The branch of chemistry concerned with identifying and quantifying the chemical constituents of matter.

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4
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1answer
57 views

Base Peak Intensity different than higher value in Mass Intensity Map

I've been working with mass spectrum data analysis (but my field is computer science). I'm using a library that allows me to get the entire Mass Intensity of the MS1 scan (such as [time, intensity])....
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10 views

Flynn-Wall-Ozawa (FWO) Method“ and ”Kissinger-Akahira-Sunose (KAS) Method [on hold]

Can any one tell me how to plot graph between 1/T and ln(β/T²) using KAS and FWO method in Microsoft Excel
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0answers
17 views

analytical chemistry [on hold]

1.Fructose, a sugar found in fruit, contains only carbon, oxygen, and hydrogen. It is used in ice cream to prevent a sandy texture. Complete combustion of 32.4 mg of fructose in oxygen produced 47.6 ...
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0answers
13 views

Equivalents and Gram equivalent weight

Are the terms 'gram equivalent weight' and 'equivalents' the same? I hace read 3-4 definitions of normality and it has used those terms interchangeably.
0
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0answers
13 views

Chemical Reagent Test sensitive at low concentrations

Would there be a spot test / tests that can detect either / both of the following molecules at low concentrations? The likely conc. are in the 10-50 mg/L range in an aqueous solution. Ideally, I'd ...
1
vote
1answer
25 views

Using IR to detect / quantify a molecule at low concentrations

I want to detect / quantify a specific terpenoid molecule from a microbiological growth medium. The molecule will however be present at very low levels approx. 10-100 mg/L. Is it viable to use the ...
-3
votes
1answer
18 views

Does anyone know how to work out the amount of sodium sulphate present in water? [closed]

I need to find out 2 ways to determine the amount of sodium sulfate in an aqueous solution. I have searched the internet for assays.
4
votes
0answers
23 views

LC-MS: Can a “bad” peak still be interpreted

I have done an untargeted metabolomics study using LC-MS. There is one peak that matches to a biologically relevant compound but analyte eluted at the beginning of the LC run and the peak shape is far ...
0
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0answers
6 views

Solubility specification in a standard

I'm reading a standard where under the specification for a substance it says: Solubility in Alcohol: 1 ml in 3 ml 50% alcohol remains clear to 8 ml. Just wanted to confirm my interpretation: I ...
0
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0answers
25 views

Quantitative analysis of Ni and Sr

I have a sample containing $\ce{K, Ni, Sr, NO3, Cl}$ and $\ce{I}$-ions. I need to determine the amount of $\ce{Ni}$ and $\ce{Sr}$-ions, and I would very much like some suggestions on how to do this.
3
votes
1answer
29 views

How does the Rf value change when changing the eluent composition?

A non-polar molecule X is analyzed by TLC chromatography on silica to determine its $R_f$ value. The first eluent was hexane:EtOAc = $9:1$ and the $R_f$ value was $0.5$. In the second run, the ...
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0answers
13 views

Experiment with magnesium-sulfur fertilizer

This fertilizer for is for soil and plant growth, and I was thinking of doing an experiment with it. The bag says it contains magnesium sulphate and water soluble sulphur trioxide. Is there anyway to ...
1
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1answer
51 views

What analytical method(s) to use for finding the contaminations in a fatty base material

In a large batch of a fatty combustible mixture there appear to be two contaminations, since after combustion there are 2 residues clogging up the injectors and exhaust system: - a calcium salt - a ...
0
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2answers
37 views

Need help identifying a soluble, olive green substance with an orange/yellow flame color

$\hspace{4.4cm}$ Working on identifying substances in a mixture. I have been able to find the identify of every other substance so far, but I am completely stumped on this olive green substance. All ...
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0answers
43 views

Which is more amphoteric: zinc or copper hydroxide?

$\ce{K_{a} ~Cu(H2O)_6^2+}{=~5*10^{-7}} $ $\ce{K_{a} ~Zn(H2O)_6^2+}{=~2.5*10^{-10}} $ Given this information, which forms a more amphoteric hydroxide? My reasoning is that copper hydroxide is more ...
8
votes
4answers
129 views

How to separate and analyse a sample of cations of alkaline and earth alkaline cations and ammonium?

I am teaching a section of qualitative analysis and I am trying to get a better grasp on the assignments the students are doing. These are the cations they may be presented with and must identify: $\...
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42 views

Sodium percarbonate and sulfuric acid reaction

If an excess sulfuric acid is added to a detergent containing sodium percarbonate, would it be possible for the excess acid to react with hydrogen peroxide? I believe that the hydrogen peroxide will ...
0
votes
1answer
31 views

Definition of drift

What does drift actually mean in analytical chemistry? I can't find the exact definition and now am not sure whether my intuitive understanding of it is correct.
3
votes
1answer
35 views

Validating a GC instrument / column

Are there any generic rules / heuristics to identify a good GC vs a bad one? The context is that during manufacturing-troubleshooting I often get shown GCs of various fine chemicals and I often ...
3
votes
1answer
37 views

Chromatography: Why does the insoluble compound get pulled along?

In paper chromatography, we see that a paper with an ink spot on it get dissolved in the liquid and travels up with water due to capillary action. Then the compounds with more affinity to the paper ...
0
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0answers
20 views

How to convert units of a molar concentration to a mass

I am trying to calculate a mass based on a molar concentration obtained after diffusion has occurred through a pore for a research project. I have the molar concentration of calcium chloride and am ...
0
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0answers
11 views

Software for ion speciation of Ni(II)?

How can I make an ion speciation curve of $\ce{Ni^{2+}}$ in a base solution $\ce{NaOH}$? Does there exists a software that does that or a tutorial? I tried using HYSS2009, but documentation is no good ...
-1
votes
1answer
46 views

Reactions of Phloroglucinol

Does phloroglucinol respond to the iodoform test? cerric ammonium nitrate test? 2,4-DNP test? I couldn't find any good sources that answer any of these. I thought of this: Tautomerism can "...
3
votes
0answers
46 views

The behaviour of Ag3PO4 in solution

To a 1L flask, we add $4.1900\mathrm{g}$ ($0.01001\ \mathrm{moles}$) of $\ce{Ag3PO4}$, then fill it up with water. Knowing the following constants, we are asked to find the concentration of all ...
2
votes
1answer
17 views

Quantitative Analysis of Urea in aq. solution

What would be a good way to assay Urea in aq. solution? The test doesn't need to be super accurate. 1% accuracy is fine. But it needs to be relatively fast & robust to carry out. NaHCO3 is a ...
3
votes
0answers
47 views

Apparent solubility of Ag2C2O4 in a buffer solution

We take the following quantities and mix them together: $20\mathrm{mL}$ solution of $\ce{AgNO3}$ $0.001 \frac{\mathrm{moles}}{\mathrm{dm^3}}$ $20\mathrm{mL}$ solution of $\ce{H2C2O4}$ $0.200 ...
1
vote
1answer
40 views

What is the process to solve this disproportionation REDOX question?

I know how to solve REDOX reactions, but this one is really confusing me, since I can't really write half reactions for it. $\ce{ClO3- -> Cl2 + O2}$ the answer is apparently $\ce{2H+ + 2ClO3- -&...
2
votes
0answers
26 views

How does pH level change the concentration of dissolved oxygen (DO) in sea water?

I am planning to investigate the relationship between $\mathrm{pH}$ and dissolved oxygen. I would like to have a reason without taking in account the plants, animals and decomposer roles. I want to ...
0
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0answers
11 views

electrophoretic mobility and EOF

I'm currently studying about capillary electrophoresis. I'm quite confuse about mobility of electrophoretic and EOF. Why does negative charge has greater electrophoresis mobility than EOF and ...
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0answers
29 views

How to test if white powder is lime fertilizer?

I found two buckets (white and black) containing a very light grey powder in the basement. The label is partially removed, but it probably originally contained lime fertilizer. However, I am not sure ...
5
votes
2answers
100 views

Remove salt from dirt

I have a mixture that contains out of dirt/sand and salt. I want to extract and measure the salt. What would be the best way to extract the salt from this mixture? P.s not sure if this is the ...
2
votes
0answers
32 views

Method and Tips for Inorganic Qualitative Analysis

In a few weeks time I will be doing a inorganic qualitative analysis test which is very pressed for time (a majority of people don't finish). The form of the test is most likely going to be that there ...
0
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0answers
40 views

What reaction distinguishes glycerol and tert-butanol?

What reaction can we use to distinguish between glycerol and tert-butanol in laboratory conditions? I know alcohols exhibit the following: deprotonation, yielding an alcoholate salt reaction with a ...
0
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0answers
14 views

Why -COOH group on the Graphene quantum dots have much more affinity with Hg(II) than other ions?

Could anybody explain why the COOH group around the edge of the GQDs have much more affinity with Hg(II) than others?
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0answers
24 views

What type of standard for HPLC capsaicin quantification?

I'm wondering which type of standard would be the most suitable for the quantitative analysis of capsaicin (8-Methyl-N-vanillyl-trans-6-nonenamide) containing products? Sigma offers the following ...
0
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0answers
29 views

Simplified Chromatography - will this work?

I am interested to separate a sample matrix via a method very similar to chromatography. The reason I am asking about this is because I am planning to integrate this method with my SERS application. ...
3
votes
1answer
29 views

Correct term/word for bias in calculations?

I ran an experiment recently and made several approximations in the calculations that led to the results being around 2 orders of magnitude less then the literature values. I will be re-doing the ...
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0answers
21 views

What means can be used to distinguish different sorts of plastic?

So, different sorts of plastic usually have different marks on them (the resin identification code, like 1/PET for polyethylene terephthalate etc). However, sometimes one can encounter a piece of ...
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0answers
32 views

Can we make chromatography less troublesome?

Thin Layer Chromatography is a very powerful method in analytical chemistry for separating complicated chemical matrices. As an engineer, I am interested to build device capable of automating TLC ...
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0answers
30 views

E / Z Isomers GC peaks for identification; Would GC-MS help?

Does a GC analysis typically seperate E / Z isomers? I'm reading a paper that confirms that the product it synthesized was indeed the (E,E) isomer by coinjecting a standard sample on the GC. My ...
0
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0answers
29 views

What is the difference between column chromatography and a fractionation column?

I'm a chemistry student doing research in a biotech lab. I'm doing the chemistry portion of the project. It is time to write the methods for my paper and I'm confused on what the proper term for what ...
1
vote
1answer
83 views

In NMR Spectroscopy why use absorption and dispersion components of the FID spectrum rather than magnitude and phase?

In chapter 4 of Dr James Keeler's book 'Understanding NMR spectroscopy' (http://www-keeler.ch.cam.ac.uk/lectures/Irvine/chapter4.pdf) he explains how to calculate the expected spectrum of a FID signal....
0
votes
1answer
81 views

Minerals in water solidify when heated?

Is it possible for minerals in drinking water to solidify when high temperatures are applied? The minerals in mind are: iron, copper, aluminum, magnesium. Background: I have small, brittle, darkish ...
2
votes
2answers
134 views

The mathematical condition for a complete complexation reaction

I'm being asked to find the volume of a $\ce{NH3}$ solution ($0.1\ \mathrm{M}$) to be added to $10\ \mathrm{mL}$ of a $\ce{AgNO3}$ solution ($0.1\ \mathrm{M}$) to assure the 'complete formation of $\...
0
votes
1answer
65 views

How to estimate the concentration of OH that comes from just the autoprolysis of water in a basic solution?

In my analytical chemistry course, a question reads: What is the pH of a 0.10 M solution of THAM? Is it valid to neglect the autoprotolysis of water? Justify and explain your answer by estimating ...
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0answers
41 views

Is there any process to determine what elements a physical sample is made from?

I'm wondering if anyone knows of laboratory services that can analyze a sediment sample to tell what it's made of. Background: our drinking water has small black flakes appearing, and our city water ...
1
vote
1answer
58 views

GCMS Peak Identification: Online or Open Source / Free Programs?

Suppose I have a GCMS peak graph for a component, what are possible options to figure out what the molecule may be? Any tips about good software that will do this? I do know that for many compounds ...
0
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0answers
13 views

White precipitate observed in bromelain assay

After adding TCA to bromelain assay, I was unable to measure absorbance for 2 days (which is not suppose to happen though), and now it has formed some white colour precipitate, and I vaguely remember ...
1
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0answers
21 views

concentration of silver nitrate solution [closed]

I have 300 litres of silver nitrate solution. From this I took 100ml solution. I need to get the concentration of this 300 litres of solution by titrating the 100 ml against pottassium chloride ...