Natural Science Forum / Chemistry / Analytical Chemistry / September 2004

I have a problem - I am being faced with a single silver nitrate
solution giving different titers when validated in different ways.
1) Mohr titration gives 0.1000 N
2) Autotitrator with electrode end point is giving 10% lower

Does anyone know of a reputable commercial lab which can carry out lipid
analysis in milk?
Thanks for any replies
RR

I am looking for a very cheap, simple and accurate method to test for
pesticides and insecticides in fresh vegtables....is there a simple
technique..preferably some "litmus" like test which changes colour or
some simle and cheap instrument..i dont want it to be sent to

Actually I'm validating methods for determinate Organochlorine
pesticides in water by GC-ECD, and PAH by HPLC. I've troubles in the
recovery rate, the recovery for DDT, metoxichlor and aldrin is poor,
and the reproducibility in high too. Wath are the aproximated recovery

I have an old 1090 (w/PDA) and a licensed copy of ChemStation going back at
least 7 years.  I'm running Windows 95.  ChemStation recognizes my HPIB
interface board (82341D), but cant communicate with the 1090.  There don't
seem to be any setup options (DIPs, etc.) in the 1090 itself ...

Dear readers,
I've been looking for detailed procedures of Extraction of Coriander
oil, from the internet without much luck.
Wonder if anyone could direct me.

I am chemistry teacher looking for UV-VIS spectra of transition metal
ions for A-level Education purposes, in particular predicting the
colour seen from the spectrum. I have searched on the internet but I
am having trouble finding resources that are simple enough for

Hello
Can anybody tell me where i can get "USP 1,4 Benzoquinone RS" Standard
as powder. We need it to produce stock standard for TOC Measuring!

I am trying to understand how HPLC would be used to detect pesticde presence in
dried egg yolk.  All the questions are practical such as
How much egg yolk is required for the process, how is it prepared?  I suppose
egg yolk is a brew of many things, so how does one pick out the ...

Hello Group,
Looking for any experience with methods for phosphate analysis...
I remember running the quimociac gravimjetric method for total
phosphate, (probably 15 yrs ago) and seem to recall that hot water

Hi, please help me to prepare a 100%(w/v) solution of TCA
(trichloroacetic acid). this acid comes in crystals, so what a 100%
solution means?
thanks

Have you ever silanized your laboratory glassware?
Do you know simple method for this?
Jedzi

In case a woman farts on the a cake, what do you expect to happen next
- will it light her farts or blow the candles with her warm wet
putrid-smelling loud fart?
Steve

Hi to all!
I am using the classic titrimetric cyanide method of determining the
sum of nickel and cobalt.
Could anyone suggest me a fast procedure of separating nickel and

I work in the GC/MS analytical section in a large lab.  In addition to
the more common pesticides, we also do degradates, personal-use
products, drugs, and about anything else someone would want to determine
in environmental samples.