Answers and how-to guides from Renew Lab Group: deionized water uses and pharmaceutical lab testing.
Both use liquid chromatography to separate a sample into its components. The difference is the detector. HPLC usually measures each compound with a UV detector, which is accurate and economical for potency against a label claim. LC-MS sends the separated compounds into a mass spectrometer that measures their mass, so it can confirm identity, find unknowns and detect far smaller amounts.
Endotoxin testing checks a product for bacterial endotoxins, fever-causing molecules from the outer membrane of Gram-negative bacteria. The standard method is the LAL test, which uses Limulus amebocyte lysate made from horseshoe crab blood cells; it reacts with endotoxin by clotting or producing a measurable signal. It is a key release test for sterile products and pharmaceutical water.
No, but they are close. Distilled water is made by boiling water and condensing the steam, which leaves minerals behind. Deionized water is made by passing water through ion-exchange resin that pulls dissolved minerals out. Both are very low in minerals, so for batteries, steam irons, humidifiers and spot-free rinsing they do the same job.
Yes, as long as you also fertilize. Orchids are sensitive to salts and minerals that build up in their potting mix, and deionized water adds none. But deionized water also contains no nutrients, so feed your orchids with a balanced orchid fertilizer and flush the pot now and then. Carnivorous plants such as Venus flytraps need low-mineral water even more.
Finish your wash with a final rinse of deionized water. Water spots are the minerals left behind when hard tap water evaporates, so if the last water on the paint has no minerals, there is nothing left to spot. At home, mist each panel with deionized water from a clean pump sprayer before it dries, and work in the shade.
Contact an independent analytical lab that accepts samples from the public, tell it the product’s labeled ingredient, strength and dosage form, and submit a sample. The lab tests it, usually by HPLC, for identity and potency, and sends you a certificate of analysis. Renew Lab Group in Houston accepts samples from consumers, pharmacies and businesses; call 936-379-5515 to start.
Very accurate, when the method is validated and run properly. HPLC is the standard technique for measuring how much active ingredient a drug product contains. Under ICH Q2(R2), a method is shown to be accurate, precise, specific and linear over its range before results are reported. The biggest real-world factors are the reference standard, sample preparation and whether the sample is representative.
Yes. Deionized water is one of the two waters battery makers recommend for flooded lead-acid batteries, along with distilled water. It has the minerals removed, so it replaces the water lost during charging without coating the plates. Never use tap water, and only add water to batteries with removable cell caps. (Trojan notes that it prefers distilled water where available, but says deionized water can be used instead.)
Usually, yes, but check your iron’s manual first. Many irons are designed for tap water, and makers differ: Philips recommends demineralized water, or a 50/50 mix with tap, in hard-water areas, while Rowenta and De’Longhi suggest mixing demineralized water 50/50 with tap rather than using it straight. Either way, lowering the minerals reduces scale and brown spitting.
Deionized water doesn’t spoil the way food does, but it doesn’t stay perfectly mineral-free forever once it is opened. Exposed to air, it slowly absorbs carbon dioxide, and it can pick up traces from dust or a dirty container. Kept sealed, at room temperature and out of sunlight, it stays suitable for household uses for a long time.
