Analytical Chemistry

Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial... | Contact experts in Analytical Chemistry to get answers

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Questions related to Analytical Chemistry

How to prevent yellowness?

What are some ways to prevent yellowness from MDI when synthesizing thermoplastic polyurethane? It will change color over time after synthesis.

06 October 2021 6,410 5 View

I am preparing polyester polyol based rigid polyurethane foam. After casting, its outer skin peels off. How can I get shiny, hard and uniform surface?

I am working on polyester polyol based rigid polyurethane foam. I am trying to develop a polyol using castor oil after transamidation with diethanolamine. When I react this polyol with pMDI and...

25 September 2021 1,411 7 View

At what wavelength does the absorbance of reduced and oxidized TMPD differ maximally?

I am setting up mitochondrial complex specific assays performed with a spectrophotometer. I am interested in setting up the assay to look at complex IV activity using the electron donor TMPD. Upon...

12 August 2021 4,239 2 View

LC-MS highly-correlated compounds with a difference in m/z ~1 and very close retention time. Would they be the same compound but with C13 isotopes?

Using non-targeted Liquid-Chromatography Mass Spectrometry I found highly-correlated compounds (r>0.95) with a difference in m/z ~1 (ex: 451.3069 and 452.3102) and very close retention time (

21 July 2021 7,134 4 View

How to calculate extraction efficiency of SPE after derivatization? Can I use external standard calibration method to calculate the EE?

Basically, I am analysing Fluorobenzoic acid using GC-NICI-MS single quadrupole system. The steps of quantification includes SPE + Derivatization but there are irregularities in the results hence...

16 July 2021 3,366 4 View

If the NCO/OH molar ratio is equal to 1 for different polyurethane syntheses, the content of hard and soft segments would be similar ?

If the NCO/OH molar ratio is equal to 1 for different polyurethane syntheses, the content of hard and soft segments would be similar in their structure ?

11 May 2021 1,297 1 View

How to compare number based D90 generated from image analysis to that of the Malvern mastersizer D90?

I have image analysis data that gives D90 based on number-based distribution. Malvern generates D90 which is based on volume-based distribution. What are the parameters that need to be looked for...

12 April 2021 7,712 4 View

Can anybody tell me how can I find the 2 D and 3 D (D=dimension) figure of Bulk modulus, Shear modulus and Young's modulus using DFT based cals. ?

Can anybody tell me how can I find the 2 D and 3 D (D=dimension) figure of Bulk modulus, Shear modulus and Young's modulus using DFT based calculations.

11 January 2021 9,346 4 View

What is the best way to identify whether a certain substance is present in a mixture based on Raman spectra?

Dear Colleagues, our imaging facility is entering the field of Raman micro-spectroscopy and we've been approached by a group who want to detect the presence of certain compounds (about 10...

09 January 2021 981 5 View

Is there anyone has an idea how to increase rebound for midsole Polyurethane foam above 40%?

The most challenge of certain application of foam technology is to achieve certain properties. These foams are depending on density. But when you increase density there are other properties will...

23 December 2020 4,101 3 View

How to identify possible metabolite from chromatogram?

We have done the analysis for a pre-clinical study and we have observed additional peaks in the chromatograms. We think that these peaks are metabolites. The concentration of the additional peaks...

03 December 2020 6,270 10 View

Alkaline hydrolysis and extraction of Vitamin D from food samples?

Hello everyone, may I ask about the purpose of adding ultrapure water after incubation for 30 minutes at 80 degree Celsius (under saponification process of vitamin D? Secondly, what is the...

03 December 2020 8,665 4 View

Acesulfame Potassium and Acesulfame and Conversion?

Dear to whom it may concern, Based on ChemAxon, I calculated pKa values of Acesulfame as follows: 1. pKa (Strongest Acidic): 3.02 2. pKa (Strongest Basic): -6 Because I would like to convert...

26 November 2020 4,757 3 View

What are the different ways of measuring surface roughness of a microhole?

What are the different ways of measuring surface roughness of a microhole produced by Abrasive assisted Electro chemical micro machining procedure.

17 November 2020 9,468 0 View

Very small peptide detection in solution?

I am looking for an assay (rapid and convenient) where I can quantify/semiquantitative amount of very small peptides (dipeptides to tetrapeptides) in solution. I have tried different commercial...

10 November 2020 6,348 6 View

Bisphenol A in water - measuring bpa protocol using a uv/vis spectrophotometer?

Hi, I'm interested in a protocol for measuring concentration of BPA in distilled water (no interference) using a uv/vis spectrophotometer . The method found...

10 November 2020 7,234 3 View

Which parameter is the most important, removal % or adsorption capacity ?

I am testing a new material as adsorbent for the removal of methyl orange dye from aqueous solution, I got the below results, do I need to go further with higher concentrations even the removal...

06 November 2020 3,218 10 View

Difference between Porous Graphitic Carbon and Graphitized Carbon Black?

Dear to whom it may concern, May I ask you about the difference between porous graphitic carbon (PGC) and graphitized carbon black (GCB) in terms of surface properties, retention mechanisms, and...

11 October 2020 4,639 3 View

How to get rid of a constant peak at fix RT every time in HPLC ?

I am running catecholamine standards in HPLC using UV/FLD detector. I am getting a constant peak at fix RT (retention time @ 3.5 min, image enclosed) every time, even if I run another standard or...

30 September 2020 1,033 7 View

In search of single HPLC drug quantification method applied to 2 drugs - one very hydrophilic, the other one very hydrophobic. What do you suggest?

I needed to simultaneously measure drug content in HPLC of two drugs on the same formulation bearing opposite water solubilities. What have been your experiences so far regarding this? One method...

14 September 2020 2,194 5 View

The quantifier for both analyte and internal standard have same product ion, will that have an impact on overall analysis?

Dear Chromatographers, This method was developed on LC MS/MS. The quantifier for both analyte and internal standard have same product ion, will that have an impact on overall analysis. Any...

01 September 2020 1,394 9 View

How to deal with negative values of autoradiography scans when plotting a calibration plot?

I am quantifying spots on an autoradiography scan, so subtracting the background pixels to get the intensity values but when nothing binds, it's the same as the background and since that's an...

19 August 2020 3,411 4 View

Why is ashing of certain organophosphorus compounds problematic?

When subjected to conventional ashing (i.e. residue on ignition through use of a furnace and noble metal crucible), compounds ArC(=O)P(=O)Ar2 [Ar = aryl] give ash values of a few percent %w/w...

13 August 2020 841 3 View

What is the best way for calibration curve for ternary system?

I'm doing experimental liquid liquied equlibrium of limonene +water+ ethanol, methanol and 1-propanol.. using UV in the analysis .. what is the best way to do calibration curve to estimate the...

21 July 2020 7,109 2 View

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