Calibrate organic d15 values with the given standards

calibrate_d18(
  data,
  d18,
  amount = amount,
  volume = volume,
  cell_volume,
  standards = c(`USGS-34` = -27.93, `IAEA-NO3` = 25.61),
  quiet = FALSE
)

Arguments

data

(can be a grouped_by data set)

d18

the d18 column

amount

the amount column

volume

the volume column

cell_volume

the volume of cells in the vial (has to be same units as volume!)

standards

a set of isotope standards Note: they are matched to the data by "category" (not by name)

d15

the d15 column (can be a column already calibrated for denitrifier method)

infer_NO3_blank

whether to infer the NO3 blank from this correction in addition to the organic blank (if using a single step correction)

ref_gas_d15

the reference gas isotopic composition (only used if infer_NO3_blank = TRUE, to constrain culture blank d15)

Value

introduces the column d15.ocal and parameters p.15o_stds, p.d15o_m_true, p.d15o_m_vol, p.d15o_m_true:vol and p.d15o_b as well as information on the organic blank p.No_blk_conc and p.No_blk_d15 and nitrate blank (only if type is 1-step!) p.N_blk_amt and p.N_blk_d15

introduces the column d18.cal and parameters p.d18_m_true, p.d18_m_conc, p.d18_m_true:conc and p.d18_b

Note

implement single point correction Calibrate d18 data with the given standards.

Uses a multivariate linear regression that takes the effective concentration in the sample vials into consideration (as well as covariance between standards and effective concentration).

FIXME: this should have a term for evaluating whether any extrapolation happens unepxectedly that then causes trouble!!