Acetone

d-Xylose (Batch No. 20160302) was purchased from Tianjin Kaixin Chemical Industry Co., LTD. Phloroglucinol, glacial acetic acid, chloral hydrate, acetonitrile (chromatographically pure), methanoic acid (chromatographically pure), ammonium hydroxide, n-butyl alcohol, methyl alcohol (chromatographically pure) and acetone were all provided by Damao Chemical Reagent Factory (Tianjin, China; Batch Nos. 20190416, 20151123, 20180716, 20200616, 20200713, 20200702, 20200316, 20201225 and 20150501). Dinitrofluorobenzene (DNFB) was provided by Tokyo Chemical Industry Co. LTD (Batch No. VP2UE-RE). DNFB solution was prepared in 1% solution with 1:1 acetone-sesame oil solution before application.

Lutein (AF8033002, purity > 95%), zeaxanthin (AF8062716, purity 98%), and trans-β-Apo-8′-carotenal (AF9100402, purity 98%) were purchased from Chengdu Alfa Biotechnology Co., Ltd., Chengdu, China. β-Carotene (10445-201802, the purity of 99.8%) was obtained from National for Food and Drug control, Beijing, China. Zeaxanthin dipalmitate (04160, purity > 95%) was supplied by Extrasynthese Chemical S.A.S., Lyon, France. The structures of the 5 carotenoids were shown in Figure 1. Methanol, acetonitrile, and dichloromethane were all chromatographic grade obtained from Fisher Scientific, Nepean, Canada. Acetone, n-hexane, toluene, 2,6-di-tert-butyl-4-methylphenol (BHT), and anhydrous ethanol were all at analytical grade and purchased from Tianjin Damao Chemical Reagent Factory, Tianjin, China. Double-distilled water was used. A total of 34 batches of LB were collected from 3 different regions of China, including Qinghai (96.719684°, 37.356337°), Gansu (104.682515°, 36.577096°), and Ningxia (105.691537°, 37.497421°). LB samples were identified by Prof. Ling Dong (Department of Pharmacognosy, Ningxia Medical University), with the corresponding voucher specimens (numbered NYYP20190701-34) were preserved in the herbarium of pharmaceutical analysis. The detailed information of the samples was presented in Table 1.

Polyvinylidene fluoride powder (PVDF, FR904, Shanghai 3F New Materials Co., Ltd., Shanghai, China), PET nuclear-track membrane (water contact angle of 60°, Liaoning Dongdaihe Tianzhirun Technology Co., Ltd, Suizhong, China, see Figure S1), nanosized SiO₂ aerogel powder (abbreviated as SiAG, Langfang Zall Thermal Insulation Material Co., Ltd., Langfang, China), anhydrous lithium chloride (LiCl, analytical reagent, Shanghai Aladdin Biochemical Technology Co., Ltd., Shanghai, China), anhydrous ethanol (purity > 99.7%, Tianjin Jiangtian Chemical Technology Co., Ltd., Tianjin, China), sodium chloride (NaCl, analytical reagent, Shanghai Aladdin Biochemical Technology Co., Ltd., Shanghai, China) are commercially available. N, N-dimethylacetamide (DMA, analytical reagent), and acetone (AC analytical reagent) are from Tianjin Damao Chemical Reagent Factory. These commercial chemicals were directly used without additional purification. Deionized (DI) water was purified through Dow XLE-2521 membranes in our lab (total conductivity < 2 μS·cm⁻¹).