A near-infrared spectroscopic(NIRS) method using competitive adaptive reweighted sampling(CARS) for variable screening was established for the rapid determination of luteolin

with imidazole ionic liquid as adsorbent enriching luteolin in dilute solution.Effects of amount of adsorbent

pH value and oscillation time on the adsorption efficiency were investigated

and the adsorption capacity of the adsorbent was explored.The adsorbent enriching luteolin was detected by near infrared diffuse reflectance spectroscopy

and a quantitative correction model for luteolin was constructed by CARS method for variable screening combined with partial least squares regression(PLS).Results showed that

under the optimal conditions of 0.15 g of adsorbent

pH 7

and 20 min of oscillation time

the adsorption rate reached to 90.9%

and the adsorption conformed to the Langmuir isotherm adsorption model

with a maximum adsorption capacity of 7.1 mg/g.In the NIRS modeling

the developed model was compared with that of the non CARS variable screening process

and the comparison showed that the results of the CARS variable screening method were better

which were also confirmed by the continuous wavelet transform(CWT) spectral preprocessing.The results exhibited that

the RPD value increased after CWT treatment

which further explain the reliability of the model.This method could be used for effective enrichment of luteolin in dilute solution

and the NIRS method combined with CWT spectrum pretreatment using CARS variable screening could realize the sensitive and rapid detection of luteolin in dilute solution.