A method to measure the contents of soluble lignin and furfural in the lingocellulosic pre-hydrolysis liquid was developed based on UV spectroscopy in the present work. The UV spectrograms of the low molecular organic acids

furfural and the pre-hydrolysis liquid were discussed. Formic acid and acetic acid had significant absorption at 205 nm

and furfural had absorption maxima close to 280 nm. The traditional methods for quantification of lignin based on lignin characteristic peak location of 205 nm and 280 nm was not suitable for the determination of soluble lignin in the pre-hydrolysis liquid. The study presented elimination of the interference of furanic compounds by reduction with alkaline sodium borohydride. The results showed that sodium borohydride significantly decreased absorbance close to 280 nm

and the higher the pre-hydrolysis conditions

the more decreased the absorbance after reduction

indicating high level of furfural. With lignin extracted from Acacia wood and reeds as standard sample

the relationship between absorbance at 280 nm and concentration of lignin was linear and pertinent coefficient reached 0.999

which met the needs of quantitative determination. The difference of absorbance between the samples before and after full reduction could be used for quantification of furfural. The pertinent coefficient of absorbance at 280 nm and concentration of furfural reached 0.998. The results of reproductive experiment showed that recovery was 98.14%—99.88% and relative standard deviation was 0.17%-0.35%.