negative peak for water in ethanol-water sample analysis

[shiva]

hai , am getting negative peak for water when analysing a water-ethanol sample on Shimadzu-GC-17A ATFW ver.3:why am getting such result?
detector:TCD.
carrier gas and makeup gas are both N2
analysis time 5 min, oven temp;130oC
inj temp:150oC
det temp: 200oC
current:35mA
column details are
column:capilary column is CBP1-S25-050,
ZB-5, 5%-phenyl-
95% -dimethyl polysiloxane
non polar
max. temperature is 320 0C
length =30 m
inner diameter= 0.32 mm ID
film thickness = 0.25 micro meter

and also i need information on analysis of [1,4-dioxane and water sample]

can i use it for analysing 1,4-dioxane and water solution,
plz tell me what can i do.[conditions etc.,will be mantain for getting good
results]

[AICMM]

shiva,

Refer to the post "Still a newb...". (searchable by "thermal conducitivity".) Lots of good information including water has higher thermal conductivity than hydrogen....

Frankly, I am surprised you are getting any separation at all on the column you are using.....

Best regards.