Lucky guy!!

As acid or base ionizes in water, I will detect the pH and then the respective anion or cation. I shall purchase a conductivity detector and suppressor to link to the existing HPLC-DAD. Is this the best choice? Can it cover as much cations and anions as possible? Is ICP-MS suitable for household products analysis? I mean the acid or base for analysis may have extreme pH values and may be corrosive.

IC would be sensible. there are special instruments on the market.

Also, I have a difficulty. If chloride ion and sulphate ion were detected in an acidic liquid, I can't say if this is hydrochloric acid or sulphuric acid. Right?

Well, if there was just 1% chlorine and 99% sulfate, I'd guess sulfuric acid

In addition, household products usually contain surfactant and solvents. Can I use Acclaim surfactant column with ELSD? Is this the best combination? Can I connect a suppressor, conductivity detector and ELSD to the existing DAD?

For "solvents" headspace GC.
Here in Europe ingredients are labelled and there are often the same suspects like lauryl sulfate. Just find methods for the most often mentioned surfactants. If you invite somebody from company D**** to introduce there ICs, he will for sure mention the CAD as the most universal and sensitive HPLC detector.

[DSP007]

With oxalic acid would recommend also microscope (with data video/photoregistration). Here's the nuance - one of the pathological mechanisms of oxalate poisoning is the loss of calcium oxalate crystals (druz) in urine. These crystals cause damage "glomerulus" glomeruli and provoke glomerulonephritis. Quite often they can be seen in the urine.
Also given me an example of citric acid against the orange juice. The microscope lets you see the fragments of plant cells and narrow down the suspects. "

[Edde]

Thanks all.

I think I will suggest purchasing a conductivity detector plus ion suppressor for inorganic and organic ions.

The relative abundance of anions in an acid give clue to the identity of the acid.

Alex,

That makes sense. I would add some oxidation test

What is oxidation test?

If you invite somebody from company D**** to introduce there ICs, he will for sure mention the CAD as the most universal and sensitive HPLC detector

What is CAD ?

I think I would use LC-MS to detect surfactant.

You guys are great! I have more ideas now.

[Alex Buske]

What is oxidation test?

bleach usually contains some oxidiser. there must be a simple wet chemistry test

What is CAD ?

Charged Aerosol Detector