TLC, application

[Oriole]

Hello,
I am a translator translating a text about TLC, so my question might seem very basic to you
I am not quite sure how to interprete the phrase:

Apply 5 µl of the sample A, 5 µl of the sample B and 5 µl of the standard 1 and 2 solutions in a 5 mm line, respectively.

1) Does it mean that each of the solutions should be applied in the form of a line which is 5 mm long?
or
2) Does in mean that the distance between the applied solutions should be 5 mm?

Could you tell me which of the two interpretations is correct?
Thank you!

[Peter Apps]

Is the sentence you gave what you are translating from, or what you have translated to ?

Applying samples and standards as lines is a standard practice in TLC, but that is not the problem.

Rather than "Apply 5 µl of the sample A, 5 µl of the sample B and 5 µl of the standard 1 and 2 solutions in a 5 mm line, respectively."

you can drop the definite articles to get; "Apply 5ul of sample A, 5 ul of sample B and 5 ul of standard solutions 1 and 2 in a 5 mm line, respectively."

There remains the problem of whether 5 ul of each of the standard solutions is to be used, or 5 ul of a mixture of the two solutions. If I had to choose I would go for 5 ul of each, and then sentence would read; "Apply 5ul of sample A, 5 ul of sample B, 5 ul of standard solution 1 and 5 ul of standard solution 2 in a 5 mm line."

The most serious problem is that it is not clear whether all of the samples and standards are applied one on top of the other to one line, or whether they are on separate lines. The singular "a 5 mm line" implies that they are all on one line. Usual practice, and the "respectively" hanging off the end of the original implies that they are on separate lines, in which case the final version reads; "Apply 5ul of sample A, 5 ul of sample B, 5 ul of standard solution 1 and 5 ul of standard solution 2 as 5 mm lines."

Peter

[Oriole]

Hi Peter! Thank you so much for the answer.

The sentence "Apply 5 µl of the sample A, 5 µl of the sample B and 5 µl of the standard 1 and 2 solutions in a 5 mm line, respectively." is the original sentence, and I am translating it from English into Russian.

I agree that the sentence is not clear in the part "5 µl of the standard 1 and 2 solutions", and I would also interprete it the way you do: 5 µl each.

As for interpretation of the phrase "in a line": do I understand you correctly that my suggestion number 2) in my original post cannot be possible? (the suggestion was "Does it mean that the distance between the applied solutions should be 5 mm?")

[Peter Apps]

There is nothing in the sentence you give that has anything to do with how far apart the lines are. The process it is trying to describe is the application of liquid samples as lines on an absorbent plate - rather like writing a series of lines on paper - - - - -. The lines are each 5mm long. Also, they need to be a certain distance from the edge of the plate and a parallel with that edge, but neither of these is mentioned in the sentence you gave us.

Peter

[Oriole]

Thanks a lot, Peter! The sentence is clear for me now.
Your answer is very valuable!