Important Terms in AnaChem

Question 1

The difference between measured or inferred value and the actual value of a quantity

Answer 1

ABSOLUTE ERROR

Question 2

How close a given set of measurements (observations or readings) are to their true value

Answer 2

ACCURACY

Question 3

Portion of a solution subjected to analysis

Answer 3

ALIQUOT

Question 4

Component of interest in the sample

Answer 4

ANALYTE

Question 5

Extremely accurate laboratory balance created to precisely measure the mass of an object

Answer 5

ANALYTICAL BALANCE

Question 6

The science of inventing and applying the concepts, principles, and strategies for measuring the characteristics of chemical system and species

Answer 6

ANALYTICAL CHEMISTRY

Question 7

If the reagent also meets the requirements of the American Chemical Society Committee on Analytical Reagents: Chemicals suitable for laboratory and general use.

Answer 7

ANALYTICAL REAGENT GRADE CHEMICALS

Question 8

Defined as the estimate of the systematic error: the difference between the average of measurements made on the same object and its true value

Answer 8

BIAS

Question 9

A sample that contains all the components of the matrix except the analyte

Answer 9

BLANK

Question 10

The process of configuring an instrument to provide a result for a sample within an acceptable range

Answer 10

CALIBRATION

Question 11

A process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture such as a suspension

Answer 11

DECANTATION

Question 12

Sealable enclosures containing used for preserving moisture-sensitive items

Answer 12

DESICCATOR

Question 13

The range of concentrations an instrument can read, from the minimum to the maximum detectable

Answer 13

DYNAMIC RANGE

Question 14

Known data from a calibration standard and unknown data from the sample are combined to generate a quantitative report

Answer 14

EXTERNAL STANDARD METHOD

Question 15

Involves the comparison of the instrument responses from the target compounds in the sample to the responses of reference standards added to the sample or sample extract before injection

Answer 15

INTERNAL STANDARD METHOD

Question 16

Are errors other than random errors or systematic errors. They are often large and, by definition, unpredictable

Answer 16

GROSS ERRORS

Question 17

The lowest concentration that can be measured (detected) with statistical significance by means of a given analytical procedure

Answer 17

LIMIT OF DETECTION

Question 18

The lowest analyte concentration that can be quantitatively detected with a stated accuracy and precision

Answer 18

LIMIT OF QUANTIFICATION

Question 19

The measurement range over which we can be confident of a good measurement within the tolerances of the standard

Answer 19

LINEAR RANGE

Question 20

A mathematical technique for fitting an equation, such as that for a straight line, to experiment data

Answer 20

LINEAR REGRESSION

Question 21

Collection of all the components in the sample

Answer 21

MATRIX

Question 22

The sum of a group of measurements divided by the number of measurements; the average

Answer 22

MEAN

Question 23

Used to measure and dispense specific volumes of liquids

Answer 23

MEASURING PIPETTE

Mohr Pipette

Question 24

The middle value of a set of numbers

Answer 24

MEDIAN

Question 25

The curve in the upper surface of a liquid close to the surface of the container or another object, produced by surface tension

Answer 25

MENISCUS

Question 26

Detailed set of instructions for a particular analysis using a specified technique

Answer 26

METHOD

Question 27

A common laboratory instrument used to measure small amounts of liquids with a volume range between 1 and 1000µl

Answer 27

MICROPIPETTE

Question 28

The value that appears most often in a set of data values

Answer 28

MODE

Question 29

A document that contains information on the potential hazards (health, fire, reactivity and environmental) and how to work safely with the chemical product

Answer 29

MATERIAL SAFETY DATA SHEET (MSDS)

Question 30

A data point that differs significantly from other observations

Answer 30

OUTLIER

Question 31

The change in the apparent position of an object when viewed from different points

Answer 31

PARALLAX

Question 32

Refers to how close measurements of the same item are to each other

Answer 32

PRECISION

Question 33

Analytical reagent of exceptional purity that is specifically manufactured for standardizing volumetric solutions and preparing reference standards

Answer 33

PRIMARY STANDARD GRADE CHEMICALS ## Footnote The National Institute of Standards and Technology is an excellent source

Question 34

Set of written instructions on how to apply a method to a particular sample

Answer 34

PROCEDURE

Question 35

Set of written guidelines for the analysis of a sample specified by an agency

Answer 35

PROTOCOL

Question 36

Arise when a system of measurement is extended to its maximum sensitivity. It is caused by uncontrollable variable

Answer 36

RANDOM ERROR

Question 37

High purity chemicals for which no established specifications exist. Are often solutions or dilution of ACS Reagent materials. Suitable for commercial, industrial, and educational application

Answer 37

REAGENT GRADE CHEMICALS

Question 38

The ratio of the absolute error of a measurement to the measurement being taken

Answer 38

RELATIVE ERROR

Question 39

Samples of about the same size that are carried through an analysis in exactly the same way.

Answer 39

REPLICATES

Question 40

Process of collecting a small amount of a material whose composition represents the bulk of the materials being sampled

Answer 40

SAMPLING

Question 41

The capacity of an analytical process to produce signals which depend almost exclusively on the target analyte(s) present in the sample.

Answer 41

SELECTIVITY

Question 42

Ability to detect very low concentrations of a given substance in a biological specimen

Answer 42

SENSITIVITY

Question 43

An experiment measurement that is proportional to the analyte concentration

Answer 43

SIGNAL

Question 44

Chemicals that have been prepared for specific applications. This includes HPLC grade and spectrophotometry grade reagents

Answer 44

SPECIAL PURPOSE REAGENT CHEMICALS

Question 45

The assay's ability to detect the intended target

Answer 45

SPECIFICITY

Question 46

A measure of imprecision. It indicates the variability or dispersion around the mean; roughly the average distance of data from the mean

Answer 46

STANDARD DEVIATION

Question 47

Substances that are tested to be homogenous and have fixed values of its concentrations

Answer 47

STANDARD REFERENCE MATERIAL

Question 48

A consistent or proportional difference between the observed and true values of something

Answer 48

SYSTEMATIC ERROR

Question 49

Allows for you to account for only the weight of the substance being measured and not the vessel it's being measured in

Answer 49

TARE

Question 50

Chemicals that do not have established standards for purity levels or for products with <90%

Answer 50

TECHNICAL GRADE

Question 51

Chemical or physico-chemical processes that provide the basis for analytical measurements

Answer 51

TECHNIQUES

Question 52

Disposable plastic pipets used to transfer small volumes of liquids

Answer 52

TRANSFERRING PIPETTE

Question 53

Process of verifying that a procedure yields acceptable results

Answer 53

VALIDATION