A modular fluid sampling device that includes an elongated handle and a sample container holder attached to one end of the elongated handle. A signal generation section 11 generates an amplitude signal and quadrature data based on input data. The formation of the protective layer continues until an etch stop condition is produced, stopping further etching of the interlayer under the first condition prior to exposing the underlying surface. The method may additionally include providing notifications and retrieval of voice mail messages, and submitting voice mail messages from the user device. Purities of more than 98%, and preferably about 99% or higher, are thus obtained.