Miniaturizing n automatic amino acid analyzer for use on Apollo mission and Mars Voyager missio

Dus, K. M.

Kraut, J.

Miller, S. L.

English

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Progress Report f o r  the Period of January -June 1967 
NASA Grant NGR 05 - 009 -03 2 
A F e a s i b i l i t y  Study on Miniaturizing an Automatic Amino Acid 
Analyzer for use on Apollo Mission and Mars Voyager Mission. 
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Stanley L. Miller - Principal  Invest igator 
Joseph Kraut - Co-Principal Invest igator  
Karl M .  Dus - Co-Principal Invest igator  
Lkpartment of Chemistry 
University of California,  San Diego 
P. 0. Box 109 
La J o l l a ,  California 92038 
https://ntrs.nasa.gov/search.jsp?R=19670021974 2020-03-12T11:00:37+00:00Z
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Introduction. 
In the period since the last progress report, substantial progress has 
been made in showing the feasibility of automatic amino acid analysis by ion 
exchange chromatography for use on Apollo and Mars Voyager missions. The 
semi-micro model has been completed and tested. The design of the micro 
model has been completed and the construction of its component parts is in 
progress. These developments re-enforce our confidence that the construc- 
tion of an automatic amino acid analyzer suitable in size and weight for 
space flight application will prove to be feasible. The details of these 
developments are as follows: 
1. Semi-Micro Model 
The overall construction of the semi-micro model according to the 
design outlined in the preceding progress report has now been completed. 
The dimensions of this instrument are 30" x 24" x 20". 
An extensive series of test experiments was performed in order to 
ensure compatibility of component parts and to establish the performance 
characteristics of the instrument. 
a) The elution pattern and the resolution of individual amino 
acids was found to be in close agreement with the data obtained on a 73 
cubic foot commercial amino acid analyzer. 
b) This semi-micro model offers several advantages over the 
commercial instruments. These are the automatic sample selection and a com- 
pletely automatic program for stepwise multi-buffer elution of amino acids 
followed by regeneration and re-equilibration of the ion exchange column. 
c) Construction of the unit for automatic hydrolysis and separation 
of amino acids from contaminating inorganic material is also nearing com- 
pletion and this unit will be tested shortly. 
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d )  Although the  p re sen t  s e n s i t i v i t y  of ou r  instrument  i s  a l r e a d y  
-8 higher  than t h e  s e n s i t i v i t i e s  provided f o r  commercial ana lyze r s  (10 moles) ,  
w e  cons ider  i t  necessary t o  raise t h i s  l e v e l  s t i l l  h igher .  This  w i l l  be 
p o s s i b l e  with the  a i d  of a s t a b i l i z e d  o p e r a t i o n a l  a m p l i f i e r  which i s  p r e s e n t l y  
being t e s t e d  i n  ou r  labora tory .  
1. New Developments. 
The cons t ruc t ion  of t h e  semi-micro model has  g r e a t l y  a ided  ou r  
e f f o r t s  t o  f u r t h e r  m i n i a t u r i z e  t h e  instrument .  Each component p a r t  was ca re -  
f u l l y  t e s t e d  and re -eva lua ted  with regard  t o  i t s  f u n c t i o n a l  des ign  and t h e  
p o s s i b i l i t i e s  for f u r t h e r  reduct ion  i n  s i ze  and weight.  
This  s ea rch  f o r  improvements led t o  t h e  fo l lowing  developments: 
a )  A more compact arrangement of b u f f e r  compartments has  been 
achieved by combining t h e  conta iners  f o r  a l l  b u f f e r s  and f o r  t h e  n inhydr in  
reagent  i n t o  one u n i t  made from molded p l a s t i c .  The s i z e  of each i n d i v i d u a l  
compartment of t h i s  u n i t  i s  made propor t iona l  t o  t h e  r e spec t ive  volumes 
r equ i r ed  by t h e  e l u t i o n  p a t t e r n .  
b)  I n  o r d e r  t o  e l i m i n a t e  the  p o s s i b i l i t i e s  of bubble development 
dur ing  t h e  e l u t i o n  per iod of t he  fou r th  b u f f e r ,  con ta in ing  sodium carbonate ,  
a s u i t a b l e  sodium bora te  b u f f e r  w a s  provided as replacement.  
c )  Although our  p re sen t  pumping system FrGved coinp?etely adequate  
f o r  t h e  requirements  of t h e  semi-micro model w e  i n t end  t o  f u r t h e r  improve 
t h e  c o n t r o l  of the l i q u i d  flow-system by a d j u s t i n g  t h e  p i s ton  s i z e  of each 
pumping head i n  propor t ion  t o  t h e  des i r ed  ou tpu t .  The design of t h i s  
component a l s o  permits  the  use of p l a s t i c  i n s t e a d  of metal as t h e  major 
c o n s t r u c t i o n  material of t h e  pumping system. This  replacement w i l l  t he re -  
f o r e  r e s u l t  i n  a s u b s t a n t i a l  reduct ion of t h e  s i z e  and t h e  weight of t h i s  
component while  s imultaneously improving t h e  c o n t r o l  of  t h e  l i q u i d  sys tem.  
d )  Experiments were conducted with t h e  a i m  of producing s u i t a b l e  
micro ion-exchange columns. One s o l u t i o n  t o  t h i s  problem is  t o  use  a 
c a p i l l a r y  column made from p l a s t i c  tub ing  and po lys ty rene  r e s i n  beads. 
Another p o s s i b i l i t y  would be t h e  cons t ruc t ion  of a polys tyrene  column 
coated with a c t i v a t e d  r e s i n .  Both approaches are being developed and 
t e s t e d .  
e )  Much e f f o r t  was spen t  on dev i s ing  a d e t e c t i o n  system s u i t a b l e  
Again two d i f f e r e n t  p o s s i b i l i t i e s  were f o r  high s e n s i t i v i t y  measurements. 
s tud ied  . 
Our high s e n s i t i v i t y  flow c e l l  of 30 mm l i g h t  path i n  combination 
with a s u i t a b l e  co lo r ime te r  and a s t a b i l i z e d  o p e r a t i o n a l  a m p l i f i e r  of low 
c u r r e n t  requirements  was found t o  permit q u a l i t a t i v e  amino a c i d  ana lyses  
down t o  t h e  l e v e l  of  10 moles. -10 
The a l t e r n a t e  p o s s i b i l i t y  e n t a i l s  t h e  use of a compact mono- 
chromator sys t em connected t o  a pho tomul t ip l i e r .  
enabled u s  t o  raise t h e  s e n s i t i v i t y  f o r  both v i s i b l e  and u l t r a v i o l e t  t o  
t h e  l e v e l  of moles. However, i t  w i l l  be necessary  t o  develop a 
This  arrangement has  
s u i t a b l e  means of suppress ing  the  r e l a t i v e l y  h igh  background no i se  p r e s e n t l y  
observed a t  t h i s  h igh  l e v e l  of s e n s i t i v i t y .  
f )  E l e c t r i c a l  hea t ing  of  the  r e a c t i o n  c o i l  occas iona l ly  r e s u l t e d  
i n  spo t  heat ing,and t h i s  undes i rab le  s i d e  e f f e c t  was prevented by 
immersing t h e  c o i l  i n  a small volume of p a r a f f i n  o i l .  Other s o l u t i o n s  t o  
t h i s  problem are being i n v e s t i g a t e d .  
g )  An e n t i r e l y  new approach t o  t h e  p re s su re  pump f o r  e l u t i o n  has  
been developed. 
on t h e  buf fer .  The bellows i s  dr iven  by a i r  pressure .  This  system has  
been s u c c e s s f u l l y  t e s t e d  and is being f u r t h e r  r e f ined .  
This  device  c o n s i s t s  of a bellows which a c t s  as a p i s t o n  
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3 .  Micro Model 
Making extensive use of our experience in the construction of the 
semi-micro model we have completed the design of most of the component 
parts of the micro model. A schematic diagram indicating the overall 
outlay and the functional arrangement of these components within the 
confinements of % ft is shown in the figure. 3 The individual weights 
have been calculated for the components. It appears that the electronics 
components will be less than 3 pounds, and the mechanical devices will be 
about 7 pounds. These components are presently under construction. 
Joseph Jraut 
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Karl i"I. Dus 
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A Feasibility Study on Miniaturizing an Automatic Amino Acid Analyzer for Use on Apollo Mission and Mars Voyager Mission Progress Report, Jan. - Jun. 1967

A Feasibility Study on Miniaturizing an Automatic Amino Acid Analyzer for Use on Apollo Mission and Mars Voyager Mission Progress Report, Jan. - Jun. 1967

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