Chem 113 Lab 2

to keep the pipet bulbs dry

what is this weeks special objective

atomic absorption spectroscopy

what technique is used to determine the presence and concentration of about 70 elements, based on the principle that ground state atoms will absorb light if specific wavelengths to reach excited states

AA spectrometer

what instrument carries out AA spectroscopy

atomized

before a sample is analyzed it must first be ….. or separated into induvial atoms

with a flame

how can a sample be atomized

hollow cathode lamp

The flame is therefore in alignment with a beam of light provided by a …….

monochromator

To accomplish this, the light that was not absorbed by the ground state atoms of interest is directed to a which ……… isolates the wavelength of light desired and directs this single wavelength of light to the detector

detector

photomultiplier tube (PMT)

The …… in our spectrometers is a …………… that can produce an electrical current that is proportional to the light intensity

absorbance

PMT produce an electrical current that is proportional to the light intensity. This current is then amplified and processed to produce a signal that can then be converted to a readout referred to as the ……….

analyte

When performing analyses like AA spectroscopy, it is important for the concentration of the …….., or substance of interest, to be within the detectable range of the instrument or method as there are lower and upper limits of detection

Standards

…….. are a set of solutions with a range of known concentrations of the analyte of interest

blank

A …… is a solution that does not contain the analyte

calibration curve

A ……… is a linear graph that is used to determine the concentration of an unknown in a sample.

independent is x

dependent is y

A calibration curve is prepared using three or more standards.

label the x and y axis with independent and dependent variable

trendline

A ……… or best-fit line is added

parts per million

when the concentration of a solute is very small, the mass percent is very small. In these situations, chemists use ……… instead find to be more useful.