Distinguishing between toxic and
nontoxic arsenic
Arsenic (As) is a naturally occurring element found in the earth's crust. Arsenic combines with oxygen, chlorine, and sulfur to form inorganic arsenic compounds, which are highly toxic. In animals and plants, arsenic combines with carbon and hydrogen to form organic arsenic compounds, which are not considered toxic. It is important to distinguish between the two forms of this element when measuring arsenic in drinking water or other consumables.
Arsenic analysis
Coupling ion chromatography (IC) with suppressed conductivity detection and inductively coupled plasma mass spectrometry (ICP-MS) is an excellent way to detect and quantify arsenic in fruit juices and wine. With this combination, both the toxic, inorganic forms ((As (III) and As (V)) and the non-toxic, organic forms (e.g. arsenobetaine) of arsenic can be determined, providing a more accurate assessment of product safety than total arsenic alone.
Regulatory information
- EPA and FDA: In drinking water, the maximum contaminant level for arsenic is 10ng/g. There is currently no legislative limit for arsenic species in fruit juices.
- WHO: Arsenic is one of the WHO’s 10 chemicals of major public health concern. The current recommended limit of arsenic in drinking water is 10μg/L, although this guideline value is designated as provisional because of measurement difficulties and the practical difficulties in removing arsenic from drinking water.
Example application notes
| Application Note | Sample | MDL | IC Column |
|---|---|---|---|
| IC-ICP-MS Speciation Analysis of As in Apple Juice Using Thermo Scientific iCAP Q ICP-MS (AN 43099) | Apple juice | 0.001–0.011ng/g | Dionex IonPac AS7 Columns |
| IC-ICP-MS Speciation Analysis of As in Organic Brown Rice Syrup (OBRS) Using Thermo Scientific iCAP Q ICP-MS (AN 43126) | Rice syrup | 0.13ng/g | Dionex IonPac AS7 Columns |