<s>
Probe	B-Algorithm
electrospray	I-Algorithm
ionization	I-Algorithm
(	O
PESI	O
)	O
is	O
an	O
electrospray-based	O
ambient	O
ionization	O
technique	O
which	O
is	O
coupled	O
with	O
mass	O
spectrometry	O
for	O
sample	O
analysis	O
.	O
</s>
<s>
Probe	B-Algorithm
electrospray	I-Algorithm
ionization	I-Algorithm
is	O
an	O
ambient	O
ionization	O
mass	O
spectrometry	O
technique	O
developed	O
by	O
Professor	O
Kenzo	O
Hiraoka	O
et	O
al	O
.	O
</s>
<s>
An	O
interesting	O
phenomenon	O
observed	O
with	O
probe	B-Algorithm
electrospray	I-Algorithm
ionization	I-Algorithm
is	O
the	O
sequential	O
and	O
exhaustive	O
ionization	O
of	O
analytes	O
with	O
different	O
surface	O
activities	O
.	O
</s>
<s>
To	O
circumvent	O
this	O
limitation	O
,	O
sheath-flow	O
probe	B-Algorithm
electrospray	I-Algorithm
ionization	I-Algorithm
(	O
sfPESI	O
)	O
was	O
developed	O
,	O
a	O
modification	O
of	O
the	O
traditional	O
PESI	O
technique	O
.	O
</s>
