Biomedical Engineering Reference
In-Depth Information
L
1
NaOH solution. For aniline-oxalic
acid solution, 0.93 g of aniline and 66 g of oxalic acid were dissolved in 100 mL
water-saturated n-butanol. The separation effect was good, and the qualitative and
quantitative analysis task could be completed.
HPLC can also be used to qualitatively and quantitatively investigate the sugar
in hydrolysate. The following is an HPLC analysis method [
134
]: France Gilson
HPLC was used with a Gilson 132-type differential refractive index detector
and Spherisorb NH
2
(250 mm
the mixture was adjusted to 4-5.0 with 200 g
4.6 mm) column, a stainless steel column. The
mobile phase was acetonitrile and water (82:18). The mobile phase was pretreated
ultrasonically for 15 min to degas. The flow rate was of 2 mL
min
1
. Injection
2)
ı
C.
The sample was quantitatively determined by the method of peak area of the external
standard. As a result, this method could separate rhamnose, xylose, fructose,
glucose, sucrose, and maltose.
volume was 20
L. Measurement temperature was room temperature (26
˙
(3) Oligosaccharides
Products of cellulose pretreated with dilute acid hydrolysis include monosaccha-
rides and oligosaccharides. The HPLC standard method used in National Renewable
Energy Laboratory (NREL) of the United States is mostly applied to quantitatively
determine oligosaccharides, which is more difficult to detect than monosaccharides.
Its basic principle follows Saeman's [
135
] methods. Lignocellulose is completely
converted into monosaccharides by two-step hydrolysis of sulfuric acid with
a concentration of 72 and 4 % separately. Then, the hydrolysis liquid of the
biomass is quantitatively hydrolyzed into monosaccharide with 4 % sulfuric acid
(that is, only the second step of the two-step acid hydrolysis). The content of
monosaccharides is quantitatively determined to calculate the conversion rates of
various monosaccharides. The specific operation is as follows: The first step is
to hydrolyze dry feedstock at 30
ı
C with 72 % sulfuric acid for 2 h. Second, a
hydrolysis liquid sample of the first step is quantitatively removed. The sample is
diluted, or sulfuric acid is added to make the sulfuric acid concentration 4 %. It is
hydrolyzed in a pressure cooker at 121
ı
C for 1 h. CaCO
3
is used to neutralize to
a pH value of 5-6. Then, it is diluted and filtered with a 0.2-
m filter membrane.
Common columns used are a Bio-Rad Aminex HPX-87C column and a column
coupled with a differential refractive index detector. The Bio-Rad Aminex HPX-87C
column can quantitatively detect glucose, xylose, and arabinose. Bio-Rad Aminex
HPX-87P column can also test cellobiose, mannose, and galactose except for the
monosaccharides mentioned.
Zhuang et al. [
136
] proposed a simple detection method for oligosaccharides that
could qualitatively and quantitatively detect monosaccharides, cellobiose, trisac-
charides, tetrasaccharides, and other sugars. The equipment used was as follows:
Agilent 1100 HPLC chromatography detection system, French SEDERE evapo-
rative light-scattering detector (ELSD) SEDEX75, Japan Shodex Sugar KS2802
column (8.0 mm
300 mm), HPLC-grade water as the mobile phase at a flow rate
min
1
, column temperature of 80
ı
C, and injection volume of 20
of 1.2 mL
L.
