A green microfluidic method for the simultaneous extraction of polar and non-polar basic compounds in biological samples

Microfluidic devices as sample treatment have showed significant advancements in recent years, becoming an important tool in pharmaceutical analysis. In this work, a green microfluidic method for the simultaneous extraction of basic polar and non-polar compounds is proposed for the first time, offering a new and more sustainable and environmentally friendly alternative. A mixture of camphor:menthol 1:1 is presented as a new green supported liquid membrane (SLM) for the simultaneous extraction of a wide log P range for basic compounds (0.4 < log P < 5): verapamil hydrochloride (VRP), tyramine (TYR), atenolol (ATN), metopropol (MTP) and nortriptyline (NRP). Different SLMs were investigated to offer new other green alternatives for polar or non-polar basic drugs. Microfluidic operational parameters were also optimized at pH 1.5, pH 11.5 and 1 µL min−1 as acceptor phase, donor phase and donor flow rate, respectively. Camphor:menthol 1:1 showed good stability and reproducibility (RSD < 5%) in human urine samples. It was found to be an attractive alternative to traditional toxic organic solvents applied in microextraction techniques. The green microfluidic method offered good recoveries between 50 and 100% for all compounds in urine sample after 7 min extraction, using only 3 µL of Ca:Me 1:1 and showing a good long-term stability system up to 6 consecutive extraction in real samples. A relative standard deviation (n = 3) was below 6 % for all compounds with and without replacing the membrane of the system.