In this month's installment, we look at the results of a recent survey on high performance liquid chromatography (HPLC) columns, examining the trends in analytical and preparative column use and purchasing patterns since the last survey. Factors investigated in this study were mode and stationary phase usage, particle sizes and column dimensions, column budgets, and the factors influencing buying decisions. Column lifetime and use of guard columns also is considered. Future column buying plans were explored.

Biannually, LCGC surveys its readers to obtain a current profile of users of high performance liquid chromatography (HPLC). The last survey on HPLC columns was conducted in 2009 (1). In the past, I have used results from these surveys to chart trends in column technology and in the practice of HPLC. In late 2010, a web-based survey was sent to subscribers whose primary chromatography technique was HPLC. A total of 324 readers responded and this number was statistically sufficient to allow comparisons to previous survey data and to investigate trends.

Table I: Types of HPLC instruments used by survey respondents

To understand the current usage rate of instruments, a question was asked pertaining to number and type of instruments personally used per respondent per week. Questions in previous surveys were less specific and, therefore, laboratory managers occasionally responded with estimates for their entire laboratory, which tended to skew the results. Table I shows the average response for each category of instrument. The numbers reported should not be construed to mean that every respondent uses every type of instrument; rather, they serve to provide an idea of the relative number of the various types of systems in general use. Later, I will look at the numbers of columns used by these instruments.

According to the survey results, a user of conventional HPLC instruments is responsible for a weighted average of 2.6 units. Because each respondent may have been responsible for a single instrument or for multiple instruments, this weighted average was derived from looking at the total number of instruments of this type identified by all respondents and then dividing this number of the total number of respondents. For example, some respondents reported that they have only one conventional HPLC system while others reported that they have five instruments for which they are personally responsible. Based on the relative numbers of Table I, for every one of these respondents that used a conventional LC system, only 1 in 16 would possess a capillary or nanoLC system; 1 in 4 might have an instrument dedicated to microbore columns; and 1 in 7 could have a preparative instrument in his or her laboratory. These numbers are slightly different from the 2009 survey (1), especially for conventional users, which was down from 3.6 per respondent (this was probably skewed by the laboratory manager contribution discussed above).