Standard curve shifting over time. How do I stabilise the ELISA?

24 February 2021 1,365 3 View

How does the injection volume impact LLOQ and ULOQ in regression analysis (LC-MSMS)?

Hello, I have run into an issue that has sparkled a debate at work: is the LLOQ/ULOQ impacted by injection volume under the following circumstances: 1) Same dilution factor of all samples 2)...

23 February 2021 9,159 3 View

Using the Pfaffl method: Is it possible that the ratio of the calibrator does not equal 1?

Hi all, I have a question regarding calculations using the Pfaffl method. I have 3 groups per experiment: 1 control group (calibrator) and 2 treatment groups with 6 to 7 biological repeats per...

19 February 2021 8,351 2 View

XRPD Quantification - Building a calibration curve of drug excipient?

I am aiming to utilise XRPD to quantify a drug excipient within a drug product and have been having a little trouble building the calibration curve to allow for this quantification up until this...

10 February 2021 6,145 3 View

Gain and offset values in Sentinel-2 L1C?

Hello everyone. I have been trying to apply radiometric calibration on Sentinel-2 L1C images (bands 2,3,4 and 8), but every time after layerstacking I come across this error: "Calibration...

28 January 2021 7,160 1 View

How can you confirm new liquid FTIR cell fits calibration?

We have an FTIR instrument which was calibrated in transmission/absorption mode using a set of cells for different ranges of D2O concentration. One of the cells at high range broke and the new one...

16 January 2021 4,791 2 View

Standard addition calibration without blank matrix available?

I have a problem of analytical chemistry. We are working on a spectroscopy technique (FTIR) for the quantification of a mineral phase in complex matrices. We intended to use chemometric techniques...

12 January 2021 7,739 1 View

How does the dilution of matrix-match calibrators impact the ionization in LC-MS/MS?

Greetings. I would like to get opinions from the experts for the improvement and optimization of multiple drug confirmation by LC-MS/MS. 1. One of our method calibration curves follows the...

10 January 2021 9,559 2 View

Do polymers with different chain lengths have UV-Vis absorption peaks at different wavelengths?

I have a sample of mixtures containing polystyrene microspheres (PS-MS) with 3 different diameter sizes (bought from thermo), they all contain a green fluorescent dye inside the polymer matrix /...

06 January 2021 2,218 5 View

How to develop mathematical model for Eye-Gaze tracking system?

Gaze tracking technologies are used in a wide variety of applications. Most gaze tracking systems require a personal calibration process where the user is instructed to gaze at certain points...

03 January 2021 9,675 5 View