0. SECTIONS ------------- 1. Project 2. Dataset 3. Terms of Use 4. Contents 5. Method and Processing 1. PROJECT ------------ Title: Investigating liquid AP-MALDI MS for large-scale analysis of liquid samples Dates: September 2014/March 2018 Funding organisation: EPSRC, Waters Corporation Grant no.: EP/L006227/1 , DTG no.1498422 2. DATASET ------------ Title: Dataset supporting research into the production and analysis of multiply charged negative ions by atmospheric pressure matrix-assisted laser desorption/ionisation mass spectrometry. Description: Dataset contains mass spectrometry datafiles supporting a project investigating negative mode performance of an in-house developed AP-MALDI source for generating multiply charged ions from liquid samples. Publication Year: 2018 Creator(s): Oliver J. Hale1, Pavel Ryumin1 and Rainer Cramer1 Contributors: Jeff Brown1,2, Michael Morris2 Organisation(s): 1:University of Reading 2: Waters Corporation 3. TERMS OF USE ----------------- This dataset is licensed under a Creative Commons Attribution 4.0 International Licence: https://creativecommons.org/licenses/by/4.0/. 4. CONTENTS ------------ File listing: Negative_Mode.zip Positive_Mode.zip The files are divided by the ion mode the data were collected in. Both contain the following folder substructure: >3-AQ >9-AA >CHCA >CHCA_3-AQ >DHB where each folder name indicates the MALDI chromophore used during analysis. All analytes are grouped by chromophore. Files appended with the suffix *dt_01 have been produced in the drift time domain. All data was obtained using proprietary software MassLynx (Waters) and stored using closed source proprietary data format. Data is stored as is to maintain full compatibility with Waters proprietary software; however several free open source software packages are available to convert the data to an open source file format mzML, e.g. msconvert utility by ProteoWizard project http://proteowizard.sourceforge.net/downloads.shtml. 5. METHOD and PROCESSING -------------------------- The dataset contains data that was generated using a commercial mass spectrometer Synapt-G2Si HDMS (Waters) equipped with an in-house developed AP-MALDI ion source. Masslynx (ver. 4.1; Waters) software was used to collect and process the data. Further processing making use of the ion mobility function was performed with DriftScope (v.2.8; Waters) as necessary (e.g. charge state filtering, drift time export). All data files contain a _HEADER and _extern file with relevant instrument settings and employed methods recorded. These can be opened in Notepad or a similar text editor. UniDec, freely available software from the University of Oxford website, is recommended for viewing and processing protein mass spectra due to its advanced binning, smoothing and background subtraction methods. Progenesis QI is required for the proprietary peak picking of lipid mass spectra for database search submission. Other software may perform the same function but with different underlying technology, in which case may result in different results than reported.