Functionalized quantum dots with dopamine dithiocarbamate as the matrix for the quantification of efavirenz in human plasma and as affinity probes for rapid identification of microwave tryptic digested proteins in MALDI-TOF-MS

Functionalized quantum dots with dopamine dithiocarbamate (QDs-DDTC) were utilized for the first time as an efficient material for the quantification of efavirenz in human plasma of HIV infected patients and rapid identification of microwave tryptic digest proteins (cytochrome c, lysozyme and BSA) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The synthesized QDs-DDTC was characterized by using spectroscopic (UV–visible, FT-IR and 1H NMR) and microscopic (SEM and TEM) techniques. Functionalized QDs-DDTC exhibited a high desorption/ionization efficiency for the rapid quantification of small molecules (efavirenz, tobramycin and aspartame) at low-mass region. QDs-DDTC has well ability to trap target species, and capable to transfer laser energy for efficient desorption/ionization of analytes with background-free detection. The use of QDs-DDTC as a matrix provided good linearity for the quantification of small molecules (R2 = ~ 0.9983), with good reproducibility (RSD < 10%), in the analysis of efavirenz in the plasma of HIV infected patients by the standard addition method. We also demonstrated that the use of functionalized QDs-DDTC as affinity probes for the rapid identification of microwave tryptic digested proteins (cytochrome c, lysozyme and BSA) by MALDI-TOF-MS. QDs-DDTC-based MALDI-TOF-MS approach provides simplicity, rapidity, accuracy, and precision for the determination of efavirenz in human plasma of HIV infected patients and rapid identification of microwave tryptic digested proteins. This new material presents a marked advance in the development of matrix-free mass spectrometric methods for the rapid and precise quantitative determination of a variety of molecules. This article is part of a Special Issue entitled: Proteomics: The clinical link.

QDs-DDTC was investigated as an efficient matrix for the detection of efavirenz in human plasma of HIV infected patients by MALDI-TOF-MS. DDTC group on QDs surfaces is capable to donate proton and efficiently transferred laser energy to the analytes for their ionization in MALDI-TOF-MS. The use of QDs-DDTC as the matrix allows the acquisition of good quality MALDI mass spectra. The trapping selectivity of QDs-DDTC towards tryptic digested proteins was quite good.Figure optionsDownload high-quality image (78 K)Download as PowerPoint slideHighlights
► We described the first use of QDs-DDTC as the matrix and affinity probes in MALDI-TOF-MS.
► QDs-DDTC-assisted MALDI-TOF-MS effectively analyzed efavirenz in human plasma of HIV infected patients.
► It exhibits good accuracy and precision for drug analysis.
► It provided rapid tool for tryptic digest proteins.
► It provided extensive peptide sequence coverages.