A method and apparatus for the continuous deposition of RP HPLC eluent, from isocratic or gradient elutions, on to a MALDI target using a parallel sample desalting method, allows increased sensitivity of the MALDI sample by pre-concentration of the analyte, separation of interfering contaminants from the analyte and increased dynamic range of peptide abundance that can be analyzed. The parallel processing of sample material allows greater throughput than that of manual methods.