Pickering Laboratories, Inc. articles

Histamine and other polyamines such as Putrescine, Cadaverine, Spermidine and Spermine are products of decomposition. The level of histamine, in particular, has been used as a regulatory guideline for degree of decomposition in fish. Also, Histamine and Tyramine levels are of interest to producers of wine and cheese.

The polyamines, Spermidine, Spermine and Putrescine are elevated in neoplastic and damaged, e.g., burned, tissue. In fact, the level of circulating and urinary polyamines

There are a number of carbamate pesticide compounds employed worldwide which are not included in the 10 compounds mandated by USEPA Method 531.1 and AOAC Protocol 29.A05. This Application Note describes methods for separating as many as 23 compounds, using a Pickering C8, 5µm silica, column with either Water/Acetonitrile or Water/Methanol gradients. Instruments, post-column derivatization and detection protocols, and reagents remain unchanged, as described Pickering’s brochure, Po

Introduction:

The stationary phase in the ALKION column is a rigid, non-porous polymeric phase that is surface sulfonated.
The two modes of separation are ion-exchange and moderate partitioning. The low capacity of the ion-exchange resin makes it an ideal phase for the separation of strongly basic and positively charged compounds. The reversed-phase character allows for discrimination between closely related species.

Concept:

Nitrite either alone or in combination with nitrate is added to food to preserve the color and taste and to prevent foods from becoming rancid. They are also used in food for their anti-microbial properties. Higher levels in vegetables and leafy greens are possible from the use of nitrate fertilizers and/or livestock manure.

Nitrate can be reduced to nitrite at certain physiological conditions in the human body. Nitrite however can oxidize Fe (II) in hemoglobin to methemoglobin, an Fe

Nonnutritive sweeteners are widely used in foods and beverages. Since some studies raised questions about long-term safety of these compounds, their concentration in food products is regulated. Among the artificial sweeteners used worldwide Saccharin and Cyclamate cause most controversy and their use is restricted in many countries, including the US. Liquid chromatography is a method of choice for artificial sweeteners but Cyclamate analysis is complicated by the fact that this compound does

Introduction

Primary amines form highly fluorescent adducts when reacted with o-Phthalaldehyde (OPA) and a mercaptan under basic conditions. At a pH>9 and ambient temperature, reaction is generally complete within 30 seconds. The products of this reaction, 1-alkyl-2-alkylthio-substituted isoindoles, exhibit optimal excitation at 330 nm and maximal emission at 465 nm. The reagents described below are intended for postcolumn derivatization of primary amines such as:<

Post-column derivatization of carbamates with hydroxide and OPA is the method of choice for the detection of carbamates because of its high selectivity and high sensitivity (US EPA 531.1 & AOAC 985.23).  To confirm the finding of carbamates in the tested samples, there are various possibilitites:

To confirm the finding of carbamates in the tested samples, there are various possibilitites:

• Alternate columns to give different retention time or order of elution.</

Voglibose is an Alpha-Glucosidase inhibitor widely used for the treatment of diabetes. Alpha-glucosidase inhibitors are agents that delay the glucose absorption at the intestinal level and thereby prevent sudden surge of glucose after a meal. Vogilbose is the safest and most effective drug of its class.

Since Vogibose has no UV chromophore, post-column derivatization is employed to produce a fluorescent derivative.
This abstract describes a very sensitive and robust analytical me

Pickering Laboratories specializes in the manufacturing of cation-exchange columns and eluants for amino acid analysis. No other tech¬nique has been shown to match the reproducibility and selectivity of ion-exchange analysis with post-column Ninhydrin detection. Nor is there a chromatography technique that provides as much information; the 570/440 nm signal ratio for each amino acid is a constant and so offers information about peak purity. Pinnacle PCX post-column derivatization system p

Simultaneous Analysis of Aflatoxins and Ochratoxin A - Sample Preparation
Aflatoxins and Ochratoxin A are produced by fungi, e.g. Aspergillus and Penicillium species. Therefore both toxin types are found together in many foods and animal feeds, e.g. cereals. Thus it is appropriate to analyze one extract for the occurrence of both mycotoxins in a single step.

A significant assistance is the cleanup of extracts by a combined immunoaffinity column for both mycotoxin