Yulia Sister entered the Department of Chemistry of the University of Kishinev in the fall 1954. While asked by Professor , who interviewed the applicants to the Department, why she has chosen this Department, she explained that thanks to her school teacher she fell in love with chemistry. At the University Yulia was involved in various campus activities, and served as an editor of the faculty newspaper "Chemist". Since her second year at the university she became a member of the student scientific society and was engaged in the research of compounds called heteropolyacids. In 1959 Sister successfully defended her Master's thesis "Precipitation chromatography of heteropolyacids." and graduated with honors from the University of Kishinev.
Upon completion of the studies Sister was assigned to the laboratory of analytical chemistry headed by Professor Yuri Lyalikov. The laboratory was a part of the Institute of Chemistry at the Moldavian branch of the Academy of Sciences of the USSR, which became the Academy of Sciences of Moldova in 1961. Working in this laboratory allowed the young chemist Sister to begin her research with new polarographic methods. In order to carry out analysis of organic compounds by the means of alternating-current (ac) polarography Yulia built with her own hands a polarograph and received the first polarograms. Sister was the first in Moldova (with Y. S. Lyalikov), who applied the methods of ac polarography and second harmonic ac polarography for analyzing organic compounds. Then, together with the physicist Vil Senkevich, they assembled an automatic device, and only later began the serial production of polarographs in the USSR. In the early 1960s Yulia published her first research articles. In 1967 she received her Ph.D. from the Institute of Chemistry of the Moldavian Academy of Sciences.
Through 25 years of research at the Institute of Chemistry Sister dealt with a wide range of topics. Her ecology oriented research included analysis of pesticides in environmental samples, food items and biological mediums. She participated in research and analysis of suspensions and was involved in analyzing new organic compounds. Sister made a substantial contribution to the development of such methods as the second harmonic ac polarography, the difference polarography with magnetic recording, the chromatopolarography. For about 20 years Yulia Sister served as a consultant on the use of the polarographic method in biology at the Department of Human and Animal Physiology of the University of Kishinev.
In 1984 Yulia Sister was invited to work with the Institute of Technology and Development where she soon headed the laboratory of physical and chemical methods. The Institute was affiliated to a research and production association in the Ialoveni (formerly Kutuzov). Sister and her laboratory were using a variety of research methods and among them the high-performance liquid chromatography being at that time a new approach in the laboratories of the country. She also contributed as a board member of Moldavian branch of the Mendeleev Chemical Society and led the program "Young Chemist" in the Moldavian Republic. Many of her students, the former young chemists, became later scientists and managers of respectable companies.