Method, systems, and techniques for determining the age of an underground space are provided. In some embodiments, determining the age of an underground space comprises taking soil samples from a plurality of surface locations within a second underground space, analyzing the soil samples from the plurality of surface locations to determine an amount of a chemical compound for each soil sample, and determining an age of the second underground space using one or more relationships based on amounts of the chemical compound measured in a plurality of soil samples taken over a period of time in a first underground space and a baseline amount of the chemical compound at one or more locations remote from both the first underground space and the second underground space.

Method, systems, and techniques for determining the age of an underground space are provided. In some embodiments, determining the age of an underground space comprises taking soil samples from a plurality of surface locations within a second underground space, analyzing the soil samples from the plurality of surface locations to determine an amount of a chemical compound for each soil sample, and determining an age of the second underground space using one or more relationships based on amounts of the chemical compound measured in a plurality of soil samples taken over a period of time in a first underground space and a baseline amount of the chemical compound at one or more locations remote from both the first underground space and the second underground space.

Aspects of the present disclosure relate to methods of complexing agent content determination. In at least one aspect, a method includes diluting a first solution with water to form a second solution. The first solution includes a nickel source and a complexing agent. The method includes introducing an indicator with the second solution. The method includes titrating the second solution with a base to provide a color change of the second solution. The method includes calculating a content of the complexing agent of the first solution.

A photometric method for determination of a concentration of a film forming amine in a liquid, including providing a buffer solution of a weak acid having a pKa≥4.5 and a strong acid having a pKa≤1; diluting an aliquot of the buffer solution with water, and determining the pH of the diluted buffer solution; adding reagent to the diluted buffer solution and measuring an initial absorbance of the diluted buffer/reagent solution; preparing a sample solution by adding liquid containing the film forming amine to an aliquot of the buffer solution and measuring the pH of the sample solution; adjusting the pH of the sample solution to match the pH of the diluted buffer solution by adding strong acid; and adding the reagent to the pH adjusted sample solution to form a colored complex, and measuring the absorbance of the resulting solution in a photometer.

A photometric method for determination of a concentration of a film forming amine in a liquid, including providing a buffer solution of a weak acid having a pKa≥4.5 and a strong acid having a pKa≤1; diluting an aliquot of the buffer solution with water, and determining the pH of the diluted buffer solution; adding reagent to the diluted buffer solution and measuring an initial absorbance of the diluted buffer/reagent solution; preparing a sample solution by adding liquid containing the film forming amine to an aliquot of the buffer solution and measuring the pH of the sample solution; adjusting the pH of the sample solution to match the pH of the diluted buffer solution by adding strong acid; and adding the reagent to the pH adjusted sample solution to form a colored complex, and measuring the absorbance of the resulting solution in a photometer.

A device and method for testing for the presence of liquid in a cannula of a medical instrument is described. The device includes a flexible guide member having a first end, a second end and a length extending from the first end to the second end, an elongated member arranged within the flexible guide member, and an absorbent material attached to one of the elongated member. The flexible guide member is inserted into the cannula, the flexible guide member is manipulated to cause the absorbent material to move through the cannula. The absorbent material is analyzed for the presence of liquid.

A device and method for testing for the presence of liquid in a cannula of a medical instrument is described. The device includes a flexible guide member having a first end, a second end and a length extending from the first end to the second end, an elongated member arranged within the flexible guide member, and an absorbent material attached to one of the elongated member. The flexible guide member is inserted into the cannula, the flexible guide member is manipulated to cause the absorbent material to move through the cannula. The absorbent material is analyzed for the presence of liquid.

A method for measuring an amount of dissolved oxygen contained in a liquid sample, including the steps of: (1) adding a deoxygenating amino compound to a liquid sample to prepare the liquid sample having a predetermined concentration of the deoxygenating amino compound; (2) after Step (1), heating the liquid sample containing the deoxygenating amino compound at a temperature of 80° C. or more; (3) after Step (2), measuring the concentration of the deoxygenating amino compound contained in the liquid sample; and (4) calculating the amount of the dissolved oxygen contained in the liquid sample in Step (1) from the amount of the reacted deoxygenating amino compound by comparing the concentration of the deoxygenating amino compound measured in Step (3) and the concentration of the deoxygenating amino compound measured in Step (1).

Systems for quantifying one or more target analyte concentrations in a process solution are provided and can be used, for example, in methods for quantifying a target analyte concentration. These systems and methods include continuous and batchwise automated titration methods that use titration chemistries to measure the target analyte concentration in the process solution using a multiwavelength detector. The methods provide for efficient and robust automated titration methods for a variety of target analytes and can include methods that analyze more than one analyte and that provide for a dynamic range for measurement of more than one target analyte concentration.

Systems for quantifying one or more target analyte concentrations in a process solution are provided and can be used, for example, in methods for quantifying a target analyte concentration. These systems and methods include continuous and batchwise automated titration methods that use titration chemistries to measure the target analyte concentration in the process solution using a multiwavelength detector. The methods provide for efficient and robust automated titration methods for a variety of target analytes and can include methods that analyze more than one analyte and that provide for a dynamic range for measurement of more than one target analyte concentration.