|Title||ANALYSIS OF MEIBOMIAN GLAND SECRETIONS USING ELECTROSPRAY IONIZATION TIME-OF-FLIGHT MASS SPECTROMETRY|
|Author, Co-Author||Corrie Ziegler, Kari Green-Church, Jason Nichols, Kelly Nichols|
|Abstract|| PURPOSE: To use electrospray ionization time-of-flight mass spectrometry (ESI-TOF) to evaluate meibomian gland secretions. In addition, the stability of meibomian gland secretions stored over time by freezing was evaluated by ESI to determine if this is associated with lipid degradation.
METHODS: Meibomian gland secretions were collected using a sterile 1.5mm curette probe from the lower eyelids of a male and female subject (mean age = 48.5) over a period of five consecutive days. Each sample was stored in a 2:1 chloroform/methanol solution. Secretions collected from the left eye were immediately processed with ESI, while secretions from the right eye were frozen at -70şC. Ten days after the initial sample was taken (five days after the last sample), the frozen meibomian gland secretions from the right eye were processed by ESI. All samples were directly infused at 20uL/min to a Micromass LCT equipped with an orthogonal electrospray source (Z-spray) operated in positive ion mode. ESI conditions that produced the best results included capillary voltage 2500V, source temperature 100şC, and a cone voltage of 35V. Data was attained in continuum mode until suitable averaged data was collected (approximately 1 minute).
RESULTS: Inter- and intra-subject agreement for samples analyzed immediately was good. Peaks were consistently observed within- and between-subjects at the following masses (m/z): 261.1, 489.2, 585.5, 727.5, 955.7. Also, observed masses were replicated upon the analysis of frozen samples both within- and between-subjects.
CONCLUSIONS: Observed peaks were within the expected ranges of both lipid and phospholipid masses. No significant changes occurred when frozen samples were analyzed, suggesting that freezing periods of one week or less is not associated with lipid degradation. Further study is necessary to determine if longer freeze periods is associated with any degradation.
|Affiliation of Co-Authors||The Ohio State University, College of Optometry, The Ohio State University, College of Optometry, The Ohio State University, College of Optometry|