In this paper, a novel method of QuEChERS-based extraction coupled with high-performance liquid chromatography has been developed for the simultaneous determination of ursolic acid (UA) and oleanolic acid (OA) in guava leaves. The QuEChERS-based extraction parameters, including the amount of added salt, vortex-assisted extraction time, and absorbent amount, and the chromatographic conditions were investigated for the analysis of UA and OA in guava leaves. Under the optimized conditions, the method showed good linearity over a range of 1–320 μg mL⁻¹, with correlation coefficients above 0.999. The limits of detection of UA and OA were 0.18 and 0.36 μg mL⁻¹, respectively. The intraday and interday precision were below 1.95 and 2.55%, respectively. The accuracies of the UA and OA determinations ranged from 97.4 to 111.4%. The contents of UA and OA in the guava leaf samples were 2.50 and 0.73 mg g⁻¹, respectively. These results demonstrate that the developed method is applicable to the simultaneous determination of UA and OA in guava leaves.

Pyrethroid residues in traditional Chinese medicines have been a serious threat to the health and treatment of patients. However, because of the matrix complexity of traditional Chinese medicine, the detection of pyrethroid residues remains a challenge. Therefore, we developed a QuEChERS method coupled with high-performance liquid chromatography and ultraviolet detection (HPLC-UV) for the determination of pyrethroid pesticides in three kinds of traditional Chinese medicine oral liquid preparations, and we investigated and optimized the extraction conditions. The matrix effect was estimated in the organic solvent and the actual samples by comparing the slopes of calibration curves, and the results showed that the matrix effect is not significant when using the modified QuEChERS method. The pyrethroid pesticides could be completely separated in 30 min. The linear correlation coefficients were more than 0.999, and the recoveries of all the pyrethroid pesticides ranged from 87.2% to 104.8%. The intra-day precisions (n = 5) were 2.44–4.62%, and the inter-day precisions (n = 5) were 1.06–3.02%. Moreover, the limits of detection were in the range of 0.007–0.018 ng mL⁻¹, while the limits of quantitation were in the range of 0.022–0.057 ng mL⁻¹. This simple, low-cost, and highly sensitive analytical method can be a potential tool for the analysis of pyrethroid residues in traditional Chinese medicine oral liquid preparations.

In this paper, the volatile components extracted from guava leaves by steam distillation (SD) was investigated and comprehensively analyzed for the first time. To obtain more sensitive and accurate analysis, the sample preparation procedure for Gas Chromatography-Mass Spectrometry (GC-MS) analysis of the volatile compounds was investigated and then 27 compounds were identified in the samples obtained by SD method. The volatile components in guava leaf were made up largely of sesquiterpenoids, including α-cubebene, caryophyllene, aromadendrene, α-cadinene, and calamenene. The results indicated that the volatile components from the guava leaves extracted by SD technology was quite different, and the research provided comprehensive information for the volatile compounds in the guava leaves.