Gas Chromatography A retention gap is placed between the injector and the front of the column to retain the sample and release it gradually to the column retain contaminants and prevent them from reaching the column prevent backflush of the injected solution All of these retain the sample and release it gradually to the column retain contaminants and prevent them from reaching the column prevent backflush of the injected solution All of these ANSWER DOWNLOAD EXAMIANS APP
Gas Chromatography Which of the following are not used as stationary phases in a GC column? Silica Polysiloxanes Cyclodextrins None are used as stationary phases Silica Polysiloxanes Cyclodextrins None are used as stationary phases ANSWER DOWNLOAD EXAMIANS APP
Gas Chromatography In column switching chromatography one column is removed and replaced by another the flow to the column is switched on and off repeatedly any of the above compounds trapped on one column are eluted to another column one column is removed and replaced by another the flow to the column is switched on and off repeatedly any of the above compounds trapped on one column are eluted to another column ANSWER DOWNLOAD EXAMIANS APP
Gas Chromatography What does the selectivity factor describe? The relative separation achieved between two species The maximum number of different species which a column can separate simultaneously None of these The proportional difference in widths of two chromatographic peaks The relative separation achieved between two species The maximum number of different species which a column can separate simultaneously None of these The proportional difference in widths of two chromatographic peaks ANSWER DOWNLOAD EXAMIANS APP
Gas Chromatography Sample injection is considered successful if the sample is concentrated at the start of the column the sample is spread evenly along the column the sample is homogenously spread along the column all of the sample in the injector has been added to the column the sample is concentrated at the start of the column the sample is spread evenly along the column the sample is homogenously spread along the column all of the sample in the injector has been added to the column ANSWER DOWNLOAD EXAMIANS APP
Gas Chromatography What does the retention factor, k', describe? The velocity of the mobile phase The migration rate of an analyte through a column All of these The distribution of an analyte between the stationary and the mobile phase The velocity of the mobile phase The migration rate of an analyte through a column All of these The distribution of an analyte between the stationary and the mobile phase ANSWER DOWNLOAD EXAMIANS APP
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