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>Is anyone aware of any methods for analysing trace levels of the compound -
>Naphthol Green B.
>We want to analyse some food products and salts to see if or what level they
>may contain.


Dear Bill,

(1)
"Naphthol Green B" aka "ACID GREEN 1" aka C.I. 10020
MW:878,46 C30H15FeN3Na3O15S3, CAS: 19381-50-1 
is a dyestuff

(2)
try to find out CAS numbers for dyestuffs somewhere,
like entering the CAS@google.com
http://europa.eu.int/comm/food/fs/sc/sccp/out123cm_en.pdf

(3)
mark other similiar compounds
ACID GREEN 1 (CAS: 19381-50-1)
ACID ORANGE 3 (CAS: 6373-74-6)
ACID RED 18 (CAS: 2611-82-7)
ACID RED 33 (CAS: 3567-66-6)
... and so on

(4)
if you dont have CAS go to 
http://chem.sis.nlm.nih.gov/chemidplus/

(5)
search in TOXLINE
you will find xome old publications like
IDENTIFICATION OF COSMETIC DYES BY ION-PAIR REVERSED-PHASE
HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY 
J CHROMATOGR; 394 (2). 1987. 345-352. 

That means you can use a HPLC procedure,
and if you need to to analyze trace levels
you can create a LC-MS method similiar to 
other dyestuff,azo dye, textile dye methods.

(LC/ESI-MS, LC/APCI-MS or LC/MS-MS for trace levels
of dyestuffs)

Kind regards
Tobias Kind
www.amdis.net

PS: still@leeder?