The collection of groundwater samples for metals, including metalloids such as arsenic and selenium, is primarily complicated by the fact that many of the target metal contaminants are also part of the immobile geologic matrix through which groundwater flows. It is the purpose of this chapter to familiarize the reader with newer techniques, their value in terms of sample quality and consistency, and the conditions under which they should be considered for use. The latter depends on sampling purpose or objectives and data quality requirements. While the focus will be on metals samples and sampling in routine monitoring wells, some discussions will also have relevance for sampling organic contaminants as well.