webchem (version 1.1.1)

nist_ri: Retrieve retention indices from NIST

Description

This function scrapes NIST for literature retention indices given CAS numbers as an input.

Usage

nist_ri(
  query,
  from = c("cas", "inchi", "inchikey", "name"),
  type = c("kovats", "linear", "alkane", "lee"),
  polarity = c("polar", "non-polar"),
  temp_prog = c("isothermal", "ramp", "custom"),
  cas = NULL,
  verbose = TRUE
)

Arguments

query

character; the search term

from

character; type of search term. can be one of "name", "inchi", "inchikey", or "cas". Using an identifier is preferred to "name" since NA is returned in the event of multiple matches to a query. Using an identifier other than a CAS number will cause this function to run slower as CAS numbers are used as internal identifiers by NIST.

type

Retention index type. One of "kovats", "linear", "alkane", or "lee". See details for more.

polarity

Column polarity. One of "polar" or "non-polar" to get RIs calculated for polar or non-polar columns.

temp_prog

Temperature program. One of "isothermal", "ramp", or "custom".

cas

deprecated. Use query instead.

verbose

logical; should a verbose output be printed on the console?

Value

returns a tibble of literature RIs with the following columns:

  • CAS is the CAS number

  • type is the column type, e.g. "capillary"

  • phase is the stationary phase (column phase)

  • RI is retention index

  • length is column length in meters

  • gas is the carrier gas used

  • substrate

  • diameter is the column diameter in mm

  • thickness is the phase thickness in <U+00B5>m

  • program. various columns depending on the value of temp_prog

  • reference is where this retention index was published

  • comment. I believe this denotes the database these data were aggregated from

Details

The types of retention indices included in NIST include Kovats ("kovats"), Van den Dool and Kratz ("linear"), normal alkane ("alkane"), and Lee ("lee"). Details about how these are calculated are available on the NIST website: https://webbook.nist.gov/chemistry/gc-ri/

References

NIST Mass Spectrometry Data Center, William E. Wallace, director, "Retention Indices" in NIST Chemistry WebBook, NIST Standard Reference Database Number 69, Eds. P.J. Linstrom and W.G. Mallard, National Institute of Standards and Technology, Gaithersburg MD, 20899, 10.18434/T4D303.

See Also

is.cas as.cas

Examples

Run this code
# NOT RUN {
myRIs <- nist_ri(c("78-70-6", "13474-59-4"), from = "cas", "linear",
"non-polar", "ramp")
# }

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