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USFS Durham Lab water analysis method detection limit (MDL) limit of quantification (LOQ), 2010 - present

General Information
Data Package:
Local Identifier:knb-lter-hbr.215.6
Title:USFS Durham Lab water analysis method detection limit (MDL) limit of quantification (LOQ), 2010 - present
Alternate Identifier:knb-lter-hbr.215
Alternate Identifier:DOI PLACE HOLDER
Abstract:

This dataset documents limits in the precision of water analyses produced by the USFS, NRS lab in Durham, NH. Generally precision of water analyses is limited at low concentrations due to limits of detection or limits of precise quantification.

These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.

Short Name:USFS Durham Lab analysis
Publication Date:2019-02-21
Language:English

Time Period
Begin:
2010-01-01
End:
2019-02-21

People and Organizations
Contact:Scott W. Bailey [  email ]
Creator:USDA Forest Service, Northern Research Station,  

Data Entities
Data Table Name:
USFS Durham Lab MDL LOQ, 2010 - present
Description:
USFS Durham Lab method detection limit (MDL) limit of quantification (LOQ), 2010 - present
Detailed Metadata

Data Entities

Data Table

Data:https://pasta-s.lternet.edu/package/data/eml/knb-lter-hbr/215/6/566a3f28c2e62b20eca5be93543b2db3
Name:USFS Durham Lab MDL LOQ, 2010 - present
Description:USFS Durham Lab method detection limit (MDL) limit of quantification (LOQ), 2010 - present
Number of Records:18
Number of Columns:3

Table Structure
Object Name:USFS_Durham_MDL_LOQ.csv
Size:315 byte
Authentication:b163a2e4cc5bedb2c896d6df72da7fda Calculated By MD5
Text Format:
Number of Header Lines:1
Record Delimiter:\r\n
Orientation:column
Simple Delimited:
Field Delimiter:,

Table Column Descriptions
 analyteMDLLOQ
Column Name:analyte  
MDL  
LOQ  
Definition:analytemethod detection limitlimit of quantification
Storage Type:string  
float  
float  
Measurement Type:nominalratioratio
Measurement Values Domain:
Definitionany text
UnitmilligramPerLiter
Typereal
UnitmilligramPerLiter
Typereal
Missing Value Code:      
Accuracy Report:      
Accuracy Assessment:      
Coverage:      
Methods:      

Data Package Usage Rights

This information is released under the Creative Commons license - Attribution - CC BY (https://creativecommons.org/licenses/by/4.0/). The consumer of these data ("Data User" herein) is required to cite it appropriately in any publication that results from its use. The Data User should realize that these data may be actively used by others for ongoing research and that coordination may be necessary to prevent duplicate publication. The Data User is urged to contact the authors of these data if any questions about methodology or results occur. Where appropriate, the Data User is encouraged to consider collaboration or co-authorship with the authors. The Data User should realize that misinterpretation of data may occur if used out of context of the original study.

While substantial efforts are made to ensure the accuracy of data and associated documentation, complete accuracy of data sets cannot be guaranteed. All data are made available "as is." The Data User should be aware, however, that data are updated periodically and it is the responsibility of the Data User to check for new versions of the data. The data authors and the repository where these data were obtained shall not be liable for damages resulting from any use or misinterpretation of the data. Thank you.

Keywords

By Thesaurus:
Hubbard Brook Ecosystem Studylimit of quantification, method detection limit, USFS Durham Lab

Methods and Protocols

These methods, instrumentation and/or protocols apply to all data in this dataset:

Methods and protocols used in the collection of this data package
Description:

Method detection limit (MDL) is defined as “…the minimum measured concentration of a substance that can be reported with 99% confidence that the measured concentration is distinguishable from method blank results” (EPA 2016). This information is applicable to determining the presence of contaminants in a water sample. But it is not useful for quantifying the precision of concentrations reported for naturally occurring solutes, particularly at levels near the MDL. A limit of quantification (LOQ) can be used to determine the minimum concentration that can be reported with some level of precision. This is sometimes taken as three times the MDL, although methods for setting this limit are not well standardized. We define the LOQ as the value above which analytical variability is within 10% of the measured value, as determined by standard solutions run as unknowns. For values above the LOQ, concentrations may be reported and interpreted with two significant figures. For values between the MDL and the LOQ, analyses are not repeatable within 10%, and could vary by 50% or greater. Concentrations below the LOQ are best interpreted to one significant figure. For calculation of solute fluxes, samples with concentrations less than MDL are assigned a value equal to ½ of the MDL. Samples with concentrations between the MDL and LOQ are assigned the measured value. Solute fluxes based on calculations where a substantial number of samples have concentrations less than the LOQ should be reported to only one significant figure and variations should be interpreted with caution.

Values of MDL and LOQ will vary as methods or analytical instruments are changed. There are also minor fluctuations year to year from minor variations in laboratory operating conditions. The limits documented here generally apply to water samples analyzed in the Durham lab starting June 1, 2010. Starting on June 1, 2013, the Durham lab took over analysis of the weekly precipitation and streamwater samples from the Hubbard Brook Experimental Forest. So this document applies to the long-term Hubbard Brook streamwater and precipitation chemistry datasets starting on that date. For QA/QC parameters of the earlier part of the Hubbard Brook long-term dataset, see Buso et al. 1999.

In the future, when major changes to procedures or instrumentation at the Durham lab alter MDL or LOQ, this data packaged will be updated to include revised values.

Buso, D. C, Gene E Likens, and J. S Eaton. 2000. Chemistry of Precipitation, Stream Water And Lake Water From The Hubbard Brook Ecosystem Study: A Record Of Sampling Protocols And Analytical Procedures. Newtown Square, PA: USDA Forest Service, Northeastern Research Station. General Technical Report NE-275.

EPA 2016. Definition and Procedure for the Determination of the Method Detection Limit, Revision 2. EPA 821-R-16-006.

People and Organizations

Publishers:
Organization:Hubbard Brook Ecosystem Study
Address:
234 Mirror Lake Road,
North Woodstock, NH 03262 United States
Creators:
Individual: USDA Forest Service, Northern Research Station
Contacts:
Organization:Scott W. Bailey
Address:
234 Mirror Lake Road,
North Woodstock, NH 03262 United States
Email Address:
scott.bailey@usda.gov

Temporal, Geographic and Taxonomic Coverage

Temporal, Geographic and/or Taxonomic information that applies to all data in this dataset:

Time Period
Begin:
2010-01-01
End:
2019-02-21
Geographic Region:
Description:Hubbard Brook Experimental Forest
Bounding Coordinates:
Northern:  43.959Southern:  43.914
Western:  -71.8062Eastern:  -71.7022

Project

Other Metadata

Additional Metadata

additionalMetadata
        |___text '\n    '
        |___element 'metadata'
        |     |___text '\n      '
        |     |___element 'unitList'
        |     |     |___text '\n        '
        |     |     |___element 'unit'
        |     |     |     |  \___attribute 'constantToSI' = '0'
        |     |     |     |  \___attribute 'id' = 'milligramPerLiter'
        |     |     |     |  \___attribute 'name' = 'milligramPerLiter'
        |     |     |     |  \___attribute 'parentSI' = 'kilogramPerCubicMeter'
        |     |     |     |  \___attribute 'unitType' = 'volumetricMassDensity'
        |     |     |     |___text '\n          '
        |     |     |     |___element 'description'
        |     |     |     |     |___text 'concentration unit, sometimes used for pigments in natural waters'
        |     |     |     |___text '\n        '
        |     |     |___text '\n      '
        |     |___text '\n    '
        |___text '\n  '

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