In isoverse/isoorbi: Process Orbitrap Isotopocule Data

# default chunk options
knitr::opts_chunk$set(collapse = TRUE, message = FALSE, comment = "#>")

# load libraries
library(isoorbi) # for Orbitrap functions
library(dplyr) # for data wrangling
library(ggplot2) # for data visualization

Data

Load data

# load and process data
data <- 
  # load file included in isoorbi package
  system.file(package = "isoorbi", "extdata", "testfile_flow.isox") |>
  orbi_read_isox() |>
  orbi_simplify_isox() |>
  # define data block where signal is stable (plateau)
  orbi_define_block_for_flow_injection(start_time.min = 0.1, end_time.min = 0.9) |>
  # flag extreme TICxIT values
  orbi_flag_outliers(agc_fold_cutoff = 2)

Calculations

Ratios

# basepeak & ratios
data_w_basepeak <- 
  data |>
  orbi_define_basepeak("M0")

# ratio summaries
data_summary <- 
  data_w_basepeak |>
  orbi_summarize_results(ratio_method = "sum")

Figures

Visualize data

#| label: fig-raw-data
#| fig-cap: Ions of isotopocules in time
#| fig-width: 6
#| fig-height: 4
#| warning: false
orbi_plot_raw_data(data, y = ions.incremental, y_scale = "log")

Raw ratios

#| label: fig-ratios
#| fig-cap: Isotopocule ratios vs M0
#| fig-width: 6
#| fig-height: 4
#| warning: false
data_w_basepeak |> orbi_plot_raw_data(y = ratio)

Ratios for 18O

#| label: fig-ratios-18O
#| fig-cap: Isotopocule ratios 18O vs M0
#| fig-width: 6
#| fig-height: 4

fig <- 
  data_summary |>
  filter(isotopocule == "18O") |>
  # plot
  ggplot() +
  aes(
    x = filename,
    y = ratio, ymin = ratio - ratio_sem, ymax = ratio + ratio_sem,
    color = filename, shape = filename
  ) +
  geom_pointrange() +
  scale_color_brewer(palette = "Dark2") +
  # theme definitions
  theme_bw() +
  theme(
    text = element_text(size = 16),
    panel.grid = element_blank()
  ) +
  # labels
  labs(
    y = expression("ratio ("^18*O/M0*")")
  )
fig