Question

You are interested in thymol in mouthwash. The manufacturer lists the active ingredients as thymol (0.064%), menthol (0.042%), eucalyptol (0.092%) and methyl salicylate. The inactive ingredients include caramel, water and alcohol (21.6%) in addition to sodium benzoate, color, poloxamer 407 and benzoic acid.

(a) Does thymol represent a major, minor or trace concentration?

(b) of the ingredients listed with concentration, which ones can be considered in trace amounts?

(c) Which substance(s) is/are the sample?

(d) Which substance(s) is/are the analyte?

(e) Which substance(s) is/are the matrix?

(f) If you were to prepare a blank for your measurement, what substance(s) would it contain?

Answer 1

a) Thymol represents a minor concentration.

b) Of the ingredients listed, the ones that qualify as being contained in trace amounts are the ones with concentrations less than 0.01%, 100ppm or 0.1mg/L. And in this question, none of the given concentrations is less than 0.01%. Maybe one of the other constituents whose concentrations weren't given is in trace amounts.

c) The mouthwash brought for analysis is the sample.

d) Thymol is the analyte.

e) The matrix is every component of the mouthwash sample apart from the analyte constituent, thymol.

Menthol, eucalyptol, methyl salicylate, caramel, water, alcohol in addition to sodium benzoate, color, poloxamer 407 and benzoic acid are all member substances of the matrix.

f) The blank can contain every constituent apart from the analyte constituent, thymol.

Step-by-step explanation:

a) The composition range for major, minor and trace components are given thus.

1-100% Major

0.01-1% Minor

1 ppb to 100ppm Trace

<1ppb ultra trace

In Chemistry terms,

•Major constituents: Substances in concentrations over 1mg/L

•Minor constituents: Substances in concentrations between 1mg/L and 0.1 mg/L

•Trace constituents: Substances in concentrations under 0.1 mg/L

Hence, thymol with a concentration of 0.064% represents a minor constituent.

b) Of the ingredients listed, the ones that qualify as being contained in trace amounts are the ones with concentrations less than 0.01%, 100ppm or 0.1mg/L. And in this question, none of the given concentrations is less than 0.01%. Maybe one of the other constituents whose concentrations weren't given is in trace amounts.

c) In chemical analysis or Analytical chemistry, a sample is a portion of material selected from a larger quantity of material.

Therefore, for this question, the mouthwash is the sample.

d) In Analytical Chemistry, an analyte or analyte component is a substance or chemical constituent that is of interest in an analytical procedure.

For this question, the analyte is thymol; the constituent the analyser is interested in.

e) In chemical analysis, matrix refers to the components of a sample other than the analyte of interest.

Therefore, the matrix is every component of the mouthwash sample apart from the analyte constituent, thymol.

Menthol, eucalyptol, methyl salicylate, caramel, water, alcohol in addition to sodium benzoate, color, poloxamer 407 and benzoic acid are all member substances of the matrix.

f) A blank solution is a solution containing little to no analyte of interest, so, the blank can contain every constituent apart from thymol.

Hope this helps!