13-mineral Flashcards
what are the minor components?
Minerals, vitamins and organic acids, enzymes and alcohols,Nutraceuticals
ex of Nutraceuticals
( e.g. phenolic compounds, pigments such as anthocyanines, some fatty acids, some peptides).
what is the classification based on?
distribution and amount of component
what is mineral?
inorganic species or substances that are of neither animal nor plant origin (i.e., natural compounds generally not containing a C, H, O, or N skeleton).
mineral don’t contain?
CHON skeleton
what are the dietary macro mineral?
Calcium (Ca) Magnesium (Mg) Sodium (Na) Potassium (K) Phosphorus (P) Chlorine (Cl) and Sulfur
how much does dietary macro mineral need daily?
more than 100mg/day by adult
ex of Food safety- contamination or adulteration
siliceous matter in grains/cereals. Sea food contamination with heavy metal
ex of food fraud?
vege protein VS animal protein
which mineral need to be labled?
The Food and Drug Regulations mandated labeling of Sodium, iron, and calcium contents
why label Ca Na AND Fe
their important roles in controlling hypertension, preventing anemia, and impeding the development of osteoporosis.
Fortification of some foods has allowed addition of ___?
minerals above levels ever expected naturally.
ex of fortification
1- Prepared breakfast cereals often are fortified with minerals such as calcium, iron, and zinc.
2- Fortification of salt with iodine.
3- Salt is added as a preservative; this increases significantly the sodium content in foods such as processed meats, pickles, and processed cheese.
list 4 classification
macromineral
trace mineral
ultra trace mineral
heavy metal
what is macromineral
required at more than 100 mg per day by the adult.
what is trace mineral
are required in milli- or microgram quantities per day
what is ultra trace mineral
are being investigated for possible biological function, but they currently do not have clearly defined biochemical role
what is heavy metal
toxic to the body
list 7 macromineral
P,Ca, S,Cl,Na,K,Mg
list 10 trace mineral
Fe,Zn, I,Cu, Cr, manganese, molybdenum, fluoride,
selenium, and silica.
list 4 heavy metal
Lead, mercury, cadmium, and arsenic.
evaporate whole milk has ___ calcium content, butter with salt has ___ calcium content
high
low
5 method to analysis food minerals
1- Potentiometry using ion-selective electrodes (ISEs)
2- Anodic stripping voltammetry (ASV)
3- Titrimetry
4- Colorimetric methods or spectrophotometry methods.
5- Instrumental methods:
what does Potentiometry use and base on?
ISE
Based on a sensor (transducer) that specifically bind to the dissolved ions to produce electrical potential
what does Anodic stripping voltammetry (ASV) involve?
involves (i) pre-concentration of a metal phase onto a solid electrode surface or into Hg (liquid) at negative potentials and (ii) selective oxidation of each metal phase species during an anodic potential sweep. Depending on the type of metal ions present, the current will change when increasing potential is applied to the electrode.
e.g. of titrimetry
(e.g. EDTA Complexometric Titration and Precipitation Titration).
which 2 method does instrumental method contain?
atomic absorption Spectroscopy AAS
atomic emission Spectroscopy AES
what 3 methods does AAS has
a- Flame Atomic Absorption Spectroscopy (FAAS).
b- Graphite Furnace Atomic Absorption Spectroscopy (GFAAS). c- Cold Vapour Atomic Absorption
what 3 methods does AES has
a- Flame Atomic Emission Spectroscopy (FAES)
b- Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) c- Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES)
what is EDTA Complexometric Titration used for
testing
hardness of water
The hexadentate ligand ethylenediaminetetraacetate (EDTA) forms __?
stable 1:1 complexes with numerous mineral ions.
how is endpoint detected?
using mineral chelators that have coordination constants lower than EDTA (i.e., less affinity for mineral ions) and that produce different colors in each of their complexed and free states.
___ and ____ are such indicators that change from blue to pink when they complex with ___ or ___.
Calmagite and Eriochrome Black T (EBT) are such indicators that change from blue to pink when they complex with calcium or magnesium.
Calmagite and Eriochrome Black T (EBT) are such indicators that change from ___ to ___ when they complex with calcium or magnesium.
Calmagite and Eriochrome Black T (EBT) are such indicators that change from blue to pink when they complex with calcium or magnesium.
____ and _____ are such indicators that change from __ to ___ when they complex with calcium or magnesium.
Calmagite and Eriochrome Black T (EBT) are such indicators that change from blue to pink when they complex with calcium or magnesium.
The endpoint of a complexometric EDTA titration using either Calmagite or EBT as the indicator is detected as the color changes from __ to ___.
pink to blue.
write down the equation
Sample with Ca or Mg+ calmagite in pH10 will get pink complex
pink complex +EDTA form Blue complex
steps of EDTA Complexometric Titration
1- Prepare 0.036M EDTA solution.
2- Prepare ammonia buffer. Mix of ammonium hydroxide and ammonium chloride (pH 10-11).
3- In a 250ml Erlenmeyer flask add 50ml of milk, 3ml ammonia buffer and few drops of calmagite indicator.
4- Titrated with EDTA solution.
what is the usage of ammonia buffer
- To maintain pH of solution at pH10 ± 0.1.
- Improve the stability of EDTA-Metal ion complex
- Improves the sharpness of endpoint
- Make sure pH does not exceed 11 as Ca and Mg will precipitate as hydroxides.
Calmagite Indicator: ( Analysis of ?
calcium and Magnesium in milk)
why pH should not excess 11?
Ca and Mg will precipitate as hydroxides.
the principle of precipitation?
- When at least one product of a titration reaction is an insoluble precipitate, it is referred to as precipitation titrimetry.
The Mohr method for ____ determination is a ____titration method.
chloride
direct or forward
Mohr method based on?
the formation of an orange-colored solid, silver chromate, after silver from silver nitrate has complexed with all the available chloride.
write down the equ of Mohr method
AgNO3 + Cl–> AgCl + NaNO3 ( until all Cl- complexed)
2Ag + K2CrO4–> Ag2CrO4 (Orange only after Cl- is all complexed)
all Cl need to be_?
complexed
write down the steps ofMohr Method Steps to determine chloride in butter:
1- Weigh about 5 g of butter into 250-ml Erlenmeyer flask and add 100 ml of boiling H2O.
2- Let it stand for 5–10 min with occasional swirling.
3-Add 2 ml of a 5% solution of K2CrO4 in H2O.
4 Titrate with 0.1 N AgNO3 until having an orange-brown color.
what does Volhard method measure?
Chloride determination
what does volhard method belong to?
precipitation titrmetry, analysis food mineral
what is the basic prinicple of volhard method?
The sample is added with AgNO3 where AgCl is precipitated out and excess of AgNO3 remains. We are measuring moles of AgNO3 left behind in the subsequent steps
volhard method Mostly used for determining __?
salt in high salt products
volhard:The sample is wet-ashed with __? why?
HNO3 (to digest organic matter)
volhard: The excess AgNO3 is back titrated with ___, using ___ as indicator
Potassium thiocyanate(KSCN), using ferric ammonium sulfate as indicator
volhard: write down the reaction equ
Ag+ + Cl- –>AgCl
Ag+ +SCN- —>AgSCN
SCN- +Fe3–>FeSCN2+
why add SCN-?
to quantitate silver not complexed with chloride
what color will show when there is any SCN that is not complexed to Ag+ after all the Ag+ ions are depleted
red
volhard: write down the pathway
sample+AgNO3–> AgCl + excess AgNO3+ organic compound
Wet wash with HNO3
get AgCl+ excessAgNO3
add FeNH4(SO4)2 12H2O as an indicator
back-titration with KSCN
ferric thiocyanate FeSCN2+ is the end point orange color
volhard:-The volume of AgNO3 solution added must be in ___ of that required ?why ?
excess
to react with the chlorides in the sample.
volhard: what is an indicator?
Ferric ammonium sulfate (FeNH4(SO4)2)
volhard: what is the titration solution?
back-titrate the excess AgNO3 with potassium thiocyante (KSCN) solution.
volhard: what indicator as endpoint?
The FeNH4(SO4)2 reacts with an excess of thiocyanate (when all the Ag ions from AgNO3 are used up), forming the salmon colored complex, ferric thiocyanate FeSCN++, indicating the end point.
what is the sequence of adding solution in volhard method? why?
The AgNO3 solution must be added first, followed by the concentrated HNO3. This order of addition is critical to ensure complete precipitation of the chlorides.
what if HNO3 is add fist?
chloride loss by volatilization as HCl could occur because HCl has a higher vapor pressure than HNO3
HCl has ___ vapor pressure than HNO3?
higher
what are chromogens?
chemicals, form colored product with compound reaction, selective react with a wide variety of mineral
-Each chromogen reacts with its corresponding mineral to produce a___product that can be quantified by____ .
Soluble colored
absorption of light at a specified wavelength
e.g. of chromogen
Alizarin 3-sulphonate for calcium determination
Calcium ions and 0-cresolphthalein forms red complex under alkaline (pH>12) Ferrozine and Ferene-S for Iron
what can be used for calcium determination? what is the color?
Alizarin 3- sulphonate
purple
what can be used for iron determination? what is the color?
ferrozine
ferene-S
Blue
__ ions and ___forms __ complex under __(pH>12)
Calcium ions and 0-cresolphthalein forms red complex under alkaline (pH>12)
how to determination iron in meat
By reacting (Ferrous) iron2+ with o-phenanthroline to form an orange-red complex ion Ferrous tris-o-phenanthroline
what is AAS
atomic absorption spectroscopy
what is AES
atomic emission spectroscopy
what does AAS have
FAAS
CVAAS
GFAAS-graphite furnace
what does AES have
FAES
ICP-AES
ICP-OES
inductively coupled plasma
Atomic spectroscopic methods are based on the measurement of the ____or ____ of the measured element in a sample.
electromagnetic radiation absorbed or emitted by the atoms of the measured element in a sample.
AAS:Atomic absorption spectra are produced when ____absorb energy from a ___
ground state atoms (or ions) radiation source
AES:Atomic emission spectra are produced when ____
emit energy on returning to the ground state or a lower energy state.
excited neutral atoms
emit energy
why are Atoms absorb or emit radiation of discrete wavelengths ?
because the allowed energy levels of electrons in atoms are fixed (not random).
Atomic spectroscopy requires that ___ of the element of interest be in the ___ state (not combined with other elements in a compound)
and that they be well separated in space.
atoms
atomic state
In foods, virtually all elements are present as ___and, therefore, must be converted to ___before atomic ___ or ____measurements can be made.
compounds or complexes neutral atoms (atomized) absorption or emission
what do atomization do?
separating particles into individual molecules (vaporization) and breaking molecules into atoms.
how to do atomization?
exposing the analyte (the substance being measured) to high temperatures in a flame or plasma although other methods may be used.
what analytical can be used when the source of enerzy for atomization is flame electrothermal ,the atomization temp is 1700-3150?
AAS
AES
what analytical can be used when the source of enerzy for atomization is flame electrothermal ,the atomization temp is 1200-3000?
GFAAS
what analytical can be used when the source of energy for atomization is inductively coupled argon plasma ,the atomization temp is 6000-7000?
ICP-AES
ICP-MS
RANK the sensitivelty of diff methods
GFAAS
based on the color of fire, __ can be test?
metal ion
when heated, the e- in metal ion gain energy and go to higher energy level. it is energetically ____, so the e- fall back, release energy. the energy release as ____
unstable
light energy
- Absorption spectroscopy- atoms ____ light
absorb
Emission spectroscopy- ions ___light (at very high temperature)
emit
2 way of atomization
ion–>atom–>gas
solution–> solid–> gas–>atom–>ion
