ETX 102B Final

From Lectures Trace Metal Analysis to Guest Lectures

What is an essential metal?

inorganic metals that are critical for human health

__ metals are elements that are in high abundance

bulk

__ metals are elements that are in low abundance

trace

Select all that apply: What are the essential metal classifications?

a. must be present in human tissue

b. must be consumed via food

c. complete absence of metal causes irreversible damage

d. supplementing the metal can help regain losses to physiological function due to deficiencies

a,c,d

__ are metals that are helpful to human health but the absence of them do not result in negative or adverse effects

beneficial metals

Sr is a __ metal due to protecting against osteoporosis, and lack of element just decreases the efficiency, and does not cause irreversible damage.

beneficial

__ was thought to be an essential metal until 2011, when an in vivo study was conducted and proved that reducing its intake had no effect. It may also interefere with iron absorption.

chromium iii

Select all that apply: What are the primary routes of exposure of metals?

a. injection

b. inhalation

c. ingestion

d. eye contact

e. dermal

b,c,e

Absorption is dependent on the __ of the metal, such as particle size, solubility, and physical state

physiochemical properties

__ are the most toxic form of metals and under go redox reactions with proteins and other biological molecules

free ions

What are chelators and how do they function?

they are molecules that bind to free ions and act as a sink to prevent damages from metals

Select all that apply: What mechanisms of action do metals take in the human body during exposure?

a. undergo redox reactions with important biological molecules

b. replace essential metals and inhibit vital biochemical reactions

c. allocate nutrients to other parts of the body they are not needed at

d. create oxidative stress and damage proteins and DNA

a,b,d

Select all that apply: chromium iv is a carcinogen due to __?

1. increasing oxidative stress

2. breakage in chromosomes

3. DNA damage via adduct formations

4. denaturing proteins for DNA replication

1,2,3

__ get __ to Cr III and forms adducts with DNA.

Cr VI gets oxidized

__ binds to thiols and carboxyl groups of proteins and inhibits their function

lead binds to these molecules

people who are __ in Ca, Zn, and Fe are more at risk to lead toxicity

deficient in these elements

__ dose exposure is most associated with CNS damage

low dose exposure

__ dose exposure leads to symptoms called lead colic

higher dose exposure

__ dose exposure can lead to encephalopathy or brain dysfunction (coma, confusion, memory loss, changes in personality)

extreme dose exposure

__ is the detection and identification of low levels of metals in a sample in ppm, ppb, and ppt

trace metal analysis

fill in the blank: ___ is important for ICP-MS because it transforms solid metal into a liquid that can be dissolved in solvent and analyzed by the instrument

acid digestion

select all that apply: what acids are used to ICP-MS analysis?

a. HCl

b. HNO3

c. Acetic Acid

d. Formic Acid

e. HF

f. Water

g. H2SO4

a,b,e,f,g

fill in the blank: in an ICP-MS, a sample solution is pumped through a _____ as the carrier gas

a nebulizer using argon gas

What is the purpose of the spray chamber in an ICP-MS? What does it form and what function does it serve?

the chamber creates an aerosol cyclone that homogenizes small droplets and aerosols, then pumps the large droplets into the waste

__ is used to ionize a sample in ICP-MS through the steps of: desolvation, vaporization, dissociation, atomization, then ionization

argon plasma

the ion beam in ICP-MS is formed as unfiltered ions bombard _____, which uses small orifices, vacuum pressure, and voltage to guide the ions to the mass analyzer

ICP cones or apertures placed in front of the plasma

What mass analyzers can be paired with ICP for trace metal analysis?

1. single quad

2. triple quad

3. scanning electron multiplier

__ occurs when polyatomic compounds are formed from solvent or sample constituents that has also been ionized by the instrument

polyatomic interference

polyatomic inference can be mitigated by __:

a. adding a metal spike or ISTD to the sample

b. using a gas that reduces the KE of larger ions like He

c. use a more organic solvent

b. using a gas that reduces the KE of larger ions

__ is when diluted acidic samples are heated to high temps with a microwave and releases CO2 gas to reduce the polyatomic interference with carbon-based molecules

microwave digestion

select all that apply: what are the benefits to ICP-MS?

a. can detect nearly all elements

b. has low limits of detection that is precise and accurate

c. can be used to isotopic analysis

d. robust enough to use any phase of sample introduction (liquid, solid, gas)

e. fast and efficient

all of the above

which statement is not true regarding the differences between ICP-MS and ICP-OES:

1. ICP-MS offers significantly higher sensitivity and detection into the parts per trillion

2. ICP-MS is cheaper and reduces the potential for decontamination of sample

3. ICP-OES struggles to detect down to part per billion for most elements

4. ICP-OES does not require as much expertise and complex labs to operate as compared to ICP-MS

the false statement is 2. ICP-MS is cheaper and reduces the potential for decontamination of sample

select true statements regarding laser ablation ICP-MS:

a. laser bean focused sample surface

b. fine particles are generated and sent through for ionization

c. untral trace metal analysis capacity

d. little to no sample prep

e. used for biological imaging

all statements above are true regarding LA-ICP-MS