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　　To improve sensitivity, the SP50 online SPE system utilizes the addition of online solid phase extraction (SPE), coupled to LCAMSMS for sample enrichment.This approach allows for significant and efficient analyte concentration,obviating the need for elaborate and time-consuming sample preparation procedures. Owing to the enrichment, large sample volumes (~ V2 liter) are no longer needed to reach part per tllin levels for estrogen monitoring in river water.