# Sorbent Strip Microextraction as a Practical Tool for Drug Screening: Application to Opioids and Local Anesthetics in Human Urine

## TL;DR

A new eco-friendly microextraction method is introduced for drug screening in urine, offering a practical and efficient alternative to traditional methods.

## Contribution

The novel Sorbent Strip Microextraction (SSμE) device simplifies preparation and reduces waste compared to existing microextraction techniques.

## Key findings

- The SSμE method achieved recoveries of 78% to 108% for opioids and local anesthetics in urine.
- The technique showed good linearity (r² ≥ 0.9922) across concentration ranges for the tested compounds.
- The validated SSμE/HPLC-DAD method was successfully applied to real urine samples with high precision and accuracy.

## Abstract

The present contribution proposes a new design for adsorptive microextraction devices that promote a user-friendly and greener analytical approach. Novel Sorbent Strip Microextraction (SSμE) devices were made using a flexible adhesive film coated with convenient sorbents. Comparing the previous adsorptive microextraction devices, i.e., bar adsorptive microextraction and multi-sphere adsorptive microextraction, the main advantage of the sorbent strip device is its simple design and reduced device preparation time and waste. To demonstrate its applicability, three opioids (buprenorphine, tapentadol, and tramadol) and two local anesthetics (articaine and bupivacaine) were used as model compounds in urine matrices, followed by high-performance liquid chromatography with diode array detector (HPLC-DAD) analysis. Key parameters such as sorbent type, desorption conditions, and microextraction variables were systematically optimized by experimental designs. Under the final conditions, the method achieved recoveries ranging from 78% to 108%, trueness within ±7% and precision expressed by relative standard deviation below 13%. The technique demonstrated good linearity (r2 ≥ 0.9922) across dynamic ranges of 5–500 ng/mL for local anesthetics and 50–5000 ng/mL for opioids. The validated SSμE/HPLC-DAD methodology was successfully applied to real urine samples, confirming its high precision and accuracy. The proposed microextraction technique offers a practical, eco-friendly, and effective alternative for routine drug screening in complex biological matrices and presents significant advantages over traditional and other microextraction-based methods.