EA.NACHO: Finalizes raw EA data from NACHO
In gholtgrieve/HEEL: Miscellaneous Functions From HEEL Members

EA.NACHO

R Documentation

Finalizes raw EA data from NACHO

Description

This function is used to decompose and finalize EA data from solid samples analyzed on the Delta V irMS systems (NACHO). The function writes a .csv with the thinned raw data and a .pdf with all relevant information about the analysis. The finalized sample data are also returned as a dataframe.

The input data file has strict formatting and data requirements. Each sample or standard should have four rows of data: two for N and two for C. Deviations from this is will result in the function failing. Blanks and zeros are an exception and can have only two rows. The follow columns must be present in the input data file for the function to work.

Row: Row number for the IsoDat sequence file.
Analysis: Unique number assigned by IsoDat for each analysis.
Identifier 1: Unique identifier for each sample or standard in the file. If two runs are combined, be sure this field remains unique. Character.
Comment: Identifies whether the particular analysis is a 'STD', 'QTY', 'SAMPLE', 'BLANK', 'ZERO', or 'DUMMY'. These are the only vaild options for this field. Character.
Amount: Mass of SAMPLE, STANDARD, QTY, or DUMMY in miligrams (mg). BLANK and ZERO can be 0.0 or blank. Numeric.
Is Ref _: Flag that identifies wheter this line line is for a reference gas peak (==1) or not (==0). Numeric.
Area 28: Peak area for mass 28 in Vs. Numeric.
d 15N/14N: Ratio of 15N to 14N in delta units relative to the reference gas (i.e., N2 tank). Numeric.
Area 44: Peak area for mass 44 in Vs. Numeric.
d 13C/12C: Ratio of 13C to 12C in delta units relative to the reference gas (i.e., CO2 tank). Numeric.

The remaining columns should be unchanged from what is created by IsoDat. There should be a total of 49 columns of data in the raw data file. Column names will be modified when imported by the function.

Usage

EA.NACHO(data.files, return.mass.percent.CN = T)

Arguments

`data.files`	Character vector that contains raw data file names with file path. If length is >1, then all the files will be combined and analyzed together using a single, combined calibration curve.
`return.mass.percent.CN`	Boolean to indicate whether sample mass data should be return as mass C or N as a percent of total sample mass. If FALSE, returned values are total mass of C or N in the sample.

Value

Dataframe of data for each unknown sample that includes following finalized values (i.e., what you want...):

d.13C.12C.VPDB: 13C:12C of bulk carbon in the sample in delta notation with units of per mil relatve to Vienna Pee Dee Belemite.
d.15N.14N.air: 15N:14N of bulk nitrogen in the sample in delta notation with units of per mil relatve to atmospheric air.
mass.percent.C: Percent carbon in the sample on a mass basis.
mass.percent.N: Percent nitrogen in the sample on a mass basis.