Barbara A. Doyle
        Spectroscopy has many applications in the industrial and consumer worlds.  This presentation will discuss the application of Spectroscopy on the industry of Toy Safety Testing.  The Spectroscopic methods of  X-Ray Fluorescence Spectroscopy (XRF) and Atomic Absorption Spectroscopy (AAS) will be presented with their specific applications to the testing of lead and phthalates in toys.  The site is organized with the same navigation bar at the bottom of each page that can lead to any part of the presentation Including this introduction, toy safety standards, sample preparation, each Spectroscopic method, conclusion and references.
        Toy safety is a great concern for most every parent, and these concerns have been brought to the forefront with all the recalls that have occurred over the last few years.  The use of lead paints in many products that are made in China have lead to many recalls.  Also the use of phthalates to soften the plastics used in manufacturing most toys is also of great concern.  This has lead to increased safety protocols for toy testing and numerous consumer groups that monitor them.  Health fairs now not only take your blood pressure but use portable XRF scanners to test children's toys on the spot.  There are even at home test kits now available to the public such as Abotex lead Inspector Kit,  Homex Lead Check and  Lead Check Household Lead Test Kit available for eight to twenty dollars.  These kits consist of a bottle of solution that is a lead indicator, swabbed on with a q-tip a change of color indicates the presence of lead.  This is great for surface testing but there could be more lead present in the material that constructs the toy as well. The sample preparation section will discuss how the toys are deconstructed and prepared for analysis.  Following find some of the effects of lead and phthalates that may effect children.

Lead is one of the most dangerous heavy metals. It is especially toxic to children damaging neuronal connections, causing brain and blood disorders.  Lead in the body inhibits cell function and can cause damage to kidneys, nervous system and red blood cells.  People with high levels of lead in their system can suffer from anemia, hearing loss, brain swelling, convulsions, coma and even death. Children are at the highest risk since they are the ones playing with the tainted toys and infants and toddlers are even more at risk since the tend to place everything in their mouths.  Symptoms that would show evidence of lead poisoning in children would be fatigue, headaches, stomach aches, muscle pain and behavioral problems.  Children may even display changes in their school performance and slow growth.

Phthalates are esters that are primarily used as plasticizers.  A Plasticizer is a substance that is added to a plastic to increase its flexability.
high doses have been shown to change hormone levels, cause birth defects, and damage liver and testes.  Phthalates have also been connected to higher percentages of allergies and asthma in children.  Infants are at a great risk for exposure since most teething rings and toys contain phthalates to make the plastics more malleable.

What is Spectroscopy?

        People have been studying light since the begining of time, earliest mention of these studies are about the refraction of light.  Ptolemy in 139 AD created tables on the reflection and refraction of light.  Theodoric of Freiberg in 1304 explained the refration of light in rain drops to create rainbows.  Royen around 1620 discovered the law of refraction and  in 1752 Melvill observed the first line spectrum.  In 1800 Hershal discovered Infrared, and the 19th century brought the discovery of ultraviolet light and the principles of interference of light.   Wave theory to explain diffraction was developed by Schwerd in 1835.  The first spectrometer was created in 1851 and emission lines of iron and copper were recorded.  Developments continued to progrss through the centuries to brig us to today's current methods (.  Specific histories will be incorporated on the XRF and AAS pages.
Spectroscopy is the study of light, the electromagnetic spectrum (pictured left) with its wide range of wavelengths and its interactions with matter.  Spectrometers measure the dispersion of light according to its wavelength, frequency and energy.  The dispersion is generally caused by a prism that is part of the spectrometer.  The spectrometer reads the emissions of this spectrum of diffracted light; these emissions then correspond to specific elements.  The collected data is then displayed as a function of intensity vs. energy, an example of a lead spectrograph using X-ray fluorescence is pictured right. 

        The energy from a photon is inversely related to its wavelength by the equation,  E = (hc)/λ.  E is the energy in photons measured in Joules, h is plank's constant, c is the speed of light, and λ is the wavelength in nanometers.  An inversely proportional relationship means the shorter the wavelength the higher the frequency and  vice versa. (pictured right) The energy of the incident light specifically excites the electrons of the atoms and takes them from their ground state to their excited state.  The energy associated with this change in state is the atoms ionization energy which is specific to each element.  As electrons fall back into the gaps created by these shifts light is emitted that reveals the ionization energies that identify the elements in the compounds.  This is how Emission spectroscopy works.  Absorption spectroscopy is the opposite, light is passed through a prism and through the sample, the emitted wavelengths are the ones not absorbed by the sample.  The elements in the sample can be identified by these missing wavelengths.      

http://www.files.chem.vt.edu/chem-ed/spec/spectros.html