Posted in Yahoo Answers on Jun 21, 2007
“What is the response factor in chromatography?” is a question on Yahoo Answers.
So far there has been two answers:
1) A wordy and a bit confusing text book reply tailored more towards Gas Chromatography.
Response Factor
The size of a spectral peak is proportional to the amount of the substance that reaches the detector in the GC instrument. No detector responds equally to different compounds. Results using one detector will probably differ from results obtained using another detector. Therefore, comparing analytical results to tabulated experimental data using a different detector does not provide a reliable identification of the specimen.
A “response factor” must be calculated for each substance with a particular detector. A response factor is obtained experimentally by analyzing a known quantity of the substance into the GC instrument and measuring the area of the relevant peak. The experimental conditions (temperature, pressure, carrier gas flow rate) must be identical to those used to analyze the specimen. The response factor equals the area of the spectral peak divided by the weight or volume of the substance injected. If the technician applies the proper technique, of running a standard sample before and after running the specimen, determining a response factor is not necessary.
2) This cute answer is from “Alright22” who obviously had “hands-on” experience with chromatography – thin-layer chromatography of M&M candies.
It depends on the experiment. If you rub a green m & m into a solvent and place the filter into the solvent, the dye used to make the green will soak into the filter into bars of yellow and blue, and thus you will prove they are using yellow and blue dye to make green tints on m & ms. The response factor may be how quickly the result appears, or how much evidence is revealed, or how long the experiment will take.
So far these are all the answers received. Let’s see if anybody else would shine more light on the response factor in chromatography.
hi..
how do you identify triglycerides (by HPLC) using the fames analysis from gc??
thank you..
please reply
Could anyone please help me in calculation for diluting internal standard for biodiesel analysis using GC-MS? should the concentration be in ppm? I am doing the enzymatic method for ethyl ester analysis. Please let me know around what range should be my internal standards?
thanks
how we prepare pH 7.0 buffer solutions?
take 7.0buffer tablet n dissolve in 100ml of milli-Q water
HI EVERYBODY
I WANT TO KNOW THE CALCULATION OF HEIGHT OF PEAK.IF I HAVE THE DATE OF RELETIVE RESPONCE FACTOR,RELETIVE RETENTION TIME,% LIMIT.SO CAN I FIND THE HOW MANY PEAK WILL GIVE IN GHROMATOGRAM BY USING THIS VALUE.
THANK YOU
What is the Importance of RF in chromatography and difference between RF & RRF.
Hello Everybody,
Right now I know the RRF value of drug.
In quantitative calculation wheather i have to multiply or divide?
WHY WE USE RF VALUES FROM 0.2 TO 5.0
1. Definition of relative response factor :
A measure of the relative response of the instrument detector to an analyte compared to an internal or external standard. Relative Response Factors are determined by the analysis of standards and are used to calculate the concentrations of analytes in samples. The RRF can be calculated using the following equation:
RFF = (Ac x Cis)/(Ais x Cc)
where,
RRF = Relative response factor
Ac = Area of the target analyze
Ais = Area of the corresponding internal standard
Cis = Concentration of the corresponding internal standard
Cc = Concentration of the target analyte
Dear, All
If u want better clarification on RF & RRF read once B.P
Dear, All
If want better clarification on RF & RRF read once B.P
dear sir, I want to know actual response of a known impurity in my sample. is there any relation between RRF & area percent of that impurity obtained in the sample?
caffiene,
it gives multi wavelength responce like 205,245,273 nm
it gives two maxima and one minima wave lengths.
How do you calculate peak area when given
time
Height (mAU)
Area (mAU.min)
Area %
In relation to HPLC
thanks
pl.dont calculate response facotr.dont take any type of tension.cool & enjoy urself.
Dear sir,
please help me.
I want quntitive of response factor 1,3 butadiene relative of vinyl actylene in gc .
for example if RF 1,3 BD 4.2
Vinyl actylene (1-butene-3-yne)= ???
thanks
Dear sir,
I’ve been doing a research about caffeine in certain brands of coffee using GC/MSD. The problem is that i don’t know how to calculate the amount of caffeine using the area that obtained from GC/MSD. How am i going to calculate the amount of caffeine?? What information should i have? And what formula should i use? Please help me. Please3…
why use caffiene for hplc calibration
We calculate RF in calculation sheet as multify the given RF Value.
Respcted sir
I want to know about response factor and validation of analytical methods calculations.
please help me.
i want calculation of response factor in gc .
thanks
how i calculate response factor in hplc ?
how i calculate response factor in HPLC
Internal standard how much do i put and why , how do i choose the internal standard . I am working on identifying the volatile constituents of some fruits and their quantities using GC and HPLC . how do i kno which internal standard and what quantities of it should i use .
what is the difference between response factor and correction factor?
if g.c gives H2S results in say 15 ppmv how can we convert it into ppmw please help me
Hi every body,
I need help in HPLC, actually I am trying to find retinol in serum on HPLC.
I am using Retinyl acetate as my internal Standard. Can anyone tell me the stepwise procedure to find the concentration of retinol after I get the responce by Height and Area.
Thanks.
Umesh,your information is insufficient.
hello everybody, just want to ask how to determine final concentration using gc:
given data
initial concentration 0.8mg/L
R time= 2.141
Area= 2413613
dear sir, i have querry of rf i n pcb analysis. my boss has given data and he told me find conc. and responce factor.
data is—
rt–3.296
responce—-7409031
shift—–0.002
conc——
answer me about this resonce factor. injected amount 0.2 micro-litre.
second
okndtaqutdutyigvwell, hi admin adn people nice forum indeed. how’s life? hope it’s introduce branch ;)
What if you have areas of everything but no concentrations. I have volumes but usually in our lab if req’d to use density they provide it. That’s the path I’ve taken so far but it seems a little, to quote one of my fav cartoons, janeky.
Matt is on the correct path but has the equation set up incorrectly.
Response Factor (RF)= (Response(area) of Standard)/(Concentration of Standard)
Therefore,
Analyte(sample) Concentration = (Response of Analyte)/RF
These equations can be used to determine analyte concentration over a linear concentration range using chromatographic methods (e.g. HPLC, GC, etc). A calibration curve must be created to determine linearity over the desired concentration for each analyte being quantified.
Hi Bethany,
Thanks for you observation but I think Matt was right and has given an explicit equation for response factor calculations involving an internal standard.
The equation above should read:
analyte conc = (analyte response x IS conc)/(IS response x avg RRF)
response factor (RF) = concentration/response.
(In GC the response is usually the area below a peak)
rearranging the equation gives you the concentration:
Conc = RF x Response
BUT: The RF may change for different concentrations. That is why you need to make a calibration curve. If the curve is linear then you can use the average of the response factors to calculate the conc. If the curve is non-linear (e.g. quadratic) You will need to use a quadratic equation that describes the line of best fit through your data to calculate the conc.
If you are using internal standard, the relative response factor (RRF) is the ratio of the response factors of the internal standard (RFis) and the analyte (RFa)
RRF = RFa/Ris
To determine analyte concentration for linear data:
analyte response x IS conc.
analyte conc. = _______________________
IS response x average relative RF
(where the average RRF is found from your calibration curve)
if the response of your analyte increases relative to your IS the concentration increases, BUT if the response of your IS and analyte decrease or increase EQUALLY (e.g. due to changed instrument conditions) then the concentration stays the same. In this way IS compensates for method variability
Suppose you give one rupee alms to five beggars,the response of these beggeres will be different for this same action,at a given time depending on the need .Now if we need to quantify this reaction, into a measurable quantity and then compare we use what is called as response as factor
response factor in HPLC & GC
please send me reply
The response factor is simply the ratio of concentration of analyte to the area (of the peak in a chromatogram) produced by that concentration, that is to say F=C/A. Response factors can be used in conjunction with an internal standard whose response factor has already been quantified previously in a dedicated chromatographic run.
IT’S WRONG………………RESPONSE FACTOR=RESPONSE/CONCENTRATION