Adapting a Low-Cost and Open-Source Commercial Pipetting Robot for Nanoliter Liquid Handling

Author(s):  
E. Enoch A. W. Councill ◽  
Nathanial B. Axtell ◽  
Thy Truong ◽  
Yiran Liang ◽  
Adam L. Aposhian ◽  
...  

Low-volume liquid handling capabilities in bioanalytical workflows can dramatically improve sample processing efficiency and reduce reagent costs, yet many commercial nanoliter liquid handlers cost tens of thousands of dollars or more. We have successfully adapted a low-cost and open-source commercial pipetting robot, the Opentrons OT-1, to accurately aspirate and dispense nanoliter volumes. Based on fluorescence measurements, the modified OT-1 was able to reproducibly transfer 50 nL of water with less than 3% measurement error and 5% coefficient of variation (CV). For 15 nL transfers, the volume measurements indicated less than 4% error and 4% CV. We applied this platform to the preparation of low-nanogram proteomic samples for liquid chromatography–mass spectrometry analysis, demonstrating that the modified OT-1 is an effective platform for nanoliter liquid handling. At a total materials cost of less than $6000, including the commercial liquid handler and all modifications, this system is also far less expensive than other platforms with similar capabilities, placing automated nanoliter handling within reach of a far broader scientific community.

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Takashi Kanamoto ◽  
Takashi Tachibana ◽  
Yasushi Kitaoka ◽  
Toshio Hisatomi ◽  
Yasuhiro Ikeda ◽  
...  

Purpose. To investigate the effect of ocular hypertension-induced isomerization of aspartic acid in retinal proteins. Methods. Adult Wistar rats with ocular hypertension were used as an experimental model. D-β-aspartic acid-containing proteins were isolated by SDS-PAGE and western blot with an anti-D-β-aspartic acid antibody and identified by liquid chromatography-mass spectrometry analysis. The concentration of ATP was measured by ELISA. Results. D-β-aspartic acid was expressed in a protein band at around 44.5 kDa at much higher quantities in the retinas of rats with ocular hypertension than in those of normotensive rats. The 44.5 kDa protein band was mainly composed of α-enolase, S-arrestin, and ATP synthase subunits α and β, in both the ocular hypertensive and normotensive retinas. Moreover, increasing intraocular pressure was correlated with increasing ATP concentrations in the retinas of rats. Conclusion. Ocular hypertension affected the expression of proteins containing D-β-aspartic acid, including ATP synthase subunits, and up-regulation of ATP in the retinas of rats.


2020 ◽  
pp. 174751982097862
Author(s):  
M John Plater ◽  
Andrea Raab

The dye mixtures formed from three commercial hair colour formers were purified by absorption onto human hair wefts, washed and dried, extracted with dichloromethane:trifluoroacetic acid (75:25) and then analysed by liquid chromatography–mass spectrometry. Only 1–2 dyes were identified from each complex mixture of commercial aromatic amines along with a broad UV absorption mainly consisting of mixtures of quaternary ammonium salts from shampoos and some surfactants. Mecetronium ethyl sulfate and didecyldimethylammonium chloride were the main ammonium salts.


Author(s):  
Luferov An ◽  
Kartashova Nv ◽  
Strelyaeva Av ◽  
Kuznetcov Rm

Objective: The study was carried out with an objective to characterize the possible bioactive phytochemical constituents from fruits of Schisandra chinensis Bail. by liquid chromatography–mass spectrometry analysis.Methods: Plant material was collected from Schisandra chinensis during August–October. The dried plant fruits were extracted with solvents using ethanol 95% extractor. The results of chromatography–MS analysis performed on the instrument Agilent Technologies established the presence of major and minor components. It was conducted a qualitative and quantitative comparison of infusions using software ChemStationE 02.00 and full library of mass spectra NIST 05.


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