12-CHO Flashcards
what are the 4 physical methods?
Refractometry
Hydrometery
Pycnometery
Polarimetry
what are the 5 methods of analysis CHO?
chemical physical enzymatic instrumental immunoassay
what are the 3 methods of chemical?
cholorimetric
titration
gravimetric
what are the 4 methods of instrumental?
chromatography
NMP
electrophoresis
IR
what are the 3 methods of colorimetric methods?
phenol sulfuric acid
anthrone
somogyi-nelson
what is the method of titration?
lane-eynon
what is the method of gravimetric?
munson-walk
what does Refractometry based on?
refractive index: The absolute refractive index of a medium is the ratio of the speed of light in vacuum relative to the speed in the medium.
The absolute refractive index of a medium is the ratio of ?
the speed of light in vacuum relative to the speed in the medium.
When a beam of light is passed from one medium to another and the ____ of the two differs, then the beam of light is ____or refracted.
density
bent
what is the principle of refractometry?
snell’s law
what does snell’s law state?
Snell’s law states that the ratio of the sines of the angles of incidence and refraction is equivalent to the ratio of phase velocities in the two media
n1 * sinα = n2* sin β
n1= refractive index of medium 1
n2= refractive index of medium 2
Refractive index is a characteristic property of a _____?
liquid
what does Refractive index of a solution related to ?
the density of the solution.
what does Refractive index of a solution depend on ?
the concentration of the solution, temperature and wavelength.
the refractive index of pure water is?
η20 = 1.33299
what does additional sugar in water change?
the density of water, leads to change refractive index (η)
what does the RI of a solution increase with concentration been used in?
analysis total soluble solids of CHO-based food such as sugar syrup, fruit product, tomato products.
where can refractometer used in?
in a liquid processing line to monitor the Brix of products such as carbonated soft drinks, dissolved solids in orange juice, and % of solids in milk.
what can refractometer monitor?
the Brix of product
give ex of the brix of product
carbonated soft drinks
dissolved solids in orange juice
% solid in milk
what are 3 types of refractometer?
abbe–handheld–benchtop
digital
what is the adv of benchtop abbe refractometer? disadv
wider measurement range
more precision
less portability携带性
what is the principle of hydrometry?
Is based on Archimedes’s principle, which states that a solid suspended in a liquid will buoyed by a force equal to the weight of the liquid displaced.
In other words, an object displaces a weight of liquid equal to its own weight.
what does hydrometry based on?
Based on displacement of a liquid by a floating body.
hydrometry: wt of an object=?
wt of the displaced liquid
hydrometry: wt=__x___
volume x density
V X D object=?
V X D displaced liquid
what does hydrometer measure?
specific gravity
specific gravity= ___/____
density of liquid/ density of water
what does lactometer used to determine?
the density of milk
what does baume hydrometer used to determine?
the density of salt solution
what does alcoholometer used to determine?
the alcohol content of beverage
what does brix hydrometer (saccharometer) used to determine?
sugar solution e.g. fruit juice, syrup
– sucrose content in solution
to measure the density of milk, which hydrometer can be used?
lactometer
to measure the sucrose content in solution, which hydrometer can be used?
saccharometer/ brix hydrometer
to measure the density of salt solution, which hydrometer can be used?
baume hydrometer
to measure the alcohol content of beverage, which hydrometer can be used?
alcoholometer
what is Brix?
a percentage of sucrose by wt. in a solution.
=% sucrose
what does one degree Brix equal?
1g sucrose in 100g solution
what does Brix reporesent?
the strength of the solution as percentage by mass.
what does 20O brix equal?
20% sucrose
what does pycnometery based on?
measuring specific gravity, but not directly
specific gravity= __/___=____/_____
specific gravity= density of liquid/ density of water= W/V of liquid/ W/V of water
what are the steps of pycnometery?
w1-empty pycnometer
w2-fill it with water
w3-fill it with liquid
w3-w1/w2-w1=SG specific gravity
what kind of molecue have the ability to rotate plane polarized light?
molecules contain an asymmetric carbon atome (chiral molecules)
what ability does optical active substance have?
rotate the polarized light.
why are sugar optical active?
they are chiral
is sugar optical active or not?
optical active
how many asymmetric carbon atoms does glu have? and their mirror images can/cannot superimpose!!
Glucose has four asymmetric carbon atoms and their mirror images cannot superimpose!!
polarimeter is used to measure?
optical activity
light source–> ______—>sample—>________
light source–>fixed polarizer—>sample—>moveable polarizer
what does polarizer absorb?
one component of the polarization but not the other
the input is natural light, what is the output?
polarized light
what are the 3 type of polarized light?
linear, circular, elliptical
how does the polarized work? to get input natural light, output polarized light?
dichroism
reflection
scattering
what is dextrorotory?
when the plane of polarized light is rotated in a clockwise direction when viewed through a polarimeter.
(+) or (d) do not confuse with D
what is levorotatory?
when the plane of polarized light is rotated in a counter-clockwise
direction when viewed through a polarimeter.
(-) or (l) do not confuse with L
what does (+) or (d) represent?
dextrorotatory
what does (-) or (l) represent?
levorotatory
what is specific rotation?
the angle of rotation of plane polarized light by a 1.00 gram per cm-3
sample in a 1 dm tube.
write the equation of specific rotation
[α ]T,D (T= temperature, D = sodium lamp).
what is rotation related to?
number of molecules in the solution, which is concentration in g substance/ 1 cc solution.
[α]D=?
α/I*d
α/I*d, what is each one represent?
α=observed rotation
I=length dm
d=concentration g/cc
[α ] 20D (+)-alanine =
+8.5
[α ] 20D (-)-lactic acid =
-3.8
[α ] 20D (+)-glucose =
+52.5
[α ] 20D (+)-sucrose =
+66.5
[α ] 20D (-)-fructose =
-93
what method can use to specific analysis of mono-oligosaccharide?
- enzymatic method
2. chromatographic method
what does carrez treatment used to?
Breaks emulsions, precipitates proteins, and absorbs colors from food products prior to enzymatic determination of carbohydrates
enzymatic method use ____ treatment to prepare sample?
carrez
write down the steps to prepare sample in enzymatic method
add potassium ferrocyanide add zinc sulfate ZnSO4 add sodium hydroxide filtration suspension use clear suspension for enzyme-catalyzed assay
which 3 reagent need to add for prepare enzyme sample?
potassium ferrocyanide
zinc sulfate
sodium hydroxide
ex of enzymatic methods
GOPOD method
glucose oxidase/ peroxidase/dye
what does glucose oxidase do?
oxidizes d-glucose quantitatively to d-glucono-
1,5-lactone and hydrogen peroxide
how is D-glu measured?
from H2O2 generated using peroxidase that turns a colorless compound (a leuco dye) to a colored
compound
H2O2+ colorless dye—(with peroxidase)–> colored compound +2H2O
how is the colored compound measure?
spectrophotometrically
give an ex of peroxidase turns color
dye 4 amino-antipyrene producing red quinoeimine in presence of H2O2 and peroxidase)
another ex of enzymatic method can treat
starch
is enzyme resistant starch detected?
no
Purity of enzyme used is _____
critical
Presence of cellulases, invertase, sucrase, β-glucanase releae D-glucose from other than starch (false ____ value)
high
what can catalase do? cause?
destroy the hydrogen peroxide, false low value
write down treat the starch steps
- starch gelatinize in hot DMSO
- get starch solution, then digest with a-amylase, which is 1,4-linked a-d-glucopyranosyl unit
- get linear and branched fragment of amylose and amylopectin
- digest with glocoamylase get D-glucose
- add GOPOD reagent to see the color
which linkage is a-amylase?
1,4-linked a-d glucopyranosyl unit
D-glu add ______ to see the color
GOPOD reagent
what are the cons of enzymatic methods
- need clear solution
- optimum condition- buffer, ph ,temp
- possible interference from other components
what are the pros of enzymatic methods?
- higher specificity
- don’t need high purity of the sample
- low detection limits
- don’t need expensive equipment
- easy automated
- commercially available kits
do enzyme method need high purity sample?
no
do enzyme method need clear solution?
yes
do enzyme method need optimum condition- buffer, ph ,temp?
yes
what is chromatography used for?
specific carbohydrate analysis
give 2 ex of chromatography
HPLC high performance liquid-c
GC gas-c
describe GC, how GC analysis cho?
Qualitative and quantitative analysis of carbohydrates
write down the 2 detector?
FID-flame ionization detector
MS-mass spectrometric
Sugars must be converted into _________
Reduction of _____groups to _______groups and conversion of the ______ (alditol) into ________ esters
- -volatile derivatives
- -aldehydic groups to primary hydroxyl groups
- -conversion of the reduced sugars (alditol) into volatile peracetate esters
HPLC: can use for what kind of analysis?
quantitative-peak integration
qualitative- identify cho
HPLC: adv
- relatively faster
- possibility of wide range of sample concentration
- high degree of precision and accuracy
what can AE-HPLC coupled to an ECD used for?
detection and quantification of carbohydrate from complex mixtures
Selection of mobile phase, column (usual one as anion exchange (AE)) and detector (pulsed electro chemical detector (ECD)) may depend on?
the specific carbohydrate analyzed
the specific carbohydrate analyzed can decide?
Selection of mobile phase, column (usual one as anion exchange (AE)) and detector (pulsed electro chemical detector (ECD))
how to detect and quantify cho from complex mixture?
AE-HPLC coupled to an ECD
what is HPAEC
high performance anion exchange chromatography
what is TLC
thin layer chromatography
