Analytical Chem Terms Quiz

Raw Data

Individual measurements obtained directly from the instrument without any treatment

Results

What we report (mean, standard deviation, CI) after apply statistics to treated data

Treated Data

Concentrations or amounted of found by applying a calibration procedure

Matrix

Everything in the sample other than the analyte

Spike

Known amount of the analyte added to the sample to insure proper instrument response (fortification)

Internal Standard

A compound different from the analyte that is added to the matrix as a reference

Sensitivity

The slope of the analytical calibration curve

Selectivity (specificity)

The ability of an analytical method to distinguish analyte from everything else that might be in the sample

False Positive

An analyte signal exceeds the legal limit even though low or no analyte is present

False Negative

Analyte signal reads below the legal limit even though analyte is above the limit

SOP

Written procedure for how a particular analysis should be performed (steps of procedure)

Use Objectives

Statements of purpose for which the results will be used

Method Blank

A sample containing all components except analyte, and it is taken through all the steps of the analytical procedure

Field Blank

A sample without any analyze that has been exposed to the site of sampling

Reagent Blank

A sample containing all components except analyte, but it has not been subjected to all sample preparation procedures

Calibration Curve

Plot of signal response of the analyte vs known analyte concentrations

Standard Addition

Known quantities of analyte are added to the unknown sample.

Chain of Custody

Who handled the sample and how it was handled from the time the sample was obtained to the time of measurement

Robustness

The ability of an analytical method to be unaffected by small changed in operating parameters

Limit of Detection

Smallest quantity of analyze that is “significantly different” from the blank 3s/m

Limit of Quantitation

Smallest amount measured with reasonable accuracy 10s/m

Accuracy

Determined by blind samples, calibration checks, fortification, and blanks

Analyte

The component you want to measure in a mixture

Linearity

How well a calibration curve fits a straight line.

Reporting limit

When the analyte detected reaches above a predetermined level it must be reported

Linear Range

Concentration interval over which the calibration curve is linear

Dynamic Range

Concentration interval over which there is a measurable response to the analyte

Range

Concentration interval over which linearity, accuracy, and precision are all acceptable

Instrument Precision

Repeatability observed when the same quantity of one sample is repeatedly introduced (>/ 10 times) into an instrument

Intra-assay Precision

Analysis of aliquots of a homogeneous material several times by one person on one day with the same equipment

Intermediate Precision

Formerly called “ruggedness”. Variation observed when an assay is preferred by different people on different instruments on different days in the same lab.

Inter-laboratory Precision

Aliquots of the same sample are analyzed by different people in different laboratories

Specifications

Statements about how good the numbers need to be and what precautions are required in the analytical procedure

Assessment

Process of collecting data to show proper operation and verifying objectives are met

Matrix Effect

A change in the analytical signal caused by anything in the sample other than the analyte

Standard Uncertainty

Standard deviation of the mean

External Standards (Standard solutions)

Set of solutions containing a series of known quantities of analyte

Control Charts

Visual representation of confidence intervals for a Gaussian distribution