IntroductionArsenic, a hazardous metalloid, is the inorganic component of a chemical warfare agent named Blue Cross, which contains diphenylchloroarsine (DA, Clark I) and diphenylcyanoarsine (DC, Clark II). These agents were mainly used during World War I as vomiting agents; the main purpose was to be “mask breakers” by penetrating the canister; thereby forcing the opposing troops to remove their masks and be further exposed to toxic agents. A concern with these compounds is the possibility of prolonged systemic effects, such as headache, mental depression, chills, nausea, abdominal cramps, vomiting and diarrhea, all lasting for several hours after exposure. The agents are dispersed as aerosols and they produce their effects by inhalation or by direct action on the eyes. When released indoors, they can cause serious illness or death.1,2Chemical warfare agent degradation products (CWDPs) include diphenylarsinic acid (DPAA), phenylarsonic acid (PAA) and phenylarsine oxide (PAO). In the degradation pathway, byproducts such as triphenylarsine (TPA) and triphenylarsine oxide (TPAO) are found and their structures are shown inFig. 1. Previous papers have mentioned that groundwater and soil have been contaminated from some of these organoarsenical compounds, leading to environmental problems.3,4Oyamaet al.reported as recently as 2007 the presence of degradation products DPAA, PAA and PAO in groundwater and soil in Kamisu City, Japan.5With known population exposure, it is important to understand the biological uptake mechanism for these degradation products in mammalian organisms. Examples of other studied arsenic species include sodium arsenate, Na2HAsO4[As(v)], sodium arsenite, NaAsO2[As(iii)], dimethylarsinic acid (DMA) and methylarsonic acid (MMA) as shown inFig. 1as well as parent agents Clark I and Clark II.Structures of primary warfare agents, their degradation products and other arsenic species used in the cytotoxicity study.The aim of this work was to do an initial study investigating CWDPs cytotoxicity on mammalian cells by comparing the effects of different CWDP concentrations over different time periods. To generate metallomics information an As speciation study was performed utilizing liquid chromatography (LC) coupled to both inductively coupled plasma mass spectrometry (ICPMS) and electrospray ionization mass spectrometry (ESI-MS) to identify the molecular level changes the CWDPs might undergo.The cytotoxicity evaluation was conducted on an African Green Monkey CV-1 cell line based on quantification of lactate dehydrogenase activity as released from damaged/dying cells. Kidney cells were chosen as target cells because kidneys take up and excrete a variety of substances produced by the cell metabolism. A comparison of different concentration levels over different time ranges was completed, following the toxic compounds addition to the cells. The cells treated with the various arsenic species were then tested for cellular arsenic uptake by ICPMS detection of the monoisotopic75As.The interest in arsenic speciation analyses continues to grow with the increasing need to assess its biological effects. Total arsenic analyses, though necessary, are insufficient to fully address the complexities and questions posed by biological systems. While As totals are useful, they provide no information on the various arsenic forms, which have widely varying toxicities. The inorganic species, which are commonly found in the environment, are known to be the most toxic species, while some of the organic arsenic forms are less toxic and even innocuous.6Hence, speciation analysis is required and further identification and verification by molecular mass spectrometry as necessary.